CA1091978A - Method for curing cheese - Google Patents
Method for curing cheeseInfo
- Publication number
- CA1091978A CA1091978A CA289,775A CA289775A CA1091978A CA 1091978 A CA1091978 A CA 1091978A CA 289775 A CA289775 A CA 289775A CA 1091978 A CA1091978 A CA 1091978A
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- cheese
- curd
- lipase
- american
- fatty acid
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Abstract
ABSTRACT OF THE DISCLOSURE
A process is described for the preparation of a natural cheese product having an intensified American cheese flavour. The American cheese flavour appears, at least in part, to be as a result of the free C2 to C10 fatty acid content of the cheese product.
Cheese products having the intensified American cheese flavour possess a C2 to C10 fatty acid content at least about 10 times the C2- C10 fatty acid content of conventional aged American-type cheeses. The process comprises providing a medium containing milk protein and fat, setting the medium to provide a coagulum, cutting the coagulum to provide curd particles and whey, separating said curd particles from said whey, mixing said curd particles with enzyme and curing said curd particles at a temperature above about 50°F for a period of time sufficient to provide a total free percent by weight and a free C4 fatty acid content of at least about 0.32 percent by weight, said lipolytic enzyme being selected from enzyme extracted from the throat tissue of calves, lambs and kids and said proteolytic enzyme is an exopeptidase having high pro-teolytic activity but only minor diastatic action. The cheese product having the highly intensified flavour is particularly useful for mixing with other food products such as unaged cheeses and bakery products in order to impart an American cheese flavour to such products.
A process is described for the preparation of a natural cheese product having an intensified American cheese flavour. The American cheese flavour appears, at least in part, to be as a result of the free C2 to C10 fatty acid content of the cheese product.
Cheese products having the intensified American cheese flavour possess a C2 to C10 fatty acid content at least about 10 times the C2- C10 fatty acid content of conventional aged American-type cheeses. The process comprises providing a medium containing milk protein and fat, setting the medium to provide a coagulum, cutting the coagulum to provide curd particles and whey, separating said curd particles from said whey, mixing said curd particles with enzyme and curing said curd particles at a temperature above about 50°F for a period of time sufficient to provide a total free percent by weight and a free C4 fatty acid content of at least about 0.32 percent by weight, said lipolytic enzyme being selected from enzyme extracted from the throat tissue of calves, lambs and kids and said proteolytic enzyme is an exopeptidase having high pro-teolytic activity but only minor diastatic action. The cheese product having the highly intensified flavour is particularly useful for mixing with other food products such as unaged cheeses and bakery products in order to impart an American cheese flavour to such products.
Description
~919~8 The sub~ect matter of the present application is relatedto the sub~ect matter of copending Canadian Application No.
158,642 filed December 12, 1972.
Generally, the present invention is directed to a natural cheese product having increased levels of C2-ClO fatty acids and an intensified American cheese flavor as compared to conventional aged natural American cheese.
More particularly, the present invention relates to an American-type cheese product having a C2-C10 fatty acid content at least about ten times the C2-C10 fatty acid content of conven-tional aged American-type cheese.
The natural cheese product having an intensified American cheese flavor is useful in the manufacture of process cheese and other cheese products or cheese-containing products wherein a high level of cheese flavor is desirable. ~merican cheese and ~merican-type cheese are descriptive terms used to identify a group of cheeses which includes Cheddar cheese, Colby cheese, Monterey cheese, Jack cheese, and stirred-curd, washed-curd, and soaked-curd Cheddar type cheese, all of which have a generally similar American cheese flavor. The cheese product of the present inven-tion has an American cheese flavor, but the flavor is of such intensity that it would not generally be considered palatable when consumed alone. However, when added to cooked cheese-containing products, such as process cheese and baked goods, in relatively small amounts it imparts an ~merican-type cheese flavor to such product, and therefore may replace all or a part of the aged American cheese normally added to such products as a flavoring ingredient~
The production of aged Cheddar cheese requires many months of curing to develop the level of flavor normally associated ~ith aged Cheddar cheese. As used herein, the term "highly Elavored cheese product" or "cheese product having an intensiEied ~merican cheese flavor" refers to a natural cheese product ~hich has a d D / ~
~L09~78 flavor level that is significantly greater than that normally associated with conventional aged American cheese. Such highly flavored cheese product may or may not have suitable flavor characteristics for direct eating. Usually, the highly flavored cheese product is used as a flavoring component in cheese or other food products, and, more particularly, in products which are cooked, as described in detail hereina~ter.
The present invention further relates to a method of manu--facturing a natural American-type cheese product of intensified American cheese flavor which includes providing a mixture of curd particles and whey by any one of a number of known American-type cheese make procedures, separating the whey from the curd, adding salt, ~ source of a proteolytic enzyme, and a source of a lipolytic enzyme to the curd, and curing the curd at a temperature above about 50F. for a period of time sufficient to provide a C2-C10 fatty acid content at least about ten times as great as the I G2-Clo fatty acid content of conventional aged natural American-type cheese.
A proteolytic micrococcus and a flavor culture, as described hereinafter, may also be added to the curd with the pro-teolytic enzyme and the lipolytic enzyme to provicle a natural cheese product which, when used as a flavoring ingredient in cooked cheese-conta-lning products, provides a more rounded and fuller American-type cheese flavored product. It has also been found desirable, particularly when the cheese product of the in-vention is utilized in the manufacture of process cheese, to prepare the cheese curd using 2 make procedure as described in Patent No. 3,650,768 in which a proteolytic micrococcus, a self-limiting lipase, and a flavor culture are added to the milk prior to setting of the milk.
In one particular aspect the present invention provides a process for manufacture of a highly flavored cheese product com-prising providing a medium containing milk protein and Eat, setting db ,~, 2-10~1978 the medium to provide a coagulum, cutting the coagulum to provide curd particles and whey, separating the curd particles ~rom the whey, mixing the curd particles with salt and an effective amount of a lipolytic enzyme and a proteolytic enzyme and curing the curd particles at a temperature above about 50F. for a period of time sufficient to provide a total free C2-C10 fatty acid con-tent in the cheese of at least about 0.46 percent by weight and a free C4 fatty acid content of at least about 0.32 percent by weight, the lipolytic enzyme being selected rom enzymes extracted from the throat tissue of calves, lamhs and kids and the proteo-lytic enzyme is an exopeptidase having high proteolytic activity but only minor diastatic action.
In another aspect,the present invention provides a method for the manufacture of process cheese wherein a mlxture of aged American-type cheese having a conventional ~merican cheese flavor and unaged cheese having minimal American cheese flavor is mixed wlth emulsifiers, heated to form a homogeneous molten cheese mass and cooled, the improvement comprising replacing at least about 5 percent of said aged American cheese with a natural American cheese product having an intensified American cheese flavor, the cheese produc~ having a free C2-C10 fatty acid content of at least about 0.46 percent by weight and a free C4 fatty acid content of at least about 0.32 percent by weight.
The invention will become more apparent from the follow-ing detailed description and from the drawings of which:
FIGURE 1 is a graph depicting the free fatty acid dis-tribution of cheese products in accordance with a preferred embodiment of the present invention and natural aged Cheddar cheese.
FIGURE 2 is a graph similar to FIGURE 1 illustrating the effect of curing temperature on free fatty acid development.
db ~
~L09~.978 .
. FIGURE 3 is a graph depicting the rate of free fatty acid development of Example II.
FIGURE 4 i9 a graph depicting the rate of free fatty acid development of Example III.
FIGURE 5 is a graph depicting the rate of free fatty acid development of Example IV.
The preferred medium for preparing the highly flavored cheese product of the present lnvention is ~whole cow's milk db;~, .. . . . . , ... .. , . ~ . . . .... .... .. .. ...... .. . .... . . .. .. . .... .. . . .. . .
`having about 3 percent protein which is principally casein, about 5 percent lactose, about 1 percent ash, and about 3.5 per-cent fat. The milk may be partially or wholly skimmed, and other fats may be used to replace or supplement a portion of the milk fat of the whole milk. In this connection, preferred fats for replacement of milk fat are coconut fat, soybean oil, cottonseed oil, peanut oil, safflower oil, and mixtures thereof. Other protein sources-may also be used in combination with the casein of the whole milk. In this connection, up t~ about 5~ percent of the casein may be replaced with protein sources such as soy protein, yeast protein, fish meal protein, whey protei~, and mixtures thereof.
The preferred method for preparing curd particles to which the enzymes and cultures of the present invenkion are applied is known and is usually referred to as the stirred curd method.
In this method, a lactic acid producing culture, preferably S. lac-tis t iS added to the medium. The medium is set with single strength calves rennet at a level of about 100 cc's of rennet per 1000 pounds milk. A setting period of thirty minutes is allowed after addition of the rennet for coagulation o the medium. The coagulum is cut with quarter-inch knives to provide curd particles and whey when the titratable acidity of the coagulum is about 0.11 to about 0.12 equivalent lactic acid, and the pH of the whey is about 6.4 as measured by the quinhydrone method. As set forth hereinp all reference to titratable acidity refers to equivalent lactic acidt and all pH values are measured by the quinhydrone method. After cutting, the curd particles are stirred in the whey and the curd particles are then heated over a period of thirty minutes to a temperature of about 103F. to cook the curd. The curd is held while being stirred in the whey at 103F.
until the titratable acidity oE the whey is about 0 17 and the curd has a pH of about 5.8, a period of about sixty minutes. The curd and whey mixture is then pumped to a drain table while the ~91~7~3 temperature oE 103F. is maintained. The whey is drawn from the curd until the level of whey is slightly higher than the level of the c~rd.
m e d is stirred in the whey for a period of about sixty minutes or until the titratable acidity of the whey is about 0.28 and then the whey is allowed to freely drain from the curd. m e curd at this time has a pH of about 5.36.
After a period of about fifteen minutes of free whey drainage, the curd is salted with sodium chloride at a level of about 2.0 pounds of salt per 1000 pounds of medium used to prepare the curd and a source of a lQ lipolytic enzyme, i.e., a lipase, and a source of a proteolytic enzyme, i.e., a protease, are added -to the curd. m e preferred source of lipase is that obtained by extraction from the throat tissue of calves, lambs, or kids. These lipases are cammercially available under the trade names Italase C and Capalase KL and their manufacture is generally disclosed in United States Patent Nos. 2,531,329 and 2,794,743. m ese particular lipases are self-limiting in the hydrolysis of fat and do not break down the fat to undesired end products. Such lipases are sametimes referred -to herein as "self-limiting lipases" to denote their restricted activity in the hydrolysls of fat.
other forms of lipolytic enzymes, such as microbial lipases and pancreatic lipases, may be substituted for all or a part of the throat tissue lipases. An example of a commercially available microbial lipase is that obtained from Candida cylindracea, Iype VIII. An example of a commercially available pancreatic lipase is that sold as porcine pancreatic lipase. One unit of the C. cylindracea microbial lipase will hydrolyze 1.0 micro-equivalent of fatty acid from a txiglyceride in one hour at pH 7.4 at 37C.
One unit of the porcine pancreatic lipase will release 1.0 micramole of acid per minute at pH 8.0 at 25C fram an olive oil substrate.
The results of a cGmparison of throat tissue lipase, microbial lipase, and pancreatic lipase are set forth in Table I. The respective samples were incubated in 36 pexcent butterfat Grade A whipping cream, fatty acids were removed by steam distillation, and fatty acid analysis :1 [)9iL9~8 was by gas chromatography. A control sample, with no adclition of lipase, - was incubated at room temperature for four and one-half hours.
~ABLE I
Wei~ht ~ Free Fatty Ac_l Sa ple c2 C4 C6 - ~ - C~o C - 2 Control ~ 0.001 0.001 0.001 0.002 0 001 P-101 ----- 0.078 0.036 0.022 0.022 0.008 p_502 _____ 0.180 0.086 0.051 0,074 0.042 M~2003 ----- 0.461 0.169 0.153 Oe207 0.059 c-20o4 0,003 0.061 0.018 O.OOg 0.016 -----K-2005 0.004 0.076 0.033 0.010 0.009 -----KI~2006 0.002 0.087 0.037 0.011 0,017 -----10 mg. porcine pancreatic lipase per 100 gm, cream incubated at rcxxn temperature 30 hours.
Same as 1 except 50 mg. lipase per 100 gm. cream.
200 mg. C. cylindracea Candida microbial lipase per 100 gm.
cream incubated at room temperature for 30 hours.
200 mg. Italase~C calf tissue lipase per 100 gm. cream incubated 4-1/2 hours at rc~m temperature.
200 mg. Capalase K kid tissue lipase per 100 gm. cream incubated 4-1/2 hours at room temperature.
200 mg. Capalase KL mixed kid and lamb tissue lipase per 100 gm.
cream incubated 4-1/2 hours at room temperature.
From the foregoing it can be seen that various sources of lipase may be u-tilized in the present invention, although suitable adjustments, wi-thin the skïll of the art, may have to be maae in concentra-tion, curing temperature, and -the like. For hest results, however, -the use of a combina-tion of the self-limiting calf, kid, 1~: . .
l~i97~3 and lamb throat tissue lipases is pref~rred, and the examples and discussion herein are limited to their use.
The source of proteolytic enzyme may be selected from any one of a number of available materials which yield a protease enzy.me having a high proteolytic activity, The type of protease and its manner of use act to enhance breakdown of the protein in the ~rd and to minimize formation of bitter peptides. Further, the protease causes complete breakdcwn of at least a portion of the protein to amino acids which is considered to be desirable to provide a more ccmplete flavor profile in the finished product.
The source of protease may be added to the curd separately frcm the source of lipase, or, in some instances, the source of lipase may naturally contain sufficient quantities of proteases having -the desired high proteolytic activity that an additional source of protease need not be added to the curd. In this connection, throat tissue lipases sold under the trade names Italase and Capalase have been found to contain sufficient protease that when a relatively high level of lipase is added to the curd no additional source of protease is required, Hcwever, for most purposes, and to provide a desired flavor profile, particularly where the cheese product is to be incorporated in process cheese, a separate source of proteolytic enzy.me is added to the curd in addition to that which may be present in the source of lipolytic enzy.me. Examples of suitable proteolytic enzymes are those derived from plant sources, such as papain, and from microorganisms, such as those sold under the trade names Rhozy.me P-ll, Rhozyme P-5 obtained from A. flavus oryzae and B. subtilis, and mixtures thereof.
The present invention camtempla-tes that other proteolytic enzymes or proteases might also be used in the present invention. Seléction of such proteolytic enzymes is considered to be within the skill of the art based upon known microbi.ological screening 7fl techniques. Regardless of the source of proteolytic enzyme, it should have a good proteolytic activity in a milk source under cheese making conditions and should not produce protein byproducts which impart bitter flavor to the cheese product.
In accordance with the present invention, it has been discovered that a highly intensified ~nerican-type cheese flavor can be imparted to a natural American-type cheese product by substantially increasing the C2-C10 fatty acid content of the cheese. This is in marked contrast to the fatty acid content of conventional aged American cheese, e.g. Cheddar cheese, which is very low and.does not markedly change during the curing cycle.
There is set forth in Table II the weight percent of the C2-C10 fatty acids of conventional Cheddar cheese at various ages.
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It can be seen from Table II that there is no appreciable free C2.-C10 fatty aci~s present in conventional Cheddar cheese throughout its curing cycle. The average fatty acid content of Samples 2, 3, 4, and ~ appear as the lower curve in FIGURE 1.
The natural cheese products of intensified flavor of the present invention have a substantially increased free fatty acid content as compared to the conventional aged Cheddar cheeses set forth in Table II. There is set forth in Table III the weight percent of the C2-C10 fatty acids of production size quantities o a preferred cheese having an intensified flavor manufactured in accord with the present invention in which the milk is inoculated with a proteolytic micrococcus and a self-limiting lipase, and a proteolytic micrococcus and flavoring microorganism are added to the curd in addition to the lipolytic enz~me and proteolytic enzyme.
TABLE_III
Weight % Free Fatty Acid No. Age C2 C4 C6 C8 C10 -6 115 days0.151 0.403 0.137 0.0480.102 7 105 days0.184 0~349 0.120 0.0440.079 8 unknown0.170 0.490 0.152 0.0510.103 The free fatty acid distxibution curves of Samples 6, 7, and 8, as well as the average free fatty acids of conventional Cheddar cheese samples 2, 3, 4, and 5 are plotted in FIGURE 1.
It is reaaily apparent that the free fatky acid content of the natural cheese of the present invention greatly exceeds that of conventional American-type cheese. In this connection, it is believed that the C2 fatty acid content is not as important as the C~~C10 fatty acid content. The marked increase in the C4 fatty acid, as compared to the C6, C8, and C10 fatty acids in Samples 6, 7, and 8, as compared to Samples 2, 3, 4, and 5, is believed ~i97~
to be important to the provision of an intensified ~merican-type cheese flavor in the cheese products of the present inventionO
FIGURE 1 demonstrates that the preferred natural cheese products of the present invention have a C2-C10 fatty acid content at least about twenty to thirty times as great as the free fatty acid content of conventional aged American-type cheese. As the increased amounts of free fatty acids decrease, the intensity of glavor of the cheese product decreases.
Accordingly, in order to provide a sufficient intensity of flavor lQ in the cheese product, the C2-C10 free fatty acid content of the cheese product of the present invention should be no less than.
ten times the free fatty acid content of conventional American-type cheese.
In addition to the foregoing, it is believed that the drastically increased C4 fatty acid content o the cheese product of the .present invention is at least partially responsible ~or the intensified American-type cheese flavor that is obtained.
Referring to FIGURE 1, it ~ill be seen that the average C4 fatty acid content of production lots in accordance with the preferred embodiment of the invention is at least about thirty times .the C4 fatty acid content of the average of Samples 2, 3, 4, and 5. Sample 7, having the lowest C4 fatty acid content of the:production samples, has a C4 fatty acid con-tent in excess of ten times.the C4 fatty acid content of Sample 4, which has the maximum C4 fatty acid content of the conventional aged Cheddar cheeses set forth in Table I.
It is to be understood that the amount of free fat-ty acid in cheese varies from lot to lot depending on milk source, enzyme source, and the like. It is therefore difficult to sta-te ) precisely the free fatty acid content that is necessary to obtain the benefits of the present invention with particular:ity. It is known, however, that the addition of a source o~ l:ipase and a source of protease in accordance with the present invention provides a cheese product o~ intensified flavor which has a greatly increased free fatty acid content. It is believed, based upon present kncwledge, that this increase should be in excess of ten times. ~lowever, the addition of lipase and protease which do not attain a tenfold fatty acid increase but yet provide an intensified flavor level equivalent to that described herein are considered to be within the spirit of the present invention.
In a preferred e~bcdiment of the invention, a proteolytic micrococcus culture is used in combination with the source of lipase and source of protease. The proteolytic micrococcus appears to act with the lipase and protease to provide a controlled level of peptide formation which contributes to the intensified American-type cheese flavor of the cheese product of the invention~ The proteolytic micrococcus is a particu'ar microorganism which provides controlled protein breakdown during curing of the cheese. The preEerred proteolytic micrococcus for this invention is a Micrococcus Cohn selected from subgroups 1 to 4 inclusive, A particularly preferred proteolytic micrococcus is a Micrococcus Cohn subgroup 2. The classification of Micrococc s Cohn and the manner of determination of the subgroups is reported in Identification Methods for _ _ _ Microbiologists, Gibbs and Skinner (1966). The relative characteristics of Micrococcus Cohn subgroups 1 through 4 are set forth in United States Patent No. 3,650,768.
The proteolytic microccccus to be used in accord with this invention will be acetoin positive and convert glucose to acid under aerobic conditions. It has been found that more preferred results are achieved with microorganisms from Micrococcus Cohn subgroup 2 and even m~re preferred results are obtained when the Micrococcus Cohn are microorganisms of s-~bgroup 2 which are obtained from raw milk~
1~9~L978 It has been found that microorganisms ~rom Micr cccc~s Cohn subgroups 5 through 8, inclusive, are not satisfactory for the production of the desired high flavor level. Microorganisms in these subgroups 5 to 8, inclusive, are acetoin negative and some in these subgroups are weak or negative in converting glucose to acid under aerobic conditions A preferred proteolytic micrococcus is a proteolytic micrococcus obtained from the University of Wisconsin designated T-3 and deposited in the American Type Culture Collection, No. 21829 The cultural and biochemical characteristics of T-3 micrococcus are also set forth in United States Patent No. 3,650,768.
It has been found that when the Micrococcus Cohn subgroups 1 to 4, inclusive, microorganims are added to the curd in addition to the lipase and protease, there is a clear contribution to the quali~y of the intensified cheese flavor that is not established without the addition of these microorganisms. It has also been found that this improvement is noticeable under the curing conditions described herein and is c æ ri~d over into the products to which the cheese product of the invention is added.
Proteolysis and lipolysis of the protein and fat in the cheese curd -to provide the desired breakdcwn of protein and fat occurs during curing of the cheese curd. In this connection, the level of protein and fat breakdcwn is greatly enhanced in a shortened period of time when the lipase, protease, and proteolytic micrococcus ccmbination of the invention are added to the curd particles after drainage of the whey and prior to pressing the curd particles into a cheese shape, a~d, as previously discussed, the C2-ClO fatty acid content is increased to at least about ten times the C2-CIO fatty acid content of conventional American-type cheese during curing.
While not wishing to be bound by any theory, it is believed that the pro-teolytic micrococcus of the ccmbination 11~9:~97~
continues to grow slowly under the acidic conditions developed during curing of the cheese. In this connection, the proteolytic activity of the micrococcus is primarily due to products produced by and during the growth of the micrococcus and acts to hydrolyze the protein into various protein fragments in addition to the hydrolysis provided by the added protease.
In accordance with the method of the present invention, the cheese containing the added source of lipase and added source of protease is cured, preferably at elevated temperatures as compared to usual curing temperatures for American-type cheese, until the desired C2-ClO fatty acid level is reached. It is usual to cure an American-type cheese product at a temperature of about 40F. The method o~ the present invention ma~ utilize curing temperatures of up to about 100F. although it is usually desirable to provide a curing temperature in the range of rom about 50F. to about 85F., preferably 72F. The time required to develop an intensified flavor level is inversely proportional to the temperature at which curing is effected. At temperatures of ~0F., the time required to develop a desired intensified flavor is usually from about six months to one year and this is considered to be an excessive curing time for the cheese product described herein. At curing temperatures approaching 90F. an intensified flavor may be developed in from about one month or less. However, too high curing temperatures may result in undesirable yas formation and development of off flavors and the like. Accordingly, it is preferred to cure at a temperature of 50F. to 85F., preferably 72F. for about six weeks whereupon a natural American-type cheese having an intensified flavor is obtained. If the temperature is then reduced to 45F., li~tle additional flavor development occurs and the cheese product may be held for extended periods of time without development of off ~09iL97~
.
flavors and the like.
A distinguishing feature of the cured, intensely flavored cheese product of the invention is that little knitting of the individual curd particles occurs. ~fter curing, the cheese blocks may be easily crumbled to provide flavored curd particles of substantially ~he same shape as before curing which are particularly suitable for providing cheese flavor in various products, such as process cheese and baked goods. It is also possible to provide an intensely flavored cheese powder by preparing an aqueous slurry of comminuted cured cheese and there-after spray-drying the slurry.
The amounts of lipase that is added to the curd are selected to provide the desired C2- Clo fatty acid development depending upon the temperature and length of the curing cycle.
The lipolytic action, as well as the proteolytic action, on the cheese continue until inactivated, for example, by cooking or cooling ~o low temperature.
When the throat tissue lipase described herein is used at a level of from about 20 to about 45 grams per 100 pounds of curd, the desired C2-ClO fatty acid content is achieved.
Alternate lipase sources may be used at equivalent levels depending upon respective activities.
The protease should be added at a level su~ficient to provide a desired amount of protein breakdown to amino acids and peptides, but should not be added at such high levels as to generate undesired flavors. At levels of addition of a dry Rhozyme P-ll protease preparation below about l gram per lO0 pounds of curd, there is little flavor contribution to the level of amino acids produced. At levels of addition above ;0 about lO grams of dry, powdered protease preparation per lO0 pounds of curd, an off-flavor may be produced. Generally, between L97~
about 5 and about 7.5 grams per 100 pounds of curd is used.
As with the lipase, other proteases may be added at equivalen-t levels depending upon activity.
The proteolytic micrococcus, if used, is added at a level sufficient to provide a viable culture.
When a natural cheese is produced containing the above-described combination of lipase, protease, and proteolytic micrococcus, the cheese has a desirable highly intensi~ied American-type cheese flavor. However, the flavor may be unduly harsh for some purposes and a more rounded flavor may be desirable for some uses. It has been found that an improved rounded flavor can be provided when ~ lactobacillus or a closely r~lated microorganism is also added to the curd on the drain table. Such a lactobacillus may be referred to as a flavoring microorganism. Addition of such a microorganism is optional, I but may be used where a particular flavor is desired. Various homofermentative lactobacilli may be used, such as Lactobacillus lactis, Lactobacillus bulgarious, and Lactobacillus caseii.
Pre~erred homofermentative lactobacilli are particular strains of L. lactis and L. caseii. The lactobacillus microorganism will also develop some acid:ity in the curd during curing. However, as previously stated, the lactobacillus microorganism is primarily used when a particular flavor is desired. A preferred L. lactis microorganism has the following characteristics:
Temperature Litmus Milk: Acid Dye +
for growth 15C. - Reduction +
22C. + Coagulation +
37C. -~ % Acid in Milk 1.74 45C. + pH 3.3 ~ 55C. + Acid from: Galactose Microscopic Evaluation + Rod Glucose +
Granules ~ Lactose -~
Colony Appearance Rough Maltose *
NH3 ~rom Arginine - Mannitol Lipolytic(Spirit Blue) - Salicin -~
Catalase - Sorbitol Sucrose -~
Trehalose -~
109:19~8 When used, the lactobacillus or closely related micro-organism is added as a milk culture of the microorganism. The milk culture is obtained by adding the lactobacillus microorganism to a suitable substrate and permitting growth of the microorganism to proceed until an equivalent lactic acid acidity of from about 1.0 percent to about 2.0 percent is obtained. The milk culture of the lactobacillus organism is then added to the curd which has been separated from the whey at a.level of from about 0.1 to about 1.0 percent by weight of the culture per 100 pounds of curd.
At levels above the stated range, an undesired ~lavor is some-times detected. At levels below the stated range, the~e is little contribution to the flavor of the cheese produced fro:m the curd after curing.
The various enz~mes and cultures, as descri.bed herein, are preferably added to the curd on the drain table and prior to pressing. However, it is contemplated to add all or a part of the enzymes to the curd after partial curing. In this instance, the curd blocks are comminuted to provide curd particles prior to adding the enzymes and cultures thereto. After the addition of the enzymes and cultures to the curd particles, the curd part.icles may be compacted into a cheese block prior to further curing, or loose curd particles may be further cured without compacting.
It is recognized that the flavor contribution from the proteolytic micrococcus and the homofermentative lactobacillus flavoring microorganism may be due to an enzymatic reaction where an enzyme is produced as a product of the growth thereof during curing of the curd. In another embodimen~ of the present invention, such enzyme may be extracted from a proteo-!) lytic micrococcus or from a homofermentative lactobacillus culture and added directly to the curd as described herein. In such instances, the enzymes are added at a level equivalent to that which would be provided by the proteolytic micrococcus or L97~
: the homofermentative lactobacillus if present. Similarly, the source of lipase and protease may be a culture medium instead of an isolate thereof which are described as the preferred embodiments herein.
The method of the present invention is particularlysuitable for the manufacture of highly flavored American-type cheese from heat-treated milk. As used in the cheese art, heat-treated milk is milk which has been heated to at least 135~F. and cooled with no-hold. Such treatment generally destroys gas-orming microorganisms but is less than pasteur-izing conditions, and such treatment may be referred to herein as subpasteurizing. The heat-treated medium ma~ be pasteur-ized, which is generally understood to mean, in re:eerence to milk, that the milk tests phosphatase negative, or may be sterilized, which is generally understood to mean that the microorganisms and enzymes present in the medium are substan-tially or completely destroyed.
American or other cheese produced from pasteurized or otherwise heat-treated milk lacks the flavor characteris-tically associated with the American or other cheese produced from raw milk. The problem of flavor development becomes more difficult as the heat trea-tment is increased. The method of the present invention, as indicated, is particularly suitable for the manufacture of highly flavored cheese from pasteurized or otherwise heat-treated milk utilizing an inoculated milk as disclosed in U.S. patent No. 3,650,768.
Various tests have been specified in the foregoing specification. These tests are generally standard and recognized tes-ts so that the specification has not been elaborated with details as to test procedures.
The following examples further illustrate various features of the present invention, but are intended to in no 1~39~97fl way limit the scope of the invention which is defined in the appended claims.
EXAMPLE I
1000 pounds of raw milk is subjected to pasteuri-zation heat treatment of 161F. for sixteen seconds. The milk is cooled to a temperature of 88F. and is inoculated with an L. lactis culture at a level of 15 pounds of the liquid culture per 1000 pounds of milk. 2-1/2 pounds of a Micro-coccus Cohn culture, subgroup 2, identified as T-3 by the University of Wisconsin, and 1 pound of a liquid culture of L. caseii liquid culture are also added to the milk. The inoculated milk is fenmented for a period of one hour at a temperature of 89F. until a titratable acidity of 0.165 is obtained in the milk.
The milk is then set with 100 cc's of single strength calves rennet per 1000 pounds of milk. A setting period of thirty minutes is allowed for coagulation of the milk after addition of the rennet. The coagulum that is formed is then cut into 1/4 inch curd cubes with curd knives~ The titra-table acidity of the whey at the time of cutting is 0.115.
The curd is lightly stirred in the whey for a period o fifteen minutes after cutting and the curd is then cooked in the whey to a temperature of 102F., allowing thirty minutes to attain the cooking temperature. The curd and whey are stirred vigorously for about ninety minutes after the cooking step until a titratable acidity in the whey of 0.165 is reached.
Thereafter, the curd and whey mixture is pumped to a drain table while maintaining a temperature of 102F.
The whey is drawn from the curd on the drain table until the whey level is slightly higher than that of the curd level. Further acidity is then developed in the curd while the curd and whey are maintained on the drain table. The remaining whey is drawn from the curd when the whey titratable acidity is 0.28 and the curd pH is 5.30. The whey is per-mitted to drain freely for about fifteen minutes. 94 pounds o curd are obtained.
The curd is then divided into four 23-pounds lots designated as Lots I-A, I-B, I-C, and I-D. Each of the lots of curd is salted with sufficient salt to provide 2 percent salt on the basis of the curd weight and proteolytic and lypolytic enzymes are added to the curd in accordance with the following schedule:
A Lot I-A 7.5 grams Italase~C; 5.25 grams Capalase KL
Lot I-B 1.5 grams Rhozyme~P-ll Lot I-C 7.5 grams Italas ~C; 5.25 grams Capalase~KL; l.O grams ~hozyme~P-ll Lot I-D 7.5 grams Italase~C; 5025 grams Capalase~ L; 1.5 grams Rhozym ~P-ll Each of lots I-A, I-B, I-C, and I-~ are divided into two portions for curing. All lots are cured at 72F~ ~or four weeks. Thereater one-half of each lot is transferred to a cooler and maintained at 45F. and the other half is maintained at 65~F. After approximately ninety days total elapsed time, the cheese products are analyzed for free fatty acid, the results of which are set forth in Table IV~
~21-. ~ .
.
:1~9:~.978 TABLE IV
.
Wei~ht % Free Fatty Acid Example Days C2 C4 C6 C8 _10 I-A-45F. 91 0.063 0.295 0.128 0.047 0.102 I-A-65F. 91 0.137 0.421 0.156 0.055 O.llS
I-B-45F. 92 0.100 0.012 0.010 Q.009 a.011 I-B-65F. 92 0.160 0.023 0.016 0.013 0.018 I-C-45F. 93 0.120 0.319 0.132 0.047 0.107 I-C-65F. 93 0.127 0.405 0.164 0.057 0.105 I-D-45F. 87 0.054 0.296 0.119 0.03~ 00081 I-D-65F. 87 0.132 0.397 00143 0.045 0.085 I
The free fatty acid distribution of Examples I-A
through I-D are plotted in FIGURE 2. Storage at 65F. results in increased fatty acid development, particularly in C4 fatty acids, as compared to storage at 45 F. It is therefore possible to exert control over the fatty acid content of the cheese product by altering and/or controlling the curing temperature, and permits speeding up or slowing down of the curing cycle by appropriate temperature adjustments. The free fatty acid development is slowed even further if the temperature is reduced below 45~F. and is completely stopped if the cheese product is frozen. While freezing of cheese is undesirable if the cheese is to be consumed as is, it does not detract from the cheese product of the invention when it is used as a flavoring ingredient in process cheese or in baXed goods.
EXAMPLE II
A cheese curd is produced in accordance with Example I and after whey removal a twenty-three pound sample of , . . ..
9~7~
curd is salted and 7.5 grams Italase~C, 5.25 grams Capalase~
KL, and 1.0 grams of ~hozym -11 are added to the curd. The curd is then cured at 72F.
Quantities of the cheese product were removed and frozen after one day, fourteen days, and twenty-eight days to stop development of fatty acids. The respective samples were analyzed for free fatty acid content and for percent total nitrogen by molecular weight fractions.
EXAMPLE _II
A further quantity of cheese is made in accordance with Example I except the milk is not inoculated with the T~3 micro-coacus and liquid culture of L. caseii. After whey removal twenty three pounds of curd is salted and 7.5 grams Italase~C, 5.25 grams Capalas ~ L, and 1.0 grams Rhozyme~P-ll are added to the curd. The curd is then cured at 72F.
Quantities of cheese were removed and frozen after one, fourteen, and twenty-eight days and analyzed ~ox free fatty acid and for percent total nitrogen by molecular weîght fractions in the same manner as Example II. The results of the analysis of Examples II and III are set forth in Tables V and VI.
TABLE V
Weight % Free Fatty Acid Example Age, C2 C4 C6 C8 C10 . . .
II-A 1 0.033 0.010 0.004 0.002 0.003 II-B 14 0.024 0.025 0.086 0.028 0.056 II-C 28 0.030 0O319 0.121 0.040 0.085 III-A 1 0.022 0.005 0.002 0.001 0 r 001 III-B 14 0.017 0.236 0.087 0.028 0.052 III-C 28 0.024 0.311 0.115 0.038 0~073
158,642 filed December 12, 1972.
Generally, the present invention is directed to a natural cheese product having increased levels of C2-ClO fatty acids and an intensified American cheese flavor as compared to conventional aged natural American cheese.
More particularly, the present invention relates to an American-type cheese product having a C2-C10 fatty acid content at least about ten times the C2-C10 fatty acid content of conven-tional aged American-type cheese.
The natural cheese product having an intensified American cheese flavor is useful in the manufacture of process cheese and other cheese products or cheese-containing products wherein a high level of cheese flavor is desirable. ~merican cheese and ~merican-type cheese are descriptive terms used to identify a group of cheeses which includes Cheddar cheese, Colby cheese, Monterey cheese, Jack cheese, and stirred-curd, washed-curd, and soaked-curd Cheddar type cheese, all of which have a generally similar American cheese flavor. The cheese product of the present inven-tion has an American cheese flavor, but the flavor is of such intensity that it would not generally be considered palatable when consumed alone. However, when added to cooked cheese-containing products, such as process cheese and baked goods, in relatively small amounts it imparts an ~merican-type cheese flavor to such product, and therefore may replace all or a part of the aged American cheese normally added to such products as a flavoring ingredient~
The production of aged Cheddar cheese requires many months of curing to develop the level of flavor normally associated ~ith aged Cheddar cheese. As used herein, the term "highly Elavored cheese product" or "cheese product having an intensiEied ~merican cheese flavor" refers to a natural cheese product ~hich has a d D / ~
~L09~78 flavor level that is significantly greater than that normally associated with conventional aged American cheese. Such highly flavored cheese product may or may not have suitable flavor characteristics for direct eating. Usually, the highly flavored cheese product is used as a flavoring component in cheese or other food products, and, more particularly, in products which are cooked, as described in detail hereina~ter.
The present invention further relates to a method of manu--facturing a natural American-type cheese product of intensified American cheese flavor which includes providing a mixture of curd particles and whey by any one of a number of known American-type cheese make procedures, separating the whey from the curd, adding salt, ~ source of a proteolytic enzyme, and a source of a lipolytic enzyme to the curd, and curing the curd at a temperature above about 50F. for a period of time sufficient to provide a C2-C10 fatty acid content at least about ten times as great as the I G2-Clo fatty acid content of conventional aged natural American-type cheese.
A proteolytic micrococcus and a flavor culture, as described hereinafter, may also be added to the curd with the pro-teolytic enzyme and the lipolytic enzyme to provicle a natural cheese product which, when used as a flavoring ingredient in cooked cheese-conta-lning products, provides a more rounded and fuller American-type cheese flavored product. It has also been found desirable, particularly when the cheese product of the in-vention is utilized in the manufacture of process cheese, to prepare the cheese curd using 2 make procedure as described in Patent No. 3,650,768 in which a proteolytic micrococcus, a self-limiting lipase, and a flavor culture are added to the milk prior to setting of the milk.
In one particular aspect the present invention provides a process for manufacture of a highly flavored cheese product com-prising providing a medium containing milk protein and Eat, setting db ,~, 2-10~1978 the medium to provide a coagulum, cutting the coagulum to provide curd particles and whey, separating the curd particles ~rom the whey, mixing the curd particles with salt and an effective amount of a lipolytic enzyme and a proteolytic enzyme and curing the curd particles at a temperature above about 50F. for a period of time sufficient to provide a total free C2-C10 fatty acid con-tent in the cheese of at least about 0.46 percent by weight and a free C4 fatty acid content of at least about 0.32 percent by weight, the lipolytic enzyme being selected rom enzymes extracted from the throat tissue of calves, lamhs and kids and the proteo-lytic enzyme is an exopeptidase having high proteolytic activity but only minor diastatic action.
In another aspect,the present invention provides a method for the manufacture of process cheese wherein a mlxture of aged American-type cheese having a conventional ~merican cheese flavor and unaged cheese having minimal American cheese flavor is mixed wlth emulsifiers, heated to form a homogeneous molten cheese mass and cooled, the improvement comprising replacing at least about 5 percent of said aged American cheese with a natural American cheese product having an intensified American cheese flavor, the cheese produc~ having a free C2-C10 fatty acid content of at least about 0.46 percent by weight and a free C4 fatty acid content of at least about 0.32 percent by weight.
The invention will become more apparent from the follow-ing detailed description and from the drawings of which:
FIGURE 1 is a graph depicting the free fatty acid dis-tribution of cheese products in accordance with a preferred embodiment of the present invention and natural aged Cheddar cheese.
FIGURE 2 is a graph similar to FIGURE 1 illustrating the effect of curing temperature on free fatty acid development.
db ~
~L09~.978 .
. FIGURE 3 is a graph depicting the rate of free fatty acid development of Example II.
FIGURE 4 i9 a graph depicting the rate of free fatty acid development of Example III.
FIGURE 5 is a graph depicting the rate of free fatty acid development of Example IV.
The preferred medium for preparing the highly flavored cheese product of the present lnvention is ~whole cow's milk db;~, .. . . . . , ... .. , . ~ . . . .... .... .. .. ...... .. . .... . . .. .. . .... .. . . .. . .
`having about 3 percent protein which is principally casein, about 5 percent lactose, about 1 percent ash, and about 3.5 per-cent fat. The milk may be partially or wholly skimmed, and other fats may be used to replace or supplement a portion of the milk fat of the whole milk. In this connection, preferred fats for replacement of milk fat are coconut fat, soybean oil, cottonseed oil, peanut oil, safflower oil, and mixtures thereof. Other protein sources-may also be used in combination with the casein of the whole milk. In this connection, up t~ about 5~ percent of the casein may be replaced with protein sources such as soy protein, yeast protein, fish meal protein, whey protei~, and mixtures thereof.
The preferred method for preparing curd particles to which the enzymes and cultures of the present invenkion are applied is known and is usually referred to as the stirred curd method.
In this method, a lactic acid producing culture, preferably S. lac-tis t iS added to the medium. The medium is set with single strength calves rennet at a level of about 100 cc's of rennet per 1000 pounds milk. A setting period of thirty minutes is allowed after addition of the rennet for coagulation o the medium. The coagulum is cut with quarter-inch knives to provide curd particles and whey when the titratable acidity of the coagulum is about 0.11 to about 0.12 equivalent lactic acid, and the pH of the whey is about 6.4 as measured by the quinhydrone method. As set forth hereinp all reference to titratable acidity refers to equivalent lactic acidt and all pH values are measured by the quinhydrone method. After cutting, the curd particles are stirred in the whey and the curd particles are then heated over a period of thirty minutes to a temperature of about 103F. to cook the curd. The curd is held while being stirred in the whey at 103F.
until the titratable acidity oE the whey is about 0 17 and the curd has a pH of about 5.8, a period of about sixty minutes. The curd and whey mixture is then pumped to a drain table while the ~91~7~3 temperature oE 103F. is maintained. The whey is drawn from the curd until the level of whey is slightly higher than the level of the c~rd.
m e d is stirred in the whey for a period of about sixty minutes or until the titratable acidity of the whey is about 0.28 and then the whey is allowed to freely drain from the curd. m e curd at this time has a pH of about 5.36.
After a period of about fifteen minutes of free whey drainage, the curd is salted with sodium chloride at a level of about 2.0 pounds of salt per 1000 pounds of medium used to prepare the curd and a source of a lQ lipolytic enzyme, i.e., a lipase, and a source of a proteolytic enzyme, i.e., a protease, are added -to the curd. m e preferred source of lipase is that obtained by extraction from the throat tissue of calves, lambs, or kids. These lipases are cammercially available under the trade names Italase C and Capalase KL and their manufacture is generally disclosed in United States Patent Nos. 2,531,329 and 2,794,743. m ese particular lipases are self-limiting in the hydrolysis of fat and do not break down the fat to undesired end products. Such lipases are sametimes referred -to herein as "self-limiting lipases" to denote their restricted activity in the hydrolysls of fat.
other forms of lipolytic enzymes, such as microbial lipases and pancreatic lipases, may be substituted for all or a part of the throat tissue lipases. An example of a commercially available microbial lipase is that obtained from Candida cylindracea, Iype VIII. An example of a commercially available pancreatic lipase is that sold as porcine pancreatic lipase. One unit of the C. cylindracea microbial lipase will hydrolyze 1.0 micro-equivalent of fatty acid from a txiglyceride in one hour at pH 7.4 at 37C.
One unit of the porcine pancreatic lipase will release 1.0 micramole of acid per minute at pH 8.0 at 25C fram an olive oil substrate.
The results of a cGmparison of throat tissue lipase, microbial lipase, and pancreatic lipase are set forth in Table I. The respective samples were incubated in 36 pexcent butterfat Grade A whipping cream, fatty acids were removed by steam distillation, and fatty acid analysis :1 [)9iL9~8 was by gas chromatography. A control sample, with no adclition of lipase, - was incubated at room temperature for four and one-half hours.
~ABLE I
Wei~ht ~ Free Fatty Ac_l Sa ple c2 C4 C6 - ~ - C~o C - 2 Control ~ 0.001 0.001 0.001 0.002 0 001 P-101 ----- 0.078 0.036 0.022 0.022 0.008 p_502 _____ 0.180 0.086 0.051 0,074 0.042 M~2003 ----- 0.461 0.169 0.153 Oe207 0.059 c-20o4 0,003 0.061 0.018 O.OOg 0.016 -----K-2005 0.004 0.076 0.033 0.010 0.009 -----KI~2006 0.002 0.087 0.037 0.011 0,017 -----10 mg. porcine pancreatic lipase per 100 gm, cream incubated at rcxxn temperature 30 hours.
Same as 1 except 50 mg. lipase per 100 gm. cream.
200 mg. C. cylindracea Candida microbial lipase per 100 gm.
cream incubated at room temperature for 30 hours.
200 mg. Italase~C calf tissue lipase per 100 gm. cream incubated 4-1/2 hours at rc~m temperature.
200 mg. Capalase K kid tissue lipase per 100 gm. cream incubated 4-1/2 hours at room temperature.
200 mg. Capalase KL mixed kid and lamb tissue lipase per 100 gm.
cream incubated 4-1/2 hours at room temperature.
From the foregoing it can be seen that various sources of lipase may be u-tilized in the present invention, although suitable adjustments, wi-thin the skïll of the art, may have to be maae in concentra-tion, curing temperature, and -the like. For hest results, however, -the use of a combina-tion of the self-limiting calf, kid, 1~: . .
l~i97~3 and lamb throat tissue lipases is pref~rred, and the examples and discussion herein are limited to their use.
The source of proteolytic enzyme may be selected from any one of a number of available materials which yield a protease enzy.me having a high proteolytic activity, The type of protease and its manner of use act to enhance breakdown of the protein in the ~rd and to minimize formation of bitter peptides. Further, the protease causes complete breakdcwn of at least a portion of the protein to amino acids which is considered to be desirable to provide a more ccmplete flavor profile in the finished product.
The source of protease may be added to the curd separately frcm the source of lipase, or, in some instances, the source of lipase may naturally contain sufficient quantities of proteases having -the desired high proteolytic activity that an additional source of protease need not be added to the curd. In this connection, throat tissue lipases sold under the trade names Italase and Capalase have been found to contain sufficient protease that when a relatively high level of lipase is added to the curd no additional source of protease is required, Hcwever, for most purposes, and to provide a desired flavor profile, particularly where the cheese product is to be incorporated in process cheese, a separate source of proteolytic enzy.me is added to the curd in addition to that which may be present in the source of lipolytic enzy.me. Examples of suitable proteolytic enzymes are those derived from plant sources, such as papain, and from microorganisms, such as those sold under the trade names Rhozy.me P-ll, Rhozyme P-5 obtained from A. flavus oryzae and B. subtilis, and mixtures thereof.
The present invention camtempla-tes that other proteolytic enzymes or proteases might also be used in the present invention. Seléction of such proteolytic enzymes is considered to be within the skill of the art based upon known microbi.ological screening 7fl techniques. Regardless of the source of proteolytic enzyme, it should have a good proteolytic activity in a milk source under cheese making conditions and should not produce protein byproducts which impart bitter flavor to the cheese product.
In accordance with the present invention, it has been discovered that a highly intensified ~nerican-type cheese flavor can be imparted to a natural American-type cheese product by substantially increasing the C2-C10 fatty acid content of the cheese. This is in marked contrast to the fatty acid content of conventional aged American cheese, e.g. Cheddar cheese, which is very low and.does not markedly change during the curing cycle.
There is set forth in Table II the weight percent of the C2-C10 fatty acids of conventional Cheddar cheese at various ages.
~L~9197fl o _l ~ ~ ~r 1`
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.
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u~
~; 3 ~ n QlN Ql ol 1~11919~8 .
It can be seen from Table II that there is no appreciable free C2.-C10 fatty aci~s present in conventional Cheddar cheese throughout its curing cycle. The average fatty acid content of Samples 2, 3, 4, and ~ appear as the lower curve in FIGURE 1.
The natural cheese products of intensified flavor of the present invention have a substantially increased free fatty acid content as compared to the conventional aged Cheddar cheeses set forth in Table II. There is set forth in Table III the weight percent of the C2-C10 fatty acids of production size quantities o a preferred cheese having an intensified flavor manufactured in accord with the present invention in which the milk is inoculated with a proteolytic micrococcus and a self-limiting lipase, and a proteolytic micrococcus and flavoring microorganism are added to the curd in addition to the lipolytic enz~me and proteolytic enzyme.
TABLE_III
Weight % Free Fatty Acid No. Age C2 C4 C6 C8 C10 -6 115 days0.151 0.403 0.137 0.0480.102 7 105 days0.184 0~349 0.120 0.0440.079 8 unknown0.170 0.490 0.152 0.0510.103 The free fatty acid distxibution curves of Samples 6, 7, and 8, as well as the average free fatty acids of conventional Cheddar cheese samples 2, 3, 4, and 5 are plotted in FIGURE 1.
It is reaaily apparent that the free fatky acid content of the natural cheese of the present invention greatly exceeds that of conventional American-type cheese. In this connection, it is believed that the C2 fatty acid content is not as important as the C~~C10 fatty acid content. The marked increase in the C4 fatty acid, as compared to the C6, C8, and C10 fatty acids in Samples 6, 7, and 8, as compared to Samples 2, 3, 4, and 5, is believed ~i97~
to be important to the provision of an intensified ~merican-type cheese flavor in the cheese products of the present inventionO
FIGURE 1 demonstrates that the preferred natural cheese products of the present invention have a C2-C10 fatty acid content at least about twenty to thirty times as great as the free fatty acid content of conventional aged American-type cheese. As the increased amounts of free fatty acids decrease, the intensity of glavor of the cheese product decreases.
Accordingly, in order to provide a sufficient intensity of flavor lQ in the cheese product, the C2-C10 free fatty acid content of the cheese product of the present invention should be no less than.
ten times the free fatty acid content of conventional American-type cheese.
In addition to the foregoing, it is believed that the drastically increased C4 fatty acid content o the cheese product of the .present invention is at least partially responsible ~or the intensified American-type cheese flavor that is obtained.
Referring to FIGURE 1, it ~ill be seen that the average C4 fatty acid content of production lots in accordance with the preferred embodiment of the invention is at least about thirty times .the C4 fatty acid content of the average of Samples 2, 3, 4, and 5. Sample 7, having the lowest C4 fatty acid content of the:production samples, has a C4 fatty acid con-tent in excess of ten times.the C4 fatty acid content of Sample 4, which has the maximum C4 fatty acid content of the conventional aged Cheddar cheeses set forth in Table I.
It is to be understood that the amount of free fat-ty acid in cheese varies from lot to lot depending on milk source, enzyme source, and the like. It is therefore difficult to sta-te ) precisely the free fatty acid content that is necessary to obtain the benefits of the present invention with particular:ity. It is known, however, that the addition of a source o~ l:ipase and a source of protease in accordance with the present invention provides a cheese product o~ intensified flavor which has a greatly increased free fatty acid content. It is believed, based upon present kncwledge, that this increase should be in excess of ten times. ~lowever, the addition of lipase and protease which do not attain a tenfold fatty acid increase but yet provide an intensified flavor level equivalent to that described herein are considered to be within the spirit of the present invention.
In a preferred e~bcdiment of the invention, a proteolytic micrococcus culture is used in combination with the source of lipase and source of protease. The proteolytic micrococcus appears to act with the lipase and protease to provide a controlled level of peptide formation which contributes to the intensified American-type cheese flavor of the cheese product of the invention~ The proteolytic micrococcus is a particu'ar microorganism which provides controlled protein breakdown during curing of the cheese. The preEerred proteolytic micrococcus for this invention is a Micrococcus Cohn selected from subgroups 1 to 4 inclusive, A particularly preferred proteolytic micrococcus is a Micrococcus Cohn subgroup 2. The classification of Micrococc s Cohn and the manner of determination of the subgroups is reported in Identification Methods for _ _ _ Microbiologists, Gibbs and Skinner (1966). The relative characteristics of Micrococcus Cohn subgroups 1 through 4 are set forth in United States Patent No. 3,650,768.
The proteolytic microccccus to be used in accord with this invention will be acetoin positive and convert glucose to acid under aerobic conditions. It has been found that more preferred results are achieved with microorganisms from Micrococcus Cohn subgroup 2 and even m~re preferred results are obtained when the Micrococcus Cohn are microorganisms of s-~bgroup 2 which are obtained from raw milk~
1~9~L978 It has been found that microorganisms ~rom Micr cccc~s Cohn subgroups 5 through 8, inclusive, are not satisfactory for the production of the desired high flavor level. Microorganisms in these subgroups 5 to 8, inclusive, are acetoin negative and some in these subgroups are weak or negative in converting glucose to acid under aerobic conditions A preferred proteolytic micrococcus is a proteolytic micrococcus obtained from the University of Wisconsin designated T-3 and deposited in the American Type Culture Collection, No. 21829 The cultural and biochemical characteristics of T-3 micrococcus are also set forth in United States Patent No. 3,650,768.
It has been found that when the Micrococcus Cohn subgroups 1 to 4, inclusive, microorganims are added to the curd in addition to the lipase and protease, there is a clear contribution to the quali~y of the intensified cheese flavor that is not established without the addition of these microorganisms. It has also been found that this improvement is noticeable under the curing conditions described herein and is c æ ri~d over into the products to which the cheese product of the invention is added.
Proteolysis and lipolysis of the protein and fat in the cheese curd -to provide the desired breakdcwn of protein and fat occurs during curing of the cheese curd. In this connection, the level of protein and fat breakdcwn is greatly enhanced in a shortened period of time when the lipase, protease, and proteolytic micrococcus ccmbination of the invention are added to the curd particles after drainage of the whey and prior to pressing the curd particles into a cheese shape, a~d, as previously discussed, the C2-ClO fatty acid content is increased to at least about ten times the C2-CIO fatty acid content of conventional American-type cheese during curing.
While not wishing to be bound by any theory, it is believed that the pro-teolytic micrococcus of the ccmbination 11~9:~97~
continues to grow slowly under the acidic conditions developed during curing of the cheese. In this connection, the proteolytic activity of the micrococcus is primarily due to products produced by and during the growth of the micrococcus and acts to hydrolyze the protein into various protein fragments in addition to the hydrolysis provided by the added protease.
In accordance with the method of the present invention, the cheese containing the added source of lipase and added source of protease is cured, preferably at elevated temperatures as compared to usual curing temperatures for American-type cheese, until the desired C2-ClO fatty acid level is reached. It is usual to cure an American-type cheese product at a temperature of about 40F. The method o~ the present invention ma~ utilize curing temperatures of up to about 100F. although it is usually desirable to provide a curing temperature in the range of rom about 50F. to about 85F., preferably 72F. The time required to develop an intensified flavor level is inversely proportional to the temperature at which curing is effected. At temperatures of ~0F., the time required to develop a desired intensified flavor is usually from about six months to one year and this is considered to be an excessive curing time for the cheese product described herein. At curing temperatures approaching 90F. an intensified flavor may be developed in from about one month or less. However, too high curing temperatures may result in undesirable yas formation and development of off flavors and the like. Accordingly, it is preferred to cure at a temperature of 50F. to 85F., preferably 72F. for about six weeks whereupon a natural American-type cheese having an intensified flavor is obtained. If the temperature is then reduced to 45F., li~tle additional flavor development occurs and the cheese product may be held for extended periods of time without development of off ~09iL97~
.
flavors and the like.
A distinguishing feature of the cured, intensely flavored cheese product of the invention is that little knitting of the individual curd particles occurs. ~fter curing, the cheese blocks may be easily crumbled to provide flavored curd particles of substantially ~he same shape as before curing which are particularly suitable for providing cheese flavor in various products, such as process cheese and baked goods. It is also possible to provide an intensely flavored cheese powder by preparing an aqueous slurry of comminuted cured cheese and there-after spray-drying the slurry.
The amounts of lipase that is added to the curd are selected to provide the desired C2- Clo fatty acid development depending upon the temperature and length of the curing cycle.
The lipolytic action, as well as the proteolytic action, on the cheese continue until inactivated, for example, by cooking or cooling ~o low temperature.
When the throat tissue lipase described herein is used at a level of from about 20 to about 45 grams per 100 pounds of curd, the desired C2-ClO fatty acid content is achieved.
Alternate lipase sources may be used at equivalent levels depending upon respective activities.
The protease should be added at a level su~ficient to provide a desired amount of protein breakdown to amino acids and peptides, but should not be added at such high levels as to generate undesired flavors. At levels of addition of a dry Rhozyme P-ll protease preparation below about l gram per lO0 pounds of curd, there is little flavor contribution to the level of amino acids produced. At levels of addition above ;0 about lO grams of dry, powdered protease preparation per lO0 pounds of curd, an off-flavor may be produced. Generally, between L97~
about 5 and about 7.5 grams per 100 pounds of curd is used.
As with the lipase, other proteases may be added at equivalen-t levels depending upon activity.
The proteolytic micrococcus, if used, is added at a level sufficient to provide a viable culture.
When a natural cheese is produced containing the above-described combination of lipase, protease, and proteolytic micrococcus, the cheese has a desirable highly intensi~ied American-type cheese flavor. However, the flavor may be unduly harsh for some purposes and a more rounded flavor may be desirable for some uses. It has been found that an improved rounded flavor can be provided when ~ lactobacillus or a closely r~lated microorganism is also added to the curd on the drain table. Such a lactobacillus may be referred to as a flavoring microorganism. Addition of such a microorganism is optional, I but may be used where a particular flavor is desired. Various homofermentative lactobacilli may be used, such as Lactobacillus lactis, Lactobacillus bulgarious, and Lactobacillus caseii.
Pre~erred homofermentative lactobacilli are particular strains of L. lactis and L. caseii. The lactobacillus microorganism will also develop some acid:ity in the curd during curing. However, as previously stated, the lactobacillus microorganism is primarily used when a particular flavor is desired. A preferred L. lactis microorganism has the following characteristics:
Temperature Litmus Milk: Acid Dye +
for growth 15C. - Reduction +
22C. + Coagulation +
37C. -~ % Acid in Milk 1.74 45C. + pH 3.3 ~ 55C. + Acid from: Galactose Microscopic Evaluation + Rod Glucose +
Granules ~ Lactose -~
Colony Appearance Rough Maltose *
NH3 ~rom Arginine - Mannitol Lipolytic(Spirit Blue) - Salicin -~
Catalase - Sorbitol Sucrose -~
Trehalose -~
109:19~8 When used, the lactobacillus or closely related micro-organism is added as a milk culture of the microorganism. The milk culture is obtained by adding the lactobacillus microorganism to a suitable substrate and permitting growth of the microorganism to proceed until an equivalent lactic acid acidity of from about 1.0 percent to about 2.0 percent is obtained. The milk culture of the lactobacillus organism is then added to the curd which has been separated from the whey at a.level of from about 0.1 to about 1.0 percent by weight of the culture per 100 pounds of curd.
At levels above the stated range, an undesired ~lavor is some-times detected. At levels below the stated range, the~e is little contribution to the flavor of the cheese produced fro:m the curd after curing.
The various enz~mes and cultures, as descri.bed herein, are preferably added to the curd on the drain table and prior to pressing. However, it is contemplated to add all or a part of the enzymes to the curd after partial curing. In this instance, the curd blocks are comminuted to provide curd particles prior to adding the enzymes and cultures thereto. After the addition of the enzymes and cultures to the curd particles, the curd part.icles may be compacted into a cheese block prior to further curing, or loose curd particles may be further cured without compacting.
It is recognized that the flavor contribution from the proteolytic micrococcus and the homofermentative lactobacillus flavoring microorganism may be due to an enzymatic reaction where an enzyme is produced as a product of the growth thereof during curing of the curd. In another embodimen~ of the present invention, such enzyme may be extracted from a proteo-!) lytic micrococcus or from a homofermentative lactobacillus culture and added directly to the curd as described herein. In such instances, the enzymes are added at a level equivalent to that which would be provided by the proteolytic micrococcus or L97~
: the homofermentative lactobacillus if present. Similarly, the source of lipase and protease may be a culture medium instead of an isolate thereof which are described as the preferred embodiments herein.
The method of the present invention is particularlysuitable for the manufacture of highly flavored American-type cheese from heat-treated milk. As used in the cheese art, heat-treated milk is milk which has been heated to at least 135~F. and cooled with no-hold. Such treatment generally destroys gas-orming microorganisms but is less than pasteur-izing conditions, and such treatment may be referred to herein as subpasteurizing. The heat-treated medium ma~ be pasteur-ized, which is generally understood to mean, in re:eerence to milk, that the milk tests phosphatase negative, or may be sterilized, which is generally understood to mean that the microorganisms and enzymes present in the medium are substan-tially or completely destroyed.
American or other cheese produced from pasteurized or otherwise heat-treated milk lacks the flavor characteris-tically associated with the American or other cheese produced from raw milk. The problem of flavor development becomes more difficult as the heat trea-tment is increased. The method of the present invention, as indicated, is particularly suitable for the manufacture of highly flavored cheese from pasteurized or otherwise heat-treated milk utilizing an inoculated milk as disclosed in U.S. patent No. 3,650,768.
Various tests have been specified in the foregoing specification. These tests are generally standard and recognized tes-ts so that the specification has not been elaborated with details as to test procedures.
The following examples further illustrate various features of the present invention, but are intended to in no 1~39~97fl way limit the scope of the invention which is defined in the appended claims.
EXAMPLE I
1000 pounds of raw milk is subjected to pasteuri-zation heat treatment of 161F. for sixteen seconds. The milk is cooled to a temperature of 88F. and is inoculated with an L. lactis culture at a level of 15 pounds of the liquid culture per 1000 pounds of milk. 2-1/2 pounds of a Micro-coccus Cohn culture, subgroup 2, identified as T-3 by the University of Wisconsin, and 1 pound of a liquid culture of L. caseii liquid culture are also added to the milk. The inoculated milk is fenmented for a period of one hour at a temperature of 89F. until a titratable acidity of 0.165 is obtained in the milk.
The milk is then set with 100 cc's of single strength calves rennet per 1000 pounds of milk. A setting period of thirty minutes is allowed for coagulation of the milk after addition of the rennet. The coagulum that is formed is then cut into 1/4 inch curd cubes with curd knives~ The titra-table acidity of the whey at the time of cutting is 0.115.
The curd is lightly stirred in the whey for a period o fifteen minutes after cutting and the curd is then cooked in the whey to a temperature of 102F., allowing thirty minutes to attain the cooking temperature. The curd and whey are stirred vigorously for about ninety minutes after the cooking step until a titratable acidity in the whey of 0.165 is reached.
Thereafter, the curd and whey mixture is pumped to a drain table while maintaining a temperature of 102F.
The whey is drawn from the curd on the drain table until the whey level is slightly higher than that of the curd level. Further acidity is then developed in the curd while the curd and whey are maintained on the drain table. The remaining whey is drawn from the curd when the whey titratable acidity is 0.28 and the curd pH is 5.30. The whey is per-mitted to drain freely for about fifteen minutes. 94 pounds o curd are obtained.
The curd is then divided into four 23-pounds lots designated as Lots I-A, I-B, I-C, and I-D. Each of the lots of curd is salted with sufficient salt to provide 2 percent salt on the basis of the curd weight and proteolytic and lypolytic enzymes are added to the curd in accordance with the following schedule:
A Lot I-A 7.5 grams Italase~C; 5.25 grams Capalase KL
Lot I-B 1.5 grams Rhozyme~P-ll Lot I-C 7.5 grams Italas ~C; 5.25 grams Capalase~KL; l.O grams ~hozyme~P-ll Lot I-D 7.5 grams Italase~C; 5025 grams Capalase~ L; 1.5 grams Rhozym ~P-ll Each of lots I-A, I-B, I-C, and I-~ are divided into two portions for curing. All lots are cured at 72F~ ~or four weeks. Thereater one-half of each lot is transferred to a cooler and maintained at 45F. and the other half is maintained at 65~F. After approximately ninety days total elapsed time, the cheese products are analyzed for free fatty acid, the results of which are set forth in Table IV~
~21-. ~ .
.
:1~9:~.978 TABLE IV
.
Wei~ht % Free Fatty Acid Example Days C2 C4 C6 C8 _10 I-A-45F. 91 0.063 0.295 0.128 0.047 0.102 I-A-65F. 91 0.137 0.421 0.156 0.055 O.llS
I-B-45F. 92 0.100 0.012 0.010 Q.009 a.011 I-B-65F. 92 0.160 0.023 0.016 0.013 0.018 I-C-45F. 93 0.120 0.319 0.132 0.047 0.107 I-C-65F. 93 0.127 0.405 0.164 0.057 0.105 I-D-45F. 87 0.054 0.296 0.119 0.03~ 00081 I-D-65F. 87 0.132 0.397 00143 0.045 0.085 I
The free fatty acid distribution of Examples I-A
through I-D are plotted in FIGURE 2. Storage at 65F. results in increased fatty acid development, particularly in C4 fatty acids, as compared to storage at 45 F. It is therefore possible to exert control over the fatty acid content of the cheese product by altering and/or controlling the curing temperature, and permits speeding up or slowing down of the curing cycle by appropriate temperature adjustments. The free fatty acid development is slowed even further if the temperature is reduced below 45~F. and is completely stopped if the cheese product is frozen. While freezing of cheese is undesirable if the cheese is to be consumed as is, it does not detract from the cheese product of the invention when it is used as a flavoring ingredient in process cheese or in baXed goods.
EXAMPLE II
A cheese curd is produced in accordance with Example I and after whey removal a twenty-three pound sample of , . . ..
9~7~
curd is salted and 7.5 grams Italase~C, 5.25 grams Capalase~
KL, and 1.0 grams of ~hozym -11 are added to the curd. The curd is then cured at 72F.
Quantities of the cheese product were removed and frozen after one day, fourteen days, and twenty-eight days to stop development of fatty acids. The respective samples were analyzed for free fatty acid content and for percent total nitrogen by molecular weight fractions.
EXAMPLE _II
A further quantity of cheese is made in accordance with Example I except the milk is not inoculated with the T~3 micro-coacus and liquid culture of L. caseii. After whey removal twenty three pounds of curd is salted and 7.5 grams Italase~C, 5.25 grams Capalas ~ L, and 1.0 grams Rhozyme~P-ll are added to the curd. The curd is then cured at 72F.
Quantities of cheese were removed and frozen after one, fourteen, and twenty-eight days and analyzed ~ox free fatty acid and for percent total nitrogen by molecular weîght fractions in the same manner as Example II. The results of the analysis of Examples II and III are set forth in Tables V and VI.
TABLE V
Weight % Free Fatty Acid Example Age, C2 C4 C6 C8 C10 . . .
II-A 1 0.033 0.010 0.004 0.002 0.003 II-B 14 0.024 0.025 0.086 0.028 0.056 II-C 28 0.030 0O319 0.121 0.040 0.085 III-A 1 0.022 0.005 0.002 0.001 0 r 001 III-B 14 0.017 0.236 0.087 0.028 0.052 III-C 28 0.024 0.311 0.115 0.038 0~073
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The free fatty acid data of Table V is depicted graphi-cally in FIGURES 3 and 4 and illustrates the increase in free fatty acid as the curing process progresses. Except or the C2 fatty acids, there is a definite increase in fatty acid content with the C4 ~atty acids increasing from a level of from about 0.01 to 0.02 percent at one day to in excess of 0.3 percent at twenty-eight days.
The molecular weight distribution data set forth in Table VI shows little difference between Examples II and III and compares favoxably with conventional aged Cheddar cheese.
EXAMPLE IV
A further quantity of cheese is made in accordance with Example II with the further addition to the curd of 1 pound of T-3 micrococcus culture and 1 pounds of L. caseii culture per 100 pounds of curd. The curd is then cured at 72F.
Samples of the cheese product were taken and frozen at one day and twenty-eight days curing time and analyzed for free fatty acids in the same manner as Examples II and III and the following results were obtained.
TABLE VII
Age, C C C C C
ExampleDays 2 ~ 6 8 10 IV-A 1 0.033 0.027 0.010 0.003 0.002 IV-B 28 0.027 0.350 0.138 0~045 O.lQ6 The data of Table VII is plotted in FIGURE 5O Comparison of FIGURE 5 with FIGURES 3 and 4 show that the fatty acid development at the end of twenty-eight days is greater in Example IV than in Examples II and III and this is believed to be due to the addi-tion of the proteolytic micrococcus and flavoring microorganism to the curd and also the addition of lipase to the milk as well as to the curd.
7~
EXAMPLE V
Process cheese is made incorporating varying levels of the natural cheese of intensified flavor prepared in accordance with Example IV. A basic preblend comprising 40 percent body cheese approximately one month old, 30 percent short held cheese approximately three months old~ and 30 percent aged Cheddar cheese is prepared. Five process cheese samples are prepared in which 5 percent, 10 percent, 20 percent, 30 percent, and 50 percent of the preblend is replaced by the intensely flavored cheese of Example IV. A control sample containing no added int,ensely flavored cheese is also prepared.
The process cheese samples are prepared in accordance with conventional processing techniques by heating the comminuted cheese together with usual emulsifier salts to a temperature of 165F. for a period of time sufficien-t to cause the cheese particles to melt and form a homogeneous mass. The process cheese is then packaged and refrigerated.
The process cheese samples containing the intensely flavored cheese of Example IV were compared against the control sample for American cheese flavor. All samples were judged to have a more pronounced American cheese :Elavox than the control sample. The 50 percent sample flavor was considered too strong for average consumption and the samples containing 5 to 30 percent intensely flavored cheese were considered acceptable.
EXAMPLE VI
1000 pounds of raw milk is subjected to subpasteuriza-tion heat treatment of 135F. for five seconds. The milk is cooled to a temperature of 88F. and is inoculated with an h. lactis culture at a level of 13.0 pounds of the liquid culture per 1000 pounds of milkO Ths inoculated mil}c is incubated, for a period of one hour at a temperature of 88F. until a ~9~g78 titratable acidity of 0.17 percent is obtained in the milk.
The milk is then set with lO0 cc's of single s-trength cal rennet per lO00 pounds of milk. A setting period of thirty minutes is allowed for coagulation of the milk after addition of the rennet. The coagulum that is formed is then cut into l/4 inch curd cubes with curd knives and the titratable acidity of the whey at the time of cutting is O.ll.
The curd is lightly stirred in the whey for a period of fifteen minutes after cutting and the curd is then cooked in the whey to a temperature of 103F., allowing thirty minutes to attain the cooking temperature. The curd and whey are stirred vigo~
ously for about ninety minutes after the cooking step until a titratable acidity in the whey of 0.17 and a curd pH of 5.80 are reached.
Thereafter, the curd and whey mixture is pumped to a drain table while maintaining the cooking temperature of 103F.
The whey is drawn from the curd on the drain table until the whey level is slightly higher than that of the curd level. Further acidity is then developed in the curd while the curd and whey are maintained on the drain table. The remaining whey is drawn from the curd when the whey titratable acidity is 0.28 and when the curd pH is 5.30. The whey is permitted to drain reely for about fifteen minutes and the curd is then salted by adding 2.0 pounds of sodium chloride salt per lO00 pounds of milk. 19.9 grams of Italas ~C enzyme obtained from the throat tissue of calves and 14.0 grams of Cat~laa~YK enzyme obtained from the throat tissue of kids or lambs is then added per lO0 pounds of curd. A protease enzyme, designated Rhozyme~P-53, is added at a level of 5.75 grams of enzyme per lO0 pounds of curd.
The enzymes and salt are thoroughly mixed in the curd and the curd is then packed into hoops at a level of :i5.0-47.0 pounds of curd per hoop. The curd is pressed in 1:he hoop at -` 3l0~1~7~
a pressure of 17 psi for a period of about twelve hours at room temperature so as to drain additional whey from the curd and to press the curd into a cheese block. The cheese block is then removed from the hoop and is subjected to 25 inches of vacuum for one hour. The cheese block is then packaged in a foil wrapper and is cured for six weeks at a temperature of 72F. At the end of the six weeks period, the curd has developed a highly intensi-fied flavor, which flavor level is substantially higher than usually associated with American-type cheese. The flavor level is judged to be too intense for direct eating, but is considered very suitable for use as an ingredient in the manufacture of process cheese.
EXAMPLE VII
1000 pounds oi raw milk is subjected to pasteurization heat treatment of 161F. ~or thirty seconds. The milk is adjusted to a temperature of 88Fo and is inoculated with an L. lactis culture at a level of 13.0 pounds of the liquid culture for each 1000 pounds of milk. A Micrococcus Cohn sub~roup 2 liquid proteolytic culture, ATCC No. 21829, is added to the milk at a level of 2.5 pounds of liquid culture per 1000 pounds of milk.
An L. caseii liquid culture is also added to the milk at a level A of ~. pounds of the culture per 1000 pounds of milk. Italase~
C lipase is added to the milk at a level of 0.25 grams per 1000 C~o~
pounds of milk. C~l~e KL lipase is added to the milk at a level of 0.17 grams per 1000 pounds of milk. The inoculated milk medium is then set and curd is manufactured by the stirred curd process described herein. Lipase and protease are then added to the curd as set forth in Example VI. The curd particles are formed into a cheese and the cheese is then cured for six weeks at a temperature of 72F. At the end of the six weeks period the cheese has developed a highly intensified flavor, which flavor level is substantially higher than usually associated with ~merican-type cheese.
- 109~L~7i!~
The flavor level is judged to be too intense for direct eating, but is considered very suitable for use as an ingredient in the manufacture of process cheese. Process cheese containing 10 percent of the cheese product of this Example has a desirable American cheese flavor and is considered to be of excellent quality.
XAMPLE VIII
1000 pounds of raw milk is made into curd particles in accordance with the procedure of Example VI. A mixture of lipase and protease is added to the curd particles as described in Example VI. A Micrococcus Cohn subgroup 2 proteolytic micrococcus, ATCC No. 2I829, i-s added to the curd particles prior to curing at a level of 1.0 pounds of culture per 100 pounds of curd. An L.lactis liquid culture is also added to the curd particles at a level of 1.0 pounds per 100 pounds of curd. The curd particles are then formed *nto a cheese and the cheese is cured as described in Example VI. After curing, the cheese has a desirable high level of flavor that is judged to be somewhat less harsh than the flavor of the cheese prepared in accordance with Example VI.
EXAMPLE IX
A 40-pound block of cheese prepared in accordance with the method of Example V is crumbled by hand to provide curd particles. The cheese block is easily crumbled and the curd particles appear to retain their identity throughout the curing period.
The curd particles are added to a bread dough formulation at the time of mixing the dough. After the bread dough has been baked, a cheese-flavored bread is obtained with a high and desirable level of Cheddar cheese flavor~ The curd particles are slightly melted but discrete curd particles are discernible in the bread. The flavor is substantially more intense than is obtained when Cheddar cheese produced by a conventional manufacturing process is added to bread dough.
EXAMPLE X
Three samples of cheese having intensified American cheese flavor are prepared in accordance with ;Example I utilizing papain as the source of proteolytic enzyme. In each of Samples X-A, X-B, and X-C the lipase source added to the curd prior to A curing is 7.5 grams Italase~C, 5.25 grams Capalase~KL. Sample X-A has 0.01 gram papain added; Sample X-B has 0.10 gram papain added; Sample X-C has 1.0 gram papain added. The curd is then cured at 72F.
After approximately twenty-five days, the samples are analyzed for free fatty acid content, the results of which are set forth in Table VIII.
TABLE VIII
Sample C2 C4 C6 C8 C10 X-A 0. 038 0. 257 0.092 0.0250.051 X-B 0.027 0.249 0.090 0.0250.047 X-C 0.048 0.2~0 0.085 0.0220.0~3 Afker curing at 72F. for six weeks, each of the cheese samples has a highly intensified American-type cheese flavor and each is useful as a flavoring ingredient for process cheese.
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The free fatty acid data of Table V is depicted graphi-cally in FIGURES 3 and 4 and illustrates the increase in free fatty acid as the curing process progresses. Except or the C2 fatty acids, there is a definite increase in fatty acid content with the C4 ~atty acids increasing from a level of from about 0.01 to 0.02 percent at one day to in excess of 0.3 percent at twenty-eight days.
The molecular weight distribution data set forth in Table VI shows little difference between Examples II and III and compares favoxably with conventional aged Cheddar cheese.
EXAMPLE IV
A further quantity of cheese is made in accordance with Example II with the further addition to the curd of 1 pound of T-3 micrococcus culture and 1 pounds of L. caseii culture per 100 pounds of curd. The curd is then cured at 72F.
Samples of the cheese product were taken and frozen at one day and twenty-eight days curing time and analyzed for free fatty acids in the same manner as Examples II and III and the following results were obtained.
TABLE VII
Age, C C C C C
ExampleDays 2 ~ 6 8 10 IV-A 1 0.033 0.027 0.010 0.003 0.002 IV-B 28 0.027 0.350 0.138 0~045 O.lQ6 The data of Table VII is plotted in FIGURE 5O Comparison of FIGURE 5 with FIGURES 3 and 4 show that the fatty acid development at the end of twenty-eight days is greater in Example IV than in Examples II and III and this is believed to be due to the addi-tion of the proteolytic micrococcus and flavoring microorganism to the curd and also the addition of lipase to the milk as well as to the curd.
7~
EXAMPLE V
Process cheese is made incorporating varying levels of the natural cheese of intensified flavor prepared in accordance with Example IV. A basic preblend comprising 40 percent body cheese approximately one month old, 30 percent short held cheese approximately three months old~ and 30 percent aged Cheddar cheese is prepared. Five process cheese samples are prepared in which 5 percent, 10 percent, 20 percent, 30 percent, and 50 percent of the preblend is replaced by the intensely flavored cheese of Example IV. A control sample containing no added int,ensely flavored cheese is also prepared.
The process cheese samples are prepared in accordance with conventional processing techniques by heating the comminuted cheese together with usual emulsifier salts to a temperature of 165F. for a period of time sufficien-t to cause the cheese particles to melt and form a homogeneous mass. The process cheese is then packaged and refrigerated.
The process cheese samples containing the intensely flavored cheese of Example IV were compared against the control sample for American cheese flavor. All samples were judged to have a more pronounced American cheese :Elavox than the control sample. The 50 percent sample flavor was considered too strong for average consumption and the samples containing 5 to 30 percent intensely flavored cheese were considered acceptable.
EXAMPLE VI
1000 pounds of raw milk is subjected to subpasteuriza-tion heat treatment of 135F. for five seconds. The milk is cooled to a temperature of 88F. and is inoculated with an h. lactis culture at a level of 13.0 pounds of the liquid culture per 1000 pounds of milkO Ths inoculated mil}c is incubated, for a period of one hour at a temperature of 88F. until a ~9~g78 titratable acidity of 0.17 percent is obtained in the milk.
The milk is then set with lO0 cc's of single s-trength cal rennet per lO00 pounds of milk. A setting period of thirty minutes is allowed for coagulation of the milk after addition of the rennet. The coagulum that is formed is then cut into l/4 inch curd cubes with curd knives and the titratable acidity of the whey at the time of cutting is O.ll.
The curd is lightly stirred in the whey for a period of fifteen minutes after cutting and the curd is then cooked in the whey to a temperature of 103F., allowing thirty minutes to attain the cooking temperature. The curd and whey are stirred vigo~
ously for about ninety minutes after the cooking step until a titratable acidity in the whey of 0.17 and a curd pH of 5.80 are reached.
Thereafter, the curd and whey mixture is pumped to a drain table while maintaining the cooking temperature of 103F.
The whey is drawn from the curd on the drain table until the whey level is slightly higher than that of the curd level. Further acidity is then developed in the curd while the curd and whey are maintained on the drain table. The remaining whey is drawn from the curd when the whey titratable acidity is 0.28 and when the curd pH is 5.30. The whey is permitted to drain reely for about fifteen minutes and the curd is then salted by adding 2.0 pounds of sodium chloride salt per lO00 pounds of milk. 19.9 grams of Italas ~C enzyme obtained from the throat tissue of calves and 14.0 grams of Cat~laa~YK enzyme obtained from the throat tissue of kids or lambs is then added per lO0 pounds of curd. A protease enzyme, designated Rhozyme~P-53, is added at a level of 5.75 grams of enzyme per lO0 pounds of curd.
The enzymes and salt are thoroughly mixed in the curd and the curd is then packed into hoops at a level of :i5.0-47.0 pounds of curd per hoop. The curd is pressed in 1:he hoop at -` 3l0~1~7~
a pressure of 17 psi for a period of about twelve hours at room temperature so as to drain additional whey from the curd and to press the curd into a cheese block. The cheese block is then removed from the hoop and is subjected to 25 inches of vacuum for one hour. The cheese block is then packaged in a foil wrapper and is cured for six weeks at a temperature of 72F. At the end of the six weeks period, the curd has developed a highly intensi-fied flavor, which flavor level is substantially higher than usually associated with American-type cheese. The flavor level is judged to be too intense for direct eating, but is considered very suitable for use as an ingredient in the manufacture of process cheese.
EXAMPLE VII
1000 pounds oi raw milk is subjected to pasteurization heat treatment of 161F. ~or thirty seconds. The milk is adjusted to a temperature of 88Fo and is inoculated with an L. lactis culture at a level of 13.0 pounds of the liquid culture for each 1000 pounds of milk. A Micrococcus Cohn sub~roup 2 liquid proteolytic culture, ATCC No. 21829, is added to the milk at a level of 2.5 pounds of liquid culture per 1000 pounds of milk.
An L. caseii liquid culture is also added to the milk at a level A of ~. pounds of the culture per 1000 pounds of milk. Italase~
C lipase is added to the milk at a level of 0.25 grams per 1000 C~o~
pounds of milk. C~l~e KL lipase is added to the milk at a level of 0.17 grams per 1000 pounds of milk. The inoculated milk medium is then set and curd is manufactured by the stirred curd process described herein. Lipase and protease are then added to the curd as set forth in Example VI. The curd particles are formed into a cheese and the cheese is then cured for six weeks at a temperature of 72F. At the end of the six weeks period the cheese has developed a highly intensified flavor, which flavor level is substantially higher than usually associated with ~merican-type cheese.
- 109~L~7i!~
The flavor level is judged to be too intense for direct eating, but is considered very suitable for use as an ingredient in the manufacture of process cheese. Process cheese containing 10 percent of the cheese product of this Example has a desirable American cheese flavor and is considered to be of excellent quality.
XAMPLE VIII
1000 pounds of raw milk is made into curd particles in accordance with the procedure of Example VI. A mixture of lipase and protease is added to the curd particles as described in Example VI. A Micrococcus Cohn subgroup 2 proteolytic micrococcus, ATCC No. 2I829, i-s added to the curd particles prior to curing at a level of 1.0 pounds of culture per 100 pounds of curd. An L.lactis liquid culture is also added to the curd particles at a level of 1.0 pounds per 100 pounds of curd. The curd particles are then formed *nto a cheese and the cheese is cured as described in Example VI. After curing, the cheese has a desirable high level of flavor that is judged to be somewhat less harsh than the flavor of the cheese prepared in accordance with Example VI.
EXAMPLE IX
A 40-pound block of cheese prepared in accordance with the method of Example V is crumbled by hand to provide curd particles. The cheese block is easily crumbled and the curd particles appear to retain their identity throughout the curing period.
The curd particles are added to a bread dough formulation at the time of mixing the dough. After the bread dough has been baked, a cheese-flavored bread is obtained with a high and desirable level of Cheddar cheese flavor~ The curd particles are slightly melted but discrete curd particles are discernible in the bread. The flavor is substantially more intense than is obtained when Cheddar cheese produced by a conventional manufacturing process is added to bread dough.
EXAMPLE X
Three samples of cheese having intensified American cheese flavor are prepared in accordance with ;Example I utilizing papain as the source of proteolytic enzyme. In each of Samples X-A, X-B, and X-C the lipase source added to the curd prior to A curing is 7.5 grams Italase~C, 5.25 grams Capalase~KL. Sample X-A has 0.01 gram papain added; Sample X-B has 0.10 gram papain added; Sample X-C has 1.0 gram papain added. The curd is then cured at 72F.
After approximately twenty-five days, the samples are analyzed for free fatty acid content, the results of which are set forth in Table VIII.
TABLE VIII
Sample C2 C4 C6 C8 C10 X-A 0. 038 0. 257 0.092 0.0250.051 X-B 0.027 0.249 0.090 0.0250.047 X-C 0.048 0.2~0 0.085 0.0220.0~3 Afker curing at 72F. for six weeks, each of the cheese samples has a highly intensified American-type cheese flavor and each is useful as a flavoring ingredient for process cheese.
Claims (15)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for manufacture of a highly flavored American-type cheese product comprising providing a medium containing milk protein and fat, setting the medium to provide a coagulum, cutting the coagulum to provide curd particles and whey, separating said curd particles from said whey, mixing said curd particles with salt and an effective amount of a lipolytic enzyme and a proteolytic enzyme and curing said curd particles at a temperature above about 50°F. for a period of time suffi-cient to provide a total free C2-C10 fatty acid content in said cheese of at least about 0.46 percent by weight and a free C4 fatty acid content of at least about 0.32 percent by weight, said lipolytic enzyme being selected from enzymes extracted from the throat tissue of calves, lambs and kids and said proteolytic enzyme is an exopeptidase having high proteolytic activity but only minor diastatic action.
2. A method in accordance with claim 1 wherein the milk source is inoculated with a source of a proteolytic micro-coccus, a self-limiting lipase, and a flavoring microorganism.
3. A method in accordance with claim 1 wherein a source of a proteolytic micrococcus and a flavoring microorgan-ism are added to the curd.
4. A method in accordance with claim 1 wherein the curing temperature is between about 50°F. and about 85°F.
5. A method in accordance with claim 1 wherein the source of lipolytic enzyme and the source of proteolytic enzyme is selected from calf throat tissue lipase, kid throat tissue lipase, lamb throat tissue lipase, and mixtures thereof.
6. A method in accordance with claim 1 wherein the source of lipolytic enzyme is selected from pancreatic lipase, microbial lipase, calf throat tissue lipase, kid throat tissue lipase, lamb throat tissue lipase, and mixtures thereof, and the source of proteolytic enzyme is selected from papain and proteases derived from A. oryzae, A. flavus-oryzae, B. subtilus, and mixtures thereof.
7. A method in accordance with claim 1 wherein the lipolytic enzyme is present at a level of between about 20 and about 45 grams per 100 lbs. of curd.
8. A method in accordance with claim 1 wherein the proteolytic enzyme is present at a level of between about 1 and about 10 grams per 100 pounds of curd.
9. A method in accordance with claim 2 wherein the proteolytic micrococcus is Micrococcus Cohn, subgroups 1 to 4.
10. A method in accordance with claim 2 wherein the flavoring microorganism is a homofermentative lactobacillus selected from L. lactis, L. bulgaricus, and L. caseii.
11. In a method for the manufacture of process cheese wherein a mixture of aged American-type cheese having a conven-tional American cheese flavor and unaged cheese having minimal American cheese flavor is mixed with emulsifiers, heated to form a homogeneous molten cheese mass and cooled, the improvement comprising replacing at least about 5 percent of said aged American cheese with a natural American cheese product made by the method claimed in claim 1 having an intensified American cheese flavor, said cheese product having a free C2 - C10 fatty acid content of at least about 0.46 percent by weight and a free C4 fatty acid content of at least about 0.32 percent by weight.
12. A method in accordance with claim 11 wherein said cheese product has a source of lipolytic enzyme and a source of proteolytic enzyme added to the curd prior to curing.
13. A method in accordance with claim 12 wherein the source of lipolytic enzyme is selected from pancreatic lipase, microbial lipase, calf throat tissue lipase, kid throat tissue lipase, lamb throat tissue lipase, and mixtures thereof, and said proteolytic enzyme is selected from papain and microbial pro-teases derived from A. oryzae, A flavus-oryzae, B. sultilus and mixtures thereof.
14. A method in accordance with claim 13 wherein the milk source from which said cheese product is made is inoculated with a proteolytic micrococcus and a flavoring microorganism.
15. A method in accordance with claim 14 wherein said cheese product has a proteolytic micrococcus and a flavoring microorganism added to the curd prior to curing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA289,775A CA1091978A (en) | 1977-10-28 | 1977-10-28 | Method for curing cheese |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA289,775A CA1091978A (en) | 1977-10-28 | 1977-10-28 | Method for curing cheese |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1091978A true CA1091978A (en) | 1980-12-23 |
Family
ID=4109889
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA289,775A Expired CA1091978A (en) | 1977-10-28 | 1977-10-28 | Method for curing cheese |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1091978A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0167309A2 (en) * | 1984-06-25 | 1986-01-08 | Genencor, Inc. | A lipolytic enzyme derived from a aspergillus microorganism having an accelerating effect on cheese flavor development |
-
1977
- 1977-10-28 CA CA289,775A patent/CA1091978A/en not_active Expired
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0167309A2 (en) * | 1984-06-25 | 1986-01-08 | Genencor, Inc. | A lipolytic enzyme derived from a aspergillus microorganism having an accelerating effect on cheese flavor development |
| EP0167309A3 (en) * | 1984-06-25 | 1987-11-04 | Genencor Inc. | A lipolytic enzyme derived from a aspergillus microorganism having an accelerating effect on cheese flavor development |
| AU595481B2 (en) * | 1984-06-25 | 1990-04-05 | Gist-Brocades B.V. | A lipolytic enzyme derived from a aspergillus microorganism having an accelerating effect on cheese flavor development |
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