CA1178113A - Method of manufacturing cheese from starter cultures - Google Patents

Abstract

ABSTRACT

cheese is manufactured from bulk starter cultures which are prepared from a whey solids-containing culture medium. The medium is rennet-coagulable but remains uncoagulated throughout the fermentation which produces the starter culture. The resulting culture is used in cheese making to produce cheese curd which is substantially free of curd fines, and which contains the protein of the medium as coagulated with the milk in the cheese vat, thereby inçreasing cheese yield.

Description

METHOD OF MANUFA~UR~ENG CHEESE FE~OM STARTER C I.TURES

Whey protein solids, such as spray-dxied sweet whey or acid whey, delactose~ whey, and whey protein concentra~e, have been used to provide part or all of the protein and ~- lactose solids in media for preparing bulk starter cultures ~ .
in the manu~acture of cheese. After pxeparation, the media are inoculated wi~h ~he lactic acid-producing bacteria desired ~or manufac~uring the particular cheese, and the bacteria are cultured therein to produce the starter culture for additio~ to the milk in the cheese vat. ~he whey protein does not coagulate i~ the cheese ~at with the casein, but part of the protein of the staxter media will be in a denatured or precipitated form, which can become associ2ted with the coagulated c~sein by physical entrapment.
By the mixing and stirring of the curd in the cheese vat, most o' the precipitated protein of the starter culture, as well as the small fragments of curd released during cutting and stirring (reerred to as "curd dustl' or "fi~es") can be xemoved from the curd and will pass out of the ~at with the whey. ~hen the whey is passed through a screen, as is conventional practice, the curd dust or fines accumulate on the screen, but complete removal of the smaller si~ed ,..,.:.
fines is not ~btained. An additional pre-filtration step -is there~ore xequired when the whey is to be subjected to ultrafiltration .

It would thérefore be desirable tv provide a method for preparing substantially fine-free s~arter media rom whey solids, and especially if the whey protein will coagulate with the casein in the cheese ~at forming a true total 30 coagulur,. The quantity of ~heese produced would thereby be increased, there would be no entrapment of precipitated protein which was not in the proper coagulated form, and there would be greater reduction of fines amount as well as an improvement in the quality of the fines, i~e., the fines would more nearly resem~le true cheese curd. Heretofore, however, the art has failed to provide such a method.

In preparing bulk starter cultures, whey solids ,- .. . . have been combined with milk solids. See United States Patents 3,8S2,158, 4,020,185 and 3,998,700. Yoguxt has also been prepared by using mixtures of whey protein and milk solids, as described in U.S. Patent 4,110,476. The latter patent discloses that the whey proteins are utilized to protect the casein of the milk protein against coagulation during the manufacture of the liquid yogurt.

Interactions of casein with serum protein have been described in the literature. See Fundamentals of Dairy Chemistry (2nd Ed., 1974), Chapt. 11, 628-631. Whey protein is comprised of serum protein, namely, the lactal-bumins and lactoglobulins. Commercial applications of the interaction or "complexing" of casein and serum protein or whey protein have been proposed. See French Pate~t 1,528,103; Polish Patent 82,699; and Schw. Milch. Forsch., 4, 1-8 (1975). As described in the cited French patent, a calcium salt is added to milk, which is then heated to a ~: temperature at which the complex of casein and serum protein precipitates. The Polish patent proposes the addition of a calcium salt to milk, which is then pasteurized to complex the casein and whey protein, and then used to prepare cheese in the usual way by the addition of a 30 starter culture and rennet. The last-cited reference proposes the addition of whey, such as a whey protein 1 concen~rate, to milk. After addition of calcium chloride the milk-whey mixture is heated to complex the casein and whey protein, which is the~ coagulated, c~rresponding to rennet coagulation in the manufacture of cheese.

S~ RY OF INVENTION

The method of the present invention provides a means for preparing ~rom whey solids a substantially fi~e-free rennet-coagulable bulk culture for use in manufacturing cheese~ The aqueous cu~ture media contain a substantial o proportion of whey solids which are preferably provided by whey protein concentrate. The whey protein-pr~viding whey solids are used in combination with milk solids, or precipitate~ casein in a water-dispersible form such as calcium caseina~e. In a presently preferred embodlment, whey protein conce~trate is used i.n admixture with calcium caseinate. In accordance with the present invention, the ratio of casein to serum protein is selected to provide sufficient casein for complexing the heat-coagulable whey protein. The medium is heated under conditions of pH, temerature, and time which promote the complexing of the casein and s~rum pxotein withou' precipit~ting the serum protein or coagulating the medium. On completion OL the heating, the medium is rennet-coagulable. A~ter i~oculation .., with the desired lactic acid-producing bac~eria, the bacteria are cultured therein to produce the bulk staxtex culture~
The cultuxing is controlled with respect to temperature and pH so that coagulation of the medium is avoided. On comple-tion of the fermentation, however, the medium remains subject to rennet-coagulation and is substantially free o~
precipitated serum protein. Therefore, on addition to the cheese vat, the protein of the medium (complexed casein and .... .

1 whey protein) coagulates at the same time as the casein of the milk, and produces a curd-whey mixture which is substantially free from culturP medium produced curd dust or fines.

~ESCRIPTION O~ PREFERRED EMBODIMENTS

The present invention may be practiced with whey solids containing soluble whey protein. Whey solids obtained by spray-drying sweet whey or acid whey contain about 12-13~ whey protein (serum protein). Higher concen-1 trations of whey protein can be obtained by removing partof the lactose from the whey, and such delactosed whey solids (16 to 27~ protein) can be used in the present invention. A preferred source of whey solids is whey protein concentrate (WPC) which is obtained by ultrafiltration of sweet whey or acid whey. Typically, such WPC will comprise 28-33~ whey protein. WPC containing up to 50~ protein can be advantageously used. The ultrafiltrate or retentate produced by the ultrafiltration is usually condensed in an evaporator and further txeated in a spray dryer to produce the dry product containing 28% or more of whey protein. In general, the concentrated whey should contain at least 16%
and preferably 20% or more whey protein. (All percentages are by weight.) The concentrated whey solids, which provide the whey '-: protein, are used in combination with media solids providing casein or a casein salt, such as calcium caseinate, for com-plexing with the whey protein. For example, good results are obtained with calcium caseinate. Where calcium caseinate is not commercially available, precipitated casein may be resolubilized, so that is is in a water dispersible salt form, such as the calcium, sodium, or magnesium salt. Precipitated casein which 1 is in a water-dispersible form, such as calcium caseinate, may be distinguished from the natural casein of milk, which may be referred to as native or unprccipitated casein.

In ge~eral, aqueous culture media for use i~ practic ing the present invention may conta~n from 6 to 21~ by .~ weight of the media solids which provlde the protein. A
,_ , preferred concentration range is from 12 to 18% solids in the media. As used herein the term l'whey solids" refers to ~he solids of whey as separated from cheese curd or milk in makins cheese, buttermilk, etc. The term "whey protein" re~ers to the serum protein of whey, and not to the serum pro ei~ o milk or milk solids which has not been processed to cause separaticn of the whey. In certat n media coming within the scope of the present invention, the total serum protein will ~omprise serum protein from mulk solids as well as serum protein fro~ whey solids.

~ he ~rLixtures of protein-providing solids whic~ may be used in practicing the present invention include (i) muxtures of whey solids and precipitated casein in water-dispersible form, or (ii) mlxtures of whey solids in milk solids, or ~iii) mixtures of whey solids, milk solids, and precipitated casein in water-dispersible form. In general, the media solids should provide a weight ratio within the range rom 0.4 to 5.0 parts of casein per part of total serum protein~ The proportion is calculated on a casein basis even if the casein is provided in salt form, such as calcium caseinate. The advantages of the present invention appear to be maximized in the range from 0.9 to 3.5 par.s of casein (casein basis) per part of total serum protein.
For example, from 1 to 3 parts of casein o~ calcium caseinate tcasein basis) can advantageously be used per part OL serum 1 pxotein, which is preferably the whey protein concentrate (WPC). Whatever the source of the whey protein, the whey protein should comprise a substantial portion of the protein of the media solids. In general, the whey protein of the whey solids comprise at least lO~ by weight of the media 501ids.
When this amount is provided by WPC, the whey protein solias will usually comprise at least 30~ of the total solids, and this level is preferred with reference to the amoUnt of whey ~ --.
protein solids to be used.

lo As indicated, the whey protein should be in substan-tially soluble form. If it has been denatured, such as by heating, to an extent that it is no longer soluble and cannot be resolubilized, then it is not useable in the present invention. Further, as already indicated, the casein should be either in its natural water-dispersible form of milk or milk solids, such as non- at dry mllk solids, or if precipi-tated as casein, it should be converted to a water~dispersible salt form.

In accordance with known practice, other minor ingredients may be incorporated in the medium, such as stimulants to promote the growth of the bacteria, or phage inhibitors, such as phosphates. (See United States Patent 3,041,248.) The present invention is concernea primarily wi~h the protein content of the media solid.s.

To complete the preparation of the medium, the solids are dispersed and/or dissolved in the water to the desired concentration, such as a concentration of 9~to 12~
solids by weight. The culture medium will usually not xequire pH adjustment and will be at a suitable pH. In general, for carrying out the heating step of the present invention, the ~7~

1 P~ may range from about 5.6 to 6.9. Conventional pH's for starter cultures may therefore be used. The medi~
is preferably stirred continuously t3 maintain a uni orm distributi~n of the solids, a~d while stirring is continued, it is heated to a temperature and for a time promoting the complexing of the casein and serum protein without precipi-........ . .
tating serum protei~ or coagulating the medium. Esrexample, the medium may be heated to a tem~erature in-the range of 160 to 195F. for 20 to 90 minutes. Good re~sul s are obtained with a heating period of 1 hour using a temperature of 185 190F. Under these conditions, and when the med?um contains the proper ratio of ~asei~ to total serum protei~ (mllk serum prot~in a~d whey serum protein), the complexing of the case~n and serum protein is obtained withou~ preci~itation of serum protei~ and heat coagulatio~
is a~oided. On completion of the heating step, the suit-ability of the media for use in practicing the present in~ention can be checked by determining its rennet-coagul2-bility. This tèst may be carried out with the medium at p~ 6.2 and 92F. by adding rennet at the rate of 3 ounces per onethousand pounds of medium.. ~nen the medium coagulates and forms the type of gel associated with ren~et-coagulation of milk casein, the medium is suitable for usa.

, . .
Under some co~ditions, the medium may contain ions which af~ect rennet-coagulability. For example, if a calcium salt or a phosphate salt has been added, the c21cium ions or the phosphate ions will have an effect. The presence of added calcium ions tends to promote rennet-coagulability and a very firm coagulum may result. In the presence of added phosphate ions, calcium ions are complexed and therefore una~ailable 2t the pH of the medium as prepared. This pro-cedure for makins the medium phage resistant will also 7~

1 interfer~ with rennet-coagulation. However, as the pH o~
- - the medium drops during the bacterial ~ermentation, th~
calcium is liberated, a~d the medium can be coagulated by rennet without added calci~m. Therefore, when the process is applied to a phage-resis,ant medium, tests for rennet r~~'...... c~agulability should be per~ormed on a corresponding medlum wi~hout the added phos~hate.

The prepared medium is then employed as a culture medium for the lactic acid-producing bacteria desired ~or 0 producing the particular kind of cheese. The culturing is carried out in the usual way, using a temperature favorable to the growth of the particular bacterial species.
For example, culture temperatures of from about 60 to 110~.
may be used. One importan, difference is that the p~ o~
the medium is not allowed to drop to a pH at which the medium coagulates. For example, the fermentation woul~
usually be permitted to continue until the p~ dropped below 5.0, such as a pH of 4.~ at which the medium coagulates.
Since the complex of the casein and serum protein used in ~he present in~ention has a somewhat lower isoelectric point than that of uncomplexed casein and serum protein, a final cu~turi~g p~ as low as 5.0 to 5 .2 can be used without causing ~- the medium to coagulate. If necessary, however, a reagent such as ammonium hydroxide can be added to the medium to maintain the p~ at a pH above the poin, at which it coagulates. Usually, however, this will not be necessary, since final pH's in the range o 5.0 to 5.2 are quite satisfactory for most starter cultures when ample bacterial growth has occurred.

Any harmless ~actic acid-producing cheese bacteria ca~ be grown in the prepared medium. Where de5ired, mixed 1 cultures. of bac~eria can be used. For mtl~ufacturing ~ Mozzarella cheese, a mixed culture of "coccus" and "rod"
bacteria can be used, such as a 3:1 to 5:1 ratio mixture of coccus to rod cells. The preferred coccus bacteria is S,reptococcus ~ ~ The rod bacteri2 may be one or .. more lactobacilli, such as L. ~, L. helveticus, and L. lac~is. Other lactic acid-producing or flavor bacteria which can be grown in the medium and the product for which they are usually used include: Swiss, Italian, and Hard Gra,ing varieties - S therm~philus tnd lactobacilli as noted.
Cheddar, Stirred and Washed Curd, Colby, Brick, Mue~ster, Montere~r Jack, Limburger, Blue, and Gorgonzola - S. lactis and 5. cremoris. Cottage, Cream, and Neufchatel - S. lactis, _ _ _ _ _ S. cremoris, S. diacetilaotis, and/or Leuconostoc Cultured suttermilk as noted for Cottage cheese. The inoculation level is not critical and follows con~entiona~ practice.
For example, the prepared medium may be inoculated wi~h from 0.01 to 5.0% by weight of the bacterial cult~re. Inoculation xate, of course, depends upon growth rate of organisms used, temperature selected, and preparation of inocula (for example:
llquid, frozen, concentrated, etc;). Duri~g culturing, the medium is stirred and heated in a conventional manner to promote the growth of the bacteria.
t...
,~ The method of the present invention is further illustrated by the following examples.

EXAMPL~ I

A staxter medium is prepared from nonfat dry milk, calcium caseinate, and whey protein concentrate. The nonfat dry milk and calciu~ caseinate may be added separately, or 3d may be purchased as a spray-dried mixture. The com~osi~ion of the medium ~nd its preparation are set out below.
.

~ 8'~3 Com~osition:
. ~

Nonfat dry milk 75 lbs.
Calcium caseinate 32 lbs.

Whey protein concentrate - (28-33% prstein) ~5 lbs.
Water 119B lbs.
1350 lbs~

Preparation:

1. Clean and ~a~itize the starter t2nk thoroughly using an lo approved sanitizer.

2. Fill the tanX with about 2/3 of the water (viz. 800 lbs.) of s-~table tap water (free ~rom i~hibitory compounds).

3. Warm the water up to 110F. and add the ingredients (according to the above formula) with the aid of a powder funnel.

4. Agitate the ingredients thoroughl~ until they are in complete solution, and ~hen add rest of the water to make it up to the weight of 1350 lbs. or the equivalent o~

150 gal.

20 ' 5. Collect a sample of starter after adding all the ingredients.
This sample can be used to determine oasein, whey protein, 2nd total protein content prior to the complexing hea~ treat-ment.

6. Heat the starter medium to 190F. and hold for 1 hour.
There should be no protein precipitation or coagulation.

7. Cool the medium to 101 to 105~. The medium is now ready for bacterial inoculation.

~ 3~

8. Drain a sterile s~mple at this stage for determination of the casein, whey pro,ein, and to~al pro~ein conten~
following heat treatment. (St2ps 5 and 8 are optional.) EX~PLE II

A medium prepared as described in Example I is used to prepare z starter culture for making ~ozzarella cheese.
The in~culation and incubation may be carried out whil maintaining a temperature in the medium of about 103 + 2~.
~ore specifically, the steps to be followed are:

1. Inoculate the medium with coccus a~d rod (S.
and L. ~ ) of thawed bacterizl concentrate using 1 ca~ (per 150 gal.) of starter medi~m.

2~ Agitate the medium for 5 to 10 min. after adding the culture concentrate.

3. Shut of~ the agitator and incubate the medium until pH
drops to 5~35 ~ 0.05. The med.ium should not coagulate.

4. When the pH drops to 5.35 ~ 0.05, start cooling the star~er with agitation.

5. Cool the uncoagulated medi~m to 45F. and hold until used for makins Mozzarella cheese.
~._ ,, ._ EXAM*LE III

A medium is prepared from no~fat dry milk and whey protein concentrate. The composition and preparation are set out below.

~1781l~3 Com~o s i t ion:

Nonfat dry milk 69 lbs.

~ney protein conc:entrate ~28-33~ protein) 32 lbs.

Water 738 lbs.

.. 839 lbs.

Pre~aration v Preparation is the same as for the medium described in Example I.

lQ EXAMPLE IV
., .
A medium is prepared ~rom whey pro~ein concentra~e and casein. The composition and preparation are set out below.

Composition:

Whey protein c~ncentrate (28-33% protein) 150 lbs.

Trisodium phosphate 15 . 25 oz.
Sodium hydroxide powder 3 lbs . and 2 o z .
Casein 5S lbs.
Silicone antifoamer 8 . 92 oz.

Calcium chloride solution (35~6 CaC12) 7 lbs. and 6.5 oz.
t~ . Water 10 32 lbs .
1250 lbs.

Preparation:

1. Clean, sanitize and ! ill the tank with two-thirds of the water (about 6 38 lbs. ) as in Exam21e I.

2 . Warm the water to 110 F., and add the whey protein concentrate, triso6iurn phosphate, and sodium hydroxide with stirring until they are dissolved in. the water.

3. Add the rest of the water, heat to 130~F., and then add the casein and antifoamer. ~eat the water gradually to 150F. with continual stirring. By that point, the casein should be in the sodium salt form and completely dissol~ed.

.
Add the calcium chloride solution.

5. Heat, cool, and szmple the medium as described in steps

6 to 8 o~ Example I.

EX~PLE V

A medium is prepared from whole m~lk, norlSat dry rnilk, and whey protein concentrate. Instead of whole milk, skimmilX
or partially skimmed milk m~y be used. The composition a~d preparation are se~ out below.

Composition.

Whole milk 1290 lbs.
Nonfat dry mllk 4 5 lbs.

Whey protein concen~rate (28-33~ protein) .100 lbs.
1435 lbs.

~E~
~. :.
.... .
1. Fill the cleaned and sa~itized starter tank with whole milk.

2~ Empty the dry ingredients into whole milk with the aid of powder fu~nel. The temperature at this stage should be around 100F.

3. Heat the medium to 170~F. and hold for 1 hour.

4. Cool the medi~m to 100 to 104F.

5. Samplës for determination of casein, whey protein, and total protein may be drawn before and after the heat treatment as in Example I.

EXAMæLE VI

A starter medium for making mozzarella cheese is ......
prepared from partially delactosed whey, nonfat dry milk, and calcium caseinate. The composition of the medium and its prepara~ion are se~ out below.

Composition: Puritein 25 67 lbs.

lo Nonfat Dry Milk 46 lbs.

Calcium Caseinate 45 lbsO
Water 1,160 lbs.
1,318 lbs.

Preparation:

1. Clean and sanitize the starter tank.
2. Fill the tank with about 2/3 of water.

3. Heat the water to 110F and then add rest of the ingredients.
4. Agitate thoroughly until the ingredients are thoroughly mixed.

5. Add rest of the water to make it up to a total of 1,318 lbs. of liquid medium.

6. Heat the medium to 190F and hold for 1 hour. The medium z should not show any sign of precipitation at this stage . ,,

7. Cool the medium to 101 to 105F.

8. Inoculate the medium with appropriate coccus and rod culture.

9. Incubate until pH drops to 5.35 - 0.05 and then start cooling the uncoagulated medium to 45F and hold until used for making mozzarella cheese. The medium is rennet coagulable.

~:~7~ 3 1 Puritein 25 is a whey product of Purity Cheese Company, Mayville, Wisconsin, which is prepared from sweet whey by removing part of the lactose and minerals and thereby increasing the protein content. A typical analysis is: protein 24-26~; lactose 50~53%; ash 13-15~; balance fat and moisture.
...
Instead of Puritein 25, Puritein 20 (Purity Cheese Company) can be used. This i5 a partially delactosed whey having as a typical analysis: protein 21-23%; lactose 49-51%;

lo ash 19-21%; balance fat and moistuxe.

All of the foregoing examples represent desirable modes of practicing the present invention. The formula selected as the preferred mode for a particular commercial use will depend on the availability and price of the ingre-dients. Media prepared according to the examples may be used to prepare starter cultures for many kinds of cheese, such as Mozzarella, Swiss, Cheddar, etc. The media may also be used for preparing added cultures for preparing Mozzarella "pizza cheese" as described in U.S. Patent 4,085,228. For example, a bulk starter culture prepared as described above in Example II for use in manufacturing Mozzarella cheese may be used in combination with an added culture using the medium of Example I and culturing Streptococcus durans ~, ...
therein, as described in the cited patent.

In practicing the present invention, it will be apparent to those skilled in the art that minor adjustments can be made where necessary to more completely achieve the objects of the invention. For example, if during the heating step the medium tends to coagulate, the casein ~7~L3 1 content can be increased and/or the total solids concentration can be decreased. Further, on completion of the fermentation, if desired a calcium salt, such as calcium chloride, can be added to the starter culture before it is charged to the cheese vat, thereby further promoting the rennet-coagulability o the znedi~n. In practicing the present invention in its . . .
- ~ preferred embodiments, however, such adjustments should rarely be necessary.

Claims (8)

1. THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR PRIVILEGEIS CLAIMED ARE DEFINED AS FOLLOWS:
   l. The method of making cheese from a starter culture medium characterized by the steps of:
   
   (a) forming an aqueous culture medium containing from 6 to 21 weight percent of protein-providing medium solids selected from the class consisting of (i) mixtures of whey solids and precipitated casein in the form of a water-dispersible casein salt or (ii) mixtures of whey solids and milk solids, or (iii) mixtures of whey solids, milk solids, and precipitated casein in the form of a water-dispersible casein salt, said whey solids having been prepared from whey by increasing the amount of whey protein in relation to lactose and containing at least 20% by weight of whey protein, said medium solids providing a weight ratio within the range from 0.4 to 5.0 parts of casein (casein basis) per part of total whey protein provided by said whey solids and said milk solids, the whey protein provided by said whey solids comprising at least 10% by weight of said medium solids;
   
   (b) heating said culture medium at a pH of from 5.6 to 6.9 to a temperature of about 160 to about 195°F for about 20 to about 90 minutes to cause the complexing of casein and whey protein without precipitating whey protein or coagulating the medium, said medium on completion of said heating being coagulable without containing added calcium or phosphate ions by addition of rennet at the rate of 3 ounces per 1000 pounds of medium with the medium at pH 6.2 and 92°F;
   
   (c) culturing harmless lactic acid-producing bacteria in the completed medium from step (b) to produce a bulk starter culture without coagulating said medium;
   and, thereafter, (d) using said bulk starter culture as a bacterial inoculant for milk in the manufacture of cheese by adding said bulk starter culture to cheese milk and coagulating the milk with rennet, whereby complexed whey protein and casein of the bulk starter culture coagulates with the milk protein to produce a curd-whey mixture which is substantially free of curd fines from the starter medium.
2. 2. The method of claim l further characterized in that said medium solids comprise a mixture of whey solids and precipitated casein in water-dispersible salt form.
3. 3. The method of claim 2 further characterized in that said precipitated casein is in the form of calcium or sodium caseinate.
4. 4. The method of claim 1 further characterized in that said medium solids comprise a mixture of whey solids and milk solids.
5. 5. The method of claim 1 further characterized in that said medium solids comprise a mixture of whey solids, milk solids, and precipitated casein in water-dispersible form.
6. 6. The method of claim 5 further characterized in that said precipitated casein is in the form of calcium or sodium caseinate.
7. 7. The method of claims 1 to 3 further characterized in that (i) said whey solids consist essentially of whey protein concentrate made from whey by ultrafiltration, (ii) said medium solids provide a weight ratio within the range from 0.9 to 3.5 parts of casein (casein basis) per part of total whey protein, (iii) said whey solids comprise at least 30% by weight of the total medium solids, and (iv) said aqueous culture medium contains from 12 to 18% by weight of total medium solids.
8. 8. The method of claims 4 to 6 further characterized in that (i) said whey solids consist essentially of whey protein concentrate made from whey by ultrafiltration, (ii) said medium solids provide a weight ratio within the range from 0.5 to 3.5 parts of casein (casein basis) per part of total whey protein, (iii) said whey solids comprise at least 30% by weight of the total medium solids and (iv) said aqueous culture medium contains from 12 to 18% by weight of total medium solids.