WO2011077739A1

WO2011077739A1 - Ice creams and method for producing same

Info

Publication number: WO2011077739A1
Application number: PCT/JP2010/007476
Authority: WO
Inventors: 中越誠; 小野田敏昭; 市場智子
Original assignee: 明治乳業株式会社
Priority date: 2009-12-25
Filing date: 2010-12-24
Publication date: 2011-06-30
Also published as: CN105767445B; CN102711507B; JPWO2011077739A1; CN102711507A; TW201130424A; JP5848611B2; HK1172797A1; JP2016063822A; HK1222299A1; TWI574627B; CN105767445A

Abstract

Provided is a method for producing ice creams which have high storage stability and excellent taste and can be easily scooped with a spoon. The method for producing ice creams comprises a desalting step, a step of adding an enzyme, a step of degrading lactose, and a cooling step. In the desalting step, a starting material, which contains 5-50 wt% inclusive of non-fat milk solids, is desalted. In the subsequent step of adding an enzyme, an enzyme capable of degrading lactose is added to the desalted material. In the step of degrading lactose, lactose contained in the material is degraded by the enzyme. In the final cooling step, the material having been treated in the lactose-degrading step is cooled. Thus, ice creams can be produced.

Description

Ice cream and method for producing the same

The present invention relates to ice creams obtained by degrading lactose contained in an ice cream mix using desalted and concentrated milk containing a large amount of protein in the ice cream mix, and a method for producing the same.

JP-A-7-67542 (Patent Document 1) discloses an ice cream using lactose and lactase as sweetening ingredients (paragraph [0037]). In this ice cream, lactose is broken down into glucose and galactose by lactase. Ice cream rich in monosaccharides excels in digestion and absorption, for example, causes no diarrhea even if eaten by a person with lactose intolerance. Lactose is broken down into glucose and galactose by lactase in the small intestine and absorbed into the body, but those with a low lactase secretion in the small intestine (people with lactose intolerance) cannot break down lactose, Therefore, lactose is not absorbed by the body and causes diarrhea.

JP 7-67542 A

On the other hand, since the ice cream disclosed in Japanese Patent Application Laid-Open No. 7-67542 contains a large amount of monosaccharides, when the temperature rises when storing (preserving) the ice cream, crystals of the ice cream grow, and flavor and food There is a problem that the feeling is impaired.

Therefore, an object of the present invention is to provide a method for producing ice cream having excellent storage stability, rich flavor, moderate softness, and good sag.

In the present invention, basically, lactose is decomposed using an enzyme to obtain ice creams having moderate softness and good sag. And in order to improve the storage stability of ice cream, the ice cream mix containing many nonfat milk solid content is used. On the other hand, when ice cream is produced using an ice cream mix containing a large amount of non-fat milk solids, the salty taste of the resulting ice cream becomes strong. Therefore, the present invention uses desalted and concentrated milk in the ice cream mix. In this way, the present invention provides a method for producing ice cream having excellent storage stability, rich flavor, moderate softness, and good sag.

The first aspect of the present invention relates to a method for producing ice creams. And the method of manufacturing this ice cream includes a desalting process, an enzyme addition process, a lactose decomposition process, and a cooling process.

The desalting step is a step for desalting a raw material containing non-fat milk solids in an amount of 5 wt% to 50 wt%. Thus, the quantity of the protein contained in an ice cream mix can be increased by using a raw material with many non-fat milk solid content. Thereby, the storage stability of ice cream can be improved. For this reason, in this invention, it is not necessary to add an emulsifier and a stabilizer. Therefore, if this method for producing ice creams is used, ice creams having excellent flavor can be produced.

The enzyme addition step is a step for adding an enzyme that decomposes lactose to the raw material that has undergone the desalting step. In this step, other raw materials may be added to the raw material that has undergone the desalting step, and then the enzyme may be added. The lactose decomposition step is a step in which the enzyme breaks down lactose contained in the raw material. A cooling process is a process of cooling the raw material which passed through the lactose decomposition process. This step may be a step of cooling the raw material after the desalting step, that is, a step of cooling the raw material before the enzyme addition step, or before the lactose decomposition step. It may be a step of cooling the raw materials.

In a preferred embodiment of the first aspect of the present invention, the cooling step is a step of cooling the ice cream mix prepared through the desalting step, the enzyme addition step, and the lactose decomposition step. This ice cream mix contains non-fat milk solids at 5 wt% or more and 40 wt% or less, and does not contain milk fat or contains milk fat at 25 wt% or less.

As demonstrated by the examples described later, according to the present invention, ice creams having a good flavor can be obtained even when a raw material containing a large amount of non-fat milk solids or an ice cream mix is used.

In a preferred embodiment of the first aspect of the present invention, the desalting step is a step in which the residual rate of sodium contained in the raw material is 35% to 80% (desalting rate is 20% to 65%). When ice cream is produced using a raw material containing a large amount of non-fat milk solids or an ice cream mix, the salty taste becomes strong. In this invention, in order to remove sodium and potassium by a desalting process, even if ice cream is manufactured using the raw material and ice cream mix which contain many nonfat milk solid content, the ice cream which has suitable salty taste is obtained. be able to.

In a preferred embodiment of the first aspect of the present invention, the desalting step includes a first nanofiltration treatment step, a dilution step, and a second nanofiltration treatment step. The first nanofiltration treatment step is a step of concentrating a raw material containing skim milk by a nanofiltration method to obtain nanofiltration concentrated skim milk. The dilution step is a step of diluting the nanofiltration concentrated skim milk obtained in the first nanofiltration treatment step to obtain nanofiltration skim milk. The second nanofiltration treatment step is a step of concentrating the nanofiltration skim milk obtained in the dilution step by the nanofiltration method to obtain desalted skimmilk.

This mode can also be used when raw material contains raw milk. On the other hand, this embodiment is preferably used when the raw material contains skim milk. As demonstrated by the examples described later, by using the production method of this aspect, the content of sodium or potassium can be effectively reduced while maintaining the nonfat milk solid content. In addition to the second nanofiltration treatment step, a third nanofiltration treatment step, a fourth nanofiltration treatment step, etc. may be provided, but the complexity of the process, the efficiency of desalination, the flavor of the product, etc. From this point of view, it is preferable to keep the second nanofiltration treatment step.

In a preferred embodiment of the first aspect of the present invention, the desalting step includes a first nanofiltration treatment step, a reverse osmosis treatment step, a desalted milk acquisition step, and a second nanofiltration treatment step. The first nanofiltration treatment step is a step of concentrating a raw material containing skim milk by a nanofiltration method to obtain nanofiltration concentrated skim milk. The reverse osmosis treatment step is a step of performing reverse osmosis treatment on the permeate obtained in the first nanofiltration treatment step to obtain a reverse osmosis membrane permeate. The desalted milk acquisition step is a step of obtaining the desalted milk by adding the nanofiltration concentrated skim milk obtained in the first nanofiltration treatment step, the reverse osmosis membrane permeate, and moisture. The second nanofiltration treatment step is a step in which the desalted milk obtained in the desalted milk acquisition step is concentrated by the nanofiltration method to obtain desalted skim milk.

In a preferred embodiment of the first aspect of the present invention, the desalting step includes a first nanofiltration treatment step, a reverse osmosis treatment step, a desalted milk acquisition step, and a second nanofiltration treatment step. The first nanofiltration treatment step is a step of concentrating the raw material by a nanofiltration method to obtain nanofiltration concentrated milk. The reverse permeation treatment step is a step of performing a reverse osmosis treatment on the permeate obtained in the first nanofiltration treatment step to obtain a reverse osmosis membrane permeate. The desalted milk acquisition step is a step of obtaining desalted milk by adding nanofiltration concentrated milk, reverse osmosis membrane permeate, and moisture. The second nanofiltration treatment step is a step in which the desalted milk obtained in the desalted milk acquisition step is concentrated by the nanofiltration method to obtain desalted skim milk.

In a preferred embodiment of the first aspect of the present invention, the enzyme added in the enzyme addition step is lactase. And lactase is added at 0.01 weight% or more and 0.1 weight% or less, when the raw material and ice cream mix which passed through the desalination process shall be 100 weight%.

Lactose decomposition rate increases as lactase addition amount increases. On the other hand, when lactase increases, the cost increases. When the added amount of lactase is the above-described added amount, ice creams having a good flavor can be obtained within an appropriate production time.

In a preferred embodiment of the first aspect of the present invention, the lactose decomposition step is a step in which lactose contained in the raw material subjected to the desalting step is decomposed at 30% to 100%. This is achieved, for example, by holding the raw material that has undergone the desalting step at a temperature of 0 ° C. or higher and 20 ° C. or lower for 2 hours or longer.

The method for producing ice cream of the present invention can be used by appropriately combining the various configurations described above or described below. Moreover, the manufacturing method of the ice cream of this invention contains not only what was described in this specification but what was suitably corrected in the range obvious to those skilled in the art.

The second aspect of the present invention relates to ice creams produced by any one of the above-described methods for producing ice creams. Examples of such ice creams are ice creams containing 4 to 15% by weight of milk protein and 1 to 10% by weight of lactose-derived glucose. These ice creams are excellent in storage stability, suitable for salty taste, rich in flavor, and are good for ice cream.

According to the present invention, it is possible to provide a method for producing ice cream having excellent storage stability, rich flavor, moderate softness, and good sag.

FIG. 1 is a process chart (flow chart) schematically showing the procedure of the method for producing ice creams of the present invention. FIG. 2 is a process diagram showing in detail the procedure for preparing the ice cream mix in step S100 of FIG. FIG. 3 is a diagram instead of a graph showing the relationship between the lactose decomposition rate and the reaction time when lactose in desalted milk is hydrolyzed by lactase. FIG. 4 is a process diagram showing in detail the procedure of an example of the desalted milk acquisition process in step S110 of FIG. FIG. 5 is a diagram replaced with a graph showing the measurement results of the hardness of the ice cream obtained in the examples. FIG. 6 is a diagram schematically showing an example of a procedure for obtaining desalted milk according to the desalted milk obtaining process (FIG. 4) according to the present invention.

The first aspect of the present invention relates to a method for producing ice creams. Ice cream is a general term for ice cream, ice milk, and lacto ice, as defined by a ministerial ordinance such as milk (a ministerial ordinance relating to ingredient standards of milk and dairy products). In addition, the example of ice cream contains milk solid content by at least 3 weight%.

The method of manufacturing ice creams is already known. In the present invention, ice creams can be produced by appropriately adopting conditions known to those skilled in the art using an already known ice cream production apparatus. And the method of manufacturing this ice cream basically includes a desalting step, an enzyme addition step, a lactose decomposition step, and a cooling step. Hereinafter, the method for producing ice cream will be described. The present invention is not limited to the following examples, and includes examples appropriately modified within the scope obvious to those skilled in the art from the examples described below.

FIG. 1 is a process chart (flow chart) schematically showing the procedure of a method for producing ice cream. According to the present invention, ice creams having a total milk solid content of 3% by weight or more (preferably ice creams containing non-fat milk solids (SNF) in an amount of 5% by weight or more and 40% by weight or less) from raw materials. Can be manufactured. This is because if the non-fat milk solid content (SNF) is 5% by weight or more, the effect of improving the flavor and physical properties of ice creams by the lactose decomposition process can be expected. And below, the case where ice cream is manufactured as ice cream is demonstrated.

Referring to FIG. 1, first, in step S100, an ice cream mix, which is an ice cream raw material milk, is prepared by blending a plurality of raw materials. Raw materials may contain raw milk, powdered milk, sugar, concentrated milk, desalted milk, and water as appropriate. This step is usually performed at room temperature or under heating (30 ° C. or more and 80 ° C. or less) in a plurality of apparatuses connected by pipes in order to prevent invasion of various bacteria. Details of the process in step S100 will be described in detail with reference to FIGS.

In the subsequent step S200, the ice cream mix solution prepared in step S100 is homogenized. For homogenization, first, if necessary, the ice cream mix solution is filtered to remove impurities. Then, for example, by using a homogenizer, the particle size of the fat in the ice cream mix is reduced to, for example, 2 μm or less at a temperature of 50 ° C. or higher and 70 ° C. or lower. Adjust. Thereafter, the ice cream mix whose particle size has been adjusted is heated to, for example, 68 ° C. or more and 75 ° C. or less, and held for 30 minutes to sterilize.

In step S300, the ice cream mix solution homogenized in step S200 is cooled to a temperature of 0 ° C. or higher and 5 ° C. or lower, for example. Here, the ice cream mix solution is not frozen and kept in a certain fluidity state.

In step S400, a known flavor (for example, vanilla flavor, chocolate flavor, strawberry flavor, cocoa flavor) is appropriately added to the ice cream mix solution in a cooled state. If no flavor is required, the process of step S400 is not performed. Moreover, when flavor is also added when preparing an ice cream mix at step S100, it is not necessary to perform the process of step S400.

Subsequently, in step S500, the ice cream mix is aged for a predetermined time. Aging is also performed at a temperature of 0 ° C to 5 ° C. By performing this aging, the fat is crystallized and the protein is hydrated to stabilize the ice cream mix.

Subsequently, freezing is performed on the ice cream mix that has been subjected to the aging process (step S600). Freezing is performed, for example, by stirring the ice cream mix for a predetermined period at a temperature of −2 ° C. to −10 ° C. This freezing cools the ice cream mix and freezes the moisture.

Then, the freezing ice cream mix is packaged (step S700). This packaging process is also performed under the same temperature as the above-mentioned freezing temperature. In addition, the date of manufacture is stamped on the container as necessary.

Finally, the ice cream mix in the shipping container is rapidly frozen to a temperature in the range of, for example, −3 ° C. to −15 ° C. by exposing it to a curing temperature of, for example, −18 ° C. or less. (Step S800). This freezes (hardens) the entire ice cream mix.

As described above, the manufacture of ice cream ready for shipment is completed. In addition, necessary inspections are performed after the completion of production and before shipment. In addition, it is preferable to store (preserve) the produced ice cream at a temperature of −25 ° C. or lower. Ice milk and lacto ice can be produced in the same manner as ice cream.

Next, the preparation of the ice cream mix in step S100 of FIG. 1 will be described in detail.

FIG. 2 is a process diagram showing in detail the preparation procedure of the ice cream mix in step S100 of FIG. In this embodiment, an example of preparing an ice cream mix from raw milk will be described.

In FIG. 2, first, in step S110, desalted milk is obtained by subjecting the raw material to desalination. For example, when desalting is performed by preparing concentrated milk using raw milk as a raw material, desalted concentrated milk is obtained. This ensures stable ice cream quality and physical properties without the use of stabilizers or emulsifiers. The process of step S110 will be described in detail later with reference to FIGS. The desalted milk may be liquid or powdered (milk powder). In addition, desalted concentrated milk may be prepared using concentrated milk in advance instead of raw milk.

Subsequently, in step S120, sugar is added to the desalted milk (sweetening treatment). Examples of the sugar content include sugar (sucrose), lactose, glucose, fructose and the like, which may be liquid or powder. Here, an example of the added sugar content may be a polysaccharide (for example, starch, fructose, glucose, cellulose, dextrin), but preferably an oligosaccharide, more preferably a disaccharide ( For example, maltose (maltose), cellobiose, sucrose, lactose (lactose), trehalose). This is to promote hydrolysis by an enzyme (glycosidase) described later. Of the disaccharides, lactose (lactose) or trehalose is preferable. In addition, when addition of sugar is not necessary, the process of step S120 is not performed. Step S120 may be performed after the enzyme is added or may be performed before the enzyme is added.

And in step S130, an enzyme is added to desalted milk. If the desalted milk is milk powder, add the enzyme after adding the liquid to the milk powder. As a raw material to which an enzyme is added, a raw material that has undergone a desalting treatment may be used as it is. In addition, the raw material to which the enzyme is added may be used by mixing several types of desalting treatments or those that have not undergone desalting treatment, or by repeating the same type of desalting treatment. It may be used. As an example of the enzyme, an enzyme (glycosidase) corresponding to the sugar contained in the desalted milk in step S110 or the sugar added in step S120 is used. A glycosidase is an enzyme capable of decomposing a corresponding saccharide (a saccharide having a monosaccharide as a structural unit) into a saccharide composed of a smaller number of monosaccharides. For example, lactase is used for lactose. For trehalose, trehalase is used. Lactase and trehalase may be derived from bacteria or yeast. Since lactose is also contained in desalted milk, the enzyme preferably contains at least lactase.

Lactase, also called β-D-galactosidase (β-D-galactoside galactohydrolase), is an enzyme that hydrolyzes the disaccharide lactose into glucose and galactose. As the lactase, for example, those disclosed in JP-T-10-504449 can be appropriately used. Lactase is preferably added in an amount of 0.01% by weight to 0.1% by weight, assuming that the raw material and ice cream mix are 100% by weight. As the amount of lactase added increases, the rate of lactose degradation increases. When adding lactase to a raw material that has undergone desalting, the results of an experiment have found that if the content of lactase is high, the flavor of ice cream is impaired. Therefore, the amount of lactase added is preferably 0.01% by weight or more and 0.08% by weight or less, more preferably 0.02% by weight or more and 0.07% by weight or less, and 0.03% by weight or more and 0.05% by weight or less. % Or less is more preferable. When the addition amount is as described above, ice cream having a good flavor can be obtained within an appropriate production time.

Subsequently, in step S140, the hydrolysis reaction is accelerated by placing the desalted milk containing the enzyme under predetermined conditions. That is, the enzyme breaks down lactose contained in the raw material and ice cream mix. The conditions for this lactose decomposition reaction will be described later. In this step, lactose contained in the raw material and ice cream mix is decomposed at, for example, 30% to 100%.

Thus, the preparation of the raw materials and ice cream mix is completed. As needed, you may concentrate the raw material and ice cream mix obtained after the process of step S140. The raw material and ice cream mix may be powdered by spray drying or the like. Moreover, cream (part rich in milk fat), other powdered milk or its reducing solution, flavor, sweetened egg yolk, water, etc. may be added to the raw material and ice cream mix as necessary.

2, sugars such as lactose contained in the desalted milk are hydrolyzed (step S140). Thereby, since the number of molecules of the saccharide contained in the ice cream mix increases, the sweetness of the manufactured ice cream can be increased. Although the sweetness level differs depending on the type of saccharide, the sweetness of the ice cream mix can be increased by increasing the number of saccharide molecules before hydrolysis even when the saccharides have low sweetness. Can do. In addition, by increasing the number of molecules of monosaccharides, the softness of the ice creams to be produced can be increased moderately, and the saji street can be improved.

For example, lactose is hydrolyzed and converted into glucose (glucose) and galactose. In this case, if the lactose decomposition rate indicating the lactose decomposition rate is 100%, the sweetness after hydrolysis is several times that before hydrolysis. In addition, when one molecule of lactose is decomposed, two molecules of monosaccharide are produced, so that the number of molecules of monosaccharide can be increased efficiently. As a result, the softness of the ice creams produced Can be increased efficiently.

FIG. 3 is a diagram replaced with a graph showing a relationship between a lactose decomposition rate when lactose in desalted milk is hydrolyzed by lactase in step S130 and a reaction time (time of lactose decomposition step). In the example shown in FIG. 3, the amount of lactase added is constant, and the relationship between the lactose decomposition rate and the reaction time when the temperature of the desalted milk when the lactose decomposition reaction is performed is 1 ° C., 5 ° C., and 10 ° C. It is shown.

As can be seen from FIG. 3, the lactose decomposition rate can be increased by increasing the reaction time of the lactose decomposition reaction. Therefore, it is preferable that the reaction time of the lactose decomposition reaction is long. On the other hand, when the reaction time is lengthened, the lactose decomposition rate can be brought close to 100% or can be made 100%, but the production efficiency is deteriorated. Therefore, from the viewpoint of production efficiency, the upper limit of the reaction time of the lactose decomposition reaction is, for example, 50 hours, and preferably the reaction time when the lactose decomposition rate exceeds 90% (24 hours in the example shown in FIG. 3). ).

The lower limit of the reaction time of the lactose decomposition reaction is, for example, 2 hours. Thereby, a lactose decomposition rate can be ensured to 30%, and the sweetness degree of the ice cream manufactured can be made high reliably. However, as can be seen from FIG. 3, when the reaction time is short, the lactose decomposition rate tends to fluctuate greatly. Therefore, when ice creams are produced in large quantities by batch processing, a certain lactose decomposition rate is ensured. Is difficult. Therefore, in order to ensure a substantially constant lactose decomposition rate (for example, within an error of 5%), the reaction time when the lactose decomposition rate exceeds 90% (24 hours in the example shown in FIG. 3). Is preferably set. In order to ensure a substantially constant lactose decomposition rate, an inhibitor (for example, acarbose, voglibose) for suppressing the hydrolysis reaction may be used. By using an inhibitor, a substantially constant lactose decomposition rate can be secured, and as a result, the quality of ice creams produced in large quantities by batch processing can be made constant.

In addition, as can be seen from FIG. 3, when the reaction time is the same, the higher the temperature during the lactose decomposition reaction, the higher the lactose decomposition rate. Therefore, it is preferable that the temperature when the lactose decomposition reaction is performed is high. On the other hand, bacteria usually tend to grow at temperatures exceeding 20 ° C. For this reason, the enzyme is generally maintained at a temperature of about 5 ° C. to 10 ° C. Therefore, from the viewpoint of suppressing bacterial growth, it is preferably 0 ° C. or higher and 15 ° C. or lower, and from the viewpoint of preventing bacterial growth, 0 ° C. or higher and 10 ° C. or lower is preferable. On the other hand, in the present invention, it has been found through experiments that the flavor of ice cream obtained by decomposing lactose at a temperature of 5 ° C. or higher becomes mellow. For this reason, the temperature in the lactose decomposition step is preferably 5 ° C. or higher and 20 ° C. or lower, more preferably 6 ° C. or higher and 15 ° C. or lower, and further preferably 7 ° C. or higher and 10 ° C. or lower.

In the case of degrading lactose, lactase is 0.01% to 0.10% by weight, preferably 0.01% to 0.08% by weight, more preferably 0.02%, based on the total amount of desalted milk. Added in the range of 0.03 wt% to 0.07 wt%, more preferably in the range of 0.03 wt% to 0.05 wt%, under refrigerated conditions where lactose decomposition is in the range of 0 ° C to 10 ° C. , Preferably for a reaction time in the range of 2 hours to 50 hours. Thereby, lactose decomposition rate can be 50% or more. Even when the sugar content is not lactose, the same argument as lactase can be applied by using the corresponding glycosidase (for example, trehalase, amylase, sucrase, maltase).

In the above-described embodiment, raw milk (milk that has been extracted) is exemplified as the raw material of desalted milk, but as cow's milk, component-adjusted milk, low-fat milk, non-fat milk, processed milk, Those milk powders may be sufficient. The raw material of desalted milk is not limited to cow milk, and may be goat milk, noodle sheep milk, or the like. However, raw milk is preferable as a raw material for desalted milk, and milk powder is preferable because it can be easily stored (preserved). The raw material of the desalted milk may be a known ice cream mix.

Next, a process for obtaining desalted milk (desalted concentrated milk) desalted by adjusting the raw materials will be described. In this step, basically, a raw material containing non-fat milk solids in an amount of 5 wt% to 50 wt% is desalted. The raw material in the desalting step preferably contains non-fat milk solids in an amount of 5 wt% to 40 wt%, and the non-fat milk solids is contained in an amount of 7 wt% to 35 wt% (eg, 13 wt% to 30 wt%). % Or less) is more preferable. An example of the desalting step is a step in which the residual rate of sodium contained in the raw material is 35% or more and 80% or less. In the desalting step, a preferable example is a method in which the residual ratio of sodium contained in the raw material is 40% or more and 75% or less, and a more preferable example is a residual ratio of sodium contained in the raw material of 45% or more and 70%. More preferable examples are those in which the residual ratio of sodium contained in the raw material is 50% or more and 65% or less. Thus, since a desalination rate is high, many nonfat milk solid content can be included in a raw material. For this reason, for example, in this invention, many skim milk powder can also be included in a raw material. On the other hand, as a result of experiments, it was found that if the desalination rate is increased too much, the body becomes weaker. For this reason, the desalination rate is preferably within the above range.

In the desalting step, for example, a nanofiltration (NF) method, a diafiltration (DF) method, an ion exchange resin (IE) method, and an electrodialysis (ED) method can be used alone or in combination.

The nanofiltration method uses, for example, a membrane filter (NF membrane) having nano-sized through-holes (for example, a pore diameter of 0.5 to 2 nm), feeds raw milk into this NF membrane, and penetrates. Filtration using pressure. The nanofiltration membrane is a membrane that mainly transmits monovalent ions and water. Therefore, in the present invention, for example, monovalent cations (sodium ions, potassium ions, chloride ions) can be removed. For this reason, desalting which removes sodium and potassium can be performed by using the nanofiltration method.

Examples of nanofiltration (NF) membrane materials are polyamide, cellulose acetate, polyethersulfone, polyester, polyimide, vinyl polymer, polyolefin, polysulfone, regenerated cellulose, and polycarbonate. In the present invention, polyamide, cellulose acetate, and polyethersulfone are preferred as materials for the nanofiltration (NF) membrane in order to remove salt. Examples of nanofiltration (NF) membrane shapes are flat membranes, spiral membranes, hollow fiber membranes, plate membranes, and tubular membranes. Moreover, the well-known conditions of a well-known filtration method are employable as a nano filtration method. Examples of the filtration method are a pressure filtration method and a vacuum filtration method. An example of the NF film is an NF film (trade name “NF-3838 / 30-FF”) manufactured by Dow Chemical. Further, there are dead end filtration methods and cross flow filtration methods as types of filtration methods. Here, since the production of ice creams is industrially performed in a batch process, it is preferable to use the cross flow method, whereby the ice produced can be produced while suppressing variations caused by clogging of the filtration membrane. The quality of creams can be kept constant.

And by this nanofiltration method, a retentate and a permeate can be obtained from raw milk. The ratio of the amount of retentate and the amount of permeate varies depending on the osmotic pressure for the NF membrane used. Usually, the total solid content (TS: total-solids) of raw milk is concentrated in the retentate within a range of 1.5 to 2.5 times (for example, 1.6 times).

In the retentate obtained by the nanofiltration method, the total solid content (TS) of raw material milk, that is, milk fat (FAT) and non-fat milk solid content (SNF) are concentrated. Therefore, in this specification, the concentrate obtained by the nanofiltration method is also referred to as nanofiltration concentrated milk. The permeate obtained by the nanofiltration method contains much of the moisture in the raw milk and part of the water-soluble components (especially monovalent ions), while the total solid content of the raw milk is , Almost no inclusion. Here, the water-soluble component of raw milk is ash. Ash is an inorganic substance such as sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), chlorine (Cl), phosphorus (S), and vitamins such as vitamin A, B1, B2, and niacin. It is a generic name.

It is a preferable aspect of the present invention to add an electrolyte that does not permeate nanofiltration to the raw material before performing the nanofiltration treatment. Desalination can be promoted by adding an electrolyte that does not permeate nanofiltration. Examples of electrolytes that do not permeate the nanofiltration membrane include milk fat, milk casein, whey protein, lactose, and some non-protein nitrogen (NPN). As will be described later, it is preferable to add a filtration retentate to the raw material because desalting can be promoted.

In the diafiltration (DF) method, water is added to milk that has been filtered and concentrated (retentate) to dilute it, and after the volume of the filtrate (retentate) is returned to the volume before filtration, filtration is performed. How to do it. An example of the DF method of the present invention is a method in which water is added to milk concentrated by filtration through an NF membrane and then filtered through an NF membrane.

The ion exchange resin (IE) method is a method of desalting by bringing a raw material and an ion exchange resin into contact with each other. As the ion exchange resin, a commercially available anion exchange resin and cation exchange resin which are usually used for the purpose of desalting may be used. Desalination using an ion exchange resin may be performed according to known conditions using known operations and equipment.

Electrodialysis (ED) is a separation technique that utilizes electrophoresis of ionic substances in a solution and the property that an ion exchange membrane selectively permeates cations and anions. Desalination using the electrodialysis (ED) method may be performed according to known conditions using known operations and devices.

In the desalting step, salts other than sodium may be removed. On the other hand, in the desalting step, it is preferable to remove the sodium salt or potassium salt without damaging the calcium salt. The residual ratio of the calcium salt after the desalting step is preferably 80% by weight or more, more preferably 90% by weight or more, and further preferably 95% by weight or more.

Next, the case where the desalting process in step S110 of FIG. 2 is diafiltration (DF) (first mode) will be described in detail.

FIG. 4 is a process diagram showing in detail the procedure of an example of the desalted milk acquisition process in step S110 of FIG. In this embodiment, a case where desalted milk (particularly desalted concentrated milk) is prepared from raw milk will be described. In addition, as above-mentioned, the raw material of desalted milk is not restricted to raw milk.

In FIG. 4, first, in step S111, raw milk is prepared as a raw material for desalted milk. The total solid content (TS) of raw milk is, for example, 12.8% by weight, and the breakdown is 3.8% by weight of milk fat (FAT: milk fat) and 9.0% by weight of non-fat milk solids. Minute (SNF). In addition, as raw material milk, the aqueous solution (reduced milk) of milk powder (for example, skim milk powder) may be used, and a well-known ice cream mix may be used.

In subsequent step S112, the first nanofiltration (NF) treatment is performed on the raw material by the nanofiltration method. In the nanofiltration treatment, for example, an NF membrane manufactured by Dow Chemical (trade name “NF-3838 / 30-FF”) is used as the NF membrane.

And by this nanofiltration treatment, a retentate (retentate) and a permeate (permeate) are obtained from the raw material. Here, when the NF membrane manufactured by Dow Chemical is used, when the flow rate per unit time of the raw material during the first nanofiltration treatment by the cross flow method is 14 t / h, for example, Almost the same amount (7 t / h) can be obtained with the permeate. Although the ratio of the amount of the retentate and the amount of the permeate varies depending on the osmotic pressure for the NF membrane to be used, the retentate usually has a total solid content (TS) of 1.5 to 2 times. Concentrate within 5X range (eg 2.0X).

In the retentate (nanofiltered concentrated milk) obtained by the nanofiltration method, the total solids (TS) of the raw material, that is, milk fat (FAT) and nonfat milk solids (SNF) are concentrated. . The permeate obtained by the nanofiltration method contains much of the raw material water and a part of the water-soluble components, but contains almost no total solid content of the raw material milk. It becomes. Here, the permeate obtained by the nanofiltration method contains sodium (Na), potassium (K), chlorine (Cl), and the like.

In step S113, reverse osmosis (RO) treatment is performed on the permeate obtained by the nanofiltration method to obtain a permeate (hereinafter also referred to as reverse osmosis membrane permeate). Note that the reverse osmosis treatment retentate is not used in this embodiment.

The reverse osmosis treatment uses, for example, a membrane-like filter (reverse osmosis membrane) that captures monovalent cations, and the permeate obtained by the nanofiltration method in step S112 is input to this reverse osmosis membrane, This is performed by applying pressure from the upstream side of the reverse osmosis membrane (the permeate input side obtained by the nanofiltration method in step S112). In the reverse osmosis treatment, the downstream side of the reverse osmosis membrane may be decompressed instead of applying pressure from the upstream side of the reverse osmosis membrane. In the reverse osmosis treatment, since a pressure higher than the osmotic pressure is used, most of the permeate obtained by the nanofiltration method in step S112 passes through the reverse osmosis membrane and becomes the RO permeate. In the reverse osmosis membrane retentate (the portion that did not pass through the reverse osmosis membrane), sodium ions and potassium ions contained in the permeate obtained by the nanofiltration method in step S112 as monovalent cations. Etc. are concentrated. In other words, performing reverse osmosis treatment on the permeate obtained by the nanofiltration method in step S112 is an example of desalting treatment. Therefore, in this specification, the reverse osmosis membrane permeate is also referred to as demineralized water.

Subsequently, in steps S114 to S115, a dilution process is performed. Specifically, first, in step S114, the desalted water obtained in step S113 is added (returned) to the nanofiltration concentrated milk obtained in step S112. Thereby, desalted milk is obtained as a mixed solution. Here, since the amount of the permeate obtained by the nanofiltration method in step S112 and the amount of the reverse osmosis membrane permeate are substantially the same, the amount of desalted milk is equal to the amount of the raw material prepared in step S111. It is almost the same. Therefore, this desalted milk contains almost the same amount of total solids (FAT and SNF) as the nanofiltration concentrated milk, and almost the same amount of ash as the nanofiltration concentrated milk. In other words, this desalted milk is desalted concentrated milk from which all of the solid content of the raw material has been concentrated while removing a part of sodium and potassium that are the source of salty taste.

In step S115, water is added to the desalted milk as necessary (hydrolysis). As water to be added, distilled water or tap water can be used, but it is preferable to use tap water in consideration of the point that it can be easily obtained and sterilized at a later stage. In addition, you may add water to the nanofiltration concentrated milk or reverse osmosis membrane permeate (hydrolysis). By doing in this way, the amount of desalted milk can be aligned with the amount of raw material. And by adjusting the amount of desalted milk to the amount of raw material, the amount of liquid flowing through the production line can be made constant. Note that step S115 need not be performed.

In step S116, the obtained desalted milk is subjected to the second nanofiltration treatment by the nanofiltration method. In this nanofiltration treatment, a retentate is obtained. This retentate can be said to be a concentrated desalted milk obtained by further concentrating the total solid content of the desalted milk and further desalting the desalted milk.

Moreover, the permeate obtained by this nanofiltration method contains water-soluble components (especially sodium and potassium) in desalted milk. Therefore, one retentate is less salty than desalted milk. In this embodiment, using this, the sodium content in the retentate is within the range of 35% to 80% (preferably 40% to 75%) of the sodium content in the raw material used in step S111. In the range of 45% to 70%, more preferably in the range of 50% to 65%. Similarly, in the retentate, the potassium content is 35% to 80% (preferably within the range of 40% to 75%, more preferably 45% to 70%) of the potassium content of the raw milk. Within a range, more preferably within a range of 50% to 65%.

In other words, by performing the process of step S116, the desalination rate of the retentate is within the range of 20% to 65% (preferably within the range of 25% to 60%, more preferably within the range of 30% to 55%. , More preferably within the range of 35% to 50%). By doing in this way, the salty taste of manufactured ice cream can be adjusted, and it can prevent reliably that the flavor of ice cream is impaired. Here, when the desalination rate exceeds the upper limit of the above range, the manufactured ice cream has a light flavor and weakness. On the other hand, if the desalination rate is below the lower limit of the above range, the ice creams produced will have a salty taste that will impair the flavor.

In addition, it is preferable to adjust the desalination rate to be within the above range by changing (or selecting appropriately) the NF membrane (that is, osmotic pressure) used in the second nanofiltration treatment. Instead, the desalination rate may be adjusted to be within the above range by performing the third nanofiltration treatment on the retentate. In this way, a plurality of nanofiltration (ie, diafiltration) processes are completed.

Furthermore, in step S117, desalted concentrated skim milk is obtained by removing the cream from the desalted concentrated milk obtained in step S116. Cream means the fat-rich portion of raw milk (here, desalted and concentrated milk). In order to remove the cream, for example, desalted and concentrated milk may be set in a centrifuge (separator) and centrifuged, and the separated cream may be collected by filtration. By doing in this way, desalted and concentrated milk can be changed to a low fat type (hereinafter also referred to as DF desalted skim milk). That is, the content (content ratio) of milk fat (FAT) can be greatly reduced without greatly reducing the content (content ratio) of non-fat milk solids (SNF) contained in the desalted and concentrated milk. . As a result, milk fat globule aggregation (churning) can be made difficult to occur. And it can prevent that variation arises in the quality of the ice cream manufactured by making it difficult to cause churning.

Thereafter, in step S118, the DF demineralized skim milk obtained in step S117 is further concentrated to obtain DF demineralized degreased concentrated milk. Specifically, DF demineralized skim milk is evaporated to evaporate the moisture of the DF demineralized skim milk to obtain DF demineralized skim concentrated milk. This concentration can be performed, for example, by heating the DF desalted skim milk under reduced pressure using a vacuum evaporator (evaporator). Furthermore, in step S119, DF demineralized skim milk powder is obtained by spray-drying the DF demineralized degreased concentrated milk using a known spray dryer as necessary. By using DF desalted nonfat dry milk, the volume (capacity) can be minimized, and storage (preservation) can be facilitated. Note that one or both of step S118 and step S119 need not be performed.

According to the process of FIG. 4, the nanofiltration process is performed a plurality of times on the raw material (steps S112 and S116). Further, reverse osmosis treatment is performed, and the obtained reverse osmosis membrane permeate is returned to the nanofiltration concentrated milk obtained from the raw material (steps S113 to S114). By these, the desalted milk which adjusted the desalination rate can be obtained. Further, since the reverse osmosis membrane permeate is returned to the nanofiltration concentrated milk (step S114), the components contained in the raw material can be effectively used without waste.

Moreover, according to the process of FIG. 4, a cream is removed from desalted milk (step S117). Thereby, even if it is low fat, the desalinated milk with high content of non-fat milk solid content (SNF) and protein can be obtained from raw materials, such as raw milk. And in this aspect, since the desalination rate is adjusted as mentioned above, even if ice cream is manufactured using desalted milk having a high protein content, the salty taste of the manufactured ice cream Is never too high. Moreover, in this ice cream, since the content rate of non-fat milk solid content (SNF) and protein is high even if it is low fat, a milk flavor is not impaired. By the way, ice cream with a high milk fat content (premium ice cream) is commercially available, but the ice cream according to this embodiment is differentiated from such ice cream in that the milk fat content is low. Can be achieved.

Next, a second example (second aspect) of the desalted milk acquisition process in step S110 of FIG. 2 will be described in detail. The second aspect is different from the first aspect only in that the reverse osmosis treatment as described above is not performed and water is added to the nanofiltration concentrate obtained by the first nanofiltration instead of demineralized water. It is. Therefore, detailed processing is omitted.

In the second embodiment, the nanofiltration treatment is performed at least twice (that is, the diafiltration (DF) treatment described above is performed). By the single nanofiltration treatment, the sodium content (content ratio) of the desalted milk is reduced within a range of, for example, 14% to 24% compared to the raw milk. Therefore, if the nanofiltration treatment is performed twice, in principle, the sodium content (content ratio) of the desalted milk will fall within a range of 26% to 42%, for example, compared to the raw milk. Become. That is, by performing the nanofiltration treatment twice, the residual rate of sodium in the desalted milk falls within the range of, for example, 58% to 74%, so that the desalting rate is as described above (20% to 65%). The possibility of being within the range (preferably within the range of 25% to 60%, more preferably within the range of 30% to 55%, and even more preferably within the range of 35% to 50%) can be increased. Thereby, the salty taste of manufactured ice cream can be adjusted, and it can prevent that the flavor of ice cream is impaired. On the other hand, if the nanofiltration treatment is performed many times, the desalination rate will be out of the above range. Therefore, the maximum number of nanofiltration treatments is 3 to 4 times. However, from the viewpoint of complexity of the process, desalting efficiency, product flavor, and the like, it is preferable to keep in the second nanofiltration treatment process. In addition, when comparing the sodium content and the desalting rate, it is preferable to convert the total solid content (TS) so that the content (content ratio) is the same (see Table 4b described later).

Next, a third example (third aspect) of the desalted milk acquisition process in step S110 of FIG. 2 will be described in detail. The third mode is different from the first mode and the second mode only in that the raw material is concentrated and desalted by an ion exchange resin (IE) method or an electrodialysis (ED) method instead of the nanofiltration treatment. It is. Therefore, detailed processing is omitted.

In the third aspect, even if there is no facility for performing the nanofiltration treatment, the same effect as the first aspect and the second aspect can be obtained. However, since the equipment for performing the nanofiltration treatment is low-cost, it is preferable to prepare the desalted milk according to the first aspect and the second aspect. In addition, in this invention, since it aims at the concentration and desalination of the total solid or non-fat milk solid content of raw material milk, an ultrafiltration process (UF: ultrafiltration) and a microfiltration process (MF: microfiltration) are not performed. . In this embodiment, the ion exchange resin (IE) method and the electrodialysis (ED) method may be executed a plurality of times, or at least one of the plurality of times may be executed by the nanofiltration method.

In the fourth aspect of the present invention, the desalted milk obtained in at least two of the first to third aspects is mixed with each other, and the prepared desalted milk is used as part or all of the raw material for ice cream. It is a kind of manufacturing. Also according to this aspect, the effect according to the corresponding aspect can be produced.

As described in detail above, according to the present invention, the total solid content of raw milk is concentrated and desalted by nanofiltration or reverse osmosis, and ice creams are stored under freezing. In addition to enhancing the sweetness, the enzyme enhances the sweetness of the ice cream and ensures moderate softness. Therefore, according to the present invention, ice creams can be manufactured with a simple manufacturing process and at low cost. In addition, according to the present invention, an ice cream made from desalted milk having a high total solid content (particularly non-fat milk solid content and protein), a high desalting rate, and a high sweetness as a raw material. Since the cream mix is prepared, by using the ice cream mix as a raw material, it is possible to produce ice creams that are soft, high in sweetness, and rich in flavor. The ice creams produced in this way have a good texture (tactile texture) because the growth of ice crystals and lactose crystals during frozen storage is suppressed, and the ice creams are preserved under freezing. In addition, it is reasonably soft, so the streets of Saji are good, and since the salty taste is suppressed, the flavor is not impaired, and because it is rich in protein, it is milky. The flavor is rich.

Therefore, in the production of the ice cream according to the present invention, it is possible to eliminate the addition of an excessive sugar content and the addition of an emulsifier and a stabilizer. Note that an emulsifier and a stabilizer may be added to the raw material, but even in that case, the ratio of the emulsifier and the stabilizer to the raw material may be lower than in the conventional case. Furthermore, milk fat can be significantly reduced by increasing the solid content of non-fat milk in ice creams to ensure a milk flavor. Therefore, in the production of ice creams according to the present invention, flavor (fragrance) is added to compensate for the milk flavor damaged by the reduction of milk fat, as in the production of conventional low fat ice creams. It is not necessary to add dextrin or dietary fiber, which is a substitute for milk fat, and even if it is added, it can be reduced compared to the conventional case.

Moreover, according to the above-described invention, ice creams having various contents can be manufactured by appropriately changing the composition of the ice cream mix. For example, the milk fat content (FAT) is 0% to 25% by weight (preferably 0% to 20% by weight, more preferably 0% to 18% by weight, and still more preferably 0% to 15% by weight). %), Non-fat milk solids (SNF) 5 wt% to 40 wt% (preferably 7 wt% to 35 wt%, more preferably 13 wt% to 30 wt%, and even more preferably 15 wt% ˜25% by weight) ice creams can be produced. The upper limit of the nonfat milk solid content of the produced ice cream may be 50% by weight. On the other hand, conventionally, if the content ratio of non-fat milk solids is increased, only ice creams with a strong salty taste and impaired flavor can be produced. It was necessary to suppress the content to 5 to 10% by weight. According to the present invention, it is possible to produce ice creams having a higher content of non-fat milk solids than before (for example, 2 to 5 times higher than before). Examples of ice creams according to the present invention are milk protein derived from 4% to 15% by weight (preferably 4% to 13% by weight, more preferably 4% to 11% by weight), derived from lactose Of 1 to 10% by weight (preferably 1.5 to 9% by weight, more preferably 2 to 8% by weight). These ice creams are excellent in storage stability, suitable for salty taste, rich in flavor, have moderate softness, and have good softness.

In Example 1, in order to confirm whether or not the object can be achieved by the production method of the present invention, DF desalted skim milk powder prepared according to the diafiltration (DF) method (second aspect described above) was used. The flavor and physical properties of the ice cream produced in this way were examined (Production Examples 1, 2, and 5). Specifically, the growth of ice crystals was evaluated by measuring the size of ice crystals produced in the produced ice cream and comparing the measured values. Moreover, the softness (goodness of a saji) was evaluated by measuring the hardness of the produced ice cream. Furthermore, the saltiness, sweetness and milk flavor of the produced ice cream were evaluated. Furthermore, in Example 1, the flavor and physical properties of the ice cream produced using an ice cream mix prepared without performing the nanofiltration (NF) method were also examined (Production Examples 3 and 4).

DF desalted skim milk powder was prepared as follows. First, skim milk (solid content concentration: about 9% by weight) was concentrated by nanofiltration (NF) method until the solid content concentration became about 20% by weight and desalted to obtain NF concentrated skim milk. At this time, NF-3838 / 30-FF (manufactured by Dow Chemical) was used as a nanofiltration (NF) membrane. Next, NF skim milk was obtained by adding water to NF concentrated skim milk so that the solid concentration was about 10% by weight. Next, NF skim milk was concentrated and desalted by a nanofiltration (NF) method until the solid content concentration was about 20% by weight to obtain DF desalted concentrated skim milk. In this case, NF-3838 / 30-FF (manufactured by Dow Chemical) was used as the nanofiltration (NF) membrane. Next, DF desalted and concentrated skim milk was sterilized, concentrated by vacuum evaporation, and spray-dried according to conventional methods. In this way, DF desalted skim milk powder was obtained. The resulting DF desalted skim milk powder contained about 1% by weight milk fat and about 95% by weight nonfat milk solids.

(Production Example 1)
The ice cream of Production Example 1 was produced using DF desalted skim milk powder containing about 1% by weight of milk fat and about 95% by weight of nonfat milk solids. During the production of ice cream, lactose contained in DF desalted skim milk powder was degraded at 56% by lactase (trade name “GODO-YNL”, manufactured by Godo Shusei Co., Ltd.) (that is, the lactose degradation rate was 56%).

(Production Example 2)
Using the same DF desalted skim milk powder as in Production Example 1, the ice cream of Production Example 2 was produced under the same conditions as in Production Example 1. During the production of ice cream, lactose contained in DF desalted skim milk powder was degraded by lactase at 84% (that is, lactose degradation rate was 84%).

(Production Example 3)
The ice cream of Production Example 3 was produced under the same conditions as in Production Example 1 using an ice cream mix containing 15% by weight of milk fat and 10% by weight of nonfat milk solids. However, this ice cream mix is not subjected to nanofiltration treatment. Furthermore, in Production Example 3, lactase was not added to the ice cream mix, but the same reaction time was maintained in the lactose decomposition step in order to achieve the same conditions as in Production Example 1. The lactose decomposition rate of the ice cream of Production Example 3 was 0%.

(Production Example 4)
The ice cream of Production Example 4 was produced under the same conditions as in Production Example 1 using the same ice cream mix as in Production Example 3 except that lactase was added. Lactose contained in the ice cream mix was degraded by lactase at 85% (that is, lactose degradation rate was 85%).

(Production Example 5)
Except that lactase was not added to the ice cream mix, the ice cream of Production Example 5 was produced under the same conditions as in Production Example 1 using the same DF demineralized skim milk powder as in Production Example 2. The lactose decomposition rate of the ice cream of Production Example 5 was 0%.

The results of hardness measured for Production Examples 1 to 3 and 5 described above are shown in Table 1 and FIG. For the hardness measurement, a rheometer (trade name “EZ-test-100N”) manufactured by Shimadzu Corporation was used, and the stress value [gf / mm ² ] measured at the set penetration distance [mm] was calculated. The measured value of hardness was used. Table 2 shows the evaluation results of the flavors and physical properties of Production Examples 1 to 5.

The ice crystals [μm] shown in Table 2 are the dimensions measured after storing the ice cream according to each production example for 1 week under freezing at −8 ° C. The dimensions of the ice crystals before storage are as follows: All were 30 micrometers.

From Table 1, Table 2, and FIG. 5, it was found that the higher the lactose decomposition rate, the softer the ice cream. Therefore, it was found that ice creams can be softened as the lactose decomposition rate increases.

Further, in Table 2, when the ice creams of Production Examples 3 and 4 and the ice cream of Production Example 2 are compared, the ice cream of Production Examples 3 and 4 has a larger ice crystal size than the ice cream of Production Example 2. It turned out to be a big tendency. Here, in the ice cream of Production Example 2, the lactose decomposition rate of the ice cream of Production Example 4 is almost the same, and the composition of the ice creams of Production Examples 2 and 4 is compared. There is much fat solid content. Therefore, it was found that by increasing the solid content of non-fat milk, it is possible to suppress the increase in the size of ice crystals when stored under freezing conditions. That is, it was found that the ice cream of Production Example 2 was excellent in storage stability under freezing.

Also, as can be seen from Table 2, when the flavors of the ice creams of Production Examples 3 and 4 were compared, the saltiness was the same in both cases, and the ice cream of Production Example 4 felt rich in sweetness. Moreover, in the ice cream of the manufacture example 5, compared with the ice cream of the manufacture examples 3 and 4, the milk flavor was felt richly. This was considered to be because in the ice cream of Production Example 5, DF desalted skim milk powder was used as the ice cream mix, and the non-fat milk solid content was high. Furthermore, in the ice creams of Production Examples 1 and 2, compared with the ice cream of Production Example 5, the milk flavor was the same, and the sweetness was felt richer. Furthermore, when the sweetness was compared between the ice creams of Production Examples 1 and 2, the ice cream of Production Example 2 felt a richer sweetness. The reason why the sweetness was felt more abundantly was thought to be due to the high lactose decomposition rate in the ice creams of Production Examples 1 and 2.

In Table 2, when the softness (hardness) was compared, it was almost the same in Production Example 3 and Production Example 5. In other words, the ease of passing Saji was about the same. Further, comparing Production Examples 1 and 2 with Production Example 5, the ice creams of Production Examples 1 and 2 are softer than the ice cream of Production Example 5, and the ice cream of Production Example 2 is the same as that of Production Example 1. It turned out to be softer than ice cream. Therefore, it was found that the higher the lactose decomposition rate, the softer the ice creams produced, the better the sagittal street. This was thought to be because the freezing point decreased as a result of the production of monosaccharides as the lactose content decreased by increasing the lactose decomposition rate as in Production Examples 1 and 2. Further, the ice creams of Production Examples 1 and 2 were excellent in texture because the production of lactose crystals was suppressed.

NF desalted and defatted concentrated milk, DF desalted and defatted concentrated milk, and NF desalted whole fat and concentrated milk so that the milk fat content is 12 to 15% by weight and the nonfat milk solid content is 13 to 20% by weight. DF desalted whole fat concentrated milk, NF cream, and ice cream mix mixed with DF cream were produced in plural types, and each was subjected to lactose decomposition to produce ice cream. As for these, compared with the manufacture example 3, although the saltiness was in the state adjusted to the grade which is comparable or just good, sweetness and milk flavor were felt richly.

From the above, as in Production Examples 1 and 2, using DF desalted skimmed milk powder as an ice cream mix, increasing the non-fat milk solid content, suppressing the salty taste of ice cream and enriching milk flavor It was found that by increasing the lactose decomposition rate, the sweetness of the ice cream can be increased, and further, the softness that is good as a saji can be secured. In addition, as in Production Examples 1 and 2, without using stabilizers and emulsifiers, by increasing the content of non-fat milk solids (ie, protein), and by increasing the lactose decomposition rate, It was found that an ice cream having excellent storage stability under freezing can be produced.

In Example 2, in order to confirm the change in the components due to desalting, first, desalted concentrated milk was produced according to the first aspect, and the composition of the obtained desalted concentrated milk (Production Example 6) and the blending ratio thereof were determined. Examined. FIG. 6 schematically shows the procedure for preparing the desalted concentrated milk according to the first embodiment. The step number S shown in FIG. 6 corresponds to the step number S shown in FIG.

First, raw milk was concentrated about 2.0 times by a nanofiltration (NF) method. Thus, nanofiltered concentrated milk (NF concentrated milk) obtained by nanofiltration was obtained (Production Example 7). The permeate obtained by the nanofiltration method was processed by reverse osmosis (RO) to prepare a reverse osmosis membrane permeate (demineralized water). The reverse osmosis membrane permeate and water were added to the nanofiltration concentrated milk to obtain the same weight as the original raw milk to obtain desalted milk. The desalted milk was subjected to nanofiltration (NF) treatment and concentrated to about 2.0 times. In this manner, diafiltered desalted milk (DF desalted concentrated milk) was obtained. This DF desalted concentrated milk was separated into DF cream and DF defatted concentrated milk by a centrifuge (separator). Thereby, DF desalted and defatted concentrated milk of Production Example 6 was obtained. It was also confirmed that DF demineralized skim milk can be obtained by concentrating DF demineralized degreased concentrated milk with a vacuum evaporator (evaporator), and having excellent storage (preservation) properties.

Then, the composition and the blending ratio of the obtained DF desalted and defatted concentrated milk were examined. In addition, the composition of nanofiltration concentrated milk (Production Example 7) obtained in the production stage of Production Example 6 and defatted concentrated milk (Production Example 8) that was defatted and concentrated without performing nanofiltration and reverse osmosis membrane treatment The content ratio was examined.

Table 3 shows the results of examining each composition, and Table 4 (Tables 4a and 4b) shows the results of examining the content ratio of each composition.

As can be seen from Table 4b, the desalted milk of Production Example 6 has a sodium content in the range of 35% to 80% described above, and the desalted milk of Production Examples 7 and 8 is more than 75%. I understood that. Therefore, it was demonstrated that the desalination rate can be adjusted by concentrating the raw materials and performing the desalting treatment according to the first aspect. In addition, it was found that the residual rate of calcium does not fluctuate greatly even if the nanofiltration treatment or reverse osmosis membrane treatment is applied to the raw material (specifically, 90% can be secured in the residual rate).

In Production Example 6, similar results could be obtained even when skim milk was used instead of raw milk. When obtaining desalted milk using skim milk, a step of separating the cream and the skim concentrated milk by a centrifuge may be provided in advance of the desalting process.

In Example 3, the DF desalted and defatted concentrated milk obtained in the first aspect and the desalted and defatted powdered milk obtained in the second aspect are mixed, and the mixture is used as a material for milk fat and nonfat milk. A plurality of ice creams (Production Examples 9 to 15) having different solid content ratios were produced. Moreover, ice cream (Manufacturing Example 16) was manufactured without using both the DF desalted and defatted concentrated milk obtained in the first aspect and the desalted and defatted powdered milk obtained in the second aspect.

Tables 5 and 6 show the mixing ratio of the raw materials of Production Examples 9 to 16. Tables 5 and 6 also show the content ratio of each composition of the produced ice cream.

As can be seen from Tables 5 and 6, it was found that according to the present invention, ice creams can be produced with various blending ratios. In addition, the ice creams of Production Examples 9 to 15 were prepared by DF desalted and defatted concentrated milk prepared according to the first embodiment (diafiltration and lactose-degraded desalted and defatted concentrated milk) and desalted and defatted powdered milk prepared according to the second embodiment ( Therefore, even if the amount of sugar (sucrose) added to the raw material is smaller than that in Production Example 16, the sweetness is sufficiently high.

The present invention can be used in the food industry.

Claims

A desalting step for desalting a raw material containing non-fat milk solids in an amount of 5 wt% to 50 wt%;
An enzyme addition step for adding an enzyme that decomposes lactose to the raw material that has undergone the desalting step;
A lactose decomposition step in which the enzyme added in the enzyme addition step decomposes lactose contained in the raw material that has undergone the desalting step;
A cooling step for cooling the raw material that has undergone the lactose decomposition step;
A method for producing ice cream.
The cooling step includes
Cooling the ice cream mix prepared through the desalting step, the enzyme addition step, and the lactose decomposition step,
The ice cream mix
Contains non-fat milk solids at 5% to 40% by weight and no milk fat or contains milk fat at 25% by weight,
The manufacturing method of the ice cream of Claim 1.
The desalting step is
It is a step of setting the residual rate of sodium contained in the raw material to 35% to 80%.
The manufacturing method of the ice cream of Claim 1.
The desalting step is
A first nanofiltration treatment step of concentrating a raw material containing skim milk by a nanofiltration method to obtain a nanofiltration concentrated skim milk;
Diluting the nanofiltration concentrated skim milk obtained in the first nanofiltration treatment step to obtain a nanofiltration skim milk; and
A second nanofiltration treatment step of concentrating the nanofiltration skim milk obtained in the dilution step by a nanofiltration method to obtain desalted skimmilk;
including,
The manufacturing method of the ice cream of Claim 1.
The desalting step is
A first nanofiltration treatment step of concentrating a raw material containing skim milk by a nanofiltration method to obtain a nanofiltration concentrated skim milk;
A reverse osmosis treatment step of performing a reverse osmosis treatment on the permeate obtained in the first nanofiltration treatment step to obtain a reverse osmosis membrane permeate,
Adding the nanofiltration concentrated skim milk obtained in the first nanofiltration treatment step, the reverse osmosis membrane permeate, and moisture to obtain desalted milk; and
A second nanofiltration treatment step of concentrating the desalted milk obtained in the desalted milk obtaining step by a nanofiltration method to obtain desalted skim milk;
including,
The manufacturing method of the ice cream of Claim 1.
The desalting step is
A first nanofiltration treatment step of concentrating the raw material by a nanofiltration method to obtain a nanofiltration concentrated milk;
In the first nanofiltration step, reverse osmosis treatment is performed on the obtained permeate to obtain a reverse osmosis membrane permeate,
Adding the nanofiltration concentrated milk, the reverse osmosis membrane permeate, and water to obtain a desalted milk;
A second nanofiltration treatment step of concentrating the desalted milk obtained in the desalted milk obtaining step by a nanofiltration method to obtain desalted skim milk;
including,
The manufacturing method of the ice cream of Claim 1.
The enzyme added in the enzyme addition step is
Lactase,
When the raw material that has undergone the desalting step is 100% by weight, it is added at 0.01% by weight or more and 0.1% by weight or less.
The manufacturing method of the ice cream of Claim 1.
The lactose decomposition process is as follows:
It is a step of decomposing lactose contained in the raw material that has undergone the desalting step at 30% to 100%.
The manufacturing method of the ice cream of Claim 1.
The lactose decomposition process is as follows:
Including the step of holding the raw material that has undergone the desalting step at a temperature of 0 ° C. or more and 20 ° C. or less for 2 hours or more,
The manufacturing method of the ice cream of Claim 1.
An ice cream produced by the method for producing an ice cream according to any one of claims 1 to 9.
4% to 15% by weight of milk protein,
Containing 1% to 10% by weight of lactose-derived glucose,
The ice cream according to claim 10.