CN105767445B

CN105767445B - Ice cream type cold drink

Info

Publication number: CN105767445B
Application number: CN201610143851.0A
Authority: CN
Inventors: 中越诚; 小野田敏昭; 市场智子
Original assignee: Meiji Co Ltd
Current assignee: Meiji Co Ltd
Priority date: 2009-12-25
Filing date: 2010-12-24
Publication date: 2020-08-28
Anticipated expiration: 2030-12-24
Also published as: TWI574627B; HK1172797A1; JPWO2011077739A1; CN102711507A; HK1222299A1; JP2016063822A; CN105767445A; WO2011077739A1; TW201130424A; CN102711507B; JP5848611B2

Abstract

The invention provides a method for preparing ice cream cold drinks, which comprises the following steps: the ice cream cold drink prepared by the method has excellent storage stability, good taste and easy scooping. The manufacturing method comprises a desalting step, an enzyme adding step, a lactose decomposing step and a cooling step. First, in the desalting step, the raw material containing 5 to 50 wt% of the solid fat-free milk is desalted. In the enzyme addition step, an enzyme capable of decomposing lactose is added to the raw material subjected to the desalting step. Then, in the lactose decomposition step, lactose contained in the raw material is decomposed by an enzyme. Finally, for example, in the cooling step, the raw material subjected to the lactose decomposition step is cooled. Thus, the ice cream-type cold drink is obtained.

Description

Ice cream type cold drink

The application is a divisional application of a case with application number 201080052305.7, the application date of the original application is 24.12.2010, and the priority date is 25.12.2009, and the invention name is ice cream cold drink and a manufacturing method thereof.

Technical Field

The invention relates to an ice cream cold drink and a preparation method thereof. The ice cream cold drink is obtained by using an ice cream mix (ice cream mix) containing a desalted concentrated milk containing a large amount of protein and decomposing lactose contained in the ice cream mix.

Background

Japanese patent laid-open No. Hei 7-67542 (patent document 1) discloses the following ice cream (paragraph [0037 ]): the sweet component is lactose and lactase. The ice cream utilizes lactase to decompose lactose into glucose and galactose. Ice cream containing a large amount of monosaccharides is easily digested and absorbed, and for example, even if eaten by lactose-allergic persons, it does not cause diarrhea. Lactose is theoretically decomposed into glucose and galactose by lactase in the small intestine and absorbed into the body, but in the case of a person with a small lactase secretion amount in the small intestine (a person allergic to lactose), lactose is not decomposed, so that lactose is not absorbed into the body, resulting in diarrhea.

Patent document 1: japanese patent laid-open publication No. Hei 7-67542

Further, the ice cream disclosed in japanese patent laid-open publication No. hei 7-67542 contains a large amount of monosaccharides, and therefore, when the temperature is increased during storage (preservation) of the ice cream, crystals of the ice cream grow, resulting in a problem that the taste and texture are impaired.

Disclosure of Invention

Accordingly, the present invention aims to provide a method for producing ice cream-type cold drinks, which comprises the following steps: the ice cream cold drink prepared by the method has excellent storage stability, good taste, moderate softness and easy scooping.

The present invention basically decomposes lactose by an enzyme, thereby obtaining an ice cream-like cold drink which has moderate softness and is easy to scoop. In order to improve the storage stability of ice cream type cold drinks, an ice cream mix containing a large amount of fat-free milk solid components is used. However, when an ice cream mix containing a large amount of fat-free milk solid matter is used to produce ice cream, the saltiness of the ice cream-like cold drink obtained becomes large. The present invention uses desalted milk concentrate in the ice cream mix. Thus, the invention provides a method for preparing ice cream cold drinks, which comprises the following steps: the ice cream cold drink prepared by the method has excellent storage stability, good taste, moderate softness and easy scooping.

Embodiment 1 of the present invention relates to a method for producing an ice cream-type cold drink. The method comprises the following steps: desalting step, enzyme adding step, lactose decomposing step and cooling step.

In the desalting step, desalting treatment is performed on the raw material containing the fat-free milk in a solid content of 5 to 50 wt%. Thus, when a raw material containing a large amount of solid components of fat-free milk is used, the amount of protein contained in the ice cream mix can be increased to improve the storage stability of the ice cream. Therefore, the present invention does not need to add emulsifier and stabilizer. Therefore, when the method for preparing the ice cream cold drink is used, the ice cream cold drink with better taste can be prepared.

In the enzyme addition step, an enzyme for decomposing lactose is added to the raw material subjected to the desalting step. In this step, other raw materials may be added to the raw material subjected to the desalting step, and then the enzyme may be added. In the lactose decomposition step, lactose contained in the raw material is decomposed by an enzyme. In the cooling step, the raw material subjected to the lactose decomposition step is cooled. In this step, the raw material subjected to the desalting step may be cooled, that is, the raw material to which the enzyme has not been added may be cooled, or the raw material to which the lactose has not been decomposed may be cooled.

Preferably, in the cooling step of embodiment 1 of the present invention, the ice cream mix prepared by the desalting step, the enzyme adding step, and the lactose decomposing step is cooled. The content of the solid component of the non-fat milk in the ice cream mixture is more than 5 weight percent and less than 40 weight percent, and the milk cream component is not contained or the content of the milk cream component is less than 25 weight percent.

As demonstrated in the examples described later, according to the present invention, an ice cream-type cold drink having a good taste can be obtained even when a raw material or an ice cream mix containing a large amount of a fat-free milk solid content is used.

In the desalting step according to embodiment 1 of the present invention, the residual ratio of sodium contained in the raw material is preferably set to 35% or more and 80% or less (the desalting ratio is preferably set to 20% or more and 65% or less). When an ice cream-type cold drink is produced using a raw material or an ice cream mix containing a large amount of fat-free milk solid components, the degree of saltiness becomes large. Since sodium and potassium are removed in the desalting step of the present invention, even if an ice cream-based cold drink is manufactured using a raw material or an ice cream mix containing a large amount of fat-free milk solid components, an ice cream-based cold drink having a suitable saltiness can be obtained.

The desalting step according to embodiment 1 of the present invention preferably includes a 1 st nanofiltration treatment step, a dilution step, and a 2 nd nanofiltration treatment step. In the 1 st nanofiltration treatment step, a raw material containing skim milk is concentrated by a nanofiltration method to obtain nanofiltration-concentrated skim milk. In the diluting step, the nanofiltration concentrated skim milk obtained in the 1 st nanofiltration treatment step is diluted to obtain nanofiltration skim milk. In the 2 nd nanofiltration treatment step, the nanofiltration skim milk obtained by the dilution step is concentrated by a nanofiltration method to obtain desalted skim milk.

The above embodiment can also be applied to the case where raw milk is contained in the raw material. However, in this embodiment, it is preferable to use the case where the starting material contains skim milk. As will be demonstrated in the examples described later, when the production method according to the above embodiment is employed, the contents of sodium and potassium can be effectively reduced while maintaining the solid content of fat-free milk. In addition to the 2 nd nanofiltration treatment step, a 3 rd nanofiltration treatment step, a 4 th nanofiltration treatment step, and the like may be provided, but from the viewpoint of the number of steps, desalting efficiency, product taste, and the like, it is preferable to stop at the 2 nd nanofiltration treatment step.

The desalting step according to embodiment 1 of the present invention preferably includes a 1 st nanofiltration treatment step, a reverse osmosis treatment step, a desalted milk obtaining step, and a 2 nd nanofiltration treatment step. In the 1 st nanofiltration treatment step, a raw material containing skim milk is concentrated by a nanofiltration method to obtain nanofiltration-concentrated skim milk. In the reverse osmosis treatment step, the permeate obtained in the 1 st nanofiltration treatment step is subjected to reverse osmosis treatment to obtain a reverse osmosis membrane permeate. In the desalted milk obtaining step, the nano-filtration concentrated skim milk obtained in the 1 st nano-filtration treatment step, and the reverse osmosis membrane permeate and water are added to obtain desalted milk. In the 2 nd nanofiltration treatment step, the desalted milk obtained in the desalted milk obtaining step is concentrated by nanofiltration to obtain desalted skim milk.

The desalting step according to embodiment 1 of the present invention preferably includes a 1 st nanofiltration treatment step, a reverse osmosis treatment step, a desalted milk obtaining step, and a 2 nd nanofiltration treatment step. In the 1 st nanofiltration treatment step, the raw material is concentrated by a nanofiltration method to obtain a nanofiltration concentrated milk. In the reverse osmosis treatment step, the permeate obtained in the 1 st nanofiltration treatment step is subjected to reverse osmosis treatment to obtain a reverse osmosis membrane permeate. In the desalted milk obtaining step, nano-filtration concentrated milk, reverse osmosis membrane penetration liquid and water are added to obtain desalted milk. In the 2 nd nanofiltration treatment step, the desalted milk obtained in the desalted milk obtaining step is concentrated by nanofiltration to obtain desalted skim milk.

Preferably, the enzyme added in the enzyme addition step of embodiment 1 of the present invention is lactase. The addition amount of lactase is as follows: if the amount of the raw material or ice cream mix subjected to the desalting step is 100 wt%, lactase is added in an amount of 0.01 wt% to 0.1 wt%.

If the amount of lactase added is increased, the decomposition rate of lactose will be increased. In addition, the addition of lactase also results in increased costs. When the amount of lactase added is within the above range, ice cream-like cold drinks having good taste can be obtained within a suitable production time.

In the lactose decomposition step according to embodiment 1 of the present invention, lactose contained in the raw material subjected to the desalting step is preferably decomposed to 30% or more and 100% or less. This step is achieved by the following method: the raw material subjected to the desalting step is kept at a temperature of 0 ℃ to 20 ℃ for 2 hours or more.

The method for producing an ice cream-based cold drink according to the present invention can be used in combination with the above or below-described various configurations. The method for producing an ice cream-type cold drink according to the present invention is not limited to the contents described in the present specification, and includes modifications that are within the scope of knowledge of those skilled in the art.

Embodiment 2 of the present invention relates to an ice cream cold drink produced by the method for producing an ice cream cold drink according to any one of the above embodiments. As an example of such ice cream-type cold drinks, milk protein is 4% by weight or more and 15% by weight or less, and glucose derived from lactose is 1% by weight or more and 10% by weight or less. The ice cream cold drink has excellent storage stability, proper salinity, good taste and easy scooping.

[ Effect of the invention ]

The invention provides a method for preparing ice cream cold drinks, which comprises the following steps: the ice cream cold drink prepared by the method has excellent storage stability, good taste, moderate softness and easy scooping.

Drawings

Fig. 1 is a flowchart (flow chart) showing the sequence of the method for producing an ice cream-based cold drink of the present invention.

Fig. 2 is a step diagram showing in detail the preparation sequence of the ice cream mix in step S100 of fig. 1.

FIG. 3 is 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 step diagram showing in detail the procedure of an example of the desalted milk acquisition process in step S110 in fig. 2.

FIG. 5 is a graph showing the results of hardness measurement of the ice cream obtained in example.

FIG. 6 is a schematic diagram showing an example of a procedure for obtaining desalted milk by the desalted milk obtaining process (FIG. 4) of the present invention.

Detailed Description

Embodiment 1 of the present invention relates to a method for producing an ice cream-type cold drink. Ice cream type cold drinks are a general term for ice cream, ice milk, and ice lactose (lactose) defined by the dairy regulations (regulations regarding the ingredient specifications of milk and dairy products, etc.). In addition, in the case of ice cream type cold drinks, the milk solids content is at least 3% by weight (i.e., 3% by weight, the same applies hereinafter).

Methods for producing ice cream-type cold drinks are known. In the present invention, an ice cream type cold drink is produced by using a known apparatus for producing an ice cream type cold drink and appropriately using conditions known to those skilled in the art. The preparation method of the ice cream cold drink basically comprises a desalting step, an enzyme adding step, a lactose decomposing step and a cooling step. The following describes a method for producing ice cream-type cold drinks. The present invention is not limited to the following examples, and includes modifications within the scope of the knowledge of those skilled in the art.

Fig. 1 is a process diagram (flowchart) schematically showing the sequence of a method for producing an ice cream-based cold drink. According to the present invention, ice cream-type cold drinks in which the total amount of milk solids is 3 wt% or more (preferably, ice cream-type cold drinks in which fat-free milk Solids (SNF) is contained in an amount of 5 wt% or more and 40 wt% or less) can be produced from raw materials. This is because if the solid fat-free milk (SNF) is 5 wt% or more, the taste and physical properties of the ice cream cold drink can be improved by the lactose decomposition step. In addition, the following describes the case of producing ice cream as an ice cream-based cold drink.

In fig. 1, first, in step S100, an ice cream mix obtained by blending a plurality of raw materials is used as raw milk for an ice cream-based cold drink. The raw materials may suitably contain raw milk, milk powder, saccharides, concentrated milk, desalted milk and water. In order to prevent the invasion of bacteria, this step is usually carried out at normal temperature or in a heated state (30 ℃ to 80 ℃) in a plurality of apparatuses connected by a pipeline. Step S100 is described in detail with reference to fig. 2 and 4.

Next, in step S200, the ice cream mix solution prepared in step S100 is homogenized. When homogenization is performed, the ice cream mix solution is first filtered as necessary to remove impurities. The particle size of the fat or the like is then adjusted, for example, using a homogenizer at a temperature of, for example, 50 ℃ or higher and 70 ℃ or lower, so that the particle size of the fat of the ice cream mix is made fine to, for example, 2 μm or less. Then, the ice cream mix adjusted in particle size is heated to, for example, 68 ℃ or higher and 75 ℃ or lower, and is kept for 30 minutes to be sterilized.

Then, in step S300, the ice cream mix solution homogenized in step S200 is cooled to a temperature of, for example, 0 ℃ or more and 5 ℃ or less. Here, the ice cream mix solution is not frozen but is kept fluid.

In step S400, a known flavor enhancer (e.g., vanilla flavor enhancer, chocolate flavor enhancer, strawberry flavor enhancer, cocoa flavor enhancer) is appropriately added to the ice cream mix solution in a cooled state. If no odorant is required, the process of step S400 is not performed. In addition, when the flavor is added already at the time of preparing the ice cream mix in step S100, the process of step S400 does not need to be performed.

Next, in step S500, the ice cream mix is subjected to a ripening process for a predetermined time. The aging treatment is also carried out at a temperature of 0 ℃ to 5 ℃. By performing the ripening treatment, the fat can be crystallized and the protein can be hydrated to stabilize the ice cream mix.

Subsequently, the ice cream mix on which the ripening process has been completed is subjected to a condensation process (step S600). The treatment consists in stirring the ice cream mix for a given period at a temperature of, for example, -2 ℃ to-10 ℃. By this condensation process the ice cream mix is cooled and its moisture etc. freezes.

Then, the ice cream mix in the condensed state is subjected to a packaging process (step S700). The packaging process is also carried out in an environment at the same condensation temperature as described above. Further, a manufacturing date and the like are marked on the container as necessary.

Finally, the ice cream mix in the shipping container is exposed to a hardening temperature, e.g., below-18 ℃, to allow it to be rapidly frozen, e.g., to a temperature in the range of-3 ℃ to-15 ℃ (step S800). This enables the ice cream mix to be frozen (hardened) in its entirety.

As described above, the ice cream is in a state of being shipped after the manufacturing process of the ice cream is completed. In addition, necessary inspections are performed during a period from the completion of manufacturing to the shipment. The storage temperature of the ice cream is preferably-25 ℃ or lower. In addition, like the method for producing ice cream, ice milk and ice cream candy can also be produced by this method.

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

Fig. 2 is a step diagram showing in detail the preparation sequence of the ice cream mix in step S100 of fig. 1. In the present embodiment, an example of preparing an ice cream mix from raw milk will be described.

In fig. 2, first, in step S110, a raw material is desalted to obtain desalted milk. If raw milk is used as a raw material to prepare concentrated milk and desalting is performed, desalted concentrated milk can be obtained. Thus, the stability of the quality and physical properties of the ice cream can be ensured without using a stabilizer or an emulsifier. The processing in step S110 will be described in detail later with reference to fig. 4 and 6. The desalted milk may be in the form of liquid or powder (powdered milk). Alternatively, the desalted and concentrated milk may be prepared by using concentrated milk in advance, instead of raw milk.

Next, in step S120, sugar is added to the desalted milk (sugar adding treatment). Examples of sugars include: granulated sugar (sucrose), lactose, glucose, fructose, etc., and may be in liquid or powder form. The sugar to be added here may be, for example, a polysaccharide (e.g., starch, fructose, glucose, cellulose, dextrin), but is preferably a oligosaccharide (oligosaccharide), and more preferably a disaccharide (e.g., maltose, cellobiose, sucrose, lactose, trehalose). This is because the hydrolysis by the enzyme (glycosidase) described later is favorably promoted. Among the disaccharides, lactose (lactose) or trehalose are preferred. In addition, when the addition of sugar is not necessary, the process of step S120 is not performed. In addition, step S120 may be performed after the addition of the enzyme, or may be performed before the addition of the enzyme.

In step S130, an enzyme is added to the desalted milk. When the desalted milk is milk powder, the enzyme is added after the liquid is added to the milk powder. As the raw material to which the enzyme can be added, a raw material subjected to desalting treatment can be used as it is. Further, as the raw material to which the enzyme can be added, a plurality of desalted raw materials or raw materials which are not desalted may be mixed and used, or raw materials which are subjected to the same desalting treatment repeatedly may be used. As examples of the enzyme, an enzyme (glycosidase) corresponding to the sugar contained in the desalted milk of step S110 or the sugar added in step S120 may be used. Glycosidases are enzymes by which the corresponding saccharide (saccharide having a monosaccharide as a constituent unit) can be decomposed into a saccharide composed of a smaller number of monosaccharides. For lactose, for example, lactase is used. For trehalose, trehalase (trehalase) was used. Lactase and trehalase can be derived from bacteria or yeast. Since lactose is contained in the desalted milk, it is preferable that the enzyme contains at least lactase.

Lactase, also known as β -D-galactosidase (β -D-galactosidase), is an enzyme by which lactose, which is a disaccharide, is hydrolyzed into glucose and galactose. Lactase disclosed in, for example, Japanese patent laid-open publication No. Hei 10-504449 can be suitably used. The addition amount of lactase is as follows: when the amount of the raw material or the ice cream mix is 100 wt%, the lactase is preferably added in an amount of 0.01 wt% to 0.1 wt%. If the amount of lactase added is increased, the decomposition rate of lactose will be increased. When lactase is added to the desalted raw material, the experimental result shows that if the lactase content is higher, the fact that the taste of the ice cream cold drink is damaged is generated. Therefore, the lactase is preferably added in an amount of 0.01 wt% or more and 0.08 wt% or less, more preferably 0.02 wt% or more and 0.07 wt% or less, and particularly preferably 0.03 wt% or more and 0.05 wt% or less. When the above-mentioned addition amount is used, an ice cream-type cold drink having a good taste can be obtained within a suitable production time.

Next, in step S140, the enzyme-containing desalted milk is placed under predetermined conditions to promote the hydrolysis reaction. That is, lactose contained in the raw material or the ice cream mix is decomposed by an enzyme. The conditions for this lactose decomposition reaction will be described later. In this step, lactose contained in the raw material or ice cream mix may be decomposed to, for example, 30% or more and 100% or less.

The preparation of the base or ice cream mix is completed as described above. The raw material or ice cream mix obtained by the processing in step S140 may be subjected to a concentration process as necessary. Also, the raw material or ice cream mix may be formed into a powder form by a method such as spray drying. In addition, the following substances can be added to the raw materials or ice cream mix as required: cream (milk fat-rich part), other milk powder or its reduced liquid, flavoring agent, sweetened egg yolk, water, etc.

By the processing of FIG. 2, sugars such as lactose contained in the desalted milk are hydrolyzed (step S140). Thus, the sweetness of the ice cream can be improved because the number of molecules of the sugar contained in the ice cream mix is increased. Further, although the sweetness varies depending on the kind of the saccharide, even when the sweetness of each saccharide is low, the sweetness of the ice cream mix can be improved by increasing the number of saccharide molecules compared to before hydrolysis. And the increase of the number of monosaccharide molecules can moderately improve the softness of the ice cream cold drink so as to ensure good scooping property.

In one embodiment, lactose is hydrolyzed to glucose (glucose) and galactose. In this case, if the lactose degradation rate indicating the degree of lactose degradation is set to 100%, the sweetness after hydrolysis is several times as high as that before hydrolysis. In addition, 1 molecule of lactose is decomposed to generate 2 molecules of monosaccharide, so that the number of molecules of the monosaccharide can be effectively increased, and the softness of the ice cream cold drink prepared by the method can be effectively improved.

FIG. 3 is a graph showing the relationship between the lactose decomposition rate and the reaction time (time of lactose decomposition step) when lactose in the desalted milk is hydrolyzed by lactase in step S130. The situation shown in fig. 3 is as follows: the lactase is added in a constant amount, and the relationship between the lactose decomposition rate and the reaction time is determined by setting the temperature of desalted milk at 1 deg.C, 5 deg.C, and 10 deg.C during the lactose decomposition reaction.

As is clear from FIG. 3, the lactose degradation rate can be improved by increasing the reaction time of the lactose degradation reaction. Therefore, the longer the reaction time of the lactose decomposition reaction, the better. However, if the reaction time is prolonged, the lactose decomposition rate can be made close to 100% or 100%, but the production efficiency is deteriorated. Therefore, from the viewpoint of production efficiency, the upper limit of the reaction time of the lactose degradation reaction is, for example, 50 hours, and it is preferable to set the reaction time at which the lactose degradation rate exceeds 90% (24 hours as illustrated in fig. 3).

The lower limit of the reaction time for the lactose decomposition reaction is, for example, 2 hours. Thus, the lactose decomposition rate can be ensured to reach 30 percent, and the sweetness of the ice cream cold drink prepared is really improved. However, as is clear from fig. 3, since the lactose decomposition rate tends to vary greatly over a short reaction time, it is difficult to ensure a constant lactose decomposition rate when ice cream-based cold drinks are mass-produced. In order to ensure a substantially constant (for example, within 5% error) lactose degradation rate, the reaction time is preferably set to a reaction time at which the lactose degradation rate exceeds 90% (24 hours as illustrated in fig. 3). In addition, in order to ensure a substantially constant lactose degradation rate, inhibitors for inhibiting hydrolysis reaction (e.g., acarbose (acarbose) and voglibose (voglibose)) may be used. By using inhibitors, a substantially constant lactose breakdown rate can be ensured, which allows the quality of ice cream-like cold drinks produced in large quantities in batches to be maintained constant.

It is clear from FIG. 3 that, when the reaction time is the same, the higher the temperature at which the decomposition reaction of lactose is carried out, the higher the decomposition rate of lactose. Therefore, the higher the temperature at which the decomposition reaction of lactose is carried out, the better. However, bacteria are generally easier to propagate at temperatures in excess of 20 ℃. Therefore, the enzyme is generally maintained at a temperature of about 5 ℃ to 10 ℃. Therefore, from the viewpoint of inhibiting bacterial growth, it is preferably from 0 ℃ to 15 ℃ and, from the viewpoint of preventing bacterial growth, it is preferably from 0 ℃ to 10 ℃. In addition, it has been found through experiments that the taste of ice cream-type cold drinks obtained by decomposing lactose at a temperature of 5 ℃ or higher becomes savoury and mellow. Therefore, the temperature in the lactose decomposition step is preferably 5 ℃ or more and 20 ℃ or less, more preferably 6 ℃ or more and 15 ℃ or less, and particularly preferably 7 ℃ or more and 10 ℃ or less.

When decomposing lactose, the lactase is added in an amount of 0.01 to 0.10 wt%, preferably 0.01 to 0.08 wt%, more preferably 0.02 to 0.07 wt%, and particularly preferably 0.03 to 0.05 wt% based on the total amount of the desalted milk, and the following conditions are preferred for decomposing lactose: under the refrigeration condition with the temperature ranging from 0 ℃ to 10 ℃, the reaction time ranges from 2 hours to 50 hours. Thus, the lactose decomposition rate can reach more than 50%. In addition, even when the sugar is not lactose, the same principle as that of lactase can be applied by using the corresponding glycosidase (e.g., trehalase, amylase, sucrase (saccharose), maltase).

In the above embodiment, raw milk (milk without any processing) is exemplified as a raw material of desalted milk, but cow's milk may be formula milk, low-fat milk, nonfat milk, or processed milk or milk powder prepared from them. The raw material of the desalted milk is not limited to cow's milk, and goat's milk, sheep's milk, and the like may be used. However, from the viewpoint of easy availability, it is preferable that the starting material of the desalted milk is raw milk, and from the viewpoint of easy storage (preservation), it is preferable that the desalted milk is powdered milk. The starting material of the desalted milk may be a known ice cream mix.

Next, a procedure for obtaining desalted milk (desalted concentrated milk) by adjusting the raw material will be described. In this step, a raw material containing substantially 5 to 50 wt% of the solid components of fat-free milk is desalted. The raw material in the desalting step preferably contains 5 wt% or more and 40 wt% or less of the fat-free milk solid content, and more preferably contains 7 wt% or more and 35 wt% or less (for example, 13 wt% or more and 30 wt% or less) of the fat-free milk solid content. In the desalting step, the residual ratio of sodium contained in the raw material is set to 35% or more and 80% or less. In the desalting step, the residual ratio of sodium contained in the raw material is preferably 40% or more and 75% or less, more preferably 45% or more and 70% or less, and particularly preferably 50% or more and 65% or less. Since the desalting rate is high in this manner, the raw material can contain a large amount of solid components of fat-free milk. Therefore, in the present invention, the raw material can contain a large amount of skim milk powder. In addition, it was found from the experimental results that if the salt rejection is excessively increased, the taste is weakened. Therefore, the salt rejection is preferably set within the above range.

In the desalting step, the following methods may be used alone or in combination: nanofiltration (NF), Diafiltration (DF), ion exchange resin (IE) and Electrodialysis (ED).

In the case of the nanofiltration method, for example, a membrane-like filter paper (NF membrane) having nanometer-sized through holes (for example, a pore size of 0.5 to 2nm) is used, and raw milk is put into the NF membrane and filtered by osmotic pressure. Nanofiltration membranes are mainly membranes that allow 1-valent ions and water to pass through. Thus, the present invention can remove, for example, 1-valent cations (sodium ions, potassium ions, chloride ions). Therefore, by using the nanofiltration method, desalting treatment can be performed to remove sodium and potassium.

As raw materials of the Nanofiltration (NF) membrane, for example, polyamide, cellulose acetate, polyethersulfone, polyester, polyimide, ethylene polymer, polyolefin, polysulfone, regenerated cellulose, polycarbonate are given. In the present invention, polyamide, cellulose acetate, and polyether sulfone are preferable as the raw material of the Nanofiltration (NF) membrane because salts are removed. Examples of the shape of the Nanofiltration (NF) membrane include a flat membrane, a spiral membrane, a hollow fiber membrane, a plate-like membrane, and a tubular membrane. In addition, as the nanofiltration method, known conditions of a known filtration method can be adopted. Examples of the filtration method include a pressure filtration method and a reduced pressure filtration method. An example of the NF membrane is an NF membrane manufactured by Dow Chemical (trade name "NF-3838/30-FF"). Examples of the filtering method include a vertical filtering method (dead end filtering method) and a cross filtering method. Here, from an industrial point of view, since batch processing is performed when ice cream type cold drinks are produced, it is preferable to use a cross filtration method, which can suppress variation due to clogging of the filtration membrane, and can maintain the quality of the ice cream type cold drinks produced to be constant.

Therefore, the retained fluid (retentate) and the permeated fluid (permeate) can be obtained from the raw milk by the above-mentioned nanofiltration. The ratio of the holding liquid amount to the penetrating liquid amount varies depending on the osmotic pressure of the NF membrane used. Usually, the total solid content (TS: total-solids) of the raw milk in the holding liquid is concentrated in the range of 1.5 times to 2.5 times (e.g., 1.6 times).

In the retained liquid obtained by the nanofiltration method, the total solid content (TS) of the raw milk, i.e., milk FAT (FAT) and non-FAT milk solid content (SNF), is concentrated in the retained liquid. Therefore, in the present specification, the concentrated solution obtained by the nanofiltration process is sometimes referred to as "nanofiltration concentrated milk". The permeate obtained by the nanofiltration contains most of the water content and some of the water-soluble components (particularly, 1-valent ions) of the raw milk, and almost no total solid components of the raw milk. Here, as the water-soluble component of the raw milk, ash may be mentioned. The "ash" is a generic term for inorganic substances such as sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), chlorine (Cl), phosphorus (S), and vitamins such as vitamin A, B1, B2, and nicotinic acid (niacin).

It is preferable to add an electrolyte that does not pass through the nanofiltration membrane to the raw material before the nanofiltration treatment is performed. Desalination treatment can be facilitated by the addition of an electrolyte that does not pass through the nanofiltration membrane. Examples of electrolytes that do not pass through the nanofiltration membrane include milk fat, milk casein, whey protein, lactose, and a portion of non-protein nitrogen (NPN). As described later, it is preferable to add a filtration-maintaining liquid to the raw material, so that the desalting treatment can be promoted.

In the Diafiltration (DF) method, water is added to milk or the like (retaining solution) which has been filtered and concentrated to dilute the milk or the like, and the volume of the filtrate (retaining solution) is returned to a volume close to the volume before filtration, followed by filtration treatment. As an example of the DF method of the present invention, water is added to milk or the like which is concentrated by filtration through an NF membrane, and then filtration treatment is performed with the NF membrane.

In the ion exchange resin (IE) method, the raw material is brought into contact with an ion exchange resin to complete the desalting treatment. The ion exchange resin may be any commercially available anion exchange resin and cation exchange resin which are generally used for the purpose of desalting treatment. The desalting treatment using the ion exchange resin may be carried out under known conditions by using known operations and apparatuses.

For the Electrodialysis (ED) method, a separation technique is implemented using electrophoresis of ionic substances in a solution and the property of an ion exchange membrane to selectively pass cations or anions. The desalting treatment by the Electrodialysis (ED) method may be carried out under known conditions by using known procedures and apparatuses.

In the desalting step, salts other than sodium may be removed. In addition, 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 particularly preferably 95% by weight or more.

Next, a case where the Diafiltration (DF) method is used for the desalination process in step S110 in fig. 2 will be described in detail (embodiment 1).

Fig. 4 is a step diagram showing in detail the procedure of an example of the desalted milk acquisition process in step S110 in fig. 2. In this embodiment, a case of preparing desalted milk (particularly desalted concentrated milk) from raw milk will be described. In addition, as described above, the raw material of the desalted milk is not limited to raw milk.

In fig. 4, first, in step S111, raw milk is prepared as a raw material of desalted milk. The Total Solids (TS) of raw milk is, for example, 12.8 wt%, of which 3.8 wt% is milk FAT (FAT: milk FAT) and 9.0 wt% is non-FAT milk Solids (SNF). As the raw milk, an aqueous solution (reconstituted milk) of milk powder (e.g., skim milk powder) may be used, and a known ice cream mix may be used.

Next, in step S112, the raw material is subjected to a 1 st Nanofiltration (NF) process by a nanofiltration method. For the nanofiltration treatment, an NF membrane manufactured by Dow Chemical (trade name "NF-3838/30-FF") is used, for example.

Then, a retained liquid (retentate) and a permeated liquid (permeate) are obtained from the raw material by the above-mentioned nanofiltration treatment. When the NF membrane manufactured by Dow Chemical is used, when the 1 st nanofiltration treatment is performed, the flow rate per unit time when the cross power method is used as the raw material is, for example, 14t/h, substantially the same amount of the retention liquid and the permeation liquid (7t/h) can be obtained. In addition, the ratio of the amount of the holding liquid to the amount of the penetrating liquid may vary depending on the osmotic pressure of the NF membrane used, but generally, the total solid content (TS) of the raw material in the holding liquid is concentrated in the range of 1.5 times to 2.5 times (for example, 2.0 times).

In the retained liquid (nanofiltration concentrated milk) obtained by the nanofiltration process, the Total Solids (TS) of the raw materials, i.e. milk FAT (FAT) and non-FAT milk Solids (SNF), are concentrated in the retained liquid. The permeate obtained by the nanofiltration contains most of the water content of the raw material and some of the water-soluble components, and almost no total solid components of the raw milk. Here, the penetration liquid obtained by the nanofiltration method contains sodium (Na), potassium (K), chlorine (Cl), and the like.

Then, in step S113, Reverse Osmosis (RO) treatment is performed on the permeated liquid obtained by the nano filtration method to obtain a permeated liquid (hereinafter also referred to as "reverse osmosis membrane permeated liquid"). In addition, the retention solution in the reverse osmosis treatment is not used in the present embodiment.

In the reverse osmosis treatment, for example, a membrane-shaped filter paper (reverse osmosis membrane) that traps cations having a valence of 1 is used, and a permeation solution obtained by the nanofiltration method in step S112 is introduced into the reverse osmosis membrane, and pressure is applied from the upstream side of the reverse osmosis membrane (the side into which the permeation solution obtained by the nanofiltration method in step S112 is introduced). In addition, when the reverse osmosis treatment is performed, a pressure reduction treatment is performed from the downstream side of the reverse osmosis membrane instead of applying a pressure from the upstream side of the reverse osmosis membrane. In the reverse osmosis treatment, since a pressure higher than or equal to the osmotic pressure is used, most of the permeate obtained by the nanofiltration in step S112 passes through the reverse osmosis membrane and becomes RO permeate. In addition, in the retaining solution of the reverse osmosis membrane (the portion that does not pass through the reverse osmosis membrane), sodium ions, potassium ions, and the like contained in the permeated solution obtained by the nanofiltration process in step S112 are concentrated as the 1-valent cations. That is, the reverse osmosis treatment is performed on the permeated liquid obtained by the nanofiltration in step S112, which is also an example of the desalting treatment. In this regard, in the present specification, the reverse osmosis membrane-penetrating fluid is also referred to as "desalinated water".

Subsequently, dilution processing is performed in steps S114 to S115. Specifically, first in step S114, the desalted water obtained in step S113 is added to the nanofiltration concentrated milk obtained in step S112 (return). Thus, desalted milk as a mixed liquid is obtained. Here, since the amount of permeate obtained by the nanofiltration process in step S112 is substantially the same as the amount of permeate obtained by the reverse osmosis membrane, the amount of desalted milk is substantially the same as the amount of the raw material prepared in step S111. Therefore, the desalted milk contains substantially the same amount of total solid components (FAT and SNF) as the amount of the nano-filtration concentrated milk, and also contains substantially the same amount of ash as the amount of the nano-filtration concentrated milk. In other words, the desalted milk is desalted and concentrated milk in which part of sodium and potassium which are basic in salinity is removed while concentrating the total solid content of the raw material.

In step S115, water is added (added) to the desalted milk as necessary. As the water to be added, distilled water or tap water can be used, and tap water is preferably used from the viewpoint of easy availability and sterilization treatment at a later stage. In addition, water (water) may be added to the nanofiltration concentrated milk or the reverse osmosis membrane permeate. This makes the amount of desalted milk equivalent to the amount of the raw material. In this case, the amount of the desalted milk is equivalent to the amount of the raw material, and this makes the amount of the liquid flowing on the production line constant. The process of step S115 may not be performed.

Then, in step S116, the 2 nd nanofiltration process is performed on the obtained desalted milk by the nanofiltration method. The maintenance liquid can be obtained by performing the nanofiltration treatment. The retaining liquid may be referred to as a desalted concentrated milk, in which the total solid content of the desalted milk is further concentrated and the desalted milk is further desalted to obtain the desalted concentrated milk.

The permeate obtained by the nanofiltration contains water-soluble components (particularly sodium and potassium) in the desalted milk. Thus, the retention solution is less salty than desalted milk. In the present embodiment, this phenomenon is utilized to set the content of sodium in the holding solution to be within the range of 35% to 80% (preferably within the range of 40% to 75%, more preferably within the range of 45% to 70%, and particularly preferably within the range of 50% to 65%) of the content of sodium in the raw material used in step S111. Similarly, the potassium content in the retaining solution is set to be within a range of 35% to 80% (preferably within a range of 40% to 75%, more preferably within a range of 45% to 70%, and particularly preferably within a range of 50% to 65%) of the potassium content of the raw milk.

In other words, the salt rejection of the retaining solution 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%, and particularly preferably within the range of 35% to 50%) by performing the process of step S116. Thus, the salinity of the ice cream cold drink can be adjusted to prevent the taste of the ice cream cold drink from being damaged. Here, if the salt rejection rate exceeds the upper limit of the above range, the ice cream-type cold drink produced exhibits a light taste and the taste becomes weak. On the contrary, if the salt rejection is lower than the lower limit of the above range, the ice cream-type cold drink produced is deteriorated in taste because of its high saltiness.

In addition, it is preferable to adjust the salt rejection rate to the above range by changing (or appropriately selecting) the NF membrane (i.e., osmotic pressure) used for performing this 2 nd nanofiltration treatment. This method was used in place of the above-described method in which the holding solution was subjected to the 3 rd nanofiltration treatment to adjust the salt rejection rate to the above-described range. To this end, the nanofiltration (i.e., diafiltration) process is completed over a number of times.

Further, in step S117, the cream is removed from the desalted and concentrated milk obtained in step S116 to obtain desalted and concentrated skim milk. By "milk fat" is meant the fat-rich fraction of the starting milk (here, the desalted and concentrated milk). For removing the milk fat, for example, the desalted concentrated milk may be centrifuged in a centrifuge (separator), and the separated milk fat may be filtered. This converts the desalted concentrated milk into a low-lipid form (hereinafter also referred to as "DF desalted skim milk"). That is, the content (content ratio) of the milk FAT (FAT) can be greatly reduced without greatly reducing the content (content ratio) of the non-FAT milk solid component (SNF) contained in the desalted and concentrated milk. This may not easily cause coagulation of the milk fat globules. Since the stirring is not easily caused, the quality of the ice cream-like cold drink can be prevented from being changed.

Then, in step S118, the DF desalted skim milk obtained in step S117 is further concentrated to obtain a DF desalted skim milk concentrate. Specifically, the DF desalted skim milk concentrate is obtained by evaporating the water of the DF desalted skim milk. In this concentration treatment, DF-desalted skim milk is heated by evacuation using, for example, a vacuum evaporator (evaporator). In step S119, the DF desalted and defatted concentrated milk is spray-dried using a known spray dryer as needed to obtain DF desalted and defatted milk powder. By forming the DF-desalted skim milk powder, the volume (capacity) can be minimized, and storage (preservation) can be facilitated. Either or both of steps S118 and S119 may not be performed.

The raw material is subjected to the nanofiltration process a plurality of times in accordance with the process of fig. 4 (steps S112 and S116). Further, the obtained reverse osmosis membrane permeate is returned to the nanofiltration concentrated milk obtained from the raw material by reverse osmosis treatment (steps S113 to S114). By these treatments, desalted milk with adjusted desalting rate can be obtained. Further, since the reverse osmosis membrane permeate is returned to the concentrated nanofiltration milk (step S114), the components contained in the raw material can be effectively used without waste.

Then, according to the processing of fig. 4, the milk fat is removed from the desalted milk (step S117). Therefore, even if the fat content is low, desalted milk having a high content ratio of the solid content (SNF) of fat-free milk and the protein content can be obtained from raw milk or the like. In addition, in the present embodiment, since the salt rejection rate can be adjusted as described above, even when an ice cream-based cold drink is produced from a desalted milk having a high protein content as a raw material, the saltiness of the ice cream-based cold drink produced is not excessively high. In addition, in the ice cream cold drink, even if the fat is low, the content ratio of the solid fat-free milk (SNF) to the protein is high, and therefore the milk flavor is not impaired. However, although ice cream (american ice cream) having a high milk fat content is commercially available, the ice cream-based cold drink of the present embodiment may be different from conventional ice cream in that the milk fat content is low.

Next, example 2 (embodiment 2) of the desalted milk obtaining process in step S110 in fig. 2 will be described in detail. The differences between embodiment 2 and embodiment 1 are only: instead of the desalted water, water was added to the nanofiltration concentrate obtained by the 1 st nanofiltration without reverse osmosis treatment as described above. And thus detailed processes thereof are omitted.

In embodiment 2, at least 2 times of nanofiltration treatment (i.e., the above-mentioned Diafiltration (DF) treatment) is performed). By performing the nanofiltration treatment 1 time, the sodium content (content ratio) of the desalted milk is reduced by, for example, 14% to 24% as compared with the raw milk. Therefore, when the nanofiltration treatment is performed 2 times, the sodium content (content ratio) of the desalted milk is reduced by, for example, 26% to 42% as compared with the raw milk in principle. That is, by performing the nanofiltration treatment 2 times, the sodium remaining ratio of the desalted milk is, for example, in the range of 58% to 74%, and thus the desalting ratio can be increased to increase the possibility that the sodium remaining ratio is in the above-mentioned range (20% to 65%) (preferably in the range of 25% to 60%, more preferably in the range of 30% to 55%, and particularly preferably in the range of 35% to 50%). Thus, the salinity of the prepared ice cream cold drink can be adjusted to prevent the taste of the ice cream cold drink from being damaged. Further, if the nanofiltration treatment is performed a plurality of times, the salt rejection rate exceeds the above range. Therefore, it is sufficient to perform the nanofiltration treatment 3 to 4 times at most. However, from the viewpoint of the number of steps, desalting efficiency, product taste, etc., it is preferable to stop at the 2 nd nanofiltration treatment step. In comparison of the sodium content and the salt rejection rate, it is preferable that the total solid content (TS) content (content ratio) is converted to the same state (see table 4b described later).

Next, example 3 (embodiment 3) of the desalted milk obtaining process in step S110 in fig. 2 will be described in detail. Embodiment 3 differs from embodiment 1 or embodiment 2 only in that: the ion exchange resin (IE) method or the Electrodialysis (ED) method is used to replace the nano-filtration treatment, and the concentration and desalination treatment are carried out on the raw materials. And thus detailed processes thereof are omitted.

In embodiment 3, even if the apparatus for the nanofiltration treatment is not provided, the same effects as those in embodiments 1 and 2 can be obtained. However, since the cost of the apparatus for performing the nanofiltration treatment is low, it is preferable to prepare the desalted milk as in embodiment 1 and embodiment 2. In the present invention, since the total solid content or fat-free milk solid content of the raw milk is concentrated and desalted, Ultrafiltration (UF) and Microfiltration (MF) are not performed. In this embodiment, the ion exchange resin (IE) method or the Electrodialysis (ED) method may be performed a plurality of times, or the nanofiltration method may be performed at least 1 time among the plurality of times.

In embodiment 4 of the present invention, the desalted milk obtained by at least 2 of embodiments 1 to 3 is blended with each other, and the blended desalted milk is used as a part or all of the raw materials to produce an ice cream-based cold drink. The present embodiment can also achieve the same effects as those of the setting method.

As described in detail above, according to the present invention, concentration and desalination of the total solid content of the raw milk can be achieved by nanofiltration or reverse osmosis to improve the keeping quality of ice cream cold drinks in a frozen state, and the sweetness of ice cream cold drinks can be improved by enzymes to ensure appropriate softness. Therefore, according to the present invention, ice cream-type cold drinks can be produced at low cost in a simple production step. Further, according to the present invention, since the desalted milk is prepared into the ice cream mix which is one of the raw materials, by using the ice cream mix as the raw material, an ice cream-like cold drink which is soft, has high sweetness and has a good taste can be produced. The desalted milk has a high content of total solid components (particularly, fat-free milk solid components and proteins), a high desalting rate and a high sweetness. The ice cream cold drink thus obtained has good texture (tongue-touching feeling) because growth of ice crystals and lactose crystals is suppressed during freezing storage, and also has excellent storability in a frozen state, good scoopability because of moderate softness, no deterioration in taste because of suppression of saltiness, and good milk taste because of its rich protein content.

Therefore, when the ice cream cold drink is prepared by adopting the invention, excessive sugar is not needed to be added, and the emulsifier and the stabilizer are not needed to be added. In addition, although the emulsifier and the stabilizer may be added to the raw material, the ratio of the emulsifier and the stabilizer to be added to the raw material may be lower than that in the prior art. Moreover, by increasing the fat-free milk solids content of ice cream type cold drinks to ensure a milk taste, the milk fat can be greatly reduced. Therefore, when the ice cream cold drink is prepared by the invention, the flavoring agent (spice) is not needed to be added for compensating the damage of milk taste caused by the reduction of milk fat as the low-fat ice cream cold drink prepared by the prior art is prepared, dextrin or dietary fiber used as a substitute of the milk fat is not needed to be added, and even if the dextrin or the dietary fiber is added, the addition amount can be less compared with the prior art.

Furthermore, according to the invention, ice cream cold drinks with various content ratios can be produced by appropriately changing the composition of the ice cream mix. For example, an ice cream-type cold drink can be produced which has a milk FAT component (FAT) of 0 to 25 wt% (preferably 0 to 20 wt%, more preferably 0 to 18 wt%, particularly preferably 0 to 15 wt%) and a non-FAT milk solid component (SNF) of 5 to 40 wt% (preferably 7 to 35 wt%, more preferably 13 to 30 wt%, particularly preferably 15 to 25 wt%). The upper limit of the solid components of the fat-free milk in the prepared ice cream cold drink can also be 50 wt%. In contrast, in the prior art, since the saltiness is increased by increasing the content of the solid fat-free milk, only ice creams with impaired taste can be produced, and therefore, the content of the solid fat-free milk needs to be controlled to 5 to 10% by weight. According to the present invention, an ice cream type cold drink having a higher solid content of fat-free milk than the prior art (for example, 2 to 5 times higher than the prior art) can be produced. An example of an ice cream type cold drink manufactured according to the present invention is an ice cream type cold drink as follows: the milk protein content thereof is 4 wt% or more and 15 wt% or less (preferably 4 wt% or more and 13 wt% or less, more preferably 4 wt% or more and 11 wt% or less); the content of glucose derived from lactose is 1 wt% to 10 wt% (preferably 1.5 wt% to 9 wt%, more preferably 2 wt% to 8 wt%). The ice cream cold drink is the following ice cream cold drink: it has excellent storage stability, proper saltiness, good taste, proper softness and easy scooping.

[ example 1]

In example 1, in order to confirm whether or not the object can be achieved by the production method of the present invention, the taste and physical properties of ice cream produced using DF-desalted skim milk powder prepared by the above-mentioned Diafiltration (DF) method (the above-mentioned embodiment 2) were examined (production examples 1, 2, 5). Specifically, the size of ice crystals formed in the prepared ice cream was measured, and the measured values were compared to evaluate the growth of ice crystals. The softness (degree of easiness of scooping) of the ice cream was evaluated by measuring the hardness of the ice cream. The prepared ice cream was also evaluated for saltiness, sweetness and milk taste. In example 1, the taste and physical properties of ice cream produced using an ice cream mix prepared without performing a Nanofiltration (NF) method were examined (production examples 3 and 4).

DF desalted and skimmed milk powder was prepared as follows. First, skim milk (solid content concentration: about 9% by weight) was concentrated to a solid content concentration of about 20% by weight by a Nanofiltration (NF) method, and desalting treatment was performed to obtain NF-concentrated skim milk. In this case, NF-3838/30-FF (manufactured by Dow Chemical) was used as a Nanofiltration (NF) membrane. Then, water was added to the NF-concentrated skim milk to dilute the NF-concentrated skim milk to a solid content concentration of about 10% by weight to obtain NF-skim milk. Next, the NF-skim milk was concentrated to a solid content of about 20% by weight by a Nanofiltration (NF) method, and at the same time, a desalting treatment was performed to obtain DF desalted concentrated skim milk. In this case, NF-3838/30-FF (manufactured by Dow Chemical) was also used as a Nanofiltration (NF) membrane. Then adopting the conventional method to perform sterilization, vacuum evaporation concentration and spray drying treatment on the DF desalted and concentrated skim milk. DF desalted skim milk powder was thus obtained. The DF desalted skim milk powder obtained contained about 1 wt% milk fat and about 95 wt% non-fat milk solids.

Production example 1

The ice cream of manufacturing example 1 was made using DF demineralized skim milk powder containing about 1 wt% milk fat and about 95 wt% non-fat milk solids. In the production of ice cream, lactose contained in the DF-desalted skim milk powder was decomposed to 56% (i.e., lactose decomposition rate 56%) by lactase (trade name "GODO-YNL" manufactured by contract alcohol gmbh).

Production example 2

Using the same DF-desalted skim milk powder as in production example 1, an ice cream of production example 2 was produced under the same conditions as in production example 1. In the production of ice cream, lactose contained in the DF-desalted skim milk powder was decomposed to 84% (i.e., lactose decomposition rate was 84%) by lactase.

(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 wt% of milk fat and 10 wt% of fat-free milk solids. But the ice cream mix was not subjected to nanofiltration. 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 so that the conditions were the same as in production example 1. The ice cream of production example 3 had a lactose decomposition rate of 0%.

Production example 4

The same ice cream mix as in production example 3 was used except that lactase was added, and the ice cream of production example 4 was produced under the same conditions as in production example 1. Lactose contained in the ice cream mix was decomposed to 85% (i.e. lactose decomposition rate 85%) using lactase.

Production example 5

The same DF-desalted skim milk powder as in production example 2 was used except that lactase was not added to the ice cream mix, and the ice cream of production example 5 was produced under the same conditions as in production example 1. The ice cream of production example 5 had a lactose decomposition rate of 0%.

The hardness results obtained in production examples 1 to 3 and 5 are shown in Table 1 and FIG. 5. In addition, in the measurement of the hardness, a rheometer (trade name "EZ-test-100N") manufactured by Shimadzu corporation was used, and a stress value [ gf/mm2] measured at a set penetration distance [ mm ] was defined as a "hardness measurement value". The results of evaluating the taste and physical properties of production examples 1 to 5 are shown in Table 2.

[ Table 1]

TABLE 1 hardness of Ice cream (softer the stress value)

[ Table 2]

TABLE 2 evaluation results on Ice cream

In addition, the ice crystals [ μm ] shown in Table 2 are the sizes measured after keeping the ice cream of each production example in a frozen state at-8 ℃ for 1 week, and the ice crystal sizes before storage are all 30 μm.

From table 1, table 2 and fig. 5, the following tendency can be seen: the higher the lactose breakdown rate, the softer the ice cream. Therefore, it is known that ice cream-type cold drinks become softer as the lactose decomposition rate is increased.

When the ice creams of production examples 3 and 4 in table 2 were compared with the ice cream of production example 2, the following tendency was observed: the ice cream of production examples 3 and 4 had ice crystal sizes larger than that of the ice cream of production example 2. Here, the lactose decomposition rate of the ice cream of production example 2 was approximately the same as that of the ice cream of production example 4, and when the compositions of the ice creams of production examples 2 and 4 were compared, the ice cream of production example 2 had a large amount of fat-free milk solids. So that it is known that: by increasing the solid content of the fat-free milk, the ice crystal size can be prevented from increasing when the milk is stored under freezing conditions. That is, it was found that the ice cream of production example 2 was excellent in storage stability under freezing conditions.

As is clear from table 2, when the ice creams of production examples 3 and 4 were compared in terms of taste, the saltiness was approximately the same in both ice creams, and the ice cream of production example 4 perceived a higher sweetness. In addition, the ice cream of production example 5 had a better milk taste than the ice creams of production examples 3 and 4. This phenomenon is considered to be caused by the following reasons: the ice cream mix of the ice cream of production example 5 used DF-desalted skim milk powder, which had a high solid content of nonfat milk. In addition, when the ice creams of production examples 1 and 2 were compared with the ice cream of production example 5, the milk flavor was of the same level, but the former perceived higher sweetness. In addition, when the ice creams of production examples 1 and 2 were compared in terms of sweetness, the ice cream of production example 2 experienced higher sweetness. The reason why the higher sweetness is perceived in this way is considered to be because the lactose decomposition rate of the ice cream of production examples 1 and 2 is high.

In table 2, softness (hardness) was compared, and the same degree was observed between production example 3 and production example 5. I.e. the ease with which ice cream is scooped out is at the same level. Further, when production examples 1 and 2 were compared with production example 5, it was found that the ice creams of production examples 1 and 2 were softer than the ice cream of production example 5, and the ice cream of production example 2 was softer than the ice cream of production example 1. Therefore, it is found that the higher the lactose decomposition rate is, the softer the ice cream prepared is and the better the scoopability is. The reason is considered to be caused by the following reasons: as in production examples 1 and 2, the decomposition rate of lactose was increased, the content of lactose was decreased, and monosaccharide was produced, resulting in a decrease in freezing point. In addition, the ice cream of production examples 1 and 2 had an excellent texture because the formation of lactose crystals was suppressed.

In addition, a plurality of ice cream mixes in which NF desalted and skimmed milk concentrate, DF desalted and skimmed milk concentrate, NF desalted and whole milk concentrate, DF desalted and whole milk concentrate, NF milk fat, and DF milk fat are mixed are produced in such a manner that the milk fat component is 12 to 15 wt% and the fat-free milk solid component is 13 to 20 wt%, and the ice cream is produced by subjecting the ice cream mixes to lactose decomposition treatment. In comparison with production example 3, both of them were perceived to have better sweetness and milk taste in a state where the saltiness was adjusted to the same degree or just to the same degree.

As can be seen from the above, in production examples 1 and 2, the use of DF-desalted skim milk powder as an ice cream mix can improve the solid content of nonfat milk, suppress the saltiness of ice cream, make the milk taste good, and improve the lactose decomposition rate, thereby improving the sweetness of ice cream, facilitating scooping, and ensuring appropriate softness. Further, it is understood from production examples 1 and 2 that even if a stabilizer and an emulsifier are not used, by increasing the content of the solid components (i.e., proteins) of the fat-free milk and increasing the lactose decomposition rate, ice cream having excellent storage stability under freezing conditions can be produced.

[ example 2]

In example 2, in order to confirm the change in the composition due to desalting, a desalted concentrated milk was first produced according to embodiment 1, and the composition and the blending ratio of the desalted concentrated milk (production example 6) were examined. Here, fig. 6 is a schematic diagram of a preparation procedure for installing the desalted concentrated milk of embodiment 1. The step number S shown in fig. 6 corresponds to the step number S shown in fig. 4.

First, raw milk was concentrated to about 2.0 times using a Nanofiltration (NF) method. To obtain a nanofiltration-treated nanofiltration concentrated milk (NF concentrated milk) (production example 7). The permeate obtained by the nanofiltration process was treated by the Reverse Osmosis (RO) method to prepare a reverse osmosis membrane permeate (desalted water). Adding the reverse osmosis membrane penetration liquid and water into the nano-filtration concentrated milk to obtain desalted milk with the same weight as the original raw milk. The desalted milk was concentrated to about 2.0 times by Nanofiltration (NF) treatment. Thus, dialyzed and filtered desalted milk (DF desalted concentrated milk) was obtained. This DF desalted and concentrated milk was separated into DF cream and DF skim concentrated milk by a centrifuge (separator) to obtain DF desalted and skim concentrated milk of production example 6. It was also confirmed that the DF desalted and skimmed milk concentrate was concentrated in a vacuum evaporator (evaporator) to obtain a DF desalted and skimmed milk powder having excellent storability (preservation).

Then, the composition and the ratio of the obtained DF desalted and defatted concentrated milk were examined. In addition, the composition and content ratio were also investigated for the following 2 items: the nanofiltration concentrated milk obtained in the production stage of production example 6 (production example 7); a skim concentrated milk obtained by subjecting a skim concentrated milk to a skim concentration treatment without subjecting the milk to nanofiltration and reverse osmosis membrane treatment (production example 8).

Table 3 shows the results of the investigation of the respective compositions, and table 4 (table 4a and table 4b) shows the results of the investigation of the content ratios of the respective compositions.

[ Table 3]

TABLE 3 composition of respective skim concentrates (% by weight)

[ Table 4]

TABLE 4a composition ratio of each skim concentrate (ratio of each composition of skim concentrates to 1.00)

TABLE 4b composition ratio of each skim concentrate (ratio of each composition of skim concentrates to 1.00)

Ratio of total solid content to 1.00

As is clear from Table 4b, the desalted milk of production example 6 had a sodium content ranging from 35% to 80% and the desalted milk of production examples 7 and 8 was more than 75%. The following is verified: the desalination rate can be adjusted by concentrating and desalting the raw material as in embodiment 1. In addition, it is known that: even if the raw material is subjected to the nanofiltration treatment or the reverse osmosis membrane treatment, the residual rate of calcium does not vary greatly (specifically, the residual rate can be ensured to be 90%).

In production example 6, similar results were obtained even when skim milk was used instead of raw milk. When the desalted milk is obtained using skim milk, a step of separating the skim milk into cream and skim concentrated milk by a centrifugal separator may be provided before the desalting step.

[ example 3]

In example 3, a plurality of ice creams having different ratios of milk fat and solid non-fat milk are produced by mixing the DF desalted and skimmed concentrated milk obtained in embodiment 1 and the desalted and skimmed milk powder obtained in embodiment 2, and using the mixture as a material (production examples 9 to 15). In addition, ice cream was produced when neither the DF desalted skim milk concentrate obtained in embodiment 1 nor the desalted skim milk powder obtained in embodiment 2 was used (production example 16).

The raw material ratios of production examples 9 to 16 are shown in tables 5 and 6. In addition, the content ratio of each composition of the ice cream produced is shown in tables 5 and 6.

TABLE 5 table 5 Ice cream mix proportion of High protein (High SNF) Low Fat (Low Milk Fat) (1)

TABLE 6 table 6 Ice cream mix ratio of High protein (High SNF) Low Fat (Low Milk Fat) (2)

As can be seen from tables 5 and 6, ice cream can be produced according to the present invention in various ratios. In addition, it is known that: the ice creams of production examples 9 to 15 contain the DF desalted and skimmed milk concentrate (desalted and skimmed milk concentrate subjected to diafiltration and lactose decomposition treatment) prepared according to embodiment 1 and the desalted and skimmed milk powder (desalted and skimmed milk powder subjected to diafiltration treatment) prepared according to embodiment 2, and therefore have high sweetness even if the amount of sugar (sucrose) added to the raw material is less than that of production example 16.

[ INDUSTRIAL APPLICABILITY ]

The invention can be applied to the food industry.

Claims

1. An ice cream cold drink is characterized in that,

the content of the solid components of the fat-free milk is 19 to 25 wt%,

the content of sodium is 46.4-65.8 mg/100g,

the content of glucose derived from lactose is 2.4-5 wt%,

the lactose-derived glucose is obtained by subjecting lactose to enzymatic hydrolysis at a decomposition rate of 50% or more and 100% or less.

2. An ice cream-type cold drink according to claim 1,

the content of calcium is 215.9-334.0 mg/100 g.

3. An ice cream-type cold drink according to claim 1 or 2,

the stress value measured at a penetration distance of 20mm using a rheometer manufactured by Shimadzu under the trade name "EZ-test-100N" was 28.48gf/mm²。

4. An ice cream-type cold drink according to claim 1 or 2,

the stress value measured at a penetration distance of 15mm using a rheometer manufactured by Shimadzu under the trade name "EZ-test-100N" was 22.00gf/mm²。

5. An ice cream-type cold drink according to claim 1 or 2,

the stress value measured at a penetration distance of 10mm using a rheometer manufactured by Shimadzu under the trade name "EZ-test-100N" was 14.77gf/mm²。

6. An ice cream-type cold drink according to claim 1 or 2,

the stress value measured at a penetration distance of 5mm using a rheometer manufactured by Shimadzu under the trade name "EZ-test-100N" was 6.96gf/mm²。

7. An ice cream-type cold drink according to claim 1 or 2,

contains no milk fat component or less than 25 wt% of milk fat component.

8. An ice cream-type cold drink according to claim 1 or 2,

the content of the milk fat component is 0.2-25 wt%.

9. An ice cream based cold drink according to claim 1 or 2, characterised in that it is free of emulsifiers and stabilisers.

10. An ice cream cold drink is characterized in that,

the content of milk protein is 4-15 wt%,

the content of sodium is 46.4-65.8 mg/100g,

the content of glucose derived from lactose is 2.4-5 wt%,