HK1164650A - Fermented whey preparation and method for producing same - Google Patents

Description

Fermented whey preparation and process for producing the same

Reference to related applications

This application is based on the priority claim of Japanese patent application No. 2008-272978 (application date: 2008-10/23), the disclosure of which is incorporated herein by reference in its entirety.

Technical Field

The present invention relates to a fermented whey preparation to which a unique sour taste and a natural sweet taste are imparted by fermentation, and which has a fresh and refreshing flavor and a good texture, and a method for producing the same. The present invention also relates to a beverage containing such a whey preparation and a method for producing the same.

Background

Whey by-produced in cheese production or the like is known to contain a large amount of various essential amino acids, proteins, vitamins, and sugars, and to have high nutritional value. On the other hand, whey is inferior in flavor only after drying, and is not sufficient for direct consumption. Therefore, attempts have been made to produce various foods utilizing the nutritional value of whey.

For example, attempts have been made to produce a beverage from an aqueous whey protein solution. However, if the whey protein aqueous solution is sterilized at high temperature, the protein is thermally aggregated and the quality is significantly deteriorated. For example, if an aqueous whey protein solution is prepared to a high concentration of 10 wt% or more, then the pH is made weakly acidic to 6.5 or less, and then high-temperature sterilization is performed at 90 ℃ or higher, a large aggregate is generated. Therefore, in mass production on a commercial scale, the aggregates cannot be sufficiently dispersed in the tank and/or the piping, and adhesion and/or deposition to the tank, the piping, and the valve become significant, thereby causing contamination. Further, if the pH of the whey protein aqueous solution is adjusted to 6.0 or less and then the aqueous solution is fermented, the functions of lactic acid bacteria and/or yeast are not easily exerted, and it is difficult to obtain a unique and good flavor by fermentation.

For example, Japanese patent application laid-open No. Sho 61-170341 relates to a method for producing a fermented whey beverage. Japanese patent application laid-open No. 62-040248 relates to a method for producing a whey fermentation substrate (whey source base). Japanese examined patent publication (Kokoku) No. 07-051046 relates to a method for producing fermented whey powder (these publications are all filed by the present applicant).

These publications disclose: the fermented whey preparation is produced by adjusting the solid content of the whey aqueous solution to about 2 to 20 wt% (i.e., the concentration of whey protein is about 1 to 13 wt%), sterilizing the aqueous solution at a relatively low temperature such as 90 ℃ for 10 minutes, and then fermenting the aqueous solution with lactic acid bacteria. Among them, sterilization under a relatively low temperature condition (low temperature sterilization) is essential. This is considered to be because if the temperature is higher than this condition, aggregates are generated by thermal denaturation (thermal coagulation) of the protein, which is not preferable in terms of product quality. Further, the sterilization efficiency of the low-temperature sterilization is not necessarily satisfactory.

Japanese patent application laid-open No. H09-238614 (Japanese patent No. 3417513) relates to a method for preparing whey, and discloses: a white whey preparation having excellent thermal stability is produced by adjusting the solid content concentration of a whey aqueous solution to about 0.1 to 10 wt% (that is, adjusting the concentration of whey protein to about 0.5 to 1.2 wt%), adjusting the pH to 5.5 to 6.5, and then sterilizing the whey aqueous solution at a high temperature of 90 ℃ or higher, for example, 120 ℃ for 2 seconds (high-temperature sterilization) to convert whey protein micelles (colloidal particles having a particle size of 20 to 600 [ mu ] m). Here, it is particularly necessary to make the concentration of the solid content of the whey aqueous solution 10 wt% or less (that is, to make the concentration of whey protein 1.2 wt% or less) and to make the pH value weakly acidic, i.e., 5.5 to 6.5. These conditions are essential in the micellization of whey proteins and in obtaining white whey.

Therefore, it is not assumed here that the solid content concentration of the whey aqueous solution is more than 10% by weight or the pH value is more than 6.5, and it is needless to say that a method for ensuring good thermal stability in such a case is not suggested. Further, fermentation with lactic acid bacteria and/or yeast is not contemplated herein.

With regard to the decomposition of lactose in lactic acid fermentation, for example, japanese patent No. 3389377 discloses a method for producing fermented milk in which lactose is decomposed. However, the use of milk as a raw material is not limited to the use of an aqueous whey protein solution as in the present invention, and the improvement of the flavor, physical properties, taste and the like of the resulting fermented product is not considered at all.

Disclosure of Invention

The present inventors have obtained an aqueous solution containing aggregates as a result of subjecting an aqueous whey protein solution having a solid content adjusted to 11 to 35 wt% and a pH adjusted to 6.5 to 8.0 to high-temperature sterilization, but have unexpectedly obtained a fermented whey preparation having excellent flavor and texture which have not been obtained so far by subjecting the aqueous solution to lactic acid fermentation and homogenizing the obtained fermentation liquid.

In this case, a good whey preparation can be obtained not only in the case of lactic acid fermentation using lactic acid bacteria but also in the case of lactic acid fermentation using yeast. Further, it has been attempted to add lactase to the whey protein aqueous solution sterilized at high temperature before, during or after the lactic acid fermentation to enzymatically hydrolyze lactose in the aqueous solution to glucose and galactose during or before the lactic acid fermentation, and as a result, no tendency is observed that the enzymatic reaction inhibits the lactic acid fermentation, and the resulting fermented whey preparation is imparted with a unique sourness and a natural sweetness by fermentation, and has a fresh and fresh flavor which is not heretofore known and is scarce for the fermented product, thereby successfully improving the flavor of the fermented whey preparation. This flavor is enhanced in natural sweetness compared to the case of not decomposing lactose with an enzyme (lactase), and the fermented whey preparation exhibits a more favorable flavor due to the excellent balance between this sweetness and sourness generated by fermentation. The fermented whey preparation obtained had smooth texture and appropriate viscosity, and also had excellent heat stability. Further, since the fermented whey preparation is subjected to a high-temperature sterilization treatment, it does not contain miscellaneous bacteria such as thermophilic bacteria and is excellent in hygiene. Further, if a beverage is prepared by using the fermented whey preparation as a raw material for a fruit juice beverage or the like, a beverage having excellent flavor and physical properties can be obtained. The present invention has been made based on such knowledge.

Accordingly, an object of the present invention is to provide a fermented whey preparation having a fresh and refreshing flavor and a smooth mouth feel to the mouth while having a good flavor imparted with a unique sour taste and a natural sweet taste by fermentation, and also having excellent thermal stability and safety. It is another object of the present invention to provide a method for producing such a fermented whey preparation.

The fermented whey preparation of the present invention is a fermented whey preparation obtained by subjecting an aqueous whey protein solution having a solid content concentration of 11 to 35 wt% and a pH value of 6.5 to 8.0 to high-temperature sterilization, then subjecting the aqueous whey protein solution to lactic acid fermentation, and homogenizing the resulting fermentation liquid, wherein the sweetness is enhanced by subjecting lactose contained in the aqueous whey protein solution subjected to high-temperature sterilization to enzymatic hydrolysis with lactase before, during, and/or after the lactic acid fermentation.

According to a preferred embodiment of the present invention, the fermented whey preparation is obtained by enzymatic hydrolysis of lactose with lactase prior to and during lactic acid fermentation, or during lactic acid fermentation.

In the present invention, typically, when the whey protein aqueous solution is subjected to lactic acid fermentation, the lactic acid fermentation is a step of producing lactic acid by fermentation using lactic acid bacteria or yeast.

According to a preferred embodiment of the present invention, the high-temperature sterilization is performed at 91 to 99 ℃ for 5 to 15 minutes, or at 100 to 150 ℃ for 1 to 30 seconds.

According to another preferred embodiment of the present invention, the pH of the aqueous whey protein solution is adjusted to 6.6 to 7.6.

In the above step, when the aqueous solution after high-temperature sterilization contains aggregates, the aggregates have a particle size of 2 to 100 μm, and the aqueous solution is directly supplied to the lactic acid fermentation step.

The beverage of the present invention contains the fermented whey preparation of the present invention.

Preferably, the beverage of the present invention is obtained by the following process: the fermented whey preparation of the present invention is added with an additive component for a beverage, and subjected to a high-temperature sterilization treatment at 100 to 150 ℃ for 1 to 30 seconds.

The method for producing a fermented whey preparation of the present invention comprises the steps of: a method for producing a fermented whey preparation, which comprises subjecting an aqueous whey protein solution having a solid content of 11-35 wt% and a pH value of 6.5-8.0 to high-temperature sterilization, subjecting the aqueous whey protein solution to lactic acid fermentation, and homogenizing the resulting fermentation liquid, wherein the method is characterized in that the sweetness is enhanced by subjecting lactose contained in the aqueous whey protein solution subjected to high-temperature sterilization to enzymatic hydrolysis with lactase before, during, and/or after the lactic acid fermentation. In this production method, it is preferable that the enzymatic hydrolysis of lactose is carried out with lactase before and during the lactic acid fermentation or during the lactic acid fermentation. Further, the manufacturing method more preferably includes the steps of: by adjusting the fermentation time, the sour taste due to lactic acid fermentation and the sweet taste due to enzymatic hydrolysis with lactase are adjusted, respectively, thereby adjusting the flavor of the whole whey preparation.

According to a preferred embodiment of the present invention, in the above production method, the high-temperature sterilization is preferably performed at 91 to 99 ℃ for 5 to 15 minutes, or at 100 to 150 ℃ for 1 to 30 seconds. In addition, the pH value of the whey protein aqueous solution used for high-temperature sterilization is preferably adjusted to 6.6-7.6.

In addition, the method preferably comprises a step of, when the aqueous solution after high-temperature sterilization contains aggregates, directly supplying the aqueous solution to the lactic acid fermentation step, the aggregates having a particle size of 2 to 100 μm.

According to a preferred embodiment of the present invention, the method for producing a beverage of the present invention includes the steps of: the fermented whey preparation obtained above is added with an additive for a beverage, and subjected to a high-temperature sterilization treatment at 100 to 150 ℃ for 1 to 30 seconds to obtain a beverage.

In the present invention, a fermented whey preparation having a flavor and a texture which have not been obtained so far, excellent heat stability and safety, and a beverage made from the fermented whey preparation can be obtained by sterilizing under conditions which have been avoided by the generation of aggregates due to thermal denaturation of proteins, directly performing lactic acid fermentation in a state of containing aggregates, and further performing homogenization. The fermented whey preparation of the present invention has enhanced natural sweetness accompanying lactose degradation, and as described above, has a good flavor imparted with unique sourness and natural sweetness by fermentation, has a fresh and refreshing flavor, has a smooth mouthfeel to the mouth, and is excellent in heat stability and safety. The fermented whey preparation of the present invention has properties (texture) and flavor (body) that have not been found so far as it is a raw material, preparation, beverage, etc. derived from whey. In the present invention, lactic acid fermentation can be carried out at about the optimum temperature (for example, 40 ℃) for lactase, so that lactic acid fermentation and enzymatic reaction can be carried out simultaneously, and as a result, the fermented whey preparation can be produced more efficiently under conditions suitable for commercial scale production. In addition, in the present invention, since it was confirmed that the enzymatic reaction does not inhibit lactic acid fermentation, it is possible to inhibit the proliferation of undesired bacteria such as thermophilic bacteria under the dominance of lactic acid bacteria, and to sanitarily perform both the enzymatic reaction and lactic acid fermentation. The fermented whey preparation and the beverage containing the fermented whey preparation having the above properties can be advantageously distinguished from existing products, and thus are said to have high commercial value.

Drawings

FIG. 1 shows an example of a process for producing a fermented whey preparation of the present invention.

Fig. 2 shows an example of a process for producing a beverage of the present invention.

Detailed Description

Fermented whey preparation

The fermented whey preparation of the present invention is a fermented whey preparation obtained by sterilizing an aqueous whey protein solution having a solid content concentration of 11 to 35 wt% and a pH value of 6.5 to 8.0 at high temperature, then subjecting the sterilized aqueous whey protein solution to lactic acid fermentation, and homogenizing the resulting fermentation liquid, as described above, wherein the sweet taste is enhanced by subjecting lactose contained in the aqueous whey protein solution subjected to the high-temperature sterilization to enzymatic hydrolysis with lactase before, during, and/or after the lactic acid fermentation.

As far as the present inventors know, there has been almost no report on an example of producing a fermented whey preparation by sterilizing an aqueous whey protein solution at a solid content of more than 10 wt% and at a high temperature of more than 90 ℃ and then fermenting the sterilized solution with lactic acid bacteria or yeast. This is considered to be because if the aqueous whey protein solution is sterilized, for example, at an ultra-high temperature (UHT), the whey protein is thermally aggregated and the quality is significantly deteriorated. For example, if an aqueous whey protein solution is prepared at a high concentration, then the pH is made weakly acidic to 6.5 or less, and then sterilization is performed at a high temperature of more than 90 ℃, a large aggregate is produced.

Therefore, in mass production on a commercial scale, the dispersion of the coagulated material in the tank, the pipe, or the like is not easy, and the adhesion and/or deposition to the tank, the pipe, or the valve becomes remarkable, which also causes contamination. Conventionally, it has been common to avoid the formation of aggregates, and to supply the aggregates to a fermentation step after homogenization or the like even if the aggregates are formed. Further, if the aqueous whey protein solution is fermented again with weak acidity of pH 6.5 or less, the function of lactic acid bacteria is not easily exerted, and the fermentation is not easily progressed, so that it is not easy to obtain a unique and good flavor by the fermentation. On the other hand, if the pH of the whey protein aqueous solution is greater than 8.0, the flavor derived from alkalinity may be too strong, and therefore, the flavor may become undesirable as a raw material for beverages.

The process for producing the fermented whey preparation of the present invention will be described. As an example of the process diagram of the manufacturing process, the process diagram shown in fig. 1 may be mentioned.

In the present invention, whey protein is intended to include a reduced solution of a raw liquid and/or a concentrated liquid of whey, whey powder, or the like. Whey proteins that may be used include whey Protein concentrate (wpc) (white Protein concentrate), whey Protein isolate (wpi (white Protein isolate)), sweet whey powder, desalted whey powder, skimmed milk powder, and the like, and these whey proteins may be used in combination. Further, commercially available products may be used. Regarding the main component composition of whey, as a typical example, WPC contains, for example, 95.5% of solid content, 76.0% of protein, 12.0% of lactose, and 2.5% of ash. For WPI, for example, the solid content is 94.1%, at which time the protein is 90.0%, lactose is 1.7%, and ash is 1.8%. In addition, in the case of sweet whey powder, for example, the solid content was 97.0%, in this case, the protein was 12.0%, the lactose was 75.5%, and the ash was 8.5%. For the desalted whey powder, for example, the solid content is 98.1%, and in this case, the protein is 11.8%, the lactose is 79.7%, and the ash content is 5.6%. In addition, in the case of skim milk powder, for example, the solid content is 95.5%, and in this case, the protein is 34.0%, the lactose is 53.5%, and the ash is 8.0%.

The amount (concentration) of the protein can be easily measured by a conventional method or apparatus such as the Kjeldahl method or the Law method, if necessary.

The whey protein used is preferably WPC, sweet whey powder, desalted whey powder, or a mixture thereof, more preferably a mixture of sweet whey powder and WPC. When such a mixture is used, the mixing ratio (on a weight basis) thereof is preferably 1: 2 to 2: 1, more preferably 1: 1 to 2: 1.

The concentration of the solid content in the aqueous whey protein solution to be used is preferably adjusted to 11 to 35% by weight, more preferably 13 to 30% by weight, and still more preferably 15 to 25% by weight. In this case, the concentration of the whey protein is preferably 1.3 to 4.5 wt%, more preferably 1.5 to 4 wt%, and still more preferably 1.7 to 3 wt%. Such a range is preferable from the viewpoint of denaturing whey protein to form aggregates having an appropriate particle size.

When the whey protein is dissolved in water, the temperature is controlled to about 40 to 60 ℃ as required, and as the dissolver, a powerful stirrer, a homomixer, a high-speed stirrer or the like can be used as required.

In a usual milk beverage or the like, the solid content concentration is often about 5 to 15 wt%. This is from the viewpoints of avoiding problems such as adhesion in the production process, and the like, and of flavor, taste, and the like. In the present invention, by increasing the solid content of the whey protein aqueous solution to make the milk component high in concentration and fermenting with lactic acid bacteria or yeast, the unique and good flavor produced by fermentation can be enhanced. In this case, it is also important to prevent the formation of excessively large aggregates from the viewpoint of the actual production characteristics of the product, and in the present invention, a whey fermented preparation having a good flavor is successfully obtained by suppressing the size of the aggregates to an appropriate size and directly utilizing the aggregates.

In the present invention, the concentration of the solid content in the aqueous solution can be easily determined by a conventional method and apparatus such as a simple water content measurement method and a sand mixing method.

The aqueous whey protein solution to be used is adjusted to a pH of 6.5 to 8.0, preferably 6.6 to 7.8, more preferably 6.6 to 7.6, still more preferably 6.8 to 7.4, yet more preferably 6.8 to 7.2, and most preferably about 7.0 before the high-temperature sterilization treatment.

Here, the pH adjustment is preferably performed using a pH adjuster. The pH adjuster that can be used here is not particularly limited as long as it can adjust the pH value within the above range and is safe for use as food, and typically can be selected from sodium hydroxide, potassium hydroxide, sodium bicarbonate, and sodium carbonate. Also, they may be used in combination. According to a preferred mode of the invention, the pH regulator is sodium hydroxide.

When a pH adjuster is used, the amount of the pH adjuster to be used may be appropriately changed depending on the type of the pH adjuster to be used, the target pH to be raised, the state of the aqueous solution to be added (e.g., temperature, pH, etc.), and the like, and when sodium hydroxide is used as the pH adjuster, the amount of the pH adjuster to be used is typically 0.01 to 0.5% by weight, preferably 0.01 to 0.3% by weight, if defined by the concentration.

In the present invention, a whey protein aqueous solution having a solid content concentration of 11 to 35 wt% and a pH of 6.5 to 8.0 is first sterilized at high temperature. Here, the heating conditions in the high-temperature sterilization treatment correspond to the normal sterilization treatment conditions. Generally, a beverage containing milk and/or whey is sterilized by various methods before being marketed as a product, and the term "high-temperature heat sterilization conditions" as used herein refers to conditions that are one mode of such a general sterilization treatment. Therefore, the heating conditions for the high-temperature sterilization treatment in the present invention are not particularly limited as long as they are the conditions for the heat sterilization treatment which are generally used in the field of beverages and/or foods, and in the present invention, heating conditions exceeding 90 ℃ are particularly used. The conditions are conditions under which thermal denaturation of the protein can occur. When high-temperature sterilization is performed, since it is possible to sufficiently kill undesired bacteria such as high-temperature bacteria, sanitation is improved, and contamination during fermentation as a later step is easily suppressed.

According to a preferred embodiment of the present invention, the high-temperature sterilization treatment is performed, for example, at 91 to 99 ℃ for about 5 to 15 minutes, preferably at 92 to 98 ℃ for about 7 to 13 minutes, more preferably at 93 to 97 ℃ for about 8 to 12 minutes, and particularly preferably at about 95 ℃ for about 10 minutes. According to another preferred embodiment, the conditions for the high-temperature sterilization treatment are, for example, 100 to 150 ℃ for about 1 to 30 seconds, preferably 110 to 140 ℃ for about 1 to 20 seconds, more preferably 115 to 135 ℃ for about 1 to 10 seconds, still more preferably 120 to 130 ℃ for about 1 to 5 seconds, and particularly preferably about 120 ℃ for about 3 seconds. After the high-temperature sterilization, the treated aqueous solution is cooled as necessary.

The cooling temperature may be set based on the fermentation temperature in the subsequent fermentation step, and is, for example, about 30 to 50 ℃.

In addition, during the high-temperature sterilization treatment, pressure may be further applied to the aqueous solution. In general, in order to prevent boiling of an aqueous solution or the like during heat sterilization treatment, the sterilization pressure is set to 1 to 10kg/cm, for example²Left and right. In the sterilization treatment in the present invention, such pressure may be applied in addition to heating. Examples of the high-temperature sterilization apparatus include a plate heat exchanger, a tube heat exchanger, a steam injection sterilizer, a steam extraction sterilizer, and an electric heating sterilizer.

In the present invention, if such a high-temperature sterilization treatment is performed, the obtained aqueous solution contains aggregates. The particle size of the agglomerates is not huge, but rather of a moderate size that does not immediately precipitate. Typically, the aqueous solution may contain aggregates having a particle size of 1 to 100 μm, preferably 2 to 80 μm, more preferably 4 to 60 μm, and still more preferably 5 to 50 μm.

Since the aggregate has such a size that it does not precipitate immediately, lactic acid bacteria or yeast can be directly added thereto to perform the subsequent lactic acid fermentation treatment.

The particle size of the aggregate can be measured by a laser diffraction particle size distribution measuring apparatus SALD-2100 (manufactured by Shimadzu corporation) or the like.

In the present invention, lactic acid fermentation refers to a step of fermenting an aqueous whey protein solution under predetermined fermentation conditions as described below using a predetermined microorganism to produce an organic acid (lactic acid, succinic acid, malic acid, etc.), particularly lactic acid. As the microorganism which can be used for lactic acid fermentation, either lactic acid bacteria or yeast is preferably used. In the lactic acid fermentation of the present invention, whether or not an organic acid, particularly lactic acid, is produced during the fermentation and the degree of production thereof can be confirmed by measuring the acidity (%) of the target solution.

Here, "acidity" can be obtained according to the "5 milk and a better-able milk-acidity perceptual rule (a measure of acidity in milk and milk products)" on page 56 of the milk industry association consortium (japan), which is leveled to 16 years (2004) for 3 months). Specifically, 10ml of the sample was diluted with an equal amount of carbon dioxide-free water, 0.5ml of phenolphthalein solution was added as an indicator, and titration was performed using 0.1 mol/L sodium hydroxide solution to the extent that reddish color did not disappear within 30 seconds, and the percentage content of lactic acid per 100g of the sample was determined from the titration amount and was taken as acidity (%). When the acidity of lactic acid is calculated, it is particularly referred to as "acidity of lactic acid" (%). Further, 1ml of 0.1 mol/L sodium hydroxide solution corresponded to 9mg of lactic acid. The indicator is prepared by dissolving phenolphthalein 1g in 50% ethanol to make 100 ml.

The lactic acid bacteria that can be used herein are not particularly limited as long as they can be used for whey fermentation, and include, for example, the genera Lactobacillus (Lactobacillus), Streptococcus (Streptococcus), and Bifidobacterium (Bifidobacterium), and specific examples thereof include the lactic acid strains Lactobacillus bulgaricus (Lactobacillus bulgaricus), and Streptococcus thermophilus (Streptococcus thermophilus).

The yeast that can be used here is not particularly limited as long as it can be used for whey fermentation, and examples thereof include Candida (Candida), Kluyveromyces (Kluyveromyces), and the like, and specific examples thereof include Candida lactis (Candida kefyr), Kluyveromyces Marxianus, and the like, which are yeast strains.

As described above, in the present invention, lactic acid fermentation may be performed using yeast, in addition to lactic acid fermentation using lactic acid bacteria. By lactic acid fermentation using yeast, a flavor different from that obtained when lactic acid bacteria are used can be obtained, and thus good and various whey preparations can be obtained. In the present invention, a fermentation liquid (or whey preparation) obtained by lactic acid fermentation using lactic acid bacteria and a fermentation liquid (or whey preparation) obtained using yeast may be mixed and used as necessary.

As the amount of added bacteria (as starter (st)arter), for example, so that the concentration of lactic acid bacteria (or yeast) in the aqueous solution is 10⁹The amount of cfu/mL is preferably about 0.1 to 3 wt% based on the weight of the sterilized whey protein aqueous solution, and specific examples thereof include 2 wt%.

The conditions for fermentation with lactic acid bacteria are, for example, 30 to 50 ℃ for 1 to 40 hours, preferably 35 to 45 ℃ for 2 to 20 hours, and more preferably 37 to 43 ℃ for 3 to 10 hours.

The conditions for fermentation with yeast are, for example, 20 to 40 ℃ for 1 to 72 hours, preferably 25 to 35 ℃ for 12 to 60 hours, and more preferably 27 to 33 ℃ for 24 to 48 hours.

In the present invention, in addition to lactic acid fermentation, the sweet taste of the fermented whey preparation is enhanced by decomposing lactose, by subjecting lactose contained in the whey protein aqueous solution sterilized at high temperature to enzymatic hydrolysis with an enzyme (lactase) before, during, and/or after lactic acid fermentation, to form glucose and galactose.

The lactase used herein is not particularly limited as long as it can decompose lactose contained in the whey protein aqueous solution into glucose and galactose, and, for example, lactase derived from bacteria or yeast can be used. The lactase that can be used in the present invention may have an optimum pH of, for example, 5.5 to 7.5, and an optimum temperature of, for example, 25 to 50 ℃.

In the present invention, it is generally preferable that the enzymatic reaction proceeds as the fermentation treatment of lactic acid fermentation of the aqueous whey protein solution proceeds, and lactase is preferably selected so that the enzymatic reaction can proceed under the fermentation conditions in lactic acid fermentation. The enzymatic treatment step for carrying out the enzymatic reaction may be provided separately from the lactic acid fermentation treatment as necessary, but from the viewpoint of simplification of the step and the like, it is preferable to carry out the enzymatic reaction using lactase under the same conditions as the lactic acid fermentation or under the conditions before and after the lactic acid fermentation.

Therefore, it is preferable to select lactase having an optimum temperature equal to the fermentation temperature for lactic acid fermentation in the practice of the present invention and having an optimum pH including a pH obtainable from an aqueous whey protein solution after pasteurization. Therefore, if considering the conditions after the whey protein aqueous solution is sterilized at high temperature and during or before the lactic acid fermentation, the optimum pH and the optimum temperature of the lactase to be used are preferably 6.0 to 7.0 and 35 to 45 ℃.

Examples of the source of lactase that can be used in the present invention include Kluyveromyces lactis (Kluyveromyces lactis), Kluyveromyces Fragilis (Kluyveromyces Fragilis), Aspergillus niger (Aspergillus niger), and Aspergillus oryzae (Aspergillus oryzae).

In addition, according to another more preferred embodiment of the present invention, lactase used for the decomposition of lactose may have a property of being inactivated at a pH of about 5.0 to 5.5 or less.

If lactase having such a property of being inactivated depending on the pH is used, the pH of the whey protein aqueous solution gradually decreases as the lactic acid fermentation proceeds, and therefore the enzyme is automatically inactivated at a stage when the lactic acid fermentation proceeds to some extent, and as a result, the enzyme reaction can be stopped. That is, the lactic acid fermentation and the progress and stoppage of the enzyme reaction can be regulated only by regulating the amount of the enzyme used and the fermentation time of the lactic acid fermentation. Lactase (enzyme) which can be inactivated in this way depending on the pH can be used, for example, as a commercially available product.

The lactase may be added to the aqueous whey protein solution after the high-temperature sterilization for a period of time after the high-temperature sterilization and before the production of the fermented whey preparation is completed. Therefore, for example, lactase may be added to the aqueous whey protein solution at a stage after the pasteurization, when the aqueous whey protein solution is appropriately cooled, and before the lactic acid fermentation. In this case, the enzymatic reaction accompanied by lactose degradation may be performed from immediately after the lactase is added to before the start of lactic acid fermentation, and the enzymatic reaction may be performed after the start of lactic acid fermentation.

Further, lactase may be added to the whey protein aqueous solution at the same time as, immediately before or immediately after the start of lactic acid fermentation, that is, simultaneously with the addition of lactic acid bacteria as a starter, immediately before or immediately after the addition, for example. In addition, lactase may be added to the whey protein aqueous solution after the addition of lactic acid bacteria and before the completion of lactic acid fermentation. In these cases, lactose contained in the whey protein aqueous solution may be decomposed by an enzyme reaction in parallel with the lactic acid fermentation.

As described above, in the present invention, lactase may be added to the whey protein aqueous solution at a stage before lactic acid fermentation, simultaneously with addition of lactic acid bacteria as a starter, immediately before or immediately after addition, or after addition of lactic acid bacteria and before completion of lactic acid fermentation, and when lactase is added thereto, it may be appropriately selected in consideration of a desired degree of enzymatic hydrolysis, an amount of enzyme to be added, a desired enzyme reaction time, and the like. Thus, according to a preferred embodiment of the invention, the enzymatic hydrolysis of lactose with lactase can be carried out before and during the lactic acid fermentation, or during the lactic acid fermentation.

In the present invention, lactase may also be added to the aqueous whey protein solution after lactic acid fermentation. In this case, it is preferable that the lactase is added after the lactic acid fermentation step, and an enzyme reaction step for performing an enzyme reaction is provided separately from the fermentation step of the lactic acid fermentation. The enzyme reaction step may be provided immediately after the lactic acid fermentation step, or may be provided after the homogenization treatment of the whey protein aqueous solution, for example. In the enzymatic reaction step, the pH and reaction temperature of the aqueous solution may be further appropriately adjusted, as necessary, taking into consideration the conditions of the optimum pH and optimum temperature of lactase at the start of the step.

In the present invention, the amount of lactase used is, for example, 10,000 to 100,000IU/g, preferably 30,000 to 70,000IU/g, and more preferably 40,000 to 60,000 IU/g.

According to a preferred embodiment of the present invention, when the enzymatic hydrolysis of lactose by lactase is performed before and during the lactic acid fermentation or during the lactic acid fermentation, the flavor of the whole whey preparation can be adjusted by adjusting the fermentation time to adjust the sourness due to the lactic acid fermentation and the sweetness due to the enzymatic hydrolysis by lactase. That is, if the time of lactic acid fermentation is too short, the fermentation itself is insufficient and the enzymatic reaction is not sufficiently performed, while if the time of lactic acid fermentation is too long, the lactic acid fermentation is excessively performed as compared with the enzymatic reaction and the sourness due to lactic acid is too strong. Therefore, the lactic acid fermentation time is preferably set so that a proper balance is maintained between the sourness due to lactic acid fermentation and the sweetness due to enzymatic hydrolysis with lactase.

The enzymatic reaction may be further treated by further performing an inactivation treatment (e.g., heating treatment) step for inactivating the enzyme, if necessary, after the completion of the reaction.

In the present invention, after lactic acid fermentation, the resulting fermentation liquid is subjected to a homogenization treatment. This makes it possible to finely pulverize aggregates contained in the fermentation liquid. In addition, when the fermentation broth is homogenized, it is directly performed in a state of containing lactic acid bacteria (or yeast) and metabolites contained therein. That is, the fermentation broth was directly homogenized. Direct homogenization is important from the viewpoint of imparting appropriate viscosity (stickiness) and stability, i.e., excellent texture and flavor, and stable storage stability to the fermentation broth.

The viscosity of the fermentation liquid is, for example, 10 to 300cp, preferably 15 to 250cp, and more preferably 20 to 200 cp. When a beverage is prepared using the fermentation liquid of the present invention, an appropriate viscosity can be imparted to the beverage by the influence of the viscosity of the fermentation liquid. Further, if the viscosity of the fermentation liquid and/or the beverage is too high, handling may be difficult in actual production, and therefore, the production conditions of the fermentation liquid may be changed and/or the viscosity of the fermentation liquid may be adjusted after the fermentation liquid is obtained, as necessary, in consideration of the workability of the production process and the like.

The homogenization treatment may be carried out, for example, at about 10 to 60 ℃, about 10 to 50MPa, and about 100 to 1000L/hr, preferably at about 12 to 25MPa, when a homogenizer is used. Further, the conditions may be changed as many times as necessary. Specific examples of the homogenization treatment include conditions under which the first stage is performed at about 20 ℃ and 8MPa, and the second stage is performed at 4 MPa.

Beverage and its preparing process

According to another aspect of the present invention, there is provided a beverage comprising the fermented whey preparation of the present invention. Therefore, a desired beverage can be produced by adding an optional additive ingredient to the fermented whey preparation of the present invention.

As an example of the process diagram of the production process of the beverage of the present invention, the process diagram shown in fig. 2 can be cited.

The concrete description is as follows: the additive ingredients for beverages containing the stabilizer are dissolved in water (for example, deionized water) as a raw material, and mixed with the fermented whey preparation. After mixing, emulsification treatment is further performed as necessary, and high-temperature sterilization treatment is performed. The conditions in this case are high-temperature sterilization conditions generally applied to beverages and the like, and are carried out, for example, at 100 to 150 ℃ for about 1 to 30 seconds.

Therefore, according to another preferred embodiment of the present invention, the beverage is obtained by further adding an additive component for beverage to the fermented whey preparation of the present invention and sterilizing the mixture at 100 to 150 ℃ for about 1 to 30 seconds.

According to a preferred embodiment of the present invention, the high-temperature sterilization treatment in the beverage production process may be performed under heating conditions known to those skilled in the art, and is preferably performed by heating at 110 to 140 ℃ for about 1 to 20 seconds. In this case, the conditions are more preferably 115 to 135 ℃ for about 1 to 10 seconds, still more preferably 120 to 130 ℃ for 1 to 5 seconds, and particularly preferably 120 ℃ for about 3 seconds.

In the production of the beverage of the present invention, there is no particular limitation on the additive components (beverage additive components) that can be used as the beverage additive components as long as they are commonly used as beverage additive components. Examples of such components include pectin, soybean polysaccharides, stabilizers such as CMC (carboxymethyl cellulose), granulated sugar (granulated sugar), liquid sugar (e.g., glucose fructose liquid sugar), casein, crystalline cellulose, proteases, flavors (e.g., orange flavor, apple flavor, yogurt flavor), fruit juice (e.g., apple juice), fruit or jam (e.g., apple jam), and acidulants (e.g., citric acid).

The amount of the additive components used is, for example, about 20 to 40 wt% of granulated sugar, fruit juice, etc. and about several wt% of essence, sour agent, etc. relative to the fermented whey preparation. If the amount is in this range, it is advantageous in preparing a beverage that maintains the original flavor and texture of the fermented whey preparation.

After the sterilization treatment, the obtained beverage may be further homogenized as necessary. For example, the homogenization treatment may be carried out at 80 to 85 ℃ and 25MPa (first stage: 20MPa, second stage: 5MPa) using a homogenizer.

Then, the beverage of the present invention can be obtained by a cooling process (for example, cooling to about 25 ℃) as necessary.

The beverage obtained according to the present invention is a beverage excellent in flavor and the like, and may further contain particles having a particle size of, for example, about 0.5 to 5 μm. In addition, the beverage of the present invention may contain fine particles as described above, but in this case, the sedimentation rate is preferably 2% or less even if centrifugation is performed. This is a characteristic (physical property) that substantially no precipitation occurs.

In the present specification, the expression "about" or "around" is used to mean a value including a variation that is allowable for a person skilled in the art to achieve the purpose of setting the value.

Examples

The present invention is explained in detail by the following particles, but the present invention is not limited to these examples.

Example 1 (invention): preparation of fermented whey preparation (in the case of using lactic acid bacteria and lactase)

As the whey protein, 140g of sweet whey powder (manufactured by mingzhi dairy corporation) was prepared, and the sweet whey powder was dissolved in deionized water to prepare an aqueous whey protein solution (aqueous whey solution) having a solid content concentration of 14% by weight, and the pH was adjusted to about 7.0 using sodium hydroxide as a pH adjuster. Then, the whey protein aqueous solution was heated and sterilized at 95 ℃ for 10 minutes by blanching in boiled water. After sterilization, the aqueous solution was observed, and as a result, it contained aggregate particles having an average particle diameter of less than 100 μm (3 μm). The resulting aqueous solution was cooled to 43 ℃.

Then, 0.1 wt% of a frozen concentrate of a lactic acid bacteria starter (isolated from "ブルガリアヨ - グルト" (trade name) manufactured by Mingzhi Dairy Co., Ltd.) was added to the whey protein aqueous solution, and 0.04 wt% (50,000IU/g) of lactase (manufactured by Godo-TNL, manufactured by Nippon Kogyo Co., Ltd.) was added thereto, and lactic acid fermentation was performed at 43 ℃.

The pH and acidity (%) of the whey protein aqueous solution (whey aqueous solution), lactose concentration (g/L), glucose concentration (g/L), and galactose concentration (g/L) were measured at each hour point from the start of lactic acid fermentation to 6 hours later. Further, the flavor of the whey protein aqueous solution in each spot was evaluated by 5 professionals in sensory manner.

Here, the acidity is obtained as described above by "milk 5" on page 56 in accordance with the milk association law set (the association of health in dairy industry (japan), levelly 16 years (2004) for 3 months) and a "method of refining the acidity of the milk. Specifically, 10ml of the sample was diluted with an equal amount of carbon dioxide-free water, 0.5ml of phenolphthalein solution was added as an indicator, and the resulting solution was titrated with 0.1 mol/L sodium hydroxide solution to the limit of a point at which reddish color does not disappear within 30 seconds, and the percentage of lactic acid per 100g of the sample was determined from the titration amount and was regarded as acidity (%).

The lactose concentration, glucose concentration and galactose concentration were measured by HPLC (column: Showa Denko K.K., Shodex sugar analysis positive phase column Asahipak NH2P-50 (4.6X 250mm), mobile phase: acetonitrile: ultrapure water: 3: 1, detector: Jaco 830-RI, measurement temperature: 40 ℃ C.), respectively.

The results are shown in Table 1.

As is clear from the results of the sensory evaluation, the sweetness and sourness can be arbitrarily adjusted depending on the fermentation time (reaction time).

Next, the fermentation liquid containing the lactic acid bacteria and the metabolites thereof was homogenized using a homogenizer set at about 10MPa and about 100L/hr.

The fermented whey preparation (example) obtained as described above is a preparation having the desired flavor and physical properties (texture) of the present invention and also excellent in hygiene.

TABLE 1

Example 2 (comparative example): preparation of fermented whey preparation (in the case where lactase is not used)

The test and evaluation were carried out in the same manner as in example 1 except that lactase (lactase) was not added at the time of lactic acid fermentation.

The results are shown in Table 2.

TABLE 2

Example 3 (comparative example): preparation of fermented whey preparation (in the case where lactic acid bacteria are not used)

The test and evaluation were carried out in the same manner as in example 1 except that the predetermined lactic acid bacterium was not added (lactase was added) in the lactic acid fermentation.

The results are shown in Table 3.

TABLE 3

Example of beverage product

The following beverage product of the present invention can be produced by using the fermented whey preparation (hereinafter referred to as whey fermented milk) obtained in example 1 and producing the fermented whey preparation by the method of the present invention using the following formulation.

The following ratio or% is a ratio or% based on weight unless otherwise specified.

Blend example 1 (beverage 1):

TABLE 4

	Percent mixing (%)	Added amount (g)
			Whey fermented milk	19.05	190.5
Granulated sugar	9.00	90.0
			Glucose fructose syrup	0.60	6.0
Citric acid (20%)	0.10	1.0
			Stabilizer (soybean polysaccharides) (Sanrongyuan FFI Co., Ltd.)	0.35	3.5
Yoghourt essence	0.15	1.5
			Water (W)	70.8	707.5
Total up to	100.00	1000.0

Blend example 2 (beverage 2):

TABLE 5

	Percent mixing (%)	Added amount (g)
			Whey fermented milk	19.05	95.3
Granulated sugar	8.00	40.0
			Glucose fructose syrup	1.60	8.0
Citric acid (20%)	0.10	0.5
			Stabilizer (HM pectin) (CP ケルコ Co., Ltd.)	0.50	2.5
Yoghourt essence	0.15	0.8
			Water (W)	70.6	353.0
Total up to	100.00	500.0

Blend example 3 (beverage 3):

TABLE 6

	Percent mixing (%)	Added amount (g)
			Whey fermented milk	19.05	190.5
Granulated sugar	3.00	30.0
			Glucose fructose syrup	6.60	66.0
Sodium citrate (20%)	0.10	1.0
			Stabilizer (CMC) (Japan paper-making Co., Ltd.)	0.40	4.0
Yoghourt essence	0.15	1.5
			Water (W)	70.7	707.0
Total up to	100.00	1000.0

Claims (16)

1. A fermented whey preparation obtained by subjecting an aqueous whey protein solution having a solid content concentration of 11 to 35 wt% and a pH value of 6.5 to 8.0 to high-temperature sterilization, then subjecting the resulting solution to lactic acid fermentation, and homogenizing the resulting fermentation solution,

wherein the sweet taste is enhanced by subjecting lactose contained in the whey protein aqueous solution sterilized at a high temperature to enzymatic hydrolysis with lactase before, during, and/or after lactic acid fermentation.

2. The fermented whey preparation according to claim 1, which is obtained by enzymatic hydrolysis of lactose with lactase before and during lactic acid fermentation, or during lactic acid fermentation.

3. The fermented whey preparation according to claim 1 or 2, wherein the lactic acid fermentation is a step of producing lactic acid by fermentation using lactic acid bacteria or yeast.

4. The fermented whey preparation according to any one of claims 1 to 3, wherein the high-temperature sterilization is performed at 91 to 99 ℃ for 5 to 15 minutes or at 100 to 150 ℃ for 1 to 30 seconds.

5. The fermented whey preparation according to any one of claims 1 to 4, wherein the pH of the whey protein aqueous solution is adjusted to 6.6 to 7.6.

6. The fermented whey preparation according to any of claims 1 to 5, wherein when the aqueous solution after high-temperature sterilization contains aggregates, the particle size of the aggregates is 2 to 100 μm, and the aqueous solution is directly supplied to the lactic acid fermentation step.

7. A beverage comprising the fermented whey preparation according to any one of claims 1 to 6.

8. A beverage obtained by adding an additive component for a beverage to the fermented whey preparation according to any one of claims 1 to 6 and subjecting the mixture to a high-temperature sterilization treatment at 100 to 150 ℃ for 1 to 30 seconds.

9. A method for producing a fermented whey preparation, comprising the steps of: sterilizing an aqueous whey protein solution having a solid content of 11 to 35 wt% and a pH of 6.5 to 8.0 at a high temperature, subjecting the sterilized aqueous whey protein solution to lactic acid fermentation, homogenizing the obtained fermentation liquid to obtain a fermented whey preparation,

the method is characterized in that lactose contained in the whey protein aqueous solution sterilized at high temperature is subjected to enzymolysis by lactase before, during and/or after lactic acid fermentation, thereby enhancing sweet taste.

10. The method according to claim 9, wherein the enzymatic hydrolysis of lactose is performed with lactase prior to and during lactic acid fermentation, or during lactic acid fermentation.

11. The method according to claim 10, comprising the following steps: by adjusting the fermentation time, the sour taste due to lactic acid fermentation and the sweet taste due to enzymatic hydrolysis with lactase are adjusted, respectively, and the flavor of the whole whey preparation is adjusted.

12. The method according to any one of claims 9 to 11, wherein the lactic acid fermentation is a step of producing lactic acid by fermentation using lactic acid bacteria or yeast.

13. The method according to any one of claims 9 to 12, wherein the high-temperature sterilization is performed at 91 ℃ to 99 ℃ for 5 to 15 minutes or at 100 ℃ to 150 ℃ for 1 to 30 seconds.

14. The method according to any one of claims 9 to 13, wherein the aqueous whey protein solution is adjusted to a pH of 6.6 to 7.6.

15. The method according to any one of claims 9 to 14, wherein, when the aqueous solution after the high-temperature sterilization contains the aggregate, the particle size of the aggregate is 2 to 100 μm, and the method further comprises a step of directly supplying the aqueous solution to the lactic acid fermentation step.

16. A method for producing a beverage, comprising the steps of: a beverage is obtained by adding an additive component for a beverage to the fermented whey preparation obtained by the method according to any one of claims 9 to 15, and sterilizing the mixture at a temperature of 100 to 150 ℃ for 1 to 30 seconds.