FI121525B - Process for the preparation of a fermented fresh dairy product - Google Patents

Description

Process for the preparation of a fermented fresh dairy product

The present invention relates to a process for the preparation of sour milk products using a transglutaminase enzyme and an enzyme activating compound. The invention further relates to a sour milk product prepared by the process of the invention. The invention also relates to a method of modifying the structure of sour milk products by means of a transglutaminase enzyme and an enzyme activating compound.

Background of the Invention

Traditionally, sour milk products have been prepared by acidifying milk with a specific fermenter at a suitable temperature. For example, strains of Lactobacillus Bulgarius and Streptococcus thermophilus are traditionally used in the production of yogurt. Before fermentation, all the necessary raw materials (sweetener, spices, and texture adjusters) are added to the milk bulk, and then the milk is typically pasteurized and homogenized. The milk is acidified to a pH value specific to each product. The structure is then broken for non-file type products and set-type yoghurt, the necessary spices are added (eg jam) and the products are packaged. In addition to lactic acid bacterial stains, filamentous molds are used in the manufacture of file-type products. Unlike other sour milk products, in the case of file-type products and set-type yoghurt, acidification takes place on the packaging.

Conventionally, the structure of sour milk formulations has been used in the control of mm. raising or lowering the milk solids content. The dry matter content can be increased by evaporating the milk or using powdered milk.

The protein content of the raw milk influences the structure of the final product by making the structure of the sour milk product thicker or looser by increasing or decreasing the protein content. The crude x 30 protein content of the milk can be increased by evaporation or by using protein powder. The protein powder supplement may be dairy, such as milk, whey protein or casein protein powder, but may also be of non-dairy origin.

CD

Protein supplements based on proteins are useful. For some products, for example, for diatomaceous earth, loosening of the structure may be an issue. This can be influenced by adding, for example, milk permeate, cheese whey, sour whey (quark, cottage cheese) 2 or lactose fractions to the raw milk. Non-lactic liquids such as water can also be used to loosen the structure.

The use of the structure-modifying transglutaminase enzyme in the manufacture of dairy products, particularly sour milk products, is known.

5 In sour milk products (yoghurt, set-type yoghurt, filiform milk, diatomaceous earth) the use of the transglutaminase enzyme can harden the structure, fine-tune the structure and reduce irritation. The enzyme can also be used to make the structure thicker.

The transglutaminase enzyme catalyzes the formation of covalent bonds between the glutamine and lysine amino acid residues in the protein molecules. As the bonds are formed, ammonia is released in the reaction. The enzyme was first used in Japan for the preparation of surimi (fish jelly) products (Kuraishi, et al., Food Rev. Int. 17 (2), 2001, pp. 221-246).

EP 610 649 (Ajinomoto) describes a process in which yoghurt milk is pretreated with a transglutaminase enzyme and the enzyme is inactivated prior to acidification during the pasteurization of the yoghurt milk. EP 689 383 (Novo Nordisk A / S) describes a process in which milk is treated with a transglutaminase enzyme followed by acidification of the milk to the desired pH reading and heat treatment of the resulting gel. The gel thus formed can be used in the manufacture of yogurt or cheese. EP 1 206 192 (Friesland Brands B.V.), in turn, describes a method in which the transglutaminase enzyme is added after the heat treatment of the milk during the acidification step and further the enzyme is added after the acidification. It is characteristic of the method that the enzyme is always added even after ha-25. JP 2001252011 (Koiwai Nyugo KK) describes a method of making yogurt, e.g. transglutaminase enzyme? is added at the acidification step where the pH has dropped close to 5 and here

O

At pH, acidification is stopped by transferring the yogurts to the cold room.

^ 7 What is common to the methods described above is that the crosslinking

30a exclusively uses the transglutaminase enzyme. EP

1 197 152 (Ajinomoto) describes a cross-linking method in which milk is

CL

by means of a transglutaminase and an adjuvant that acts on the enzyme, for example, glutathione. After treatment, the transglutaminase is inactivated

LO

g by heat treatment and milk is used in the manufacture of various dairy products. By this method, cross-linking is effected more efficiently than transglutaminase treatment alone. The process is specifically a process for pre-processing raw milk 3 prior to the traditional production of dairy products.

In the methods described above, the enzyme, any enzyme-acting adjuvant present, and the respective acid addition agent 5 are added to the reaction mixture at various stages of the treatment, and the enzyme, possibly an enzyme-acting adjuvant and acid, are not reacted simultaneously.

It has now surprisingly been found that adding a transglutaminase enzyme, an enzyme activating compound, and an acid to a protein source under conditions where the enzyme is active during and / or during acidification provides a simpler, less-acidifying process that structure without losing it.

BRIEF DESCRIPTION OF THE INVENTION The present invention relates to a process for preparing acidic milk products using a transglutaminase enzyme, an enzyme activating compound and an acid and adding them to a protein source under conditions where the enzyme is active during acid addition and / or during acidification. The method allows the structure of sour milk products to be modified more cheaply and simpler than known methods. Furthermore, the method can significantly reduce the protein content of sour milk products without affecting the structure of the preparation.

DETAILED DESCRIPTION OF THE INVENTION

It has now surprisingly been found that adding sour milk product o 25 to the transglutaminase enzyme, the enzyme activating compound, and the acid to the protein source under conditions where the enzyme is active essä when acidifying and / or the raw milk pre-treatment method described above. The method of the invention wherein crosslinking occurs during acidification is about 20% more effective than the method using only the transglutaminase enzyme during acidification. The process according to the invention allows the preparation of sour milk products such as yoghurt, filet and

C \ J

with a significantly lower protein content, while the structure remains the same as in a conventionally made acidic milk product. Through this, it is possible to prepare sour milk products at a lower raw material cost than the conventional protein level in the production of sour milk products.

The transglutaminase enzyme (EC 2.3.2.13) catalyzes the formation of covalent bonds between the glutamine and lysine amino acid residues in the protein molecules. Food approved microbial transglutaminase preparations are commercially available. Manufacturers generally recommend the enzyme in amounts of 1-3 U / g of protein, depending on the intended use.

Any compound having the required property may be used as the enzyme activating compound. Among those useful are compounds whose function is chemically based on either reduction or oxidation. Examples of reducing compounds include glutathione, cysteine, γ-glutamyl cysteine, thior sulfuric acid, thio-glycolic acid, sulfuric acid, ascorbic acid, erythrobinic acid, dithiothreitol, and their food-acceptable salts, NaBH, An example of an oxidizing agent is formic acid.

The enzyme activating compound is preferably glutathione. Glutathione reduces whey proteins and its potency when used with the transglutaminase enzyme 20 is thought to be based on this property. Glutathione can be used as such, for example, as a commercially available purified compound. Alternatively, a mixture containing glutathione may be used. An example of a blend containing glutathione approved for use in the food industry is a yeast extract.

According to the method of the invention, the transglutinase kinase enzyme, the enzyme activating compound and the acid are added to a protein source under conditions where the enzyme is active during acid addition and / or during acidification. Thus, the enzyme and the enzyme activating compound may be added to the protein source before, during or after acidification. It is essential for the process according to the invention that the conditions after the addition of the enzyme and enzyme activating compound before the addition of the acid or, in the reverse order after the addition of the acid, the addition of the enzyme and enzyme activating compound do not change and / or they are not altered such that the enzyme is inactivated. Thus, provided that the enzyme is active during acid addition and / or during acidification, the enzyme and enzyme activating compound of the invention can be added to the protein source for several hours, for example 2 to 10 hours, before the acid is added. The conditions under which additions are made to the process of the invention depend on the properties of the enzyme used in the process. Enzyme properties such as activity and substrate specificity typically depend, e.g. temperature and pH. Currently, the commercially available transglutaminase enzymes are active in the temperature range of 0 to 80 ° C, with the enzyme inactivated at temperatures above 80 ° C and being most active at about 50 ° C. In milk-based applications, ent-10 enzymes can be used advantageously at a temperature in the range of 3 to 60 ° C. When the transglutaminase enzyme is used in connection with the acidification reaction, the temperature range is preferably 20 to 50 ° C. Currently, the commercially available transglutaminase enzymes are active in the pH range of 3 to 10, most active in the range of pH 5 to 8. For milk-based applications, the pH is preferably between 3.5 and 7.5 or adjusted to that range. The pH-value slot.

In the process of the invention, the source of protein is generally raw milk as such or pre-treated as desired. An example of a pretreatment is the reduction of the protein content of the raw milk. Calculation of the protein level can also be performed simultaneously with the addition of the ha-20 particle. For calculating the protein level, e.g. milk permeate, whey, lactose fraction, concentrates thereof or a mixture of milk permeate, whey, lactose fraction and / or these concentrates. Additionally, water, corn leach water, juice, or any food grade liquid can be used to lower the protein level. The above-mentioned liquids or mixtures thereof suitable for the calculation of the protein-25 level can be added up to 20% by volume to the protein source used in the method.

? Raw milk here refers to milk obtained from an animal, for example a cow or a goat, as such or when treated differently. The milk can be treated by removing, for example, fat or lactose, to obtain skimmed, low fat, lactose or low lactose milk. Raw milk in this context also means pre-treated or used for the manufacture of yoghurt, filet and sour milk.

CD

unprocessed milk, termed yoghurt, g skimmed milk and sour milk by experts in the field.

o

(M

6

The milk can be fractionated, for example, by chromatographic separation and / or micro, nano or ultrafiltration into fractions containing different amounts of different components, which in turn can be used to control the protein content of the milk as such or in different mixtures.

Milk permeate refers to a permeate obtained by ultrafiltration of milk, containing mainly lactose, ash and protein. The protein content of milk permeate depends on the filtration conditions, but most commonly ranges from about 0.2 to 0.4% by weight, typically about 0.3% by weight of protein.

Whey refers to the non-precipitated liquid portion of milk that is used in cheese or curd making. The whey protein content is generally in the range of about 0.5 to 0.7% by weight, typically about 0.6% by weight.

By lactose fraction is meant the fraction obtained by chromatographic separation which contains mainly lactose but also e.g. proteins. The protein content of the lactose fraction depends on the separation conditions, but is most commonly in the range of about 0.2 to 0.4% by weight, typically about 0.3% by weight of protein.

Furthermore, vegetable fluids such as oat, soy, rice or coconut milk, which are commercially available, can be used as a source of protein instead of milk of animal origin. Oat, soy and rice milk may be industrially prepared by a process whereby the grains or beans are crushed and the desired nutrients are extracted into a suitable liquid such as water, which may also contain an oil such as rapeseed oil.

Except for the addition of the transglutaminase enzyme and the enzyme activating compound, and the possible adjustment of the protein content of the protein source, acidification occurs as with the corresponding conventionally prepared acidic milk formulations, using appropriate acidic and the method is suitable for the preparation of flavored and non-flavored fresh or fat-free products, whether homogenized or not. Still, it is suitable for lactose-

CL

and low-lactose (such as HYLA®) products, δ In one embodiment of the invention, the process comprises the following:

LO

§ steps:

O

- m 35 - add the transglutaminase enzyme, the enzyme activating compound and the acid 7 - to the protein source - acidify - recover the resulting product.

In another embodiment of the invention, the method further comprises the step of reducing the protein content of the protein source by adding to the protein source a suitable fluid. In this case, the method comprises the steps of: adding to the protein source a liquid suitable for decreasing the protein content, such as milk permeate, whey, lactose fraction, their concentrate or a mixture of milk permeate, whey, lactose fraction and / or their concentrates.

- adding the transglutaminase enzyme, the enzyme activating compound and the acid to the protein source - allowing it to acidify - recovering the resulting product.

In addition to these steps, the process according to the invention preferably includes any other necessary manufacturing steps to obtain the final product, such as the addition of jam and / or sugar and / or heat treatment (post-pasteurization).

An advantage of the process of the invention is that it can utilize raw milk with a lower protein content than the known methods described above. The protein content of the raw milk used in the process of the invention may be as low as about 0.5% by weight, whereas in the known manufacturing methods, the lower limit of protein content is in the range of 2-3% by weight, depending on the sour milk product. When using known manufacturing methods, the protein content of yogurt is typically in the range of 3 to 5% by weight, in the range of 3 to 5% by weight of the yoghurt. %, in the range of 3 to 5% by weight of sour milk, and in the range of 2 to 4% by weight of drinkable yogurt.

There is no actual upper limit for protein content, but in practice, more than 10% protein content of raw V milk is rarely exceeded in the industrial production of yoghurt, wine and / or milk.

An advantage of the method of the invention is that the amount of enzyme required in the method Q is less than that required by the known methods S. The enzyme may be used in the process of the invention in an amount of 0.1 to 300 ppm, preferably 1 to 200 ppm. The reduction in the amount of enthusiasts required entails clear cost savings in manufacturing. A further advantage of the process of the invention is that the refining process is simplified by eliminating the extra energy and time-binding process steps.

The invention also relates to a process for modifying the structure of sour milk products by the action of the transglutaminase enzyme and the enzyme acting on the Akti-5-capable compound. This method is characterized in that the transglutaminase enzyme, the enzyme activating compound, and the acid are added to a protein source under conditions where the enzyme is active during acidification.

The following examples illustrate the present invention. These 10 are not intended to limit the requirements in any way.

Example 1. Preparation of yogurt

The example investigated how pre-treatment of milk with transglutaminase enzyme and glutathione according to the prior art and treatment of transglutaminase enzyme and glutathione with an acidifier according to the present invention affected the manufacturing process and the properties of the final product.

The reference yoghurt was made from raw milk with a protein content of 4.2% and a fat content of 2.5%. To the milk was added 0.252 g of Activa® YG powder (Ajinomoto, including transglutaminase and yeast extract) / 1000 20 g of milk. The enzyme was allowed to act at 6 ° C for 16 hours. The milk was then pasteurized at 92 ° C for 5 min and cooled to 42 ° C. Yogurt acid paste was added and matured at 42 ° C until the pH had dropped to 4.5.

The test yoghurt according to the invention was prepared from raw milk having a protein content of 3.8% and a fat content of 2.5%. The milk was pasteurized at 92 ° C for 5 min and cooled to 42 ° C. To the milk was added ^ Activa® YG powder 0.171 g / 1000 g milk together with yoghurt acid and matured at 42 ° C until the pH had dropped to 4.5. In the preparation of the test yoghurt according to the invention, smaller amounts of transglutacase 30 enzyme and yeast extract were used than in the case of the control yoghurt.

In addition, the preparation of the test yoghurt according to the invention differed from that of the comparative yoghurt in that Activa® YG powder was added together with the yeast, g The yoghurts were monitored for organoleptic quality and viscosity for 20 days. The process according to the invention made it possible to use 35 milk with a protein level of 4.2% to 3.8% as raw milk without any deterioration in the quality of the yoghurt. On the contrary, the test yoghurt was slightly thicker in structure than the reference yoghurt (see Table 1) and the amount of enzyme preparation used was lower than that of the reference yoghurt.

Table 1. Viscosity of comparator yoghurt and test yoghurt by shelf life 5 ____ Shelf life Comparison, viscosity Test yoghurt, viscosity [day] _ [Pas] _ [Pas] __ ____ 2__JJ> __ 2.3 20 2.1 2.5

Example 2. Preparation of yogurt

In the example, it was investigated how the transglutaminase treatment of milk during application to the prior art and the use of the yeast extract containing transglutaminase and glutathione during acidification according to the present invention affected the manufacturing process and the properties of the final product.

The reference yoghurt was made from raw milk with a protein content of 4.2% and a fat content of 2.5%. The milk was pasteurized at 92 ° C for 5 min and cooled to 42 ° C. To the milk was added 0.252 g Activa® MP powder (Ajinomoto, containing transglutaminase) / 1000 g milk and yoghurt acid was added and matured at 42 ° C until the pH dropped to 4.5.

The test yoghurt according to the invention was otherwise prepared in the same manner as the comparative yoghurt except Activa® MP powder containing 0.168 g / 1000 g milk instead of Activa® MP powder was added instead of Activa® MP powder.

o

The method of the invention was able to produce yoghurt v of the same quality with a 33% lower dosage of the enzyme preparation? 25 using Activa® YG powder containing the yeast extract as compared to conventional Activa® MP powder. The enzyme cost is thus achieved

CL

significant savings.

CD

CD

m

LO

o o

(M

10

Table 2. Viscosity of comparator yoghurt and test yoghurt Shelf life [day] Comparison, viscosity [Pas] Test yoghurt, viscosity [Pas] _3 _2j2__2.2 21 2.7 2.6

EXAMPLE 3. Yoghurt Production 5 This Example investigated how the transglutaminase and glutathione treatment of milk with yeast in accordance with the present invention in the manufacture of yoghurt and the production of yoghurt without enzyme treatment according to the prior art influenced the manufacturing process and the properties of the final product.

Comparative yogurt was made from raw milk with a protein content of 4.2% and a fat content of 2.5%. The milk was pasteurized at 92 ° C for 5 min and cooled to 42 ° C. Yoghurt acid was added to the milk and matured at 42 ° C until the pH had dropped to 4.5.

The test yoghurt according to the invention was prepared from raw milk having a protein content of 3.65% and a fat content of 2.5%. The milk was pasteurized at 92 ° C for 5 min and cooled to 42 ° C. To the milk was added 0.15 g of Activa® YG powder / 1000 g of milk together with yoghurt acid and matured at 42 ° C until the pH had dropped to 4.5. In addition to the yeast, transglutin-20 kinase enzyme and yeast extract were used in the preparation of the test yoghurt according to the invention.

The method according to the invention made it possible to use as a raw milk milk with a reduced protein level of 4.2% to 3.65% without any change in the quality of the yogur-2 t. The viscosity of both yoghurts was at the same level of ™ and organically the yoghurts could not be distinguished.

Example 4. Preparation of Set-Type Yogurt The example investigated how the transglutaminase enzyme and glutathione treatment of milk together with an acid in accordance with the present invention for the preparation of set-type yoghurt and the preparation of set-type yoghurt without enzymatic treatment. influenced the manufacturing process and the properties of the final product.

The reference yoghurt was made from raw milk with a protein content of 4.2% and a fat content of 2.5%. The milk was pasteurized at 92 ° C for 5 min and cooled to 42 ° C. Yoghurt acid was added to the milk and matured at 42 ° C until the pH had dropped to 4.5.

The test yoghurt according to the invention was prepared from raw milk having a protein content of 3.65% and a fat content of 2.5%. The milk was pasteurized at 92 ° C for 5 min and cooled to 42 ° C. To the milk was added 0.15 g of Activa® YG powder / 1000 g of milk together with yoghurt acid and matured at 42 ° C until the pH had dropped to 4.5.

The process according to the invention made it possible to use milk with a protein content of 4.2% to 3.65% as raw milk without any change in the quality of the yoghurt. The consistency of both yoghurts was at the same level and organically the yoghurts could not be distinguished.

Example 5. Preparation of file

The test file of the invention was prepared by adding 94 g of milk permeate to 906 g of filamentous milk having a fat content of 2.5%. The mixture was pasteurized at 93 ° C for 5 min and cooled to 65 ° C. The raw material was then homogenized at 65 ° C at 200 bar. Subsequently, the raw material was cooled to an acidification temperature of 24 ° C, and carbonic acid and 88 mg of the Activa® YG enzyme preparation were added.

Otherwise, the reference file was prepared in the same manner as the test file except 1000 g of milk (2.5% fat content) was used and no milk permeate or Activa® YG enzyme preparation was added to the milk. Both filings were packed in 200 g beakers and cooled at 24 ° C until the pH dropped to 4.5. The files were then transferred to a cold room. During a three-week survival period of 25 weeks, sensory awakening, dish disintegration, structure and structure. In addition, the consistency was measured at weekly intervals, and the method of the invention allowed milk with a lower protein content than raw milk to be used as raw milk for the preparation of the file without loss of quality of the 30 dun file. Although the

CL

the protein produced by the method had a lower protein content (2.9%)

CD

to the protein content of the reference filament (3.2%), both filings were organoleptic

LO

g had similar properties and had almost equal consistency.

12

Example 6. Preparation of milk

The test milk of the invention was prepared by adding 180 g of milk permeate to 820 g of skim milk. The mixture was high pasteurized at 90 ° C for 10 min and tempered to an acidification temperature of 24 ° C. Silica acids-5 teas and 100 mg of Activa® YG enzyme preparation were added. The milk was allowed to acidify for 24 hours until the pH was 4.5.

The control milk was otherwise prepared in the same manner as the test milk except that 1000 g of skimmed milk was used and no milk permeate or Activa® YG enzyme preparation was added to the milk. Both finished 10 diatoms were mixed and packed in liter containers. The buttermilk was then transferred to a cold room. During the three-week storage period, organoleptic sensation, taste and texture were monitored. In addition, the viscosity was measured weekly.

The process according to the invention made it possible to use as a raw milk milk whose protein content had been reduced from 3.3% to 2.7% without loss of milk quality. Both diatoms were similar in organoleptic properties and had almost the same viscosities.

o δ

Door

O

X

cc 0- co δ m m o o

Door

Claims (13)

A process for the preparation of a fresh dairy fermented acid product, characterized in that the process comprises adding a transglutaminase enzyme, a compound activating the enzyme function and an acid to a protein source under conditions where the enzyme is active during acidification, and recovering the resulting preparation. Process according to claim 1, characterized in that the compound activating the enzyme is a yeast extract. 3. A method according to claim 1 or 2, characterized in that the compound activating the enzyme function is glutathione. Method according to any one of claims 1 to 3, characterized in that the enzyme and the compound activating the enzyme function are added to the protein source before the addition of the acid. Method according to any one of claims 1 to 3, characterized in that the enzyme and the compound activating the enzyme function are added to the protein source upon addition of the acid. 6. A method according to any one of claims 1-4, characterized in that the enzyme and the compound activating the enzyme function are added to the protein source after the addition of the acid. Method according to any one of claims 1 to 6, characterized in that the protein content of the protein source used in the method is reduced. The method according to claim 7, characterized in that the protein content is reduced by adding to the protein source milk permeate, whey, lactose fraction, a concentrate thereof or a mixture of milk permeate, whey, lactose fraction and / or these concentrates. "1 Method according to any one of claims 1 to 8, characterized in that the protein source used in the method has a protein content of at least 0.5% by weight. Method according to any one of claims 1 to 9, characterized in that the protein source used in the method has a protein content between about 0.5% and about 10% by weight. Method according to any one of claims 1 to 10, characterized in that the protein source used in the method is raw milk. Process according to any one of claims 1 to 11, characterized in that the fresh fermented dairy product is yoghurt, set-type yoghurt, filet or buttermilk. 13. A method of modifying the structure of a fresh milk-derived acidified product 5, characterized in that the transglutaminase enzyme, the enzyme activating compound and the acid are added to a protein source under conditions where the enzyme is active during acidification. o o {M o X cc CL CD S LO LO O O CM