KR100355264B1 - soy yogurt and process for preparation thereof - Google Patents

Abstract

The present invention relates to a soybean yogurt using an isolated soy protein, and a method for producing the same.A.oryzaeBacillus bifidum (Isolated Soy Protein) Treated with Protease, Bromelain or α-chymotrypsin Extracted fromB.bifidum) Or cultured alone or Bacillus bifidum and Lactobacillus acido pyrus (L.acidophilus) Or Bacillus bifidum and Lactobacillus vulgaris (L. bulgaricusIt is characterized by the production of mixed culture).

Description

Soy yogurt using enzymatically isolated soy protein and its preparation method

The present invention relates to a soybean yoghurt prepared using an enzyme-treated isolated soy protein and a method for producing the same. More specifically, the present invention is to culture the Bacillus bifidum alone in isolated soy protein treated with protease, bromelain or α-chymotrypsin extracted from Asparagus duckase or Bacillus bifidum and Lactobacillus asidofyrus. Or it relates to a method for producing soybean yogurt by mixed culture of Bacillus bifidum and Lactobacillus vulgaris.

Soy protein is a high quality vegetable protein that provides abundant essential amino acids and is used as a substitute for animal protein because it is cheaper than animal protein. Soy protein is limited in its use because of its unique soybean odor, but it has been used in the food industry because it shows many functional characteristics of animal protein. In addition, soy protein is not only in terms of food nutrition but also excellent in physiological activity, thus lowering serum cholesterol content. Anti-cancer effect, prevention of osteoporosis, and renal dysfunction symptoms are improved.

Isolated soy protein contains more than 90% protein, and when added to food, it gives the protein's functional properties such as water-binding, emulsifying and foaming properties. In other words, in the food industry, soy protein is not only used to improve the physical properties of products, but also to improve the texture and binding of frozen foods. Since it can also be used in processed products, such as research on the use of soybeans as a dairy substitute food has been reported.

As the consumption of fermented milk has increased recently, new concepts such as yogurt carbonate and frozen yogurt have been developed. Especially, frozen yogurt with soft and cool characteristics of ice cream is already commercialized due to its palatability while maintaining the nutritional characteristics and flavor of fermented milk. . Research on frozen soy yogurt, which has excellent characteristics of crude or skim milk, which is the main ingredient of frozen yogurt, and has been replaced by relatively inexpensive soy protein, has been conducted, but its use is limited due to soybean odor. When soybean yogurt is manufactured, the soybean protein is replaced with milk solids, and the texture is very coarse and the smell of soybean is detected.In particular, the soybean protein is not chemically formed due to problems such as overrun, which is an important quality characteristic of frozen soybean yogurt. By enzymatic modification, its functional properties can be improved. Chemical modification of soy protein by acid or alkali treatment has several disadvantages such as reducing the content of essential amino acids, forming bonds that are not degraded by digestive enzymes in the body, and producing undesirable substances.

The present inventors confirmed that the soybean yogurt and frozen soy yogurt, which had a softer texture and reduced soybean odor, were prepared by enzymatic treatment of isolated soy protein and fermented using live bacteria. By this, the present invention was completed.

Accordingly, an object of the present invention is to culture Bacillus bifidum alone or isolate Bacillus bifidum and Lactobacillus asidofyrus in isolated soy protein pretreated with protease, bromelain and α-chymotrypsin extracted from Aspargillus duckase. Or it provides a soybean yogurt prepared by mixing and cultured with Bacillus bifidum and Lactobacillus vulgaris.

Another object of the present invention to provide a method for producing the soybean yogurt.

Still another object of the present invention is to provide a frozen soy yogurt using the soy yogurt.

Another object of the present invention to provide a method for producing the frozen soybean yogurt.

The above object of the present invention is the enzyme-treated soy protein isolated Bacillus BPB.bifidumCultured alone or Bacillus bifidum and Lactobacillus asidophilus (L.acidophilus) Or Bacillus bifidum and Lactobacillus vulgaris (L.bulgaricusSoy yogurt was prepared by mixing and cultured), and frozen soy yogurt was prepared therefrom, and the physical and quality characteristics of the product were investigated. As a result, pH was lower and acidity was higher than that of non-processed soy protein. In addition, the viscosity is moderate and high in organic acids, frozen soy yogurt is achieved by confirming that there is almost no reduction in the number of viable cells, has a very good effect of strong resistance to acid resistance and bile acid resistance and low degree of melting.

1 is a manufacturing process of soybean yogurt and frozen soybean yogurt.

Figure 2 is a result showing the pH of soybean yogurt prepared by different culture methods and enzyme treatment.

Figure 3 is a result showing the acidity of soybean yogurt prepared by different culture method and enzyme treatment.

Figure 4 is a result showing the viscosity of soybean yogurt prepared by different culture method and enzyme treatment.

5 is a result of measuring the overrun change during soybean yogurt frozen in an ice cream maker at 5 minute intervals for 30 minutes.

6 is a result of measuring the degree to which the frozen soy yogurt melts for 10 minutes at a room temperature of 20 ~ 22 ℃ over time for 60 minutes.

The present invention comprises the steps of preparing soy yogurt by alone or mixed culture of Lactobacillus strains in the enzyme-treated soy protein; Measuring the physical and chemical properties of the soybean yogurt prepared; And measuring the quality characteristics of the frozen soy yogurt prepared from soybean yogurt.

As a soybean protein (SPI) of the present invention, Proten 972, manufactured by ADM (Decatun, IL, USA), was used, and the stabilizer was a mixture of sodium alginate and carrageenan. Was used provided by Kwangil Co., Ltd.

Protease (P = 4032, activity; 3.8 units / mg protein), bromelain (B-4882, activity; 6.1 units / mg protein) extracted from A.oryzae used for enzyme treatment ), α -chitotrypsin (C-4129, activity; 54 units / mg protein) was used as the product of Sigma. The strains used were Bifidobacterium bipidum (KCTC 3176), Lactobacillus asidofyrus (ATCC 2182), and Lactobacillus vulgaris (KCTC 3188) from Korea Research Institute of Bioscience and Biotechnology. The oligosaccharides used were isomaltooligosacchride. It was provided by Samyang Genex Research Institute.

Acetic acid and citric acid in standard reagents used for organic acid analysis were supplied by Borak Co., Ltd., and used as lactic acid (L-6402) and pyruvic acid (P- 2256), succinic acid (S-3674) was used as the product of Sigma (St. Louis, MO, USA). Acetone, ethanol, and methanol in the standard volatile components used in the analysis of volatile components were obtained from Merck (KGaA, Darmstadt, Germany). Diacetyl (D-3634) and hexanal (H-9008) Sigma's product was used, and acetaldehyde and butyl alcohol were used by Borak Co., Ltd. In addition, the standard reagent used for free amino acid analysis was used by the product of Sigma.

Hereinafter, the specific configuration and operation of the present invention will be described in detail with reference to Examples, but the scope of the present invention is not limited to these Examples.

Example 1 Preparation of Sample

Experimental Example 1 Cultivation of Strains

Lactobacillus asidophilus and Lactobacillus vulgaris were cultured in Lactobailli MRS medium, and Bifidobacterium bifidum was cultured in Lactobacilli MRS medium added with 0.05% L-cysteine (24%) in an incubator fixed at 37 ° C. Soybean yogurt was prepared by incubation for a time, and when inoculated with yogurt, centrifuged at 1770 × g for 20 minutes at 4 ° C., the supernatant was removed, and only cells were recovered and inoculated.

Experimental Example 2 Enzyme Treatment of Isolated Soy Protein (SPI)

A 10% soybean protein solution (w / v) was prepared using 6N NaOH to pH7.5 ( protease extracted from A.oryzae ), 7.0 (bromelain) and 7.8 ( α - chitotrypsin ), respectively. After adjusting, make the temperature of sample at 37 ℃ in a constant temperature water bath, add 0.5% (w / w) enzyme of crude protein, and react for 20 minutes with stirring.The separated soy protein solution is immediately stirred at 87 ℃ for 5 minutes. The reaction was stopped by heating to inactivate the enzyme and then adjusted to pH 7.0 with 6N HCl.

Experimental Example 3 Preparation of Soy Yogurt and Frozen Soy Yogurt

As shown in FIG. 1, 50 g of soybean protein was added to disperse 410 mL of distilled water, followed by enzymatic or non-enzymatic treatment. 20 g of soybean oil and 2.5 g of stabilizer were added to prepare a soybean yogurt mix, followed by 15 minutes at 121 ° C. Sterilized. In addition, 40 ml of isomaltooligosaccharide was added to 40 g of isomaltooligosaccharide to prevent a mail reaction, and then made into an aqueous solution. The solution was sterilized at 121 ° C. for 15 minutes, mixed well with soybean yogurt mix, and then cooled to 37 ° C., Bacillus bifiderum, Inoculate 2% (v / v) of Lactobacillus acidospirus and Lactobacillus vulgaris cultures in Bacillus bifidum alone cultures and 1% in a mixed culture of Bacillus bifidum and Lactobacillus asidofyrus or Lactobacillus vulgaris, respectively. v / v) was inoculated and incubated at 37 ° C. for 14 hours. After incubation, the soybean yogurt was stored at 2-8 ° C for 18-30 hours, and 0.2 g of aspartame was added and frozen for 30 minutes using an ice cream maker (Model HR2305, 1200 mL, Philips Co., USA). Soybean yogurt was prepared.

Example 2 Measurement of Physicochemical Properties of Soybean Yogurt

Experimental Example 1: pH measurement of soybean yogurt

In order to measure the pH of soybean yogurt prepared by different culture methods and enzyme treatment, a pH meter (Model 520A, Orion Co., U.S.A) was used.

Experimental results, as shown in Figure 2, according to the culture method and enzyme treatment pH is different in the two cultures Bacillus Bifiderm Lower than monoculture (p <0.001). In the non-enzyme group, Bacillus bifiderm When grown alone, Bacillus bifidum did not grow well, so the pH was 6.44, which was not suitable for yogurt, but Lactobacillus asidofyrus Or Lactobacillus vulgaris In the mixed culture, 4.75 and 4.95 were shown, respectively. In the protease-treated group and bromelain-treated group extracted from Aspargillus aurise, the pH of Bacillus bifidum alone was the highest (p <0.001), but the lowest when mixed with Lactobacillus vulgaris. Bacillus bifidum in α-chymotrypsin treated group In single culture, the pH was 5.87, higher than the two mixed cultures. In addition, the pH of the protease-treated group and bromelain-treated group extracted from asiphaginus aurise was lower than that of the non-enzyme-treated group (p <0.001).

According to the enzyme treatment, the pH is Bacillus bifidum Bacillus Bifidum and Lactobacillus asidophilus were higher in the order of non-enzyme treatment, α-chymotrypsin treatment, proteolytic enzyme treatment group extracted from Aspargillus aurise, and bromelain treatment group. In the case of Lactobacillus vulgaris mixed culture, pH was the highest in the α-chymotrypsin treatment group (p <0.001), and the protease treatment group extracted from the non-enzyme treatment group, bromelain treatment group, and Asparagus duckase. Highest in order.

Experimental Example 2 Measurement of Acidity of Soybean Yogurt

10 g of the sample was diluted with the same amount of distilled water, and 0.5 mL of phenolphthalein solution was added as an indicator, and neutralized to 0.1N NaOH solution until it became pink. At this time, the number of mL of 0.1N NaOH consumed was measured and converted into lactic acid (LA)% using the following equation.

Experimental results As shown in Figure 3, the titratable acidity according to the culture method and the enzyme treatment is Bacillus non-pidem in the two types of mixed culture Acidity was higher than monoculture (p <0.001).

According to the cultivation method, titratable acidity was the highest in the non-enzyme-treated group when the mixed culture of Bacillus bifidum and Lactobacillus acido pyrus was 0.76% (p <0.001). The pH of the mixed culture was 4.95, Bacillus bifidum and Lactobacillus vulgaris of the α-chymotrypsin treatment group. It was lower than pH 5.66 at the time of the mixed culture, but inversely lower in the acidity. In the protease-treated group and bromelain-treated group extracted from Aspargillus duckase, the acidity was 0.97-1.38% and the optimum acidity of acidic yogurt was 1.0-1.3% at the two types of mixed cultures. Generally The titratable acidity of the protease-treated group extracted from Aspargillus duckase tended to be higher than that of the bromelain-treated group or the α-chymotrypsin-treated group.

Depending on the enzyme treatment, titratable acidity was determined by Bacillus bifidum alone culture and Lactobacillus acido pyrus. Or, in the mixed culture with Lactobacillus vulgaris, the enzyme treatment group showed a higher tendency than the non-enzyme treatment group.

Experimental Example 3 Measurement of the Viscosity of Soybean Yogurt

A viscometer (Brookfield viscometer; Model LVF, Broolfield Eng., U.S.A) was used to measure the viscosity of the sample. 100 mL of the sample was taken in a beaker and measured at 60 rpm with spindle No. 4 at 4 ° C. for 1 minute. As shown in Figure 4, the viscosity was significantly different according to the culture method and enzyme treatment. Depending on the cultivation method, the viscosity of the Bacillus non-pidem in the non-enzyme-treated group at the two cultures It was higher than the monoculture (p <0.001), and the proteinase-treated group extracted from Aspargillus duckase had the lowest viscosity in the mixed culture of Bacillus bifidum and Lactobacillus asidofyrus, but Bacillus bifidum It was highest in monoculture (p <0.001). In addition, the viscosity of the bromelain treatment group and the α-chymotrypsin treatment group was highest in the mixed culture of Bacillus bifidum and Lactobacillus vulgaris, and the mixed culture of Bacillus bifidum and Lactobacillus asidophilus, and Bacillus bifidum alone. As high.

Viscosity also affects the texture, especially in the quality of yogurt, if the viscosity is too high or too low will adversely affect the overall texture. As a result of measuring the viscosity of the commercially-rich yogurt, 4412-7160 cp was shown. In the present invention, the mixed culture of Bacillus bifidum and Lactobacillus asidophilus or Lactobacillus vulgaris of the non-enzyme treated group was significantly higher than the viscosity of commercial yogurt. In this case, the texture in the mouth was evaluated to be rough, and the texture in the mouth of the α-chymotrypsin treatment group, which exhibited a viscosity in the range of 4000 to 6000 cps, was evaluated to be soft.

According to the enzyme treatment, the viscosity tended to be lower in the enzyme treatment group than in the non-enzyme treatment group. In addition, in the case of mixed culture with Bacillus Bifidum and Lactobacillus asidofyrus or Lactobacillus vulgaris of the non-enzyme group, the viscosity of the soybean yogurt was rougher and harder than that of the enzyme treatment group as the pH decreased. Was high.

Experimental Example 4. Determination of Organic Acid Content in Soybean Yogurt

To 5 g of sample, 5 mL of deionized water and 20 mL of acetonitrile were added, shaken for 2 minutes in a 50 mL centrifuge tube, and then centrifuged at 5420 × g for 5 minutes. A sample for HPLC analysis was used by filtration with a supernatant 0.2 μm membrane filter. The chromatogram analyzed by HPLC was calculated by comparing the retention time and area of the standard organic acid.

Organic acids are produced in the dairy products as a result of the hydrolysis of milk fat or metabolism by microbial growth, and the main organic acids of yogurt are lactic acid, acetic acid, citric acid, formic acid, succinic acid and fumaric acid.

Experimental results As shown in Table 1, the composition and content of organic acid according to the culture method and the enzyme treatment showed a distinct difference depending on the culture method, Bacillus bifidum In the case of monoculture, the contents of acetic acid and succinic acid were the highest, followed by lactic acid and citric acid. In contrast, the mixed culture of Bacillus bifidum and Lactobacillus asidophilus or Lactobacillus vulgaris showed the highest content of lactic acid, followed by acetic acid and pyruvic acid. Citric acid and succinic acid produced at the time of monoculture were not detected.

Acetic acid content depends on the culture method In the single culture, 33.5-51.6% of the total organic acid was used, but 7.6-19.2% of the total organic acid was mixed in the mixed culture of Bacillus bifidum and Lactobacillus asidofyrus or Lactobacillus vulgaris. Bacillus bifiderm, a lactic acid-fermenting bacterium, reported that the acid produced as the final product of glucose metabolism produces acetic acid and lactic acid at a ratio of 1.5: 1 and produces a small amount of formic acid, succinic acid and ethanol. Acetic acid content was higher than mixed culture with Lactobacillus asidofyrus or Lactobacillus vulgaris, a normal lactic acid-fermenting bacterium that only generates lactic acid when cultured alone. In monoculture, the ratio was 1.8: 1 to 2.8: 1.

The acetic acid content of the enzyme treatment was Bacillus bifidum and Lactobacillus acidophyrus in the protease-treated group and bromelain-treated group extracted from Aspargillus aurise. 18.7 and 23.4 ppm of mixed cultures were more than 13.9 and 13.6 ppm of mixed Bacillus bifidum and Lactobacillus vulgaris, respectively. The acetic acid content was similar.

The amount of lactic acid increased greatly in the mixed culture of Bacillus bifidum and Lactobacillus asidofyrus or Lactobacillus vulgaris, depending on the culture method, accounting for 80.8-92.4% of the total organic acids. Is believed to be primarily due to miscarriage. In particular, lactic acid content of non-enzyme-treated group, proteolytic enzyme-treated group and bromelain-treated group extracted from Asparagus bifidus was the highest in the mixed culture of Bacillus bifidum and Lactobacillus vulgaris among the culture methods. The trypsin-treated group was the most common in the mixed culture of Bacillus bifiderm and Lactobacillus asidophilus. Bacillus Bifiderm In monoculture, lactic acid content in the total organic acid accounted for 14.4-21.5%. The lactic acid content of enzyme treatment was the highest in the protease treatment group extracted from Asparagus duckase, which had the highest titratable acidity, followed by bromelain treatment, non-enzyme treatment, and α-chymotrypsin treatment.

Citric acid, an important precursor for the production of flavors, is Bacillus bifidum It was detected only in the culture alone, 6.5 ppm in the non-enzyme treatment group, and 5.4 and 4.2 ppm in the bromelain treatment group and α-chymotrypsin treatment group, respectively. On the other hand, citric acid was not detected in the protease-treated group extracted from Aspargillus duckase. The content of citric acid in yogurt is reduced by 25-30% during yogurt production, especially the change in the content of citric acid depends on the presence of strains that can use citric acid. In the present invention, citric acid is Bacillus Bifidum and Lactobacillus acido pyrus Or citric acid was used by Lactobacillus asidofyrus and Lactobacillus vulgaris in that it was not detected in the mixed culture with Lactobacillus vulgaris.

Pyruvic acid was detected in trace amounts in most sample groups, but not in Bacillus bifidum alone cultures.

Succinic acid is Bacillus bifider Detected only in culture alone, the highest value was 52.9 ppm in the α-chymotrypsin treatment group, and the protease treatment group extracted from Asparagus duckase.,The bromelain treatment group and the non-enzyme treatment group showed 38.6, 28.8 and 20.9 ppm, respectively.

Organic Acids of Soybean Yogurt Prepared by Different Culture Methods and Enzyme Treatment Product Organic acid Acetic acid Legacy Citric acid Pyruvic acid Succinic acid U-Bb 19.4 7.9 6.5 Tr 20.9 U-BbLa 12.2 104.0 ND 0.1 ND U-BbLb 12.1 108.0 ND 0.1 ND P-Bb 67.3 24.4 ND ND 38.6 P-BbLa 18.7 142.0 ND Tr ND P-BbLb 13.9 169.0 ND ND ND B-Bb 63.0 26.8 5.4 ND 28.8 B-BbLa 23.4 133.0 ND 0.1 ND B-BbLb 13.6 154.0 ND 0.1 ND C-Bb 40.1 22.3 4.2 ND 52.9 C-BbLa 16.8 73.7 ND 0.1 ND C-BbLb 17.0 71.6 ND 0.1 ND Co., Ltd. U: non-enzymatic treatment, P: protease extracted from the asparagus duckase, B: bromelain, C: α -chymotrypsin, Bb-bacillus bifidum, BbLa: B.bifidium + lactobacillus acido Russ, BbLb: Bacillus bifiderum + Lactobacillus vulgaris, ND: not detected, Tr: Trace

Example 3 Effect of Enzyme Treatment on Quality Characteristics of Frozen Soy Yogurt

Experimental Example 1. Measurement of Viable Cell Count of Frozen Soy Yogurt

Aseptic soy yogurt and frozen soy yogurt immediately after preparation were each aseptically diluted by 10-fold dilution with sterile peptone water and plated on Latobacilli MRS medium, and then Bacillus bifidum was subjected to anaerobic jars (anarobic jar; Difco, Ketroit, MI). , USA) incubated anaerobicly for 48-72 hours in an incubator fixed at 37 ° C., and Lactobacillus asidofyrus and Lactobacillus vulgaris were cultured aerobicly to yield 25 to 250 colonies. Was calculated by selecting. In addition, the viable cell count of frozen soy yogurt during the freezing storage period was measured in the same manner as the above method.

As shown in Table 2, The viable bacterial counts of Bacillus bifidum in soybean yoghurt and frozen soybean yogurt were Bacillus bifidum and Lactobacillus asidofyrus Bacillus bifiderm for Lactobacillus bulgaricus culture More than the single culture, which contained oxygen in the substrate and the aerobic bacteria Lactobacillus asidofyrus. It was used by Lactobacillus vulgaris to make anaerobic conditions, thereby promoting the growth of the anaerobic bacillus bifidum.

Bacillus bifidum in viable cell count according to the culture method The number of viable bacteria of Bacillus bifidum was 10⁷CFU / g but in the enzyme treatment group 10⁸CFU / g was increased because enzymatic treatment of the isolated soy protein produced Bacillus bifidum, which made available nitrogen, which promoted the growth of Bacillus bifidum. However, in the mixed culture, enzyme treatment did not significantly affect the viable count. In the case of the mixed culture with Bacillus bifidum and Lactobacillus acido pyrus or Lactobacillus vulgaris, the non-enzyme-treated group, the protease-treated group extracted from Aspargillus duckase and the bromelain-treated group were⁹CFU / g was maintained but α-chymotrypsin treated group was 10⁸CFU / g is shown.

According to the ingredient specification of yogurt,⁸It should be more than CFU / ml, in the present invention the number of live bacteria Bacillus non-pidem of the non-enzyme treated group 10 for all sample groups except for single culture⁸Since it was CFU / g or more, it conformed to the component specification of yoghurt.

In addition, after measuring the viable cell count of frozen soy yogurt after freezing soy yogurt for 30 minutes in an ice cream maker, the viable cell counts of Bacillus bifidum, Lactobacillus asidofyrus and Lactobacillus vulgaris were similar to those of soybean yogurt. Similarly, there was almost no reduction in viable counts due to freezing.

That is, in the present invention, the viable cell counts of Bacillus bifidum, Lactobacillus asidofyrus and Lactobacillus vulgaris were not reduced by freezing, and oxygen inflowed during freezing of soy yogurt in an ice cream maker for 30 minutes in the preparation of frozen soy yogurt. The viable cell count of Bacillus bifidum, an anaerobic bacterium, was hardly reduced.

Viable Cell Counts of Soy Yogurt and Frozen Soy Yogurt Prepared by Different Culture Methods and Enzyme Treatment Starter culture Bb BbLa BbLb Enzyme treatment Product B.bifidum B.bifidum L.acidophilus B.bifidum L.bulgaricus Non-enzymatic treatment Soybean Yogurt 0.4 13.1 13.6 19.9 27.6 Frozen soy yogurt 0.2 11.1 14.8 15.3 16.1 Protease Treatment Extracted from Asparagus Oris Soybean Yogurt 2.5 22.4 21.8 69.3 32.8 Frozen soy yogurt 1.2 21.7 21.3 30.8 25.2 Bromelain Soybean Yogurt 2.8 31.8 40.2 34.8 49.6 Frozen soy yogurt 1.8 19.5 22.3 20.4 25.5 α-chymotrypsin Soybean Yogurt 2.1 2.5 2.6 7.5 7.1 Frozen soy yogurt 3.5 1.6 2.1 2.78 2.5 Bb: Bacillus Bpiderm, BbLa: Bacillus Bpiderm + Lactobacillus acido pyrus, BbLb: Bacillus Bpidemum + Lactobacillus Bulgaricus

Experimental Example 2 Measurement of Acid Resistance of Frozen Soy Yogurt

Immediately after the preparation and frozen storage soybean yogurt was added to 1.25N HCl adjusted to pH 2.5 and incubated for 90 minutes in a fixed incubator at 37 ℃ and incubated in the same conditions as the above-described bioburden measurement experiments acid resistance of frozen soy yogurt Was measured.

As a result, Bacillus bifidum of frozen soybean yogurt incubated with culture method and enzyme treatment,Lactobacilli And acid resistance of Lactobacillus vulgaris is as shown in Table 3, Bacillus bifidum 3.2 × 10 in non-enzyme-treated group, protease-treated group and bromelain-treated group, respectively⁵, 1.2 × 10⁵, 1.6 × 10⁵CFU / g and 1.9 × 10 in the α-chymotrypsin group.⁶CFU / g, which is 10 compared to the viable count of frozen soy yogurt²To 10³CFU / g was decreased. Bacillus bifiderm and Lactobacillus asidophilus In the case of mixed culture, the acid resistance of Bacillus bifiderum was reduced in all sample groups.²Of CFU / g Decreased, and Lactobacillus asidophilus 10²CFU / g was decreased, but in the protease treatment group extracted from Asparagus duckase 10³The CFU / g was reduced, further lowering acid resistance. Bacillus Bifidum and Lactobacillus Bulgaricus In the mixed culture, the acid resistance of Bacillus bifidum and Lactobacillus vulgaris was the lowest in the protease treatment group extracted from Asparagus duckase, respectively, 3.8 × 10.⁶, 6.4 × 10⁶CFU / g, so 10³CFU / g was decreased.

Bacillus Bifiderm in the present invention,Lactobacilli Survival rate was 0.1-2.5% under acidic conditions of Lactobacillus vulgaris and did not show any difference according to the culturing method and enzyme treatment. High.

That is, Bacillus bifidum used in the present invention,Lactobacilli AndL. bulgaricusAcid resistance of 10 was higher than that of frozen soy yogurt²To 10³As the CFU / g was decreased, acid resistance was relatively good.

Acid Resistance of Bacillus Bifidum , Lactobacillus asidophilus and Lactobacillus Bulgaricus of Frozen Soy Yogurt by Culture Method and Enzyme Treatment Product Types of Heritage Bacteria Viable Cell Count (10 ⁶ CFU / g) Survival rate (%) U-Bb B.bifidum 0.3 1.5 U-BbLa B.bifidum 11.0 1.0 L.acidophilus 15.1 1.0 U-BbLb B.bifidum 26.5 1.7 L.bulgaricus 16.1 1.0 P-Bb B.bifidum 0.1 1.0 P-BbLa B.bifidum 22.0 1.0 L.acidophilus 1.6 0.1 P-BbLb B.bifidum 3.8 0.1 L.bulgaricus 6.4 0.3 B-Bb B.bifidum 0.2 0.1 B-BbLa B.bifidum 16.0 0.8 L.acidophilus 53.7 2.4 B-BbLb B.bifidum 24.1 1.2 L.bulgaricus 4.6 0.2 C-Bb B.bifidum 1.9 0.5 C-BbLa B.bifidum 1.7 1.1 L.acidophilus 5.9 2.8 C-BbLb B.bifidum 4.4 1.6 L.bulgaricus 6.2 2.5 Co., Ltd. U: non-enzymatic treatment P: proteolytic enzyme extracted from Asphagillus aurise, B: bromelain, C: α-chymotrypsin, Bb: Bacillus bifiderm + Lactobacillus bulgaricus, BbLa: Bacillus bifiderm + Lactobacillus asidophilus, BbLb: Bacillus bifiderm + Lactobacillus bulgaricus,

Experimental Example 3 Measurement of Bile Acid Resistance of Frozen Soy Yogurt

Immediately after preparation and 1 g of frozen stored soybean yoghurt aseptically, diluted by 10-fold dilution with sterile peptone water, and 0.3% of bile acid oxgall (Difco, Detroit, MI, USA) was added to Latobacilli MRS medium. After the plate was incubated under the same conditions as the viable cell count, the bile acid resistance of the frozen soy yogurt was measured.

Lactic acid bacteria must be resistant to acid and bile acids in order to survive and multiply in the digestive organs of the human body. Bile is a type of surfactant that is secreted from the gallbladder into the duodenum.Cholic acid, deoxycholic acid, and chenodeoxycholic acid are the main constituents. (oxgall) must be resistant enough to grow in medium containing 0.3%.

Experimental results As shown in Table 4, there was a difference in the bile acid resistance of the strain according to the culture method and enzyme treatment. Bacillus B. pepidem of non-enzyme treated group Independent Culture, Bacillus B. Pidum And Lactobacillus asidophilus Or rockTobacillus BulgaricusWith Reduced bile acid resistance in mixed cultures 10 Decreased CFU / g, In the protease-treated and bromelain-treated groups extracted from Aspargillus duckase, Bacillus bifidum 3.7 × 10 each in single culture⁷, 3.2 × 10⁷10 to CFU / g Reduction of CFU / g viable cell counts, but Bacillus bifidum and Lactobacillus acido pyrus Or rockTobacillus BulgaricusWith In the mixed culture, there was no change in viable cell counts due to the resistance to bile acids. Bacillus bifiderm in the α-chymotrypsin group When cultured alone, it showed resistance to bile acids, and there was no decrease in viable cell count, whereas Bacillus bifidum and Lactobacillus acido pyrus In the case of mixed culture, the resistance to bile acid of Bacillus bifidum decreases to 1.7 × 10.⁸8.4 × 10 at CFU / g⁷Although reduced to CFU / g, Lactobacillus asidofyrus showed resistance to bile acids. Bacillus bifidum and lactoseBacillus BulgaricusBacillus bifiderm in mixed culture,LactoseBacillus BulgaricusBoth were found to be resistant to bile acids. In other words, Bacillus bifidum in the mixed culture of two kinds of protease-treated group and bromelain-treated group extracted from Aspargillus duckase,Lactobacilli And lactoseBacillus BulgaricusWas resistant to bile acids and Bacillus bifidum of the α-chymotrypsin group. Monoculture and Bacillus bifiderum and lactoseBacillus BulgaricusIt was shown that bile acid resistance was strong at the time of the mixed culture.

Bacillus Bifiderm in the present invention,Lactobacilli Or lactoseBacillus Bulgaricusof Survival rates for bile acids were 13.6-94.8%, depending on the culture method and enzyme treatment. Survival was higher than that of monoculture, and according to the enzyme treatment, it was higher in the protease treatment group extracted from Asparagus duckase.

Investigation of Bile Acid Resistance in Strains Product Types of Heritage Bacteria Viable Cell Count (10 ⁶ CFU / g) Survival rate (%) U-Bb B.bifidum 0.3 13.6 U-BbLa B.bifidum 85.7 77.2 L.acidophilus 66.8 45.1 U-BbLb B.bifidum 87.7 57.3 L.bulgaricus 91.8 57.0 P-Bb B.bifidum 3.7 31.1 P-BbLa B.bifidum 133.0 61.3 L.acidophilus 189.0 88.7 P-BbLb B.bifidum 265.0 86.0 L.bulgaricus 239.0 94.8 B-Bb B.bifidum 3.2 17.7 B-BbLa B.bifidum 16.1 82.6 L.acidophilus 166.0 74.4 B-BbLb B.bifidum 128.0 62.7 L.bulgaricus 144.0 56.4 C-Bb B.bifidum 10.2 29.0 C-BbLa B.bifidum 8.4 53.8 L.acidophilus 12.2 57.8 C-BbLb B.bifidum 22.5 80.9 L.bulgaricus 23.4 92.1 Co., Ltd. U: non-enzymatic treatment P: proteolytic enzyme extracted from Asphagillus aurise, B: bromelain, C: α-chymotrypsin, Bb: Bacillus bifiderm + Lactobacillus bulgaricus, BbLa: Bacillus bifiderm + Lactobacillus asidophilus, BbLb: Bacillus bifiderm + Lactobacillus bulgaricus,

Experimental Example 4. Overrun Measurement of Frozen Soy Yogurt

The change in overrun during ice cream maker operation was quickly weighed by placing the sample taken out of the maker at 5 minute intervals for 30 minutes in a 100 mL cup.

Experimental results As shown in Figure 5, according to the culture method Bacillus BP In the case of single culture, the overrun of the non-enzyme treated group was highest at 21.06% (p <0.001) at the initial 5 minutes, but Bacillus bifidum and Lactobacillus acidospirus were the highest. In the mixed culture, it was the lowest in the bromelain group (2.70%). Bacillus Bifidum and Lactobacillus Bulgaricus In the mixed culture, the α-chymotrypsin treated group was the highest (p <0.001), but the lowest value was 4.91% in the non-enzyme treated group. As the operating time in the ice cream maker increased, the overrun increased relatively slowly, reaching an overall peak with 20 to 25 minutes of operation for most of the sample groups. At this time, if you compare the overrun of each sample group, Bacillus bifiderm Monoculture, Bacillus bifiderm and Lactobacillus acido pyrus Or with Lactobacillus vulgaris 24.33-40.82, 16.18-34.87, and 8.66-89.48% were formed in the mixed culture, respectively. In the non-enzyme treatment group, Bacillus bifidum and Lactobacillus acido pyrus were observed. Or Lactobacillus vulgaris In the case of mixed culture, the formation of overrun was much lower than that of other sample groups. Bacillus bifiderum and Lactobacillus vulgaris In the case of mixed culture, it was 4.91 to 9.33% in 30 minutes operation. Soybean yogurt made from two kinds of mixed cultures has a hard curd and separates from water, so the free water freezing below 0 ° C during freezing in the ice cream maker increases the amount of free air, resulting in an overrun. It could not be formed. In the protease-treated group extracted from Aspargillus duckase, the culture method did not affect the formation of overruns and showed similar tendency without significant difference between samples. Bacillus bifiderm and Lactobacillus vulgaris in the bromelain group and α-chymotrypsin group Overruns were highest in mixed cultures and Bacillus bifidum Monoculture, Bacillus bifiderm and Lactobacillus acido pyrus It was higher in the order of mixed culture. Overall, the overrun of the α-chymotrypsin treated group showed high tendency, especially Bacillus bifidum and Lactobacillus vulgaris. In the case of the mixed culture, the ice cream maker showed the highest value of 89.48% in 20 minutes operation.

In other words, the present invention showed a difference in overrun formation according to the cultivation method and the enzyme treatment. In all sample groups except mixed culture, an overrun of 9.33-36.43% was formed by 30-minute operation of the ice cream maker.

Thus, in the present invention, the overrun of the frozen soy yogurt showed a lower tendency than the frozen yogurt made of milk, which is a factor affecting the formation of the overrun, that is, the content and composition of the total solid content of the yogurt mix, and the foam of the protein. It was judged by the difference in production capacity and rotation speed of the stirrer.

Experimental Example 5 Measurement of Melting Degree of Frozen Soy Yogurt

An entangled wire mesh was placed on the measuring cylinder, followed by a frozen soy yogurt with an ice cream scooper. The amount of melting to the bottom of the measuring cylinder at intervals of 10 minutes for 60 minutes was calculated as a percentage per scoop capacity and the melting pattern was observed. In addition, the degree of melting during freezing storage was measured in the same manner as described above after leaving the sample for 30 minutes at room temperature 20 ~ 22 ℃.

Experimental results, as shown in Figure 6, during the initial 10 minutes there was no significant difference in the degree of melting of most of the sample group, but the melting degree increased over time and increased compared to the initial 10 minutes at 60 minutes (p <0.001 ). Depending on the culture method, the degree of melting is Bacillus bifidum Non-enzyme-treated group and protease-treated group extracted from Aspargillus duckase during single culture In the bromelain treatment group, it increased rapidly for 30 or 40 minutes, but there was almost no change thereafter, and the degree of melting was increased from 68.0 to 77.3% at 60 minutes, compared to the two cultures. The degree of melting of the α-chymotrypsin treatment group gradually increased for 60 minutes and was 11.2% at 60 minutes, which was very low compared to other sample groups.

Bacillus bifiderm and Lactobacillus asidophilus In the mixed culture, the bromelline treated group had the highest melting rate, while the non-enzyme treated group had the lowest melting ratio of 0 to 1.32% for 60 minutes, and all the sample groups gradually melted for the first 10 to 60 minutes. Increased. Bacillus Bifidem and Lactobacillus Bulgaricus In the mixed culture, the protease treatment group extracted from Asparagus duckase had the highest level of melting, but the lowest in the non-enzyme treatment group, Bacillus bifidum and Lactobacillus asidofyrus. As in the case of mixed culture, the degree of melting from the first 10 minutes to 60 minutes was gradually increased.

The overrun of commercially sold soft ice cream forms 40-80%, and when the overrun is formed too much, the amount of air injection increases, so that it melts too quickly in the mouth. Bifidum and Lactobacillus vulgaris of the α-chymotrypsin treated group The degree of melting at the time of mixed culture was 0-15.57% until 60 minutes, and the formation of overrun did not significantly affect the degree of melting of the sample group.

Bacillus Bifiderm In the single culture, the dissolution of all sample groups except α-chymotrypsin treatment group showed a tendency to dissolve together solids and water. Bacillus BP derm that solids and moisture melt together Melting tended to be much lower than in single culture.

Soybean yogurt of the present invention, as described through the above examples, was prepared by the alone or mixed culture of Lactobacillus strains in the enzyme-treated soy protein, so that the pH is low, and the acidity is higher than that prepared using the non-treated soy protein. The present invention is very effective in the fermented food industry because it has a moderate viscosity, high organic acid content, almost no decrease in viable cell count due to freezing, strong resistance to acid resistance and bile acid, high overrun and low melting rate. It is a useful invention.

Claims (5)

(a) treating soybean protein (SPI) with a protease derived from Aspergillus strain to prepare and sterilize the soy protein sample; (b) preparing and sterilizing an aqueous solution of isomaltooligosaccharide; (c) mixing the sterilized soybean protein sample of step (a) and the sterilized isomaltooligosaccharide aqueous solution of step (b) to prepare a medium; (d) B. bifidum ( B. bifidum) alone or cultured in the medium prepared in step (c) or Bacillus bifidum and L. acidophilus ( L. acidophilus ) or Bacillus bifiderum and Lactobacillus Bulgari ( L) .bulgaricus ) method of producing soybean yogurt comprising the step of inoculating and mixed culture. The method of claim 1, wherein the protease is a protease, bromelain, or α -chymotrypsin extracted from Asparagus aurise ( A.oryzae) . Soybean yogurt prepared by the method of claim 1. The soybean yogurt of claim 3 is stored and frozen at 2 to 8 ° C., and the frozen soy yogurt is prepared by mixing 0.02 to 0.08% aspartame and 0.01 to 0.2% vanilla essence to the frozen soy yogurt. A soybean yoghurt prepared by the method of claim 4.