A probiotic-containing fermented dairy product made from pea type III resistant starch and its applications

Abstract

The present invention provides a fermented dairy product containing probiotics and pea type III resistant starch and its application. The composition of pea type III resistant starch and Bifidobacterium animalis subsp. lactis is applied to the preparation of fermented dairy products. The active ingredients of the composition consist of pea type III resistant starch and Bifidobacterium animalis subsp. lactis ZYhyy-003. The Bifidobacterium animalis subsp. lactis ZYhyy-003 is preserved in the General Microbiology Center of the China Committee for Culture Collection of Microorganisms. The preservation date is August 5, 2024, and the preservation number is CGMCC No. 31553. The taxonomic name is Bifidobacterium animalis subsp. lactis Bifidobacterium animalis subsp. lactis . Experiments have confirmed that the composition of pea type III resistant starch and Bifidobacterium animalis subsp. lactis can significantly improve the quality of fermented milk products, providing consumers with fermented dairy products with weak after-acid, stable viable probiotic counts, and good sensory qualities.

Description

Technical Field

[0001] The present invention belongs to the field of microbial technology, and particularly relates to a type III resistant starch-fermented dairy product containing probiotics and its application. Background Art

[0002] With the continuous improvement of people's health awareness, more and more consumers are beginning to pay attention to the nutrition and health of their diet. As a dairy product rich in probiotics and protein, yogurt is considered to be helpful for improving digestive system health, enhancing immunity, etc., and thus is favored by more and more consumers. Fermented milk has become an important part of the Chinese dairy market, and its market share has been expanding year by year. Currently, the proportion of fermented milk in the Chinese dairy market is roughly between 20% and 30%. With the continuous increase in the demand for healthy foods among Chinese consumers, it is expected that the market share of fermented milk will continue to rise. However, long-term storage can lead to too high acidity of fermented milk, which in turn affects the taste and flavor of the product. This is mainly because the starter culture in fermented milk converts lactose into lactic acid, resulting in an increase in acidity. During storage, the phenomenon of whey and curd separation often occurs in fermented milk, resulting in uneven product appearance, poor taste and texture. Some fermented milk may even become too hard due to protein coagulation or water loss, losing its delicate and smooth taste. These defects not only affect the quality and taste of fermented milk, but also reduce the market competitiveness of the product and the satisfaction of consumers. Therefore, during production and storage, appropriate measures must be taken to prevent these problems from occurring to ensure the quality and safety of fermented milk.

[0003] To address this problem, improving the texture of fermented milk and continuous acid production during storage has become the research focus. As a special type of starch, type III resistant starch has attracted extensive attention in recent years. Studies have shown that type III resistant starch can significantly increase the consistency and taste of fermented milk, making it more rich and smooth, and enhancing the texture and taste quality of the product. At the same time, due to the addition of type III resistant starch, the water retention of fermented milk is more stable, effectively reducing the product separation phenomenon and maintaining the uniformity and stability of the product. Generally speaking, fermented milk added with type III resistant starch shows better taste, consistency, stability and persistence in texture, and can significantly improve the taste quality of the product and the consumption experience of consumers. At the same time, weak post-acid starter cultures have become an important part of fermented milk production. Such starter cultures can maintain the continuous stability of the product while ensuring the best taste of fermented milk. Studies have shown that selecting appropriate probiotics for co-fermentation during the fermentation process can improve the interaction efficiency between strains and play a synergistic role, thereby reducing the generation of adverse products during fermentation. Different strains make up for their own metabolic defects by using the metabolic products of each other, thus achieving mutualistic symbiosis. This efficient interaction can not only maintain the viable count of probiotics in fermented milk, but also significantly improve the quality of fermented milk.

[0004] However, the synergistic effect of the weak post-acid complex starter and resistant starch has not been studied. SUMMARY OF THE INVENTION

[0005] Aiming at the problems existing in the prior art, the purpose of the present invention is to provide a fermented dairy product containing probiotics and pea type III resistant starch and its application. The composition of pea type III resistant starch and Bifidobacterium animalis subsp. lactis is used for the preparation of fermented milk, which can significantly improve the quality of fermented milk products and provide consumers with fermented dairy products with weak post-acid, stable viable probiotic count and good sensory quality.

[0006] From the past relevant research and practical applications of the inventors, type III resistant starches from different sources and structures have different effects when interacting with the fermented milk system due to differences in their molecular structure, particle size and other characteristics. Therefore, the inventors conducted research on this, hoping to clarify the influence law of the compound combinations of different type III resistant starches and probiotics on the quality of fermented milk and obtain a compounding scheme with the best consistency, taste, stability and microbial characteristics. The resistant starches screened in the early stage of the research included: pea type III resistant starch, Novelose 260 resistant starch and Xiangyu Y90 resistant starch; the probiotics screened included: Bifidobacterium animalis subsp. lactis ZYhyy-003, Bifidobacterium animalis BB12, Lactobacillus rhamnosus GG, Lactobacillus paracasei L9 and Lactobacillus acidophilus La5. However, through experiments, it was found that pea type III resistant starch + Bifidobacterium animalis subsp. lactis ZYhyy-003 showed an obvious synergistic effect. Compared with other single resistant starch groups, single probiotic groups and resistant starch + probiotic compound groups, it could significantly reduce the post-acid of fermented milk during storage and maintain the stability of the probiotic count. In view of this, the inventors provided the following scheme of the present invention.

[0007] To achieve the above purpose, in the first aspect of the present invention, a composition of pea type III resistant starch and Bifidobacterium animalis subsp. lactis is provided, and the active ingredients of the composition are composed of pea type III resistant starch and Bifidobacterium animalis subsp. lactis ZYhyy-003;

[0008] The Bifidobacterium animalis subsp. lactis ZYhyy-003 is preserved in the General Microbiological Center of the China Committee for Culture Collection of Microorganisms. The preservation date is August 5, 2024, and the preservation number is CGMCC No. 31553. The taxonomic name: Bifidobacterium animalis subsp. lactis Bifidobacterium animalis subsp.lactis ;

[0009] In the composition, the concentration of Bifidobacterium animalis subsp. lactis ZYhyy-003 is the viable cell count of 5×10 6 ~5×10 8CFU / mL, and / or the content of type III pea resistant starch is 0.5 w / v% - 2.5 w / v%. Preferably, the concentration of Bifidobacterium animalis subsp. lactis ZYhyy - 003 is viable count 8×10 6 ~5×10 7 CFU / mL, and the content of type III pea resistant starch is 1 w / v% - 2 w / v%.

[0010] Furthermore, the preparation method of the type III pea resistant starch includes the following steps:

[0011] Mix HCl with pea starch, heat up and stir to hydrolyze the pea starch, adjust the pH = 7 to obtain acid - hydrolyzed pea starch; the acid - hydrolyzed pea starch is gelatinized by stirring at high temperature for 20 - 30 min to obtain gelatinized pea starch; after adding pullulanase to the gelatinized pea starch, stir at 45°C for 30 - 35 hours to obtain debranched pea starch; the debranched pea starch is kept at 30°C for 20 - 25 hours, and the lower - layer starch obtained after centrifugation is further dried to obtain type III pea RS3; the type III pea RS3 is formulated into a starch milk with a moisture content of 30% and then hydrated for 20 - 25 hours, heat - treated under pressure at 115°C for 150 - 200 minutes, and dried at 50°C to obtain type III pea resistant starch.

[0012] The second aspect of the present invention provides the application of the composition of the type III pea resistant starch and Bifidobacterium animalis subsp. lactis in the above - mentioned first aspect in the preparation of food.

[0013] Furthermore, the food is fermented dairy products.

[0014] Furthermore, the composition of the type III pea resistant starch and Bifidobacterium animalis subsp. lactis is used to reduce the post - acidification during storage of fermented dairy products, maintain the stability of the number of probiotics, and improve the quality of fermented dairy products at the same time.

[0015] Furthermore, improving the quality of fermented dairy products includes increasing the hardness, adhesiveness, elasticity and water - holding capacity of dairy products.

[0016] The third aspect of the present invention provides a fermented dairy product, which contains the composition of the type III pea resistant starch and Bifidobacterium animalis subsp. lactis described in the first aspect.

[0017] The fourth aspect of the present invention provides a microbial preparation, which contains the composition of the type III pea resistant starch and Bifidobacterium animalis subsp. lactis described in the first aspect.

[0018] The fifth aspect of the present invention provides a preparation method of a pea type III resistant starch fermented dairy product containing probiotics, including the following steps:

[0019] (1) Preparation of fermented milk base: Add 0.5 w / v% - 2.5 w / v% of pea type III resistant starch to pure milk. After material mixing, homogenization, and sterilization, a pea type III resistant starch fermented milk base is obtained;

[0020] (2) Preparation of compound probiotic starter: The compound probiotic starter includes a basic starter and Bifidobacterium animalis subsp. lactis ZYhyy - 003. Among them, the addition amount of the basic starter is 0.02‰ - 0.05‰ (weight percentage), and the concentration of Bifidobacterium animalis subsp. lactis ZYhyy - 003 is the viable count of 5×10 6 ~ 5×10 8 CFU / mL; Preferably, the addition amount of the basic starter is 0.03‰ - 0.04‰ (weight percentage), and the concentration of Bifidobacterium animalis subsp. lactis ZYhyy - 003 is the viable count of 8×10 6 ~ 5×10 7 CFU / mL.

[0021] (3) Inoculation and fermentation: Inoculate the compound probiotic starter described in step (2) into the pea type III resistant starch fermented milk base obtained in step (1), and the fermentation time is 5 - 5.5 hours, thereby obtaining a pea type III resistant starch fermented dairy product containing probiotics.

[0022] Further, in step (1), the material mixing is as follows: At 50°C - 55°C, stir at 500 r / min for 30 - 50 min to obtain a mixed emulsion;

[0023] The homogenization is as follows: The mixed emulsion is homogenized at 15 - 20 MPa at 50°C - 55°C to obtain a homogeneous mixed emulsion;

[0024] The sterilization is as follows: The homogeneous mixed emulsion is sterilized at 95°C for 5 - 10 min, and then cooled to 43°C to obtain a pea type III resistant starch fermented milk base.

[0025] Information on strain preservation:

[0026] Bifidobacterium animalis subsp. lactis ZYhyy - 003, Preservation institution: China General Microbiological Culture Collection Center (CGMCC); Address: No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, Zip code: 100101; Preservation date: August 5, 2024; Preservation number CGMCC No. 31553; Taxonomic nomenclature: Bifidobacterium animalis subsp. lactis Bifidobacterium animalis subsp.lactis .

[0027] The beneficial effects of the present invention compared with the prior art are:

[0028] This application uses the composition of pea type III resistant starch and Bifidobacterium animalis subsp. lactis to prepare fermented dairy products. Compared with the base starter culture and the addition of Bifidobacterium animalis subsp. lactis ZYhyy-003 alone, it can reduce the post-acidification of fermented milk during storage, maintain the stability of probiotic numbers, and significantly improve the quality of fermented milk products. Specifically, it increases the viscosity of fermented milk and has a smooth taste. And the effect is significant due to the combination of the positive control bacteria Bifidobacterium animalis BB12, Lactobacillus rhamnosus GG, Lactobacillus paracasei L9, Lactobacillus acidophilus La5 and pea type III resistant starch. Description of the Drawings

[0029] The present invention will be further described below in conjunction with the drawings and embodiments:

[0030] Figure 1 Shows the fermentation end time of each group of fermented milk described in Test Example 1;

[0031] Figures 2 to 5 Respectively show the hardness, adhesiveness, elasticity and water holding capacity of each group of fermented milk described in Test Example 2;

[0032] Figure 6 Shows the acidity change of each group of fermented milk during storage described in Test Example 3;

[0033] Figure 7 Shows the change in the number of probiotic bacteria in each group of fermented milk during storage described in Test Example 3. Detailed Description of the Invention

[0034] The implementation of the present invention is not limited to the following embodiments. Any form of modification and / or change made to the present invention will fall within the protection scope of the present invention. In the present invention, unless otherwise specified, all equipment and raw materials can be purchased from the market or are commonly used in this industry. Unless otherwise specified, the methods used in the embodiments are general techniques in the art.

[0035] For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be considered as specifically disclosed herein.

[0036] In the following embodiments, Novelose260 resistant starch was purchased from Shanghai Naijin Industrial Co., Ltd.; Xiangyu Y90 resistant starch was purchased from Quanyin Xiangyu (Beijing) Biotechnology Co., Ltd.; Bifidobacterium animalis subsp. lactis ZYhyy-003 was derived from Zhongyuan Food Laboratory; Lactobacillus paracasei L9 (the strain preservation number is CGMCC No. 9800).

[0037] In the following embodiments, the detection methods involved include:

[0038] 1. The detection of titratable acidity (°T) is carried out in accordance with the provisions of the national standard GB 5009.239–2016: Weigh approximately 10 g of the fermentation base material, add 20 g of pure water, and add 2 drops of phenolphthalein (2 mL, 1% (w / v) ethanol solution); titrate the mixture with a standard 0.1 M NaOH, and record the volume of NaOH consumed; calculate the titratable acidity based on the mass m and the volume of NaOH consumed, and express it as degrees Thörner (°T).

[0039] °T = (c × v × 100) / (m × 0.1)

[0040] Wherein:

[0041] c — Molar concentration of the NaOH standard solution;

[0042] v — Volume consumed in the titration of the NaOH standard solution;

[0043] m — Mass of the weighed fermentation base material.

[0044] 2. The texture of fermented milk (including viscosity, cohesiveness, chewiness, etc.) is measured using a Brookfield CTX texture analyzer. The specific method is as follows: The sample is tested using a TA10 probe. The plastic cylinder probe with a diameter of 40 mm penetrates 15 mm downward through the surface of the yogurt. The descending speed, test speed, and probe return speed are 1, 3, and 3 mm / s respectively. All samples are in triplicate.

[0045] 3. The method for detecting the water-holding capacity of fermented milk is as follows: Weigh the mass of an empty centrifuge tube and record it as M / g; Weigh 8 g of the sample into each centrifuge tube, and weigh the total mass and record it as M 1 / g; The sample is centrifuged at 4 °C and 4000 × g for 15 min. After discarding the supernatant, it is inverted on filter paper for 10 min, and the total mass is weighed and recorded as M 2 / g. The water-holding capacity is expressed as %:

[0046] Water-holding capacity / % = (M 2 - M) / (M 1 - M) × 100%

[0047] Wherein: M is the weight of the centrifuge tube, g; M 1 is the total weight of the sample, g; M 2 is the weight of the sample after centrifuging to remove whey, g.

[0048] 4. Detection method for viable count of fermented dairy products: Adopt the national standard GB 4789.35-2016 "National Food Safety Standard Food Microbiological Examination Lactic Acid Bacteria Examination".

[0049] 5. The water-holding capacity of fermented milk products is reflected by measuring the centrifugal sedimentation rate. The detection steps of the centrifugal sedimentation rate include: Take a 50 mL centrifuge tube, and record the mass as M , Weigh 20 g of fermented milk ( M1 ), centrifuge at 4070 × g for 15 min, invert the centrifuge tube on the filter paper for 10 min, and weigh the mass of the bottom precipitate as M2 , and calculate the centrifugal sedimentation rate.

[0050] Centrifugal sedimentation rate / % = (M2 - M) / (M1 - M) × 100%

[0051] Example 1: Composition of type III pea resistant starch and Bifidobacterium animalis subsp. lactis

[0052] This example provides a composition of type III pea resistant starch and Bifidobacterium animalis subsp. lactis. The active ingredients of the composition are composed of type III pea resistant starch and Bifidobacterium animalis subsp. lactis ZYhyy-003;

[0053] The Bifidobacterium animalis subsp. lactis ZYhyy-003 is deposited in the China General Microbiological Culture Collection Center. The deposit date is August 5, 2024, and the deposit number is CGMCC No. 31553. Taxonomic name: Bifidobacterium animalis subsp. lactis Bifidobacterium animalis subsp.lactis ;

[0054] In the composition, the concentration of Bifidobacterium animalis subsp. lactis ZYhyy-003 is viable count 1×10 7 CFU / mL, and the content of type III pea resistant starch is 0.5 w / v% - 1.5 w / v%.

[0055] The preparation method of the pea type III resistant starch comprises the following steps: adding HCl to pea starch, mixing, heating and stirring for 30 - 32 h to hydrolyze the pea starch, and adjusting the pH to 7 to obtain acid-hydrolyzed pea starch; subjecting the acid-hydrolyzed pea starch to gelatinization by stirring at 120 °C for 20 - 30 min to obtain gelatinized pea starch; adding pullulanase to the gelatinized pea starch, and stirring at 45 °C for 30 - 35 h to obtain debranched pea starch; keeping the debranched pea starch at 30 °C for 20 - 25 h, centrifuging, and drying the lower-layer starch obtained to obtain pea RS3 of type III; configuring the pea RS3 of type III into a starch milk with a moisture content of 30%, hydrating for 20 - 25 h, subjecting to pressure heat treatment at 115 °C for 150 - 200 min, and drying at 50 °C to obtain RS3 resistant starch.

[0056] Example 2

[0057] In this example, a fermented dairy product is prepared using the composition of the pea type III resistant starch and Bifidobacterium animalis subsp. lactis described in Example 1, providing a pea type III resistant starch fermented dairy product containing probiotics. The preparation method comprises the following steps:

[0058] (1) Preparation of the fermented milk base: adding 0.5 w / v% - 1.5 w / v% of the pea type III resistant starch to pure milk, and after batching, homogenizing and sterilizing, obtaining the pea type III resistant starch fermented milk base.

[0059] Specifically: stirring at 500 r / min for 30 - 50 min under the condition of 50 °C - 55 °C to obtain a mixed emulsion; homogenizing the mixed emulsion at 15 - 20 MPa under the condition of 50 °C - 55 °C to obtain a homogeneous mixed emulsion; subjecting the homogeneous mixed emulsion to sterilization treatment at 95 °C for 5 - 10 min, and cooling to 43 °C to obtain the pea type III resistant starch fermented milk base.

[0060] (2) Preparation of the compound probiotic starter: The compound probiotic starter includes a basic starter and Bifidobacterium animalis subsp. lactis ZYhyy - 003. Among them, the basic starter is selected from Streptococcus thermophilus subsp. salivarius and Lactobacillus delbrueckii subsp. bulgaricus with rapid acidification ability, and the addition amount is 0.025‰ (weight percentage), and the concentration of Bifidobacterium animalis subsp. lactis ZYhyy - 003 is the viable count of 1×10 7 CFU / mL.

[0061] (3) Inoculation and fermentation: inoculating the compound probiotic starter described in step (2) into the pea type III resistant starch fermented milk base obtained in step (1), and fermenting at 43 ± 1 °C for 5 - 5.5 h to obtain the pea type III resistant starch fermented dairy product containing probiotics.

[0062] Comparative Example

[0063] To explore the influence law of different compound combinations of type III resistant starch and probiotics on the quality of fermented milk, this comparative example prepared fermented dairy products containing resistant starch according to the method described in Example 2. The difference is that the fermented milk was prepared according to the resistant starch and probiotic combinations shown in Table 1 (where Group C is Example 2).

[0064] Table 1 Addition amounts of resistant starch and strains in different groups

[0065]

[0066] Test Example 1: Fermentation end time of fermented milk with different combinations of resistant starch and probiotics

[0067] In this test example, the fermentation was ended when the titratable acidity (°T) reached approximately 70 °T detected by adopting the national standard GB 5009.239–2016.

[0068] The results are as Figure 1As shown in the figure, the pH value of the starter culture 4.0 fermented milk without probiotics and resistant starch (Group A) reached 4.55 at 7 hours, and the acidity was 69.64 ± 1.71 °T; the pH value of the fermented milk with only Bifidobacterium animalis subsp. lactis ZYhyy-003 (Group B) reached 4.55 at 6 hours, and the acidity was 70.80 ± 1.58 °T; the pH value of the fermented milk with both Bifidobacterium animalis subsp. lactis ZYhyy-003 and 1.5% RS3 resistant starch (Group C) reached 4.55 at 6 hours, and the acidity was 70.83 ± 2.95 °T; the pH value of the fermented milk with both Bifidobacterium bifidum BB12 and 1.5% RS3 resistant starch (Group G) reached 4.54 at 6.5 hours, and the acidity was 70.80 ± 2.54 °T; the pH value of the fermented milk with both Lactobacillus rhamnosus LGG and 1.5% RS3 resistant starch (Group H) reached 4.55 at 6 hours, and the acidity was 71.55 ± 1.45 °T; the pH value of the fermented milk with both Lactobacillus paracasei L9 and 1.5% RS3 resistant starch (Group I) reached 4.55 at 6 hours, and the acidity was 70.98 ± 3.57 °T; the pH value of the fermented milk with both Lactobacillus acidophilus La5 and 1.5% RS3 resistant starch (Group J) reached 4.54 at 6.5 hours, and the acidity was 70.23 ± 1.99 °T; the pH value of the fermented milk with only RS3 resistant starch (Group F) reached 4.55 at 6.7 hours, and the acidity was 70.29 ± 0.66 °T; the pH value of the fermented milk with both Bifidobacterium animalis subsp. lactis ZYhyy-003 and Novelose260 resistant starch (Group D) reached 4.55 at 7 hours, and the acidity was 70.23 ± 0.59 °T; the pH value of the fermented milk with both Bifidobacterium animalis subsp. lactis ZYhyy-003 and Y90 resistant starch (Group E) reached 4.55 at 7 hours, and the acidity was 72.82 ± 3.69 °T.

[0069] The above results show that when Bifidobacterium animalis subsp. lactis ZYhyy-003, Lactobacillus rhamnosus LGG, Lactobacillus paracasei L9 and Lactobacillus acidophilus La5 are co-added with RS3 resistant starch, they can all promote the rapid fermentation of the starter culture 4.0.

[0070] Test Example 2: Texture of Fermented Milk with Different Combinations of Resistant Starch and Probiotics

[0071] In this test example, a Brookfield CTX texture analyzer was used to measure the texture of the fermented milk, including viscosity, cohesiveness, chewiness, etc.

[0072] The results of hardness are as Figure 2As shown in the figure, the hardness of the starter 4.0 fermented milk (Group A) without adding probiotics and resistant starch was 6.01 ± 0.09 g; the hardness of the RS3 resistant starch fermented milk (Groups H, I, and J) added with Lactobacillus rhamnosus LGG, Lactobacillus paracasei L9, and Lactobacillus acidophilus La5 was 5.28 ± 0.29, 5.13 ± 0.26, and 5.13 ± 0.29 g respectively, and its hardness was significantly lower than that of the starter group (Group A). The hardness of the fermented milk added with Bifidobacterium animalis subsp. lactis ZYhyy-003 alone and the RS3 resistant starch fermented milk of Bifidobacterium animalis BB12 (Groups B and G) was 6.53 ± 0.26 and 6.45 ± 0.25 g respectively, and its hardness was significantly higher than that of the other probiotics added.

[0073] In the resistant starch group, the hardness of the fermented milk added with RS3, Novelose260, and Y90 resistant starch (Groups F, D, and E) was 6.93 ± 0.05, 6.58 ± 0.25, and 6.03 ± 0.56 g respectively, and the hardness of the RS3 resistant starch fermented milk was the highest. The hardness of the fermented milk added with Bifidobacterium animalis subsp. lactis ZYhyy-003 and RS3 resistant starch simultaneously (Group C) was 7.33 ± 0.28 g, and its hardness was significantly higher than that of the other groups.

[0074] The results of adhesiveness are as Figure 3 shown. The adhesiveness of the fermented milk without adding probiotics and resistant starch (Group A) was 0.11 ± 0.02 mJ; the adhesiveness of the RS3 resistant starch fermented milk added with Lactobacillus rhamnosus LGG, Lactobacillus paracasei L9, and Lactobacillus acidophilus La5 (Groups H, I, and J) was 0.08 ± 0.02, 0.08 ± 0.02, and 0.06 ± 0.02 mJ respectively, and its adhesiveness was not different from that of the starter group (Group A). The adhesiveness of the fermented milk added with Bifidobacterium animalis subsp. lactis ZYhyy-003, Bifidobacterium animalis BB12 + RS3 resistant starch, and only RS3 resistant starch (Groups B, G, and F) was 0.18 ± 0.01, 0.17 ± 0.02, and 0.16 ± 0.02 mJ respectively, and its adhesiveness was significantly higher than that of the other probiotics and resistant starch groups. The adhesiveness of the fermented milk added with Bifidobacterium animalis subsp. lactis ZYhyy-003 and RS3 resistant starch simultaneously (Group C) was 0.19 ± 0.02 mJ, and its adhesiveness was significantly higher than that of the other groups.

[0075] The results of elasticity are as Figure 4As shown in the figure, the elasticity of the fermented milk without probiotics and resistant starch (Group A) was 1.57 ± 0.32 mm; the hardness of the fermented milk with only Bifidobacterium animalis subsp. lactis ZYhyy-003, and the fermented milk with RS3 resistant starch added with Bifidobacterium animalis BB12, Lactobacillus rhamnosus GG, Lactobacillus paracasei L9, and Lactobacillus acidophilus La5 respectively (Groups B, G, H, I, J) was 2.29 ± 0.02, 2.27 ± 0.49, 1.84 ± 0.18, 0.74 ± 0.38, and 1.52 ± 0.32 mm. The elasticity of the fermented milk added with RS3, Novelose260, and Y90 resistant starch respectively (Groups F, D, E) was 2.65 ± 0.09, 2.24 ± 0.16, and 1.85 ± 0.51 mm. The elasticity of the fermented milk added with both Bifidobacterium animalis subsp. lactis ZYhyy-003 and RS3 resistant starch (Group C) was 2.71 ± 0.33 mm, and its elasticity was significantly higher than that of other groups.

[0076] Furthermore, the water-holding capacity of the fermented milk at the end of fermentation for each group was detected. The results are as Figure 5 shown. The water-holding capacity of the fermented milk without probiotics and resistant starch (Group A) was 87.44%; the water-holding capacity of the fermented milk with RS3 resistant starch added with Bifidobacterium animalis subsp. lactis ZYhyy-003, Bifidobacterium animalis BB12, Lactobacillus rhamnosus GG, Lactobacillus paracasei L9, and Lactobacillus acidophilus La5 respectively (Groups B, G, H, I, J) was 84.55%, 82.90%, 70.05%, 72.16%, and 69.49%. The water-holding capacity of the fermented milk added with RS3, Novelose260, and Y90 resistant starch respectively (Groups F, D, E) was 89.04%, 83.66%, and 88.16%. The water-holding capacity of the fermented milk added with both Bifidobacterium animalis subsp. lactis ZYhyy-003 and RS3 resistant starch (Group C) was 92.16%, and its water-holding capacity was significantly higher than that of other groups.

[0077] The above results showed that the fermented milk added with both Bifidobacterium animalis subsp. lactis ZYhyy-003 and RS3 resistant starch (Group C) showed significantly better texture quality than other groups in terms of hardness, adhesiveness, elasticity and water holding capacity. The possible reasons are as follows: When Bifidobacterium animalis subsp. lactis ZYhyy-003 and RS3 resistant starch were added to the milk fermentation process, the whey protein would undergo disulfide bond exchange between molecules through sulfhydryl and disulfide bonds. The denatured α-lactalbumin and β-lactoglobulin would form aggregate binding, resulting in the formation of larger whey protein aggregates, which increased the hardness of the fermented milk. The fermented milk of Bifidobacterium animalis subsp. lactis ZYhyy-003 and RS3 resistant starch had a compact structure, could better maintain its shape, and had a strong resilience, and could quickly recover after being compressed. This might be because ZYhyy-003 and RS3 resistant starch helped the whey protein and β-lactoglobulin interact with casein, and the curd formed a stable coagulum. After the addition of resistant starch, the interaction between proteins could be changed and the syneresis could be reduced. The pore size of the protein network inside the yogurt decreased, resulting in limited permeability of the casein gel and increased water holding capacity, forming a solidified yogurt with a dense gel network structure.

[0078] Test Example 3: Post-acidification and stability of viable count of fermented milk with different combinations of resistant starch and probiotics

[0079] This test example explored the changes in the fermentation performance and viable count of probiotics of fermented milk prepared with different combinations of resistant starch and probiotics during the storage period.

[0080] The titratable acidity (°T) of the fermented milk during the storage period was detected according to the national standard GB 5009.239–2016. As Figure 6As shown in the figure, the acidity of the fermented milk without probiotics and resistant starch (Group A) was 80.94 ± 2.21 °T after 21 days of storage; the acidity of the fermented milk with only Bifidobacterium animalis subsp. lactis ZYhyy-003 (Group B) was 81.44 ± 1.26 °T; the acidity of the fermented milk with both Bifidobacterium animalis subsp. lactis ZYhyy-003 and 1.5% RS3 resistant starch (Group C) was 77.73 ± 0.61 °T, with the weakest post-acidification; the acidity of the fermented milk with both Bifidobacterium bifidum BB12 and 1.5% RS3 resistant starch (Group G) was 81.24 ± 1.96 °T; the acidity of the fermented milk with both Lactobacillus rhamnosus LGG and 1.5% RS3 resistant starch (Group H) was 89.55 ± 3.12 °T, with the strongest post-acidification; the acidity of the fermented milk with both Lactobacillus paracasei L9 and 1.5% RS3 resistant starch (Group I) was 87.54 ± 1.07 °T; the acidity of the fermented milk with both Lactobacillus acidophilus La5 and 1.5% RS3 resistant starch (Group J) was 84.03 ± 3.02 °T; the acidity of the fermented milk with only RS3 resistant starch (Group F) was 80.15 ± 2.68 °T; the acidity of the fermented milk with both Bifidobacterium animalis subsp. lactis ZYhyy-003 and Novelose260 resistant starch (Group D) was 81.01 ± 3.01 °T; the acidity of the fermented milk with both Bifidobacterium animalis subsp. lactis ZYhyy-003 and Y90 resistant starch (Group E) was 80.93 ± 2.57 °T.

[0081] The results showed that the post-acidification of the yogurt was the weakest when both Bifidobacterium animalis subsp. lactis ZYhyy-003 and 1.5% RS3 resistant starch were added.

[0082] Furthermore, the probiotic counts of the fermented milk during storage were detected according to the national standard GB 4789.35-2016. The results were as Figure 7 shown. The microbial count of the fermented milk with only Bifidobacterium animalis subsp. lactis ZYhyy-003 (Group B) was 7.02 ± 0.04 log 10 CFU / mL after 21 days of storage; the microbial count of the fermented milk with Bifidobacterium bifidum BB12 and RS3 resistant starch (Group G) was 7.06 ± 0.03 log 10 CFU / mL after 21 days of storage; the microbial count of the fermented milk with Lactobacillus rhamnosus LGG and RS3 resistant starch (Group H) was 8.00 ± 0.03 log 10 CFU / mL after 21 days of storage; the microbial count of the fermented milk with Lactobacillus paracasei L9 and RS3 resistant starch (Group I) was 8.60 ± 0.03 log 10CFU / mL; The microbial count of the RS3 resistant starch fermented milk supplemented with Lactobacillus acidophilus La5 (Group J) at 21 days of storage was 7.72 ± 0.03 log 10 CFU / mL; The microbial count of the fermented milk supplemented with both Bifidobacterium animalis subsp. lactis ZYhyy-003 and RS3 resistant starch (Group C) at 21 days of storage was 6.75 ± 0.08 log 10 CFU / mL.

[0083] The intensity of post-acid is usually related to the accumulation of acidic substances produced by lactic acid bacteria fermentation. Fermented milk with weaker acidity usually means relatively less metabolic activity of lactic acid bacteria and a slower rate of lactic acid production, which has an important impact on the taste and taste stability of fermented milk. Combining the results of post-acid and microbial counts shows that different probiotic strains have different effects on the microbial count in fermented milk. The counts of Lactobacillus paracasei L9 and Lactobacillus rhamnosus GG are relatively high. Lactobacilli have high acid resistance and adaptability to low-temperature storage conditions during long-term storage, enabling them to maintain a relatively high viable count during storage and trigger higher post-acid. Excessive acidity will affect the taste of fermented milk, making it taste sour. In contrast, after adding Bifidobacterium animalis, the microbial count in the fermented milk is lower than that of the fermented milk supplemented with Lactobacillus. The microbial count of the fermented milk with ZYhyy-003 and RS3 resistant starch is relatively low, but the post-acid is the weakest. The addition of resistant starch may enable ZYhyy-003 to utilize more starch rather than lactose, resulting in a reduced production of lactic acid. Therefore, the acidity of the fermented milk does not increase significantly, and the post-acid is also weak. Its taste is softer, the flavor is more mellow, and it is more acceptable to consumers.

[0084] In summary, the composition of pea type III resistant starch and Bifidobacterium animalis subsp. lactis described in this application for preparing fermented dairy products has the characteristics of weak post-acid, stable microbial count, and improved quality of fermented milk products.

[0085] Finally, it should be noted that the above is only used to illustrate the technical solution of the present invention and not to limit it. Although the present invention has been described in detail with reference to the preferred arrangement, those of ordinary skill in the art should understand that the technical solution of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. A composition of pea type III resistant starch and Bifidobacterium animalis subsp. lactis, characterized in that: The active ingredients of the composition consist of pea type III resistant starch and animal Bifidobacterium lactis subspecies ZYhyy-003; The animal Bifidobacterium lactis subsp. ZYhyy-003 is deposited in the General Microbiological Center of the China Microbiological Culture Collection Administration, with a deposit date of August 5, 2024, a deposit number of CGMCC No. 31553, and a classification name of: animal Bifidobacterium lactis subsp. Bifidobacterium animalis subsp.lactis ; In the composition, the concentration of animal Bifidobacterium lactis subspecies ZYhyy-003 is 1×10 7 CFU / mL, the content of pea type III resistant starch was 1.5w / v%; The preparation method of the pea type III resistant starch comprises the following steps: HCl is added to pea starch, the mixture is heated and stirred to hydrolyze the pea starch, and the pH is adjusted to 7 to obtain acid-hydrolyzed pea starch; the acid-hydrolyzed pea starch is stirred at high temperature for 20-30 minutes to achieve gelatinization to obtain gelatinized pea starch; pullulanase is added to the gelatinized pea starch, and the mixture is stirred at 45° C. for 30-35 hours to obtain debranched pea starch; the debranched pea starch is kept at 30° C. for 20-25 hours, and the lower starch obtained after centrifugation is dried to obtain III pea RS3; the III pea RS3 is configured into a starch milk with a moisture content of 30%, and then hydrated for 20-25 hours, autoclaved at 115° C. for 150-200 minutes, and dried at 50° C. to obtain pea type III resistant starch.

2. Use of the composition of pea type III resistant starch and animal Bifidobacterium lactis subsp. as claimed in claim 1 in the preparation of fermented dairy products; The composition of pea type III resistant starch and animal bifidobacterium lactis subspecies is used to reduce the post-acidity of fermented dairy products during storage, maintain the stability of the number of probiotics, and improve the quality of fermented dairy products.

3. The use according to claim 2, characterized in that: Improving the quality of fermented dairy products includes increasing the hardness, adhesion, elasticity and water holding capacity of dairy products.

4. A fermented dairy product, characterized in that A composition comprising pea type III resistant starch as claimed in claim 1 and Bifidobacterium animalis subsp. lactis.

5. A microbial preparation, characterized in that: A composition comprising pea type III resistant starch as claimed in claim 1 and Bifidobacterium animalis subsp. lactis.

6. A method for preparing a pea type III resistant starch fermented dairy product containing probiotics, characterized in that: The preparation method comprises using the composition of pea type III resistant starch and animal Bifidobacterium lactis subsp. as claimed in claim 1, and the preparation method comprises the following steps: (1) Preparation of fermented milk base: 1.5 w / v% pea type III resistant starch was added to pure milk, and after chemical treatment, homogenization and sterilization, a pea type III resistant starch fermented milk base was obtained; (2) Preparation of composite probiotic fermentation agent: The composite probiotic fermentation agent comprises a basic fermentation agent and animal Bifidobacterium lactis subspecies ZYhyy-003, wherein the addition amount of the basic fermentation agent is 0.02‰-0.05‰, and the concentration of animal Bifidobacterium lactis subspecies ZYhyy-003 is 1×10 7 CFU / mL; The basic fermentation agent is Streptococcus salivarius thermophilus subspecies and Lactobacillus delbrueckii subspecies bulgaricus; (3) Inoculation and fermentation: inoculating the composite probiotic fermentation agent of step (2) into the pea type III resistant starch fermented milk base obtained in step (1) for a fermentation time of 5-5.5 hours, thereby obtaining a pea type III resistant starch fermented milk product containing probiotics.

7. The preparation method according to claim 6, characterized in that: In step (1), the chemical material is: stirred at 50°C-55°C for 30-50 minutes at 500 r / min to obtain a mixed emulsion; The homogenization comprises: homogenizing the mixed emulsion at 50°C-55°C and 15-20MPa to obtain a uniform mixed emulsion; The sterilization step is as follows: the uniformly mixed emulsion is sterilized at 95° C. for 5-10 minutes, and then cooled to 43° C. to obtain a fermented milk base of pea III type resistant starch.

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