阅读说明：本技术 功能性多糖酸奶发酵剂及功能性多糖酸奶的制备方法 (Functional polysaccharide yoghourt starter and preparation method of functional polysaccharide yoghourt ) 是由 薛依婷 李明杰 王彩薇 徐沛沛 陈义勇 于 2020-06-03 设计创作，主要内容包括：本发明公开了功能性多糖酸奶发酵剂及功能性多糖酸奶的制备方法,发酵剂包括保加利亚乳杆菌、嗜热链球菌、双歧杆菌和干酪乳杆菌,其中保加利亚乳杆菌和嗜热链球菌占发酵剂总质量的73.3％-81.2％,双歧杆菌占发酵剂总质量的0-6.2％,干酪乳杆菌占发酵剂总质量的18.8％-20.5％,保加利亚乳杆菌和嗜热链球菌的质量比为1：1；制备方法：(1)在纯牛奶中加入蔗糖,煮沸后冷却；(2)按照0.1％-0.2％的浓度在纯牛奶中加入真菌多糖；(3)按照1％-4％的接种量接种发酵剂；(4)混匀、密封,放到恒温箱中发酵；本发明获得的酸奶感官评分高(8.913分),酸度(76.3°T)、硬度(0.167N)适宜。(The invention discloses a functional polysaccharide yoghourt leaven and a preparation method of functional polysaccharide yoghourt, wherein the leaven comprises lactobacillus bulgaricus, streptococcus thermophilus, bifidobacterium and lactobacillus casei, wherein the lactobacillus bulgaricus and the streptococcus thermophilus account for 73.3-81.2% of the total weight of the leaven, the bifidobacterium accounts for 0-6.2% of the total weight of the leaven, the lactobacillus casei accounts for 18.8-20.5% of the total weight of the leaven, and the mass ratio of the lactobacillus bulgaricus to the streptococcus thermophilus is 1: 1; the preparation method comprises the following steps: (1) adding sucrose into pure milk, boiling, and cooling; (2) adding fungal polysaccharide into pure milk according to the concentration of 0.1-0.2%; (3) inoculating a fermentation agent according to the inoculation amount of 1-4%; (4) mixing, sealing, and fermenting in a thermostat; the yogurt obtained by the invention has high sensory score (8.913 points), and proper acidity (76.3 DEG T) and hardness (0.167N).)

1. The functional polysaccharide yoghourt leaven is characterized by comprising 73.3-81.2% of lactobacillus bulgaricus, 0-6.2% of bifidobacterium and 18.8-20.5% of lactobacillus casei, wherein the ratio of lactobacillus bulgaricus to streptococcus thermophilus is 1: 1.

2. the functional polysaccharide yogurt starter of claim 1, wherein: the lactobacillus bulgaricus and the streptococcus thermophilus account for 81.2% of the total mass of the starter culture, and the lactobacillus casei accounts for 18.8% of the total mass of the starter culture.

3. The preparation method of the functional polysaccharide yoghourt is characterized by comprising the following steps:

(1) adding sucrose into pure milk, boiling, and cooling;

(2) adding fungal polysaccharide into pure milk according to the concentration of 0.1-0.2%;

(3) inoculating a leavening agent according to the inoculation amount of 1-4%, wherein the leavening agent comprises lactobacillus bulgaricus, streptococcus thermophilus, bifidobacterium and lactobacillus casei, wherein the lactobacillus bulgaricus and the streptococcus thermophilus account for 73.3-81.2% of the total mass of the leavening agent, the bifidobacterium accounts for 0-6.2% of the total mass of the leavening agent, the lactobacillus casei accounts for 18.8-20.5% of the total mass of the leavening agent, and the mass ratio of the lactobacillus bulgaricus to the streptococcus thermophilus is 1: 1;

(4) mixing, sealing, and fermenting in a thermostat.

4. The method for preparing functional polysaccharide yoghourt according to claim 3, wherein the method comprises the following steps: in step (1), after boiling, it is cooled to 50 ℃.

5. The method for preparing functional polysaccharide yoghourt according to claim 3, wherein the method comprises the following steps: in the step (1), sucrose is added into pure milk according to the purity of 6%, and the milk is cooled after being boiled.

6. The method for preparing functional polysaccharide yoghourt according to claim 3, wherein the method comprises the following steps: in step (2), the fungal polysaccharide is added to the pure milk at a concentration of 0.1%.

7. The method for preparing functional polysaccharide yoghourt according to claim 3, wherein the method comprises the following steps: in the step (3), the lactobacillus bulgaricus and the streptococcus thermophilus account for 81.2 percent of the total mass of the leavening agent, and the lactobacillus casei accounts for 18.8 percent of the total mass of the leavening agent.

8. The method for preparing functional polysaccharide yoghourt according to claim 3, wherein the method comprises the following steps: in step (3), a starter was inoculated at an inoculum size of 4%.

9. The method for preparing functional polysaccharide yoghourt according to claim 3, wherein the method comprises the following steps: in the step (4), the mixture is put into a thermostat with the temperature of 42 ℃ for fermentation for 4 h.

Technical Field

The invention relates to a functional polysaccharide yoghourt leaven which is used as a specific microbial culture material for preparing yoghourt. The invention also relates to a preparation method of the functional polysaccharide yoghourt.

Background

The yoghurt is generally yoghurt, which is a milk product prepared by taking fresh milk as a raw material, adding beneficial bacteria (leavening agent) into the milk after pasteurization, fermenting, and then cooling and filling. At present, most of yoghourt products in the market are in a set type, a stirring type and a fruit taste type added with various auxiliary materials such as fruit juice, jam and the like. The yoghourt not only retains all the advantages of milk, but also makes good use of the advantages and avoids the disadvantages in certain aspects through the processing process, thereby becoming a nutritional health-care product more suitable for human beings. The steamed bread made from flour by fermentation is easy to digest and absorb, the yogurt made from milk by fermentation has the same effect, and about 20% of sugar and protein in milk are decomposed into small molecules (such as galactose, lactic acid, small peptide chain and amino acid) by fermentation. The fat content in milk is typically 3-5%. After fermentation, the fatty acids in milk can be increased 2-fold over the starting milk. These changes make the sour milk more digestible and absorbable, and the utilization rate of various nutrients is improved. The yogurt is prepared by fermenting pure milk, retains all nutrients of fresh milk, and during fermentation, lactobacillus can also produce multiple vitamins such as VB₁、VB₂、VB₆、VB₁₂And the like. Particularly for people with lactose indigestion, the phenomena of abdominal distension, much qi or diarrhea can not occur when people eat the yoghourt. The fresh milk has rich calcium content, and after fermentation, the minerals such as calcium and the like do not change, but the utilization rate of calcium and phosphorus in the human body can be effectively improved by the lactic acid generated after fermentation, so that the calcium and the phosphorus in the yoghourt are more easily absorbed by the human body. Although the nutritional content of yogurt is said to depend on the source and composition of the raw milk, yogurt is generally said to be more specific than raw milkThe milk components are improved, on one hand, because the requirements on the quality of the raw materials are high, and on the other hand, a small amount of milk powder is added in the preparation of some yoghurt. Therefore, in general, a cup of 150 g yoghurt can meet 1/3 calcium amount required by children under 10 years old and 1/5 calcium amount required by adults.

The functional yoghourt is based on the common yoghourt, functional factors are added, the advantages of the yoghourt are kept, meanwhile, the functionality of the yoghourt is enhanced, better nutrition is provided for human bodies, and the nutritional value and the research value of the functional yoghourt are higher than those of the common yoghourt. Besides the function of nutrition supplement, the health-care food also has one or more functional activities, and can obviously improve the physiological function of a human body. Due to the difference between the selected strains and the production process, the functional yoghurt has rich taste and health care function, so the market prospect is wide. In foreign countries, especially developed countries, over 3000 kinds of functional yoghurt are available, and become leading products in local dairy industry, and the sales volume is second to fresh milk. In our country, the development of functional yoghourt is just started, the first functional yoghourt product appears in 2000, and the product has the effects of maintaining beauty and keeping young and delaying senility, and is popular with consumers once being on the market. From this time, the industrialization of functional yogurt enters a development stage, but the speed is still slow, and a certain dairy group pushes out yogurt products in 2009, so that consumers can know various effects of the yogurt through the strong publicity of media, and the development of the functional yogurt is really pushed up to a new height. In 2015, a plurality of new dairy enterprises launch a plurality of functional yogurts containing bioactive substances, and the product market is greatly enriched.

At present, research and development institutions at home and abroad develop various types of yoghourt in the aspects of improving the micro-ecological balance of human bodies, optimizing intestinal flora, improving immunity and the like. The lucid ganoderma, the inulin, the medlar, the black fungus, the five cereals, the yam, the coconut and the like are applied to the yoghourt to develop the yoghourt with various flavors and various health-care functions. Some researchers also apply pholiota nameko polysaccharide, curdlan, ginseng polysaccharide, mulberry leaf polysaccharide, tricholoma matsutake polysaccharide, red date polysaccharide and the like to the research and development of the yoghourt to develop the polysaccharide yoghourt. Researches show that the polysaccharide added into the yoghourt can promote the fermentation of lactic acid bacteria, reduce the whey separation of the yoghourt during storage, improve the stability of the yoghourt, prolong the shelf life of the yoghourt and the like, and also can keep the efficacy of polysaccharide.

The yoghourt is used as a fermentation product, the lactobacillus leavening agent determines the quality of the yoghourt to a great extent, and the yoghourt fermentation process technology is also an important factor influencing the product quality. At present, the mixed material design is widely applied to formula tests of food, medicine and chemical industry and pesticides, such as successful construction of watermelon envelope controlled release urea proportion and the like. Due to the superiority, a mixing test is gradually applied to the combination of microorganisms, and the Tibetan mushroom milk pure culture fermentation formula is optimized by applying mixing design such as Zhou Jian faithfulness (Zhou Jian faithfulness, yellow-red blossoming, exuberant, and the like) in the Tibetan mushroom milk pure culture starter formula design [ J ] Chinese agricultural science, 2008,41(3):816 and 822.), so as to obtain the optimized formula of five bacteria such as lactococcus lactis. He Qiu Shi (2013) (He Qiu Shi. mixing design method is applied to multi-strain fermentation for preparing soybean gel protein [ J ]. Chinese food and oil academy, 2013,28(3):5-11.) the soybean gel protein is effectively prepared by multi-strain fermentation by applying mixing design. Liu Rui (Liu Rui, Niao, Wanchun Yun, etc.) applies mixing material experimental design to prepare straw composite degrading bacteria agent [ J ]. Chinese Journal of bioengineering, 2009,29(9):50-55.) and other application mixing material designs to prepare straw composite degrading bacteria agent, the proportion of five strains of lignocellulose degrading bacteria which can be cultured together is obtained, and bacteria agent Lamia eye (Ayed L, Achour S, Kheifi E, et al. use of active consortium of structural and microbiological degradation bacteria is obtained by analyzing fermentation products and is suitable for different fermentation purposes, and other application mixing material designs determine the optimal proportion of 3 strains of bacteria to eliminate the toxicity of ammonia coupling dyes.

At present, most of domestic enterprises lack microbiological research on yoghourt products, the yoghourt starter is insufficient in source, and the development of high-quality functional yoghourt lacks theoretical and technical basis.

Disclosure of Invention

The invention aims to provide a functional polysaccharide yoghourt starter and a preparation method of functional polysaccharide yoghourt, and the obtained yoghourt has good taste and proper acidity and hardness.

In order to solve the technical problems, the functional polysaccharide yoghourt leavening agent comprises lactobacillus bulgaricus, streptococcus thermophilus, bifidobacterium and lactobacillus casei, wherein the lactobacillus bulgaricus and the streptococcus thermophilus account for 73.3-81.2% of the total weight of the leavening agent, the bifidobacterium accounts for 0-6.2% of the total weight of the leavening agent, the lactobacillus casei accounts for 18.8-20.5% of the total weight of the leavening agent, and the mass ratio of the lactobacillus bulgaricus to the streptococcus thermophilus is 1: 1.

the lactobacillus bulgaricus and the streptococcus thermophilus are necessary strains for yoghourt fermentation, are symbiotic in a synergistic mode, are the most stable fermentation strains with the lowest industrial fermentation cost, but are easily inactivated by gastric acid and bile in vivo, cannot be colonized in intestines, and are low in survival rate. In order to solve the problem, lactobacillus casei and bifidobacterium are added into the leavening agent of the invention as probiotics, which can tolerate enzyme, gastric acid and bile in vivo, survive in large amount in intestinal tract, regulate the balance of intestinal flora and promote digestion and absorption. In addition, the lactobacillus casei can endow the yogurt with the flavor of the yogurt in the fermentation process, and the mouthfeel is improved. Therefore, the four bacteria are compounded, and the obtained mixed starter is favorable for ensuring the optimal taste of the functional polysaccharide yoghourt. The lactobacillus casei accounts for 18.8-20.5% of the total mass of the starter culture, the lactobacillus casei accounts for less than 18.8% of the total mass of the starter culture, the flavor of the yoghourt is too low, and the sensory evaluation value is poor. The lactobacillus casei accounts for more than 20.5 percent of the total quality of the starter, the ratio of streptococcus thermophilus to bulgaricus is reduced, the acid production is too low, the taste is weak, the coagulability of the yoghourt is poor, the water retention is reduced, and the texture and the taste are influenced finally.

Preferably, the lactobacillus bulgaricus and the streptococcus thermophilus account for 81.2 percent of the total mass of the leavening agent, and the lactobacillus casei accounts for 18.8 percent of the total mass of the leavening agent. The lactobacillus bulgaricus (L.bulgaricus), the streptococcus thermophilus (S.thermophilus) and the lactobacillus casei (L.casei) have obvious influence on sensory evaluation of the fermented polysaccharide yoghourt, the growth and metabolism of the three bacteria are mutually influenced, and finally the promotion effect on the promotion of the mouthfeel of the yoghourt is realized. The mouthfeel of the yoghourt is improved along with the increase of the acidity, and the mouthfeel is gradually reduced when the acidity reaches a certain limit.

When the ratio of the lactobacillus bulgaricus to the streptococcus thermophilus is 1:1, the acid production of the starter is fastest, the sensory evaluation is highest, and the acidification degree of the yoghurt product with the streptococcus thermophilus predominates is slightly lower than that of the yoghurt product with the lactobacillus bulgaricus predominate. The lactobacillus bulgaricus and the streptococcus thermophilus are symbiotic and antagonistic to each other, the change of the ratio of the lactobacillus bulgaricus and the streptococcus thermophilus directly influences the acid production speed of the mixed bacteria, and when the ratio of the lactobacillus bulgaricus and the streptococcus thermophilus is 1:1, the lactose is converted into lactic acid, so that the time required for the pH value of milk to be reduced to the isoelectric point of casein so as to be solidified is shortest, the acidity is highest, and the water retention, the fineness and the smoothness are optimal.

The preparation method of the functional polysaccharide yoghourt comprises the following steps:

(1) adding sucrose into pure milk, boiling, and cooling. Specifically, in this step, sucrose was added to pure milk at a purity of 6%, boiled and then cooled to 50 ℃.

(2) Adding fungal polysaccharide into pure milk according to the concentration of 0.1% -0.2%. In this step, the fungal polysaccharide is preferably added to the pure milk at a concentration of 0.1%. The fungus polysaccharide can enhance the functionality of the yoghourt and provide better nutrition for human body while keeping the advantages of the milk.

The sensory evaluation of the yoghurt is lower and lower along with the increase of the polysaccharide concentration (more than 0.1%), while the acidity of the yoghurt is higher along with the increase of the addition amount of the polysaccharide (more than 0.1%), and the too high acidity affects the mouthfeel of the yoghurt. Glucose in the polysaccharide structure can be used as a carbon source to be utilized by lactic acid bacteria, so that the fermentation of the polysaccharide structure is facilitated to generate lactic acid, the available carbon source is increased along with the increase of the concentration of the polysaccharide, the acidity is gradually increased, and the taste of the polysaccharide structure is influenced if the acidity is too high.

(3) Inoculating a leavening agent according to the inoculation amount of 1-4%, wherein the leavening agent comprises lactobacillus bulgaricus, streptococcus thermophilus and lactobacillus casei, the lactobacillus bulgaricus and the streptococcus thermophilus account for 73.3-81.2% of the total weight of the leavening agent, the bifidobacterium accounts for 0-6.2% of the total weight of the leavening agent, the lactobacillus casei accounts for 18.8-20.5% of the total weight of the leavening agent, and the mass ratio of the lactobacillus bulgaricus to the streptococcus thermophilus is 1: 1.

in the step (3), the lactobacillus bulgaricus and the streptococcus thermophilus account for 81.2 percent of the total mass of the leavening agent, and the lactobacillus casei accounts for 18.8 percent of the total mass of the leavening agent. In step (3), a starter was inoculated at an inoculum size of 4%.

The sensory evaluation score of the yogurt reaches the highest value from high to low when the inoculation amount is 4% along with the increase of the inoculation amount, the acidity of the yogurt is continuously increased along with the increase of the inoculation amount, the acidity of the yogurt is greatly improved when the inoculation amount is 5%, but the mouthfeel of the yogurt is reduced along with the increase of the acidity. With the increase of the inoculation amount of the starter, the strain concentration is gradually increased, the fermentation capacity of the lactic acid bacteria is improved, the acid production is increased, the pH is quickly reduced, the coagulability of the yoghourt is better and better, and the mouthfeel of the yoghourt is gradually improved; when the inoculation amount is 5%, the fermented yoghourt has good coagulability, moderate hardness, proper sour and sweet taste and best mouthfeel; when the inoculation amount exceeds 5%, the concentration of the lactic acid bacteria is too high, the acid production is excessive, and the yoghourt is acid, too high in hardness and poor in taste.

(4) Mixing, sealing, and fermenting in a thermostat. In this step, the mixture was placed in a 42 ℃ incubator and fermented for 4 hours.

The yogurt obtained by the invention has high sensory score (8.913 points), and proper acidity (76.3 DEG T) and hardness (0.167N).

Drawings

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

FIG. 1 shows the effect of the addition of polysaccharides on the sensory evaluation and acidity of yogurt.

FIG. 2 is a graph showing the effect of inoculum size on yogurt sensory evaluation and acidity.

Detailed Description

Bacterial and fungal polysaccharides, purchased from Dalian Suiyuan Biotech limited:

lactobacillus bulgaricus (Lactobacillus bulgaricus) powder with viable count of 1 ×10¹⁰CFU/g

Streptococcus thermophilus (Streptococcus thermophilus) powder with viable count of 1 × 10¹¹CFU/g

Bifidobacterium (Bifidobacterium) powder with viable count of 1 × 10¹¹CFU/g

Lactobacillus plantarum (Lactobacillus plantarum) powder with viable count of 1 × 10¹¹CFU/g

Lactobacillus casei (Lactobacillus casei) powder with viable count of 1 × 10¹¹CFU/g

Fungal polysaccharides: auricularia auricula polysaccharide