CN116369385A

CN116369385A - Preparation method of novel plant-based yoghurt

Info

Publication number: CN116369385A
Application number: CN202310217346.6A
Authority: CN
Inventors: 邢巾
Original assignee: Northeast Agricultural University
Current assignee: Northeast Agricultural University
Priority date: 2023-03-08
Filing date: 2023-03-08
Publication date: 2023-07-04

Abstract

The potato-Shu-two is a coarse grain-based fermented yoghourt prepared by taking sweet potatoes and soybeans as raw materials, has smooth taste and high nutritional value, contains extremely low cholesterol and lactose, and is suitable for healthy food consumers. The product innovatively uses potato and soybean plant bases, and adds various probiotics for compound fermentation, and also adds nutrition enhancers such as broccoli, okra and other functional substances, so that the product has more comprehensive nutrition. The main raw materials form a sweet potato-soybean system, and interact with a thickener polymeric whey protein-xanthan gum system (PWP-XG) to enable the texture of the plant-based yoghurt to be more similar to that of the cow lactic acid milk, ensure no granular feel, smooth mouthfeel and have unique good flavors of sweet potatoes and soybeans. Compared with the yogurt fermented by animal cow milk, the yogurt fermented by combining sweet potatoes and soybeans is lower in carbon and environment-friendly, and accords with the consumption concept of green and environment-friendly. As an environment-friendly player, the combination of the plant base and the strain can better exert the due nutritional value.

Description

Preparation method of novel plant-based yoghurt

Technical Field

The invention relates to the technical field of yoghurt preparation, in particular to novel plant-based yoghurt and a preparation method thereof. More specifically, the invention relates to coarse grain-based fermented yoghourt prepared by taking sweet potatoes and soybeans as raw materials, which has smooth taste, high nutritional value, extremely low cholesterol and lactose, and is suitable for healthy food consumption groups. The invention also relates to a thickener and polymerized whey protein-xanthan gum system (PWP-XG) interaction, so that the texture of the plant-based yoghurt is more similar to that of the cow lactic acid milk, no granular feel is ensured, the mouthfeel is smooth, and the unique good flavor of sweet potatoes and soybeans is maintained.

Background

The traditional yoghurt is a dairy product prepared by taking cow milk as a raw material and fermenting the cow milk by lactic acid bacteria, and is also one of the most popular dairy products. The yoghurt not only has unique flavor, but also has the functions of promoting digestion and absorption of human bodies and regulating the immunity of human bodies. However, in order to cope with the threat of climate change while guaranteeing sustainable development in a situation where the world population is growing, there is an increasing market demand for superior plant proteins that can replace animal proteins, wherein plant-based foods have become a rapidly developing industry as a substitute for dairy products. Soy protein is an excellent vegetable protein which is rich in all essential amino acids required for human body and is considered to be applicable as a substitute for milk protein in plant-based foods. In addition, soy proteins are widely used in the processing of various foods due to their excellent emulsifying, gelling and film forming properties. At present, domestic soybean resources are extremely abundant, soybeans contain abundant proteins and plant bioactive substances such as lecithin, saponin, soybean isoflavone, inositol and the like, and the soybeans do not contain cholesterol and have the effects of reducing cholesterol in human blood, scavenging free radicals in the body, delaying aging and preventing cancers. In particular, transgenic soybean in northeast China accounts for 80% of the world's production, while the production of domestic and instant soybean flour is listed as the world's top. People in China have the habit of eating soybean milk for a long time, the cognition and the acceptability of the soybean product are obviously higher than those of other plant-source protein products, and the soybean flour is more stable and economical than other protein product sources in China. However, single-function plant-based products have failed to meet consumer pursuits for diverse health. In addition, soy protein plant-based yogurt has poor acceptance in the market due to the beany flavor problem. These problems can be solved by compounding soy protein with other functional materials. Sweet potatoes are called sweet potatoes, sweet potatoes and the like, belong to annual herbaceous plants, have sour and sweet taste and attractive color, and simultaneously have multiple physiological activities of building body, resisting cancer, supplementing vitamins and the like. Therefore, sweet potatoes can be used as a functional raw material for preparing the plant-based yoghurt by being compounded with soy protein. However, no report is currently made on the research on the physicochemical properties of sweet potato soybean protein plant-based yogurt. Furthermore, research on plant-based yogurt has focused mainly on the nature of the plant-based yogurt itself, and there is no analogy with animal-based yogurt.

The plant-based yoghurt is prepared by taking plant-based raw materials as protein sources, adding white granulated sugar or other saccharides as carbon sources, adding (or not adding) other raw materials, homogenizing, sterilizing, inoculating lactobacillus starter and fermenting. The plant-based yoghurt is used as a pure plant fermentation product, has safe protein source and mild nutrition, does not contain any animal milk or milk powder, truly achieves the advantages of 0 cholesterol, 0 hormone, 0 saturated fat, 0 lactose, 0 trans fat and the like, and is suitable for milk allergy, lactose intolerance and worry about three-high consumers or vegetarian people to drink.

Development of non-dairy probiotic products is a hot topic in the food industry. It has been found that fermentation can significantly improve the nutrient quality and flavor of cereals and exhibit good physiological functions. Therefore, we borrow the reference to the coarse food grain for fermentation so as to fully excite the nutrient substances. And sweet potatoes and soybeans are rich in polysaccharide and protein, so that the cost is low. The former deep processing needs to be improved, and the high-value utilization and echelon utilization of the former deep processing are improved as high-quality fermentation raw materials.

The yogurt is prepared by fermenting fresh milk, and is rich in protein, calcium and vitamins. Yoghurt may be a good choice, especially for those who are not able to enjoy milk because of lactose intolerance.

The domestic yogurt market is always growing at a high level, the sales amount of the low-temperature yogurt in 2018 is 690 billions, the market insight of Asia quick consumer products in 2018, the fourth quarter of Kai is published, the soymilk is the most class consumed by China in 2018, the global plant-based yogurt market scale in 2018 is 9.74 billions dollars according to European International data, the Western European market is maximum, north America is poor in Asia performance, the consumer is generally accepted, and the Chinese market scale is almost blank. The market is lack of brands, products need to be upgraded, and only farmer mountain springs, ternary, illite enterprises and other enterprises release single series of products in the current market.

Disclosure of Invention

The invention relates to a preparation process of novel plant-based yoghurt, which comprises the following steps: firstly, sweet potatoes and soybeans are ground and then mixed with water to prepare paste, and linseed oil and a polymerized whey protein-xanthan gum system (PWP-XG) are put into the paste to prepare a yoghurt fermentation base material, so that the texture of the plant-based yoghurt can be more similar to that of cow lactic acid milk, the granular sensation is avoided, the taste is smooth, and the excellent flavors of the sweet potatoes and the soybeans are maintained. And adding the broccoli and okra extracts into the prepared yoghurt base material, uniformly mixing, sterilizing, cooling, inoculating, fermenting, cooling and the like, and canning and refrigerating.

The invention has the problem of optimizing the raw materials of the product. (1) optimizing the ratio of sweet potato to soybean: the influence of the proportions of different sweet potatoes and soy protein concentrates on the fermentation characteristics, the texture characteristics and the synthesis of flavor substances of the yoghurt is researched, indexes such as rheological index, texture, water holding capacity and microstructure of the yoghurt are measured, and the compound proportions with the optimal nutrition proportion and flavor are comprehensively compared and selected. (2) Improvement of gelatinization temperature and heating time of sweet potato: and comparing the fermentation characteristics, the texture characteristics, the microstructure and the flavor characteristics of the sweet potato pulp sweet potato soybean yoghourt prepared by the sweet potato pulp with different heating times and heating temperatures, and determining the optimal conditions of gelatinization treatment of the sweet potato pulp.

The invention optimizes the auxiliary material additive. (1) optimizing the PWP-XG system compounding process: determining an optimal total adding amount, and preparing the PWP-XG system according to a compounding proportion with a certain gradient. The influence of PWP-XG with different proportions on the characteristics of the yogurt is studied by taking the rheological property, the texture property and the microstructure of the sweet potato soybean yogurt as indexes. (2) selecting the addition amount of the nutrition enhancer: according to the addition of the raw materials such as sweet potatoes and soybeans and the calculation of nutrition balance, a proper amount of functional substances such as broccoli and okra are added, so that the overnutrition of the product is avoided.

The invention optimizes the fermentation condition. (1) optimization of the addition amount of the fermentation agent: inoculating strains with a certain concentration gradient respectively for fermentation, taking the number of viable bifidobacteria, the number of viable lactobacillus, the pH value and the viscosity in the finished product as indexes, selecting the group with the highest number of viable probiotics and the highest viscosity value, and researching the influence of the addition amount of the fermenting agent on the properties of the sweet potato soybean yoghourt. (2) optimization of fermentation temperature: and (3) fermenting for 5 hours at different temperatures (within 20-50 ℃) by referring to the optimal addition amount of the strain. The method takes the viable count of bifidobacteria, the viable count of lactobacillus, the pH value and the viscosity in the finished product as indexes, and preferentially selects the group with the highest viable count of probiotics and the highest viscosity value, so as to study the influence of fermentation temperature on the properties of sweet potato soybean yoghourt. (3) optimization of fermentation time: and respectively fermenting for different time (within 3-6 h) under the optimal addition amount and optimal fermentation temperature of the ABY-8 strain. According to the index of (2), the group with the highest probiotics viable count and viscosity value is selected, and the influence of fermentation time on the properties of the sweet potato soybean yoghourt is studied.

The invention also provides a method for determining the shelf life of the product. The sweet potato soybean yoghourt is subjected to 6-week storage characteristic study, and the nutritional ingredients, the probiotics change trend, the pH value change trend, the texture characteristics, the harmful bacteria content and the sensory characteristics of the sweet potato soybean yoghourt are measured and evaluated.

Drawings

Fig. 1 is a PWP solution prepared by the method of the present invention.

FIG. 2 is a diagram of a plant-based yogurt product prepared by the method of the invention using sweet potatoes and soybeans as raw materials, adding nutrient supplements such as broccoli, okra and the like, and adding a thickener to polymerize whey protein-xanthan gum system (PWP-XG) interaction.

Fig. 3 is an exterior view of the result of the present invention.

Detailed Description

The invention discloses a method for producing yoghourt, wherein sweet potatoes and soybeans are proportioned in a certain amount to achieve the effect of both nutrition and taste, and a certain amount of PWP solution is added to strengthen the texture of the yoghourt so that the texture of plant-based yoghourt is closer to that of cow lactic acid milk, and the yoghourt has no granular feel and smooth taste. Table 1 shows the composition ratios and the operation requirements of the plant-based yoghurt.

TABLE 1 ingredients and operating requirements of vegetable-based yogurt

The yoghourt prepared by the method accords with the original effect, and can have better effect and quality.

In order to improve the nutritive value and appearance of the product, the sweet potato is specially added, has sweet taste, is rich in more than 10 microelements such as carbohydrate, dietary fiber, carotene, vitamin, potassium, magnesium, copper, selenium, calcium and the like, can protect the structural integrity of human epithelial cells, inhibit the activity of viruses, block the generation of nitrosamine in gastrointestinal tracts, eliminate toxic effects caused by mercury, cadmium, arsenic and the like in foods or environments, and block the carcinogenic process of toxic metals. Therefore, sweet potatoes are called the most nutritionally balanced health food by the expert. The unique dehydroepiandrosterone of sweet potato is a steroid hormone secreted by adrenal gland and similar to androgen, and can prevent cancer and prolong life. The sweet potato added in the product can not only increase the color of the product, but also has balanced nutrition.

Table 2 evaluation of flavor of plant-based yogurt

Evaluation index	Sensory evaluation	Analysis of causes
			Color	Yellowish light yellow	Sweet potato pigment
Tissue state	Macroscopic small particles	Control of gelatinization time and temperature
			Smell of	Sweet potato has heavy flavor	Sweet potato flavor substance
Taste and flavor	Moderate sour and sweet, no obvious granular feel	Sweet potato self-contained sweet taste and fermentation acidogenesis neutralization

In order to reduce the texture of the plant-based yoghurt, the invention is specially added with a polymerized whey protein-xanthan gum system (PWP-XG) to improve the taste of the plant-based yoghurt, so that the plant-based yoghurt is closer to the milk of cow lactic acid, the granular sensation of sweet potatoes and soybeans is reduced, the taste of the plant-based yoghurt is smoother, and the plant-based yoghurt is more suitable for children and old people to eat.

Development of non-dairy probiotic products is a hot topic in the food industry. It has been found that fermentation can significantly improve the nutrient quality and flavor of cereals and exhibit good physiological functions. Therefore, the experiment uses coarse grains for fermentation in a referential manner so as to fully excite the nutrient substances of the coarse grains. And sweet potatoes and soybeans are rich in polysaccharide and protein, so that the cost is low. The former deep processing needs to be improved, and the high-value utilization and echelon utilization of the former deep processing are improved as high-quality fermentation raw materials.

One of the pain spots in the yogurt industry at present is low in nutritive value and cannot meet the requirement of body growth, and aiming at the pain spot, the invention adds nutrition enhancers such as functional substances of broccoli, okra and the like into the product. The dosage is 5% -10%, and the nutrient components in the broccoli are high in content and complete, and mainly comprise protein, carbohydrate, fat, mineral substances, vitamin C, carotene and the like. According to analysis, 3.5 g-4.5 g of protein is contained in every 100 g of fresh broccoli flower bulbs, which is 3 times of cauliflower and 4 times of tomato. In addition, the mineral components in the broccoli are more comprehensive than other vegetables, and the contents of calcium, phosphorus, iron, potassium, zinc, manganese and the like are all very rich and are much higher than those of the cabbage flowers belonging to the cruciferae. Okra has effects of protecting skin, promoting digestion, invigorating stomach, regulating stomach and intestine, removing liver-fire, supporting yang, invigorating kidney, and enhancing immunity. According to the invention, after the yogurt fermentation base material is prepared, the ground broccoli and okra are added into the yogurt fermentation base material, so that the nutritional value of the product is increased while the flavor of the product is not changed, and the product is more suitable for old people and children to eat.

The processing technology of different types of plant-based yoghurt has a certain similarity, and the whole processing technology comprises four steps of cleaning, soaking, pulping and filtering, but the processing sequence also has differences, and special processes added for coping with certain limiting factors and the like. In the current research, although the preparation process of the plant-based fermented yoghourt is relatively mature, a plurality of limiting factors exist, such as difficult removal of the fishy smell of plants, easy discoloration of the plant milk and the like; such limitations reduce consumer acceptance, so to address these limitations, processes that address such limitations, such as fishy smell removal, color protection, etc., have been particularly added to some processing processes.

The fishy smell removing process is very practical in plant milk, especially soybean milk can generate beany smell, and research shows that the fermented soybean milk is soaked in water for 30 hours and then soaked in NaHCO3 solution (pH 7.5-7.8) for 2 h, so that most beany smell can be removed. Research has also shown that microwave treatment of 20 s prior to soybean soaking can effectively deactivate the enzymes responsible for the fishy smell in soybeans, reducing the production of the beany smell. At present, researchers use the principle of protein deamidation to reduce the combination of flavor substances and protein, so as to develop a novel deodorization process technology; plant and cereal germination method is used for weakening the fishy smell of plants; removing plant fishy smell by adopting an anaerobic pulping technology. Experiments show that the micro-pressure cooking pulp can generate more flavor components by controlling the pressure to be 1-2 standard atmospheric pressures, and the fishy smell of the plant milk is covered, so that the sensory quality of the plant milk is superior to that of the normal-pressure cooking pulp. Therefore, the invention improves and innovates the processing technology of the plant-based yoghourt by referring to the existing research results, thereby meeting the production requirements.

Some vegetable milks may produce browning due to oxidation, affecting the organoleptic quality of the product. Therefore, some processing procedures also need to be carried out with color protection treatment, such as soybean is soaked in acid liquor for a period of time to have color protection effect on vegetable protein liquor. In addition, the soaked soybean hulls and soybean flakes are soft, loose in structure and easy to dissolve intracellular proteins in water, so that the mechanical loss during grinding can be reduced, the granular sensation of the yoghurt can be reduced, and the mouthfeel is improved.

The main problems of the organoleptic qualities of the plant-based yoghurt affecting the flavour of the plant-based yoghurt are: plant odor, serious granular sensation, and uneven tissues. The plant-based yoghurt prepared from the pure plant protein liquid has rancidity taste and tissue collapse, and is not smooth in inlet; the invention adopts plant protein liquid as main material, small amount of milk, milk powder and other auxiliary materials, and adds proper amount of flavoring matters to prepare the plant-based yoghourt, which has the advantages of good taste and nutrition, unique flavor and product characteristics. The ratio of the vegetable protein liquid to the cow milk is the factor which has the greatest influence on the tissue state of the vegetable-based yoghurt and has a certain influence on the fermentation end point. Secondly, the selection of the fermentation temperature has great influence on the survival rate and propagation metabolism of the strain, the generation of flavor substances can be changed, the relation between the generation of the flavor substances and the fermentation time in the growth process of the strain is great, the fermentation time has a certain influence on the organization and structure of the plant-based yoghurt, and the low-temperature after-ripening has a great influence on the acidity of the finished product.

Claims

The preparation method of the potato-vegetable-based yoghurt is characterized by comprising the following steps:

the plant-based yoghurt is mainly added with sweet potato and soybean materials, and interacts with a thickener-polymerized whey protein-xanthan gum system (PWP-XG) to ensure that the texture of the plant-based yoghurt is more similar to that of cow lactic acid milk, so that no granular feel is ensured, and the taste is smooth.
2. The plant-based yoghurt as claimed in claim 1, wherein: the method comprises the following steps:

(1) Removing fishy smell of soybean: firstly, soaking soybeans in water for 30 hours, and then soaking the soybeans in NaHCO3 solution (pH 7.5-7.8) for 2 h;

(2) Preparing a yoghurt fermentation base material: grinding sweet potato and the soy protein treated in (1) into powder and mixing it with white sugar and water according to 10:10:1:40, uniformly mixing the materials in proportion to prepare a fermentation base material;

(3) Adding a certain amount of polymerized whey protein-xanthan gum system (PWP-XG) and linseed oil into the yoghurt fermentation base material in the step (2), wherein the polymerized whey protein-xanthan gum system (PWP-XG) can enable the texture of the plant-based yoghurt to be more similar to that of cow lactic acid milk, ensure no granular feel, smooth mouthfeel and have unique good flavors of sweet potatoes and soybeans;

(4) Grinding broccoli and okra into powder, adding the powder into the mixed fermentation base material in the step (3) and uniformly mixing the powder;

(5) Homogenizing the mixture processed in the step (4), sterilizing, cooling and inoculating;

(6) Fermenting the treated mixture in step (5) for 5 hours at different temperatures (within 20-50 ℃) by referring to the optimal addition amount of strains, taking the number of viable bifidobacteria, the number of viable lactobacillus, the pH value and the viscosity in the finished product as indexes, preferentially selecting the group with the highest number of viable probiotics and the highest viscosity value, and researching the influence of the fermentation temperature on the properties of sweet potato soybean yoghourt;

(7) Respectively fermenting for different time (within 3-6 h) under the optimal addition amount and optimal fermentation temperature of the ABY-8 strain, and according to the index of (6), optimizing the group with the highest probiotics number and viscosity value, and researching the influence of fermentation time on the properties of the sweet potato soybean yoghourt;

(8) Cooling the fermented homogenate, canning and refrigerating.
3. The method for preparing the plant-based yogurt according to claim 2, wherein in the step (1), the soybeans used in the plant-based yogurt must be soaked with acid, so that the beany flavor can be eliminated and the oxidative browning thereof can be prevented.
4. The method for preparing a plant-based yoghurt as claimed in claim 2, wherein in step (2), the ratio of sweet potato to soybean to water is maintained at 1:4, thereby maintaining good mouthfeel.
5. The method for preparing a plant-based yogurt according to claim 2, wherein in the step (3), the plant-based yogurt is added with a polymeric whey protein-xanthan gum system (PWP-XG) to achieve smooth mouthfeel.
6. The method for preparing the plant-based yoghurt as claimed in claim 2, wherein in the step (4), 5% -10% of extracts of broccoli and okra are required to be added, mineral components in the broccoli are more comprehensive than other vegetables, and the content of calcium, phosphorus, iron, potassium, zinc, manganese and the like are rich, so that the okra has the effects of protecting skin, helping digestion, strengthening stomach, regulating intestines and stomach, clearing liver toxin, strengthening yang, strengthening kidney and enhancing the immune function of a human body.
7. The method for preparing a plant-based yoghurt as claimed in claim 2, wherein in the step (6), the plant-based yoghurt needs to be fermented for 5 hours to ensure that the product is edible and has a good taste.