In recent years, with the continuous improvement of people’s living standards the demand for yogurt is also increasing. Combining fermentation agents and plant-based raw materials to make healthy yogurt drinks rich in plant protein and microbial protein is one of the current trends in the development of functional beverages.

Soy Plant Yogurt

Soybean plant yogurt, also known as plant-based yogurt, is a fermented product in the deep-processed soymilk stale products, which possesses a thick organization and viscous taste, and its most important role is to greatly extend the shelf life of soymilk. Compared with animal yogurt, the most prominent advantage of soy yogurt is that it is cholesterol-free and suitable for lactose intolerant patients.

Factors affecting the taste of soy plant yogurt

1. Different ratios of strains used

Yogurt fermentation strains with milk as the main ingredient mainly use lactose in milk as the fermentation substrate, while plant-based yogurt fermented with instant soy flour as the main ingredient, the fermentation strains mainly use sucrose as the fermentation substrate. Lactobacillus plays an acidifying role in yogurt fermentation; Streptococcus thermophilus plays a thickening role in yogurt fermentation.

①Classical mixed fermentation

This type of fermentation is the classic strains of yogurt processing: Lactobacillus bulgaricus and Streptococcus thermophilus, which are complementary in fermentation characteristics, and the yogurt made has the composite health value of the two strains.

②Mixed fermentation with Lactobacillus plantarum

This kind of fermentation uses Lactobacillus plantarum, Lactobacillus bulgaricus and Streptococcus thermophilus together. Lactobacillus plantarum is more suitable for Chinese digestive system and can be used to ferment soy flower or yogurt.

Lactobacillus plantarum is mainly used in traditional food fermentation and is a healthy microbial organic food ingredient. It aids digestion while also relieving intestinal dysfunction and preventing soy allergies.

③Lactobacillus acidophilus mixed fermentation

This type of fermentation uses Lactobacillus acidophilus, Lactobacillus bulgaricus and Streptococcus thermophilus together. Lactobacillus acidophilus has the function of increasing the vitality of macrophages and lymphocytes, helping digestion, and maintaining intestinal acid-base balance.

④ Mixed fermentation of Lactobacillus acidophilus and Streptococcus lactis

This kind of yogurt makes use of a certain symbiotic relationship between the two bacteria to increase the rate of acid production, shorten the fermentation time, and take advantage of the latter’s property of producing butanedione, thus improving the flavor of the product and making the yogurt delicate in texture, sweet in acidity, and fragrant in sweetness.

⑤ Mixed fermentation of Lactobacillus acidophilus and Bifidobacterium bifidum

This type of fermentation utilizes the mutualistic relationship between Bifidobacterium and Lactobacillus acidophilus. Bifidobacterium bifidum not only produces acetic acid but also synthesizes many vitamins such as vitamin B2 and folic acid, which are supplied to Lactobacillus acidophilus to promote the growth and proliferation of Lactobacillus acidophilus.

Lactobacillus acidophilus needs acetate, vitamins and folic acid as nutrients to promote the growth of bifidobacteria. Meanwhile, mixed fermentation can speed up acid production, shorten curdling time and make better flavor.

In short, different enterprises can choose different strains or composite strains according to their own product positioning.

2. Fermentation time and fermentation temperature

Fermentation temperature: the effect of temperature on fermentation and its regulation and control is one of the most important factors affecting the growth and reproduction of organisms, because any biochemical enzymatic reaction is closely related to temperature changes.

As the temperature rises, cell growth and reproduction accelerate; but as the temperature rises, the rate of enzyme inactivation is also faster and faster, so that the aging advance fermentation cycle is shortened, which adversely affects the fermentation production.

Fermentation time: the time required from the start of inoculation to the termination of fermentation. Fermentation time is too long or too short has an effect on the quality of yogurt; fermentation time is too long, the bacteria breed too much, the yogurt taste will be too acidic; fermentation time is too short, the amount of bacteria breeding is not enough, it will cause the protein coagulation is not good, and the yogurt appeared to be out of the water thinning phenomenon.

So when the fermentation is over, the yogurt should be put into a low-temperature environment for storage. The most suitable fermentation temperature for yogurt is 42℃-43℃; fermentation time is 7-8 hours.

3. Selection and proportion of raw materials

Most of the raw materials used in plant yogurt are from plants, and the auxiliary materials are sugar, stabilizer and modified starch, and sometimes milk powder is added to adjust the flavor of the product.

Fermentation slurry can not be less than 11 concentrations, protein content of 3.0 or more. Plant yogurt is conducive to the human digestive function and promotes appetite, lactose fermentation produces a large amount of lactic acid, which can reduce the pH in the intestinal tract, regulate intestinal flora, inhibit the growth and reproduction of harmful microorganisms in the intestinal tract, inhibit the growth and reproduction of pathogens such as pneumonia, mastitis, etc., and also help the body to synthesize B vitamins, and it has a composite aroma of soybeans and yogurt. Figures 1 and 2 indicate the effect of fermentation of milk powder and soybean powder in certain ratios on pH and acidity.

Production process analysis

1, to soybean plant yogurt as an example of process flow:

Process 1, soybean screening → peeling (or soaking) → grinding → filtration → enzyme sterilization → standardization → ingredients → filtration → preheating → homogenization → sterilization → cooling → inoculation → packaging → fermentation → refrigeration.

Process 2: Soybean milk powder → recovery → dosage → filtration → preheating → homogenization → sterilization → cooling → inoculation → portioning → fermentation → refrigeration.

2, the key control points:

Process 1, there are grinding (affecting the protein extraction rate), enzyme (affecting the flavor of soybean taste), standardization (affect product quality and stability), sterilization, inoculation (strain selection affects the flavor), fermentation.

Process 2, standardization (affect product quality and stability), sterilization, inoculation, fermentation.

3, process differences:

Process I. Disadvantages: the need for equipment and energy consumption, large investment, the need for soybean milk production equipment and enzyme processing equipment, key control points more management difficulties. Advantages: strong cost control.

Process 2, disadvantages: relatively small selection of raw materials. Advantages: the required equipment is the same as ordinary yogurt, the key control points are the same, and the process is relatively mature.

If the dairy company as a new product or rich variety is recommended to use the second process.

Conclusion

Soybean is the most cost-effective raw material for vegetable yogurt protein base. Instant soybean powder is made by sterilizing, concentrating, spraying and drying soybean milk, which is a kind of plant protein food with high nutritional value.

This food is characterized by easy preservation and convenient consumption. It has the natural color, aroma and taste of soybeans, especially it does not contain cholesterol, which will not cause cholesterol deposition, and contains unsaturated fatty acids, which in turn have the effect of preventing cholesterol deposition from other sources. Therefore it is very popular among the general public.

Soybean plant yogurt made with instant soybean flour, eliminating the tedious process of making soy milk, convenient for consumers to make at home and the environmental pressure of factories, and reduce energy consumption. And instant soybean meal and the use of soy milk to make plant yogurt compared to the uniformity of good, the flavor of the product will not have a greater change.