Hygiene and management of bean food

作者：admin  点击次数：136  发布时间：2025-05-28

1. Overview
Soybeans contain more protein (35%~40%) and fat (15%~20%), and relatively less carbohydrates (20%~30%). The amino acid pattern of soybeans is close to the needs of the human body, and it is rich in lysine, which is lacking in grains, so soybean protein is called high-quality protein. In addition, soybeans are also rich in inorganic salts such as calcium, phosphorus, and iron, as well as vitamin B and vitamin B. The content of unsaturated fatty acids in soybean oil accounts for 85%, and linoleic acid is the largest. According to traditional production and sales habits, the scope of bean food mainly includes bean products made from soybeans, which are divided into two categories: non-fermented bean products and fermented bean products according to different production processes.
2. Soy products and microbial contamination
At present, the production of soy products in my country is mostly manual, and the sanitary conditions are poor. Therefore, microbial contamination plays an important role in the hygiene of soy products. The health and epidemic prevention department believes that the main microorganisms that cause the corruption of soy products are Gram-positive Bacillus, Alcaligenes faecalis, Gram-positive Capsular Bacillus, etc., which can cause soy products to become corrupt and deteriorate in a short time in midsummer. In addition to making soy products sticky and deteriorating, cocci and Serratia marcescens also produce pigments that change color. Scientists believe that the corruption of soy products is closely related to processing conditions. For example, the corruption of soy milk is closely related to the boiling time during processing. Boiling for 10 to 15 minutes kills most of the bacteria brought by soybeans, and only heat-resistant bacillus spores remain. Semi-finished products can also be contaminated by various bacteria and become corrupt when they are stored in water. The main bacteria on tofu are Pseudomonas, coliform bacteria, Lactobacillus, Micrococcus, Flavobacterium, Achromobacter, etc.
3. Removal of toxic and harmful factors in bean foods
Mixed beans and grains can improve the quality of protein in the diet and increase the source of vitamins and inorganic salts. This is of great significance for changing the dietary structure of the Chinese people, increasing high-quality protein, and improving nutritional status. However, beans contain a variety of physiologically harmful substances, such as trypsin inhibitors, coagulants, and substances that cause thyroid swelling, so you should pay attention before eating. Tests have shown that these substances are all water-soluble, and almost all of them can be destroyed after heating treatment, and the residual amount is very small. Therefore, heating pretreatment is very important during processing. However, due to insufficient heating temperature or time, these harmful substances cannot be completely destroyed, causing poisoning.
(-) Anti-nutritional factors
1. Protease inhibitors
There are 7 to 10 types of protease inhibitors, which are mainly found in soybeans. They partially inhibit the enzyme activity of substances such as trypsin, protease, and pepsin, hinder the digestion and absorption of protein, and have an inhibitory effect on animals. 2. Plant hemagglutinin
This is a protein that can agglutinate human and animal red blood cells and can affect the growth of animals.
3. Flatulence factor This is stachyose and raffinose, which account for half of the carbohydrates in soybeans, and produce gas under the action of intestinal microorganisms. These problems can usually be solved to varying degrees through the processing process. For example, the protein digestibility of soybeans is low, only 65%. If it is processed by soaking, grinding, heating, fermentation, germination and other processing methods, the digestibility of the soy products produced will be significantly improved, such as the digestibility of soy milk is 85%, and the digestibility of tofu is 92%~96%. Using normal pressure steam for 30 minutes can destroy the protease inhibitors in raw soybeans. When soybeans are processed into soy products, the flatulence factor will also be partially or completely removed.
2) Treatment of beany, bitter and other odors
Beans contain a variety of enzymes, among which lipoxygenase is the main enzyme that produces beany and other odors. Under appropriate conditions, this enzyme causes fat to rot and oxidize and degrade to produce a variety of substances with beany odor. At the same time, it can also react with unsaturated fatty acids such as linoleic acid and linolenic acid to produce aldehydes, ketones and other substances with beany odor. The activity of lipoxygenase is related to temperature, moisture and pH. Using NaHCO to adjust the pH of the slurry, deodorizing treatment is carried out at a temperature where lipoxygenase is inactivated, and the time from slurry preparation to sterilization is shortened as much as possible, which can reduce the generation of beany and bitter odors.
4. Molds and mycotoxins that contaminate beans
Beans can be contaminated by molds at all stages of the field growth period, harvesting and storage process. When the humidity is high and the temperature is high, molds tend to grow and multiply in beans and decompose their nutrients, produce acid and gas, and cause beans to mold. This not only changes the sensory properties of beans, reduces and loses their nutritional value, but also may produce corresponding mycotoxins, which are harmful to human health. Preventive measures: First, when washing soybeans, remove broken seeds and grass seeds from the seeds and reduce the moisture content of soybean seeds to below 12%. Secondly, the temperature of the warehouse should be controlled well. The temperature of the grain pile should be kept within the range of 5~10℃ of the average monthly outdoor temperature. Only in this way can the reproduction and toxin production of molds be prevented and controlled.
V. Processing and sanitation of bean foods
Production tools, containers, pipelines and operators are the main pollution links, followed by the storage method of the products. Therefore, to prevent the contamination of bean products, easily disassembled conveying pipelines can be designed, cleaned after each shift of production, and sterilized by hot steam before production. Tofu boards, cold bamboo curtains and wrapping cloths should be cleaned with hot alkaline water and then boiled for disinfection before use. , boxes and other tools and containers must be washed with hot alkaline water before use, and the environment, workshop and operators must be kept clean. Soybeans are a specialty of my country. They are not only of many varieties, but also of many ways to eat. The most widely used soybean products in my country are tofu, soy milk, bean sprouts, etc.
(-) Tofu
The method of making tofu is generally to soak the beans or bean cakes, then crush, filter, heat and boil, and then add brine or gypsum to precipitate the soybean protein. Drain the water to make tofu. Tofu is also the basic product of some other soy products such as thousand sheets, fried tofu, and dried tofu. In order to preserve the nutrition of tofu and its products, cold-pressed tofu is often used in processing, that is, 10% of the oil is first extracted from the soybeans by cold method, and then the bean cakes are made into tofu. The following aspects should be paid attention to during processing:
(1) The bean cakes should be thoroughly cleaned before oil extraction to prevent dirt from entering the soy products. This is an important step in making the tofu white and clean.
(2) The cold-pressed bean cakes should be properly stored to prevent mold and deterioration, which will make the soy products bitter.
(3) When cold pressing soybean oil, the heating temperature of soybeans should not exceed 30℃, otherwise the protein will partially denature and make the tofu less loose and harder.
(4) The water used to make tofu should be of good quality. Some areas use circulating water, which must be purified and boiled and disinfected in advance. To ensure the sanitary quality of soy products, mechanized, continuous and closed production should be used as much as possible.
(II) Soy milk
Soy milk is a favorite food of the general public and is a good milk substitute for the growth of infants and young children. Its preparation method is the same as the steps before tofu precipitation. Generally, the ratio of soybeans to water is 1.7:9, and its water content is about 95%.
Soy milk must be boiled and cooked to prevent saponins from causing food poisoning. Heating can destroy anti-trypsin factors. Ensure the nutritional value of soy products and facilitate digestion and absorption.
(III) Bean sprouts
After soybeans or mung beans sprout, their ascorbic acid content is as high as 17~20mg/100g, which is a good vegetable substitute, especially suitable for winter in the north.
When growing bean sprouts, pay attention to water hygiene and do not use chemical fertilizers to promote germination.