Daily preservation methods and precautions of soybeans
Author：Anhui Bright Grain and Oil Industry Co., Ltd. Time：2018/6/23
The fruit of the bean is a pod, which consists of two parts, the seed coat and the embryo. Soybeans are rich in protein and fat, and have poor storage stability. During storage, they often form mold due to moisture absorption, reddening due to oil immersion, poor high-temperature resistance, and loss of germination power.
2. Reddening due to oil immersion: Typically, soybeans contain more than 13% moisture. When the temperature is higher than 25 ℃, after a period of storage, the beans will become soft, and the part of the two cotyledons near the umbilicus will turn red. Subsequently, the red color of the cotyledons gradually deepens and expands, which is called "red change". In severe cases, there will be obvious peeling of the oil immersion, and the cotyledons are waxy and transparent, which is called "oil immersion". The reason for this phenomenon is that under the action of high temperature and high humidity, the protein in soybean will solidify and denature, destroy the emulsified state in which fat and protein coexist, and make the fat exudate in a free state, resulting in soybean oil immersion. At the same time, the pigment in the fat is gradually deposited, which will cause the cotyledons to turn red and redden. "oil immersion" is sometimes also referred to as "oil running".
3. Good insect resistance: the surface of soybean grains is smooth, the seed coat tissue is relatively hard, and contains more cellulose and wax, which can enhance their resistance to insect pests.
4. Sensitive to heat, not resistant to high temperature: The fat contained in soybeans is mainly unsaturated fatty acids. In storage, they are easily affected by oxygen or microorganisms, and undergo oxidation and hydrolysis. They are heat sensitive and not resistant to high temperatures. For high-moisture soybeans, only low-temperature drying can be used, and heat treatment cannot be used, otherwise the quality of soybeans will be damaged.
5、 Germination rate is easily lost: soybeans with normal moisture content have difficulty maintaining germination rate when the temperature reaches 25°C.
6. Storage of soybeans: The key is to control moisture. Keeping soybeans dry effectively is the main measure for keeping soybeans well. In Northeast China, the moisture standard for safe soybean storage is generally 14.0% in winter, 13.5% in spring and autumn, and 13.0% in summer
