Soybean contains remarkable nutrients with the highest protein up to 40%, among which are a variety of amino acids, especially for the human body necessary and unable to synthesize various amino acids, the content is close to that of the FAO/WHO recommended ideal composition , higher than the FNB standard, different processing method for daikon protein requisite amino acid content has no visible influence, and the lysine and L-Tryptophan content are very high, and it is not a kind of high-quality plant protein, which is present in people's meals. Now people can apply advanced technology. It is widely used in a variety of food systems, such as meat products, baked goods, milk products, beverages, etc., among which the largest amount of use is meat products.
Physical character
1） Water absorption and an oil absorption
There are various polar groups on the surface of protein molecules. They are easy to combine with water-soluble substances, while the non-polar groups prone to combine with fat-soluble ones. Therefore, soybean protein has both of water and oil absorption and can maintain stability.
2） Emulsification
The hydrophilicity and lipophilicity of soybean protein contribute to emulsification and stability.
3） Cohesion
The protein is of a large molecular weight, well solubility and adsorption making it sticky. It is ideal to adjust the physical properties of food.
4） Solubility and Divisibility
Some polar parts in soybean protein molecules can be ionized, such as amino groups and hydroxyl groups, their polarity and solubility can be changed by changing the pH value.
When the pH value is 0.5, about 50% of the protein dissolves. pH value reaching 2.0, about 80% of the protein is dissolved. As the pH value increases, less protein dissolve. With the pH value reaching 4--5, the isoelectric point, the protein solubility decreases to the minimum value, which is about 10%.
With a gradual increase in pH, the solubility of the protein increases rapidly again. When the PH value is 5.6, the protein solubility can reach more than 80%, and when the pH value is 12, the maximum solubility can reach more than 90%.
Based on such properties, isolated soybean protein can be added to the salted water. Through injection and rolling, the brine can be evenly diffused into the muscle tissue and cooperate with salt-soluble meat protein to keep large pieces such as ham and beef complete.
5) bonding property
The solution with more than 80% isolated protein will form a gel when heated, which can improve the hardness, elasticity, and texture of processed meat. Due to the excellent properties of soybean protein, besides its application in traditional meat products, it also takes a key role in creating new foods. Isolated soybean protein, a substitute for fat can soften and tender the sausage. Thanks to this application, Frankfurter fish sausage contains a protein content of up to 19 % while the fat is below 3%.
A variety of simulated meat products can also be manufactured with the addition of soybean protein.
Especially in recent years, due to the limited animal production, it is hard to fill the gap between raw meat demand and supply, especially sausages; Soybean protein is proposed to replace partial meat, which can not only improve the nutritional value but also increase the production at a lower cost. In this way, it also opens up a path for the processing of soybeans.
