Change response of frozen food in freezer

The protein in the food placed in the freezer in the freezer will be frozen and denatured during the freezing process. During the freezing process, the temperature of the frozen storage and the growth of the frozen product will increase the degree of freezing and denaturation of the protein. It is generally believed that the lower the freezing temperature, the smaller the degree of protein freezing denaturation. The cod meat frozen at -35 ° C by air blowing was frozen at -14'C, -21.7 ° C, and -2yC respectively, and the solubility of protein in 5 saline was changed. The lower the freezing temperature, the higher the amount of soluble protein, indicating that the freezing denaturation of the protein is smaller.

Depending on the fish species, the degree of protein freezing denaturation varies greatly, which is related to the stability of the fish protein itself. For example, the protein of cod meat is easily frozen and denatured, but the perch uranium and the scorpionfish are not easily denatured. In addition, the frozen denaturation of fish protein is also affected by coexisting substances. For example, the presence of fat, especially free fatty acids produced by the breakdown of phospholipids, is a factor that promotes protein denaturation.
In addition, water-soluble salts such as calcium and magnesium will promote the freezing and denaturation of fish protein, while phosphates, sugars, and glycerin can reduce the freezing and denaturation of fish protein. According to the experiments done by Akira Minoru. Immerse the cod meat in 0.5% pyrophosphate, oatmeal, rhizome, rhizome, and dry in a mixed aqueous solution of 0.5% sodium pyrophosphate and sodium tripolyphosphate, and then put them at -5 ℃, -30gC, -90 ℃ Freeze at temperature and store at -26 ° C for about 2 months. Compared with untreated cod, the thawing effluent is less, and the amount of deoxyribonucleic acid (DNAP) in the effluent is also less. Therefore, it is believed that phosphates have a certain effect on inhibiting protein degeneration and changes in muscle tissue.