食物在冷冻贮藏时的化学变化

SOME CHEMICAL CHANGES IN FOODS DURING FROZEN STORAGE

本文讨论了食物在冷冻贮藏过程中某些物质的化学变化.冷冻时,食物未冻水相中高浓度的盐作用于粒状体,使其释出低密度脂蛋白(LDL).LDL浓度的增加,促使LDL在原生质中发生聚合;同时,蛋白在低温下也发生聚合,溶解度下降;不饱和脂肪酸在微环境氧的作用和酶催化下发生氧化.以上变化,随贮存温度、贮存时间、贮存环境、食物种类、pH值、化学添加剂而有所不同.

Some chemical changes in foods duriug frozen storage were discussed in this paper. The granules were disrupted by the high concentration of salts in unfrozen phase and release the low density lipoproteins (LDL). The LDL then aggregated in the plasma The proteins aggregate rapidly when it were exposed to frozen storage. This may be the cause of decrease in the solubility of proteins during frozen storage of muscle. The unsaturateb fatty acid which existed in the lipid can be autoxidated by the microenvironmental oxygen. Some lipoxygenase fatalize the process of oxidation. The chemical changes during storage of frozen oods depend the PH value, chemical additives, species of foods, temperature and storage time of frozen period.