Chemical during frozen storage

Chemical Deterioration of Muscle Proteins During Frozen Storage... 

Findings in the authors laboratory (100) demonstrated that the number of cross bonds in carp actomyosin and myosin increases during frozen storage and that solubility of these proteins decreases. Based on the types of chemicals that resolubilized these proteins at various rates, it was concluded that ionic bonds, hydrogen bonds, covalent bonds (S-S), and hydrophobic associations all are involved in the aggregation process. 

Farouk, M.M. and Swan, J.E. 1998. Effect of muscle condition before freezing and simulated chemical changes during frozen storage on protein functionality in beef, Meat Sci., 50, 235. 

Wastewater samples have usually been collected in precleaned amber glass containers. Both discrete and composite samples have been used for the analysis of effluents and influents of WWTPs. Unpreserved samples are normally stored at 4 °C for 48 h, or frozen [48]. Other authors add chemical agents such as methanol, sulfuric acid, or mercuric chloride to prevent bacterial activity during storage, and/or store the samples in supports used for extraction [26,35,57]. 

During the process, the product loses more than 90% of the water it initially contains. One feature of freeze-drying that singles it out from other dehydration techniques is that dehydration takes place from a frozen — and hence less chemically active — product and in vacuum — which minimizes the effects of oxidation. These assets have made freeze-drying a widely accepted technique for processing heat-labile products such as enzymes and proteins for long-term storage. 

Shrewsbury, C. L., Horne, L. W., Braun, W. Q., Jordan, R., Milligan, O., Vestal, C. M., and Westkamp, N. E. 1942. Chemical, histological and palatability changes in pork during freezing and storage in the frozen state. Purdue Univ. Agr. Expt. Sta. Bull. No. 472. 

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