The quality assessment of frozen shrimp (Metapenaeus ensis): protein changes, texture and total volatile basic nitrogen

Proteins of shrimp muscle suffered chemical and physical changes during frozen storage which may result in quality deterioration. There are lots of parameters widely used to assess the degree of protein changes. While, not much information was available on using different parameters to investigate changes in proteins of frozen shrimp. The present study was conducted to evaluate the changes in proteins using different parameters, including myofibrillar solubility, myofibrillar size distribution and myofibrillar UV absorption spectrum. Meanwhile, in order to make clear the direct effects of these protein changes on frozen shrimp quality, the variation in total volatile basic nitrogen (TVB-N), texture and microstructure were determined as well. The results of this research may help to better understand the mechanism of frozen shrimp quality deterioration. The results showed that the protein had been changed during shrimp frozen storage which could result from protein freeze denaturation, protein oxidation, protein degradation and other biochemical actions. All the three parameters could well characterize the changes in protein during shrimp frozen storage. It was shown that the TVB-N levels increased, and the texture and microstructure went worse over shrimp frozen storage. These variations could be the results of protein changes.