Effects of Deheading and Intestinal Removal on Protein Degradation and Quality Changes in Chilled Litopenaeus vannamei

This study evaluated the effects of deheading and intestinal removal on protein degradation and quality changes in chilled Litopenaeus vannamei. The results showed that shrimp subjected to heads removed (HR) and both heads and intestines removed (HIR) maintained better muscle integrity and sensory characteristics compared with intact (CK) and intestines removed (IR) shrimp. Furthermore, the HR and HIR treatments significantly inhibited the accumulation of total volatile basic nitrogen, trichloroacetic acid-soluble peptides, and bitter free amino acids (including His, Lys, Leu, Val, and Tyr), while maintaining consistently low activities of trypsin, cathepsin B, cathepsins B+L, and cathepsin D in the muscle throughout storage. Additionally, intrinsic fluorescence spectroscopy, SDS-PAGE, and microstructural analyses revealed that HR and HIR treatments significantly delayed muscle protein degradation and effectively preserved the structural integrity of muscle tissue. These findings suggest that quality deterioration of shrimp during chilled storage may be largely associated with the migration of endogenous proteases from the hepatopancreas in the cephalothorax into the muscle tissue.