Effect of the Removal of Digestive Enzymes and Different Cos-Polyphenol Conjugates on the Quality of Harpiosquillid Mantis Shrimp Stored in Iced Water

Abstract

Chitooligosaccharide (COS) and various COS-polyphenol conjugates including COS-gallic acid (GAL), COS-caffeic acid (CAF), COS-ferulic acid (FER), COS-catechin (CAT) and COS-epigallocatechin gallate (EGCG) were prepared, characterized and examined for inhibition toward purified trypsin from Harpiosquillid mantis shrimp (HMS). Different COS-polyphenol conjugates showed varying inhibitory effects. COS-CAT at 2.5% showed a maximum inhibition (72.90%) against purified trypsin. Conversely, COS and individual polyphenols inhibited trypsin activity to a low extent. COS-CAT could inhibit autolysis of HMS meat under optimum conditions as witnessed by more retained protein band intensity analyzed by SDS-PAGE and lower α-amino acid content. The incision and drainage of digestive fluids from whole HMS after treated with COS-CAT solution retained the major muscle proteins and sensory acceptability, mainly by delaying proteolytic degradation until day 5 in iced water. Thus, the removal of digestive fluid prior to COS-CAT treatment could be a potential means to maintain the quality of HMS.

Keywords: Harpiosquillid mantis shrimp, Trypsin inhibition, Texture softening, Chitooligosaccharides-polyphenol conjugates, COS-Catechin