The debittering effect of β-cyclodextrin, lactoferrin or flavourzyme at various concentrations on bone collagen peptide was evaluated by electronic tongue, color analysis and sensory evaluation. The debittering mechanism was elucidated by hydrophobicity, free amino acid content and Fourier transform infrared (FTIR) spectroscopy. Meanwhile, the impact of the different debittering methods on antioxidant properties of bone collagen peptide was explored in terms of total antioxidant capacity, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity, and 2,2’-azinobis-(3-ethylbenzthiazoline-6-sulfonate) (ABTS) cation radical scavenging capacity. β-Cyclodextrin at 4 g/100 mL, lactoferrin at 5 g/100 mL and flavourzyme at 1.5 g/100 mL greatly reduced the bitterness of bone collagen peptide, and flavourzyme at 1.5 g/100 mL reduced it to the lowest level. In addition, surface hydrophobicity of all debittered samples was lower than that of the control group (P < 0.05). After debittering with β-cyclodextrin or lactoferrin, the content of hydrophobic free amino acids was significantly decreased, but increased after debittering with flavourzyme (P < 0.05), suggesting that the principles of these debittering methods are different. Compared with the other debittering methods, flavourzyme treatment significantly enhanced the antioxidant ability of bone collagen peptide (P < 0.05). Thus, flavourzyme treatment offers a potential approach for the production of bone collagen peptide with acceptable bitterness intensity and high antioxidant activity.

This study aimed to identify the lipid composition and the positional distribution of fatty acids in dried shrimp and to select differential lipids and investigate lipid changes and the lipid transformation mechanism during storage using lipidomics analysis. Results showed that a total of 790 lipids belonging to 7 major classes were identified, among which glycerophospholipids were the most abundant, followed by glycerolipids and sphingolipids. In phosphatidylcholine (PC), phosphatidylethanolamine (PE), triglycerides (TG), and diglycerides (DG), saturated fatty acids were found to be mainly located at the sn-1 position, while unsaturated fatty acids, especially oleic acid, linoleic acid, docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA), were mainly distributed at the sn-2 position. Using multivariate statistical analysis, 151 differential lipids were selected, 121 of which were up-regulated and the remaining 30 were down-regulated, indicating that storage had a significant effect on the types and contents of lipids in dried shrimp. After storage for 20 days, the relative contents of lyso-phosphatidylcholine, lyso-phosphatidylethanolamine, and lyso-phosphatidylserine in dried shrimp increased, and the relative contents of PC, PE, and phosphatidylserine decreased significantly, indicating the occurrence of lipid transformation.

In this study, the changes in myofibrillar protein oxidation, taste substance and taste characteristics of dried Penaeus vannamei were investigated under accelerated storage conditions, and a correlation analysis was carried out between myofibrillar protein oxidation and taste characteristics. As a result, the color of dried Penaeus vannamei gradually changed to dark brown, the content of total sulfhydryl group decreased, and the carbonyl group content and surface hydrophobicity increased, which indicated increased degree of oxidation of myofibril protein. The content of inosine monphosphate and umami free amino acids in dried shrimp showed a trend of first increasing and then decreasing, while the contents of sweet free amino acids and total free amino acids decreased gradually. The electronic tongue was used to characterize the taste change of dried Penaeus vannamei, and it was found that the umami and sweetness intensity of dried Penaeus vannamei decreased, the bitterness intensity increased, but the saltiness intensity did not obvious change. The richness first increased and then decreased. The correlation analysis between protein oxidation and taste indexes showed that the degree of protein oxidation of dried Penaeus vannamei was positively correlated with the bitterness intensity, and negatively correlated with the umami, sweetness, saltiness intensity and richness. These results showed that there was no significant difference in the taste of dried white shrimp during short-term storage, but with the extension of storage time, the appearance and color deteriorated, the oxidation of myofibrillar protein increased, and the taste quality decreased. The findings from this study provide a theoretical and data basis for regulating the storage quality of white shrimp.