Extraction, Identification, Modification, and Antibacterial Activity of Histone from Immature Testis of Atlantic salmon.

In the present study, histone from immature testis of Atlantic salmon was extracted and identified, and its antibacterial activity after enzymolysis was investigated. Histone extracted from Atlantic salmon (Salmo salar) testis using the acid extraction method was successfully identified by LC-MS/MS, and revealed significant inhibitory activity on both the Gram-negative and Gram-positive bacteria. With a low concentration of 10 mg/mL, the observed inhibitory zone diameter (IZD) could significantly reach up to 15.23 mm. After modification of enzymatic hydrolysis by pepsin, histone could be digested to three fragments, while the antibacterial activity increased up to 57.7%. All the results suggested the leftovers from commercial fishing could be utilized for the extraction of antimicrobial peptides.

Allergenicity of acrolein-treated shrimp tropomyosin evaluated using RBL-2H3 cell and mouse model.

BACKGROUND: Food processing effects can modify protein functional properties. However, protein was oxidized inevitably by lipid peroxidation during food processing. Acrolein, a primary by-product of lipid peroxidation, can modify the structural and functional properties of protein. The aim of the research was to analyze the effect of acrolein on allergenicity of TM, a major allergen in shrimp. RESULTS: The overall allergenic effects of acrolein-treated TM were evaluated using female BALB/c mice and a mediator-releasing RBL-2H3 cell line. Acrolein-treated TM significantly decreased TM-specific immunoglobulin E/G1 levels, and histamine and mMCP-1 release in mouse serum. Release of inflammatory mediators such as ß-hexosaminidase, histamine, cysteinyl leukotriene and prostaglandin D2 was clearly suppressed after acrolein treatment. CONCLUSION: These results indicate that acrolein-induced tropomyosin modification can decrease the allergenicity of TM. This reduction contributes to allergenic potential changes in shrimp during processing and preservation. © 2018 Society of Chemical Industry.

Determination of four different purines and their content change in seafood by high-performance liquid chromatography.

BACKGROUND: Seafood is regarded as a high-purine food that may induce gout, which has attracted extensive attention concerning its safety. Therefore, the aim of this study was to develop a simple and reliable method to determine the purine content in seafood and its change during storage to offer consumers healthy diet information. RESULTS: Chromatographic separation was carried out using Waters Atlantis dC18 column, and potassium phosphate monobasic solution (0.02 mol L-1 , pH 3.6) as a mobile phase. The average recovery yields of four purines were 91.5-105.0%, and relative standard deviation values were around 1.8-6.5%. Shrimp and snail contained higher amounts of purine than fish and bivalves; the livers and skins of fish contained higher amounts of purine than muscles; and the main purine varied depending on the type of seafood. Also, purine content of seafood changed during storage. CONCLUSION: The purine content of seafood differed depending on species, body part and degree of freshness, which could recommend consumers a healthy diet, especially for people with hyperuricemia and gout. © 2016 Society of Chemical Industry.

Effect of transglutaminase-catalyzed glycosylation on the allergenicity and conformational structure of shrimp (Metapenaeus ensis) tropomyosin.

Tropomyosin (TM), a myofibrillar protein, is a major allergen in shrimp. The aim of this study was to evaluate the effect of transglutaminase (TGase)-catalyzed glycosylation on the potential allergenicity and conformational structure of TM in Metapenaeus ensis. Results showed that glycosylation of TM induced unfolding of the primary protein structure followed by loss of the secondary structure. Cleavage of certain free amino groups was observed during TGase-catalyzed glycosylation. The glycosylation rate correlated with reaction temperature. Western blotting and indirect ELISA with TM-specific polyclonal antibodies from rabbit and sera from patients allergic to shrimp demonstrated that antigenicity and potential allergenicity of TM decreased, which correlated well with the conformational changes in its structure. Considering TGase is widely utilized in the food industry, these results indicate that TGase-catalyzed glycosylation has the potential to serve as a mild method for reducing the allergenicity of shrimp products.