This study aimed to examine the effects of grape seed extract (GSE) on enhancing the quality of Altay sheep meat during repeated freeze-thaw cycles. The surface of the Longissimus dorsi muscle was sprayed with 0.5 g/100 mL GSE aqueous solution prior to undergoing 1, 3, 5 or 7 freeze-thaw cycles. At each cycle, meat color, myoglobin oxidation status, pH, shear force, thiobarbituric acid reactive substances (TBARS) value, total volatile basic nitrogen (TVB-N) content and volatile compound profile were determined. The results indicated that with increasing freeze-thaw cycles, lightness (L*), redness (a*), relative content of oxymyoglobin (OMb), pH, and shear force decreased; yellowness (b*), TBARS value, and relative contents of deoxymyoglobin (DMb) and metamyoglobin (MMb) showed an increasing trend; TVB-N contents initially increased and then decreased. The incorporation of GSE was found to mitigate the pH decrease and significantly lower the TBARS value (P < 0.05) during freeze-thaw cycles, but had no significant effect on the color, shear force or TVB-N content of mutton. Additionally, the levels of major volatile flavor compounds such as hexanal, 1-octene-3-ol, (E,E)-2,4-decenal, (E,Z)-2,4-decenal, (E)-2-octanal, octanal, heptanal, 3-octanone, carbon disulfide, and 2-pentylfuran initially rose and then fell with increasing freeze-thaw cycles, resulting in flavor deterioration. Compared with the blank group, GSE addition significantly curtailed the formation of aldehydes, ketones, alcohols, and furans resulting from lipid oxidation during repeated freeze-thaw cycles, thereby improving mutton flavor. This research provides a theoretical foundation and technical support for the flavor preservation and regulation of meat products during cold-chain circulation.

Sesame is one of the eight major allergens that cause food allergies. Study of the epitopes of sesame allergens is important for understanding their sensitization mechanisms. Currently, less information is available on the epitope studies of sesame allergens. In this study, we analyzed the molecular characteristics, structure and homology of Ses i 3, one of the important sesame allergens. We predicted the B-cell linear epitopes of Ses i 3 using bioinformatics tools and characterized them by slot blot immuno-microarrays technology. Eight peptides as B-cell linear epitopes of Ses i 3 were identified, in addition, key amino acids in these epitopes were predicted and leucine 422 was identified as a key amino acid. The present work will contribute to further understanding of the sesame allergen and provide some help in the prevention and treatment of sesame allergy.