Effects of enzymatic hydrolysis and glycation on antioxidant properties of different salmon by-products (frame, head, and skin)

Abstract

The salmon processing industry generates considerable quantities of by-products, including frames, heads, and skins. The objective of this study was to determine the changes in antioxidant properties of salmon by-products through part-specific enzymatic hydrolysis and subsequent glycation. The salmon by-products were enzymatically hydrolysed (Alcalase, 0.1 AU/g protein) at 55 degrees C for 60 min, followed by glycation with 1% (w/v) xylose or glucose at 95 degrees C for 60 min. The frame hydrolysate exhibited the highest degree of hydrolysis and total free amino acids (p < 0.05). The glycation with xylose significantly increased the browning index, as confirmed by protein electrophoresis. The by-product types and glycation treatment could change radical scavenging activity, reducing power, and inhibition of lipid peroxidation. In particular, enzymatic hydrolysis and glycation with xylose could significantly improve the antioxidant potential of the salmon by-products, and such changes were clearly categorized through principal component analysis. This study shows that the critical role of targeted enzymatic hydrolysis and glycation in improving the antioxidant properties, which could be a way to alleviate antioxidant differences due to raw materials. Moreover, the industrial application of these serial processes could contribute to the sustainability of salmon production systems.