No abstract

The aim of this study was to investigate the characteristics and oxidative stability of chitosan-glutathione conjugate (CS-GSH) and CS-GSH nanoparticles (CS-GSH NPs) to explore the potentials of these nanoparticle systems for GSH delivery. CS-GSH was synthesized using a radical polymerization method, and CS-GSH NP was prepared by ionic gelation of CS-GSH with sodium tripolyphosphate (TPP). The sizes of CS-GSH NPs significantly increased with increasing CS-GSH concentration and CS-GSH/TPP ratio. The entrapment efficiency (EE) significantly increased with increasing CS-GSH concentration and significantly decreased with increasing CS-GSH/TPP ratio. The immobilized GSH could be protected against oxidation compared to free GSH. The thiol content in the nanoencapsulated GSH was more effectively maintained than those in free GSH and CS-GSH, regardless of the presence of oxidative stress-inducing agents. These results suggest that CS-GSH NP can be used to enhance the oxidative stability of GSH.

Wheat gluten was subjected to enzymatic hydrolysis with various proteases (Alcalase, Flavourzyme, Protamex) and the taste-enhancing properties and antioxidant activities of the resulting wheat gluten hydrolysates (WGHs) were characterized. The contents of the hydrophobic amino acid of the WGHs were highly correlated with the degree of hydrolysis by Flavourzyme and Protamex, except Alcalase. The taste profiles of the Alcalase-treated WGHs showed decreased bitterness while umami and overall acceptability increased. On the other hand, the WGHs produced by Flavourzyme and Protamex showed increased bitterness with increasing hydrolysis duration. However, taste profiles, such as umami, kokumi, and overall acceptability of the WGHs by Flavourzyme and Protamex were unaffected by the degree of hydrolysis. The WGH treated by Alcalase for 24 h (A24h) exhibited tasteenhancing property and its antioxidant effects were concentration-dependent. As a result, the A24h may be used as a multi-functional seasoning ingredient having potential antioxidant activity.