Antioxidant peptides and biodegradable films derived from barley proteins

Abstract

Barley protein derived antioxidant peptides and biodegradable /edible films have been successfully prepared. Alcalase hydrolyzed barley glutelin demonstrated significantly higher antioxidant capacity than those treated by flavourzyme in radical scavenging capacity (O2•¯/OH˙), Fe2+-chelating effect and reducing power assays. The alcalase hydrolysates (AH) was separated using ultra-filtration and reversed-phase chromatography, and assessment of the fractions indicated that the molecular size, hydrophobicity and amino acid composition of AH all contributed to their activity. Final peptides sequences were identified using LC-MS/MS. Hydrolyzed barley glutelin is a potential source of antioxidant peptides for food and nutraceutical applications. The other barley protein application—biofilms is also included in the research work. Barley protein films were prepared by thermo-pressing using glycerol as a plasticizer. The combined effects of heating temperature and the amount of plasticizer interacted to determine protein conformation subsequently the properties of the film matrix. The film barrier and mechanical properties were investigated; moreover, the changing of protein structures during forming process also been characterized. In vitro degradation experiments demonstrated that barley films were resistant in gastric conditions, but can be completely degraded by intestinal enzymes. The prepared barley films have potential for the development as delivery systems for gastric-sensitive bioactive compounds to the intestine for release