Preparation, Physicochemical Properties, and Antioxidant Capacity of Edible Agar Films Containing Hull-Less Barley Grass Polysaccharide Extracts

Hull-less barley grass polysaccharide extracts (HBP) are prepared, and the physicochemical and antioxidant properties of agar films with different HBP contents (0, 0.5, 1, 1.5, and 2% w/w of agar mass) are investigated. Infrared spectroscopy shows that HBP interacts with the agar matrix via intermolecular hydrogen bonds. The incorporation of HBP causes rougher surface morphology with increased film thickness ( p < 0.05). The films with HBP exhibit decreased brightness with a greenish and yellowish hue. The flexibility of the films is improved gradually as HBP contents increase from 0 to 1.5% w/w ( p < 0.05), however, a slight reduction is observed with 2% w/w HBP addition ( p > 0.05). The water resistance and surface hydrophobicity of the films are enhanced by adding HBP ( p < 0.05). The antioxidant test reveals the strong antioxidant capacity of the HBP-loaded films, which is positively correlated with the HBP contents ( p < 0.05), with 2% w/w HBP leading to 59.28% DPPH radical scavenging and 69.00% ABTS radical scavenging. Results suggest that HBP is a promising functional agent for developing antioxidant biopolymer films, and the agar/HBP edible films prepared in this study have potential in food packaging fields.