Physical, rheological and antioxidant properties of gelatin gel as affected by the incorporation of β-glucan

Abstract

Rheological properties and antioxidative activities of fish gelatin (FG) gel incorporated with β-glucan (BG) at different levels (0, 5, 10, 15 and 20% substitutions) were investigated. Gel strength of FG-BG mixed gel decreased as BG content increased (P < .05). Rheological measurements revealed that incorporation of BG slightly influenced elastic modulus (G′) and loss modulus (G″) of FG as observed from time and temperature sweep. Gelling temperature of FG-BG mixed gel slightly decreased when BG was higher than 5% substitution (P < .05). Melting temperatures of all mixed gels were higher than that of FG (P < .05), but no differences in melting temperature were obtained among FG-BG mixed gel, regardless of levels (P > .05). FG-BG mixed gels exhibited the lower L∗, a∗ and b∗-values, compared with FG gel. Based on gel microstructure, FG gel had a fine network with small voids. Conversely, looser gel network with larger voids were found in mixed FG-BG gels. When FG-BG mixed gels were subjected to a gastrointestinal tract model system (GIMs), the addition of BG increased antioxidative activity of resulting mixed gels in a dose dependent manner as indicated by the increases in ABTS radical scavenging activity, FRAP (ferric reducing antioxidant power) and reducing power. Therefore, the incorporation of β-glucan into fish gelatin gel slightly affected the rheological and textural properties, but yielded the gel product with enhanced health benefits.