2014 Volume 20 Issue 3 Pages 607-611
Small and large deformation rheological tests for mixed gels of gelatin, konjac glucomannan (KGM) and locust bean gum (LBG) were performed. For a total ingredient content of 1.1%, the hydrocolloid mixtures behaved as entangled polymer solutions. Higher relative weight fraction of KGM at this total hydrocolloid content resulted in G'-G" crossover at a lower frequency. Addition of KGM and LBG to 4% gelatin resulted in an increase in storage and loss moduli. Presence of LBG led to a stronger increase of the elastic modulus and a stronger decrease of the fracture force in puncture. The puncture peak force of binary gelatin/KGM and gelatin/LBG mixed gels was similar to that of ternary gelatin/LBG/KGM mixed gels at the same ratio of polysaccharide to protein, and was lower than the puncture peak force of pure gelatin gels at the same total hydrocolloid concentration. Addition of LBG and/or KGM to gelatin decreased the sensory hardness of the gels. Difficulty in chewing and swallowing was highest for hard pure gelatin gels and soft, but very sticky mixed gels with a substantial addition of LBG. The gel judged to be the easiest for mastication and swallowing was a gel obtained from 5% gelatin, 1% KGM and 0.5% LBG.
