Characters of rice starch gel modified by gellan, carrageenan, and glucomannan: A texture profile analysis study

Mixed gel was prepared with rice starch (indica, japonica, or sticky rice starch), polysaccharides (gellan, carrageenan, or konjac glucomannan), CaCl2, and deionized water. Rice starch, deionized water, and CaCl2 were kept constant; a mixture design was used to study the effects of varieties of rice starch, polysaccharides and its concentration on the quality of the mixed gel by texture profile analysis (TPA) method. The texture profile of the rice starch-polysaccharides mixed gel was dependent not only on the variety of rice and polysaccharides, but also on the concentration of the polysaccharide. The addition of the non-suitable polysaccharide or non-proper concentration would lead to deterioration of the gel. Only the suitable polysaccharide at a proper concentration would endow the gel with the excellent quality. Low concentration (< 0.2% (w/w)) of carrageenan and high concentration of gellan (> 0.3% (w/w)) could increase the hardness and adhesiveness significantly; the indica rice starch-polysaccharides always owned the largest hardness, adhesiveness, and chewiness. Considering the economic factor, adding 0.2% (w/w) carrageen to the indica, rice starch was found to be valuable for improving the texture of rice gel food, when a higher adhesiveness/hardness ratio was needed, 0.3% (w/w) gellan could be added to indica rice starch. The konjac glucomannan could not improve the adhesiveness, chewiness, and hardness significantly for any kinds of rice starches. The three varieties of rice starch, polysaccharides and their concentration had no significant effect on the springiness of the mixed gel. (C) 2007 Published by Elsevier Ltd.