Application of curdlan and waxy corn starch on the development of soft tofu with freezing resistance

• Main Authors: Chen, Jian-Fu, 陳建富
• Other Authors: V. An-Erl King
• Format: Others
• Language: zh-TW
• Published: 1998
• Online Access: http://ndltd.ncl.edu.tw/handle/46805490032170635091

碩士 === 國立中興大學 === 食品科學系 === 86 === Soft tofu, because of its high moisture content, is liable to deterio-ration and possesses no freezing resistance. Since its texture becomes sponge-like after freezing, this makes it inconvenient in production, transportation, consumption, and storage. Curdlan could effectively en-hance the freezing resistance, and waxy corn starch, on the meanwhile, could improve the water holding capacity. A smooth and soft texture might be remained after frozen storage, and freeze-dried soft tofu with good qualities could also be obtained by using curdlan and waxy corn starch. Freezing resistance and water holding capacity was affected sig-nificantly by concentrations of both curdlan and waxy corn starch applied. Therefore, effects of curdlan (0~2 %), waxy corn starch (0~4 %), and coagulant (0.2~0.4 %) concentrations on soft tofu by using response surface methodology (RSM) was examined in this study in order to obtain a soft tofu with freezing resistance. In the respect of freeze-drying, freezing temperature (-5~-45℃) would be combined with those three above-mentioned conditions to develop a product with good qualities and to expand the applicability of soft tofu in modern foods. The results indicated that soft tofu made from curdlan 0.3 %, glucono-d-lactone 0.3 %, and waxy corn starch 3.6 % had good physical properties (such as gel strength, water holding capacity, and texture profile analysis) and sensory evaluation, after the experiements of without freezing, freeze- thawing, and frozen storage. As to freeze-drying, the optimum processing condi-tion was found to be curdlan 2 %, glucono-d- lactone 0.3 %, waxy corn starch 4 %, and freezing temperature -45℃, and the products were more acceptable to the taste panel. Keywords : soft tofu, curdlan, waxy corn starch, texture profile analysis (TPA), response surface methodology (RSM), freeze-drying, freezing, frozen storage