Effect of Additives on Retrogradation of Taro Starch and Stability of Taro Starch Gel

• Main Authors: Chi-Chuan Hsiao, 蕭祺娟
• Other Authors: Chiun-Chuang Wang
• Format: Others
• Language: zh-TW
• Published: 1998
• Online Access: http://ndltd.ncl.edu.tw/handle/66102193212976792700

碩士 === 靜宜大學 === 食品營養學系 === 87 === This study were to investigate the effect of sucrose, sodium chloride and soybean oil on retrogradation of taro starch and on stability of taro starch gel. Several techniques, including differential scanning calorimetry (DSC), dynamic rheometer, texture analyzer and scanning electron micrometer (SEM), were applied in this study to incestigate the change of thermal properties of taro starch and the stability of taro starch gel during storage at 4℃. According to the thermograms of DSC, gelatinization temperature(To, Tp, Tc) of taro starch increased with the increase of sodium chloride and sucrose concentrations (p<0.05), but no significant difference (p>0.05) was found in To and Tp when soybean oil was added into taro starch. No significant difference (p>0.05) was found in gelatinization enthalpy among taro starch with low concentration of sucrose (5-20%) but significantly increased (p<0.05) in high concentration of sucrose (40%) and sodium chloride (5%). In presence of sucrose solution (5-10%), retrogradation of taro starch was retarded in the initial period (0-1 day). However, a high sucrose concentration (20-40%) of taro starch appeared to increase retrogradation enthalpy. In the effect of sodium chloride on retrogradation enthalpy, it is interesting that 6% soybean oil retarded the increases of retrogradation enthalpy in the period of 7 days storage. The higher sodium chloride addition on taro starch showed higher retrogradation enthalpy. The SEM results showed that the development of microstructure of taro gel become denser in the initial 12 hours after gelling. However, taro starch gel with sucrose and sodium chloride addition retarded the development of amylose network. According to the resultsof texture profile analysis and rheological analysis, the firmness and storage modulus (G'') of taro starch gel increased rapidly at the early stage (0-2 days), then slowly increased at later stage (7-28 days). The increase of firmness of taro starch gel was contributed mainly from the formation of amylose network. A minor contribution of firmness came from the crystallization of starch during storage. The addition of sucrose and sodium chloride limited the increase of firmness and G''-value of taro starch gel during 28 days storage. The degree of retrogradation of taro starch gel was increased when sucrose or sodium chloride were added during 28 days storage.