Abstract:

The mechanical properties of lotus-seed starch gels formed under different conditions, including starch milk concentration, pH value, and additions of NaCl, sugar and Tween-80 concentration were studied. Results showed that the gel strength, elastic modulus of lotus-seed starch gels increased linearly with increasing starch milk concentration, while the gel elasticity changed little. The gel strength and elastic modulus of lotus-seed starch gels first increased and then decreased, whilethe gel elasticity exhibited a decreasing trend with increasing NaCl concentration. All the mechanical properties of lotus-seed starch gels decreased with the increasing NaCl concentration when pH value was between 4.0 and 7.2. The gel strength was also significantly increased by adding sugars, with fructose most effective, followed by glucose and sucrose. Meanwhile, the gel elasticity and elastic modulus were slightly increased. The addition of Tween-80 of less than 0.5% resulted in a sharp decrease in gel strength and elastic modulus and a slight increase in gel elasticity, while little changes were observed in all the mechanical properties when the addition of Tween-80 was more than 0.5%.

Key words: lotus-seed starch gels, affecting factors, mechanical properties