Retrogradation of Waxy Rice Starch Gel in the Vicinity of the Glass Transition Temperature

• Main Authors: Sanguansri Charoenrein, Sunsanee Udomrati
• Format: Article
• Language: English
• Published: Hindawi Limited 2013-01-01
• Series: International Journal of Food Science
• Online Access: http://dx.doi.org/10.1155/2013/549192

The retrogradation rate of waxy rice starch gel was investigated during storage at temperatures in the vicinity of the glass transition temperature of a maximally concentrated system (), as it was hypothesized that such temperatures might cause different effects on retrogradation. The value of fully gelatinized waxy rice starch gel with 50% water content and the enthalpy of melting retrograded amylopectin in the gels were investigated using differential scanning calorimetry. Starch gels were frozen to −30°C and stored at 4, 0, −3, −5, and −8°C for 5 days. The results indicated that the value of gelatinized starch gel annealed at −7°C for 15 min was −3.5°C. Waxy rice starch gels retrograded significantly when stored at 4°C with a decrease in the enthalpy of melting retrograded starch in samples stored for 5 days at −3, −5, and −8°C, respectively, perhaps due to the more rigid glass matrix and less molecular mobility facilitating starch chain recrystallization at temperatures below . This suggests that retardation of retrogradation of waxy rice starch gel can be achieved at temperature below .