Retrogradation kinetics and glass transition temperatures of Pueraria lobata starch, and its mixtures with sugars and salt

摘要

Retrogradation kinetics of Pueraria lobata starch and T-g of maximally freeze-concentrated state (Tg) of its mixtures with sugars or salt were investigated by using XRD and DSC. The results showed that as for P. lobata starch stored at 4 degrees C, both intensity and retrogradation degree (RD) reached the utmost values. The RD of P. lobata starch stored at -22 degrees C was greater than that of P. lobata starch stored at 28 degrees C. Retrogradation rate of P. lobata starch stored at 4 degrees C was 1.6 times faster than that of P. lobata starch stored at -22 degrees C, and 3.4 times faster than that of P. lobata starch stored at 28 degrees C, as indicated XRD analysis. Besides, as indicated DSC analysis, the Tg of P. lobata starch was decreased after sugars and NaCl were added at 4 and -22 degrees C, while its RD was increased under the same conditions