Effects of preprocessing at low or ultralow temperatures combined with sodium alginate on retrogradation properties of normal cornstarch during chill storage

In this research, normal cornstarch (NCS) was preprocessed at low and ultralow temperatures, both with and without the addition of sodium alginate (AG), and then stored at 4 degrees C for 14 days to evaluate the retrogradation properties. The results showed that preprocessing with low (-18 degrees C) or ultralow (-80 degrees C) temperature could reduce the gel hardness, retrogradation enthalpy (Delta H-r), the ratio of intensity at a value of 1047-1022 cm(-1) (R-1047/1022), and the relative crystallinity (RC) value of NCS. These four parameters were obviously decreased when NCS was preprocessed at low or ultralow temperature and combined with AG. The results suggested that the preprocessing combined with the addition of AG could retard NCS gel retrogradation much more effectively than the preprocessing by itself. These results provided a good method for retarding retrogradation of starch gel or starchy food.