Research On The Mechanism And Control Technology Of Starch Retrogradation

There are many methods of retarding starch retrogradation. Recent studies found that there is a good inhibitory effect on starch retrogradation with food additives. And it is easy to operate. The food additives are non-toxic, harmless and with great nutritional value. And we can added the different types of food additives to make starch have different physical functions and nutrition. This research has studied the inhibitory effect on starch retrogradation with four kinds of additives(tea polyphenols, antioxidant of bamboo leaves,polyphenols in pomegranate and citric acid). There are few studies about the effect on starch retrogradation with antioxidant of bamboo leaves and polyphenols in pomegranate added. This research has focused on the inhibitory effect on starch retrogradaton with this two kinds of additives, and make a simple comparison with the other two kinds of additives.The results are as follows:We found that tea polyphenols can significantly decrease the enthalpy and thansition temperature of starch gelatinization using differential scanning calorimetry (DSC). It can also significantly decrease the enthalpy and transition temperature of starch retrogradation.After 7 days, there are no enthalpy of starch retrogradation with tea polyphenols. The antioxidant of bamboo leaves has been used in various food systems in China. The effect on starch retrogradation with the antioxidant of bamboo leaves and polyphenols in pomegranate were similar. They can increase the transition temperature of starch gelatinization and little effect on enthalpy of starch gelatinization and retrogradation, but polyphenols in pomegranate can slightly decrease the enthalpy of starch retrogradation.Citric acid had little effect on transition temperature and enthalpy of starch gelatinization,but it significantly decreased the enthalpy of starch retrogradation. After 21 days, the enthalpy of retrograded starch with 20% citric acid was decreased to 0.8 J/g.After determined by RVA and TPA, we found that tea polyphenols can alter the pasting and viscosity properties and swelling power of rice starch. It can also decrease the hardness of retrograded gels. The antioxidant of bamboo leaves and polyphenols in pomegranate can alter the pasting properties and swelling power of rice starch,but has little effect on texture properties.Citric acid can significantly alter the pasting properties and decrease the swelling power, but had no significant effect on texture properties of retrograded gels.After determined by XRD,FTIR and Raman,we found that tea polyphenols can alter the long-range and short-range ordered structure. The antioxidant of bamboo leaves and polyphenols in pomegranate had no significant effect on the long-range ordered structure of retrograded gels, but they can decrease the short-range ordered structure.Citric acid can also decrease the short-range ordered structure, but had no obvious effect on long-range ordered structure.All in all, tea polyphenols and citric acid can change many properties of starch gelatinization and retrogradation and has a significant effect on inhibiting starch retrogradation. The antioxidant of bamboo leaves and polyphenols in pomegranate can change a few properties of starch gelatinization and retrogradation,but there is not a significant effect on inhibiting starch retrogradation.