Complex formation, physicochemical properties of different concentration of palmitic acid yam (Dioscorea pposita Thunb.) starch preparation mixtures

The starch-palmitic acid complex was prepared by the reaction of different concentrations (0.1%-5.0%) of palmitic acid and yam starch. In order to find out the effects of concentration of palmitic acid on the properties of the complex, the physicochemical properties, morphological properties, freeze-thaw stability, antioxidant activity and bile acid binding capacity of complexes were studied. It was found that with the increase of palmitic acid concentration, the complex index of starch-fatty acid increased first and then decreased. When the concentration of palmitic acid was 2%, the complex index was the highest (26.39%). The crystal type has gradually changed from Ca type into mixtures of V-type pattern and B-type pattern when introduced palmitic acid. The water binding capacity, solubility, swelling power and paste clarity were decreased, while the content of resistant starch and freeze-thaw stability were obviously increased. Compared with the native starch, the antioxidant activity and bile acid binding capacity of the complex were significantly increased. All the result showed that the concentration of palmitic acid has a great influence on the physicochemical properties of modified starch and the starch-palmitic acid complexes have higher ability of controlling cholesterol and improving the anti-oxidant activity than native yam.