Encapsulation and antioxidant activity of ascorbyl palmitate with normal and high amylose maize starch by spray drying

Abstract

Amylose-lipid complexes can be formed by interaction between amylose and lipid as ligands. This study determines the effects of ascorbyl palmitate (0, 15, 50, 100, and 200 mg/g starch) on the functional properties of maize starches (normal and high amylose maize starch), amount of ascorbyl palmitate bound, release of ascorbyl palmitate after enzymatic hydrolysis and ascorbyl palmitate antioxidant activity after spray drying. Spray drying of starches (normal maize starch and high amylose maize starch) with ascorbyl palmitate at 185 °C resulted in the formation of type I amylose-lipid complexes. Entrapment of ascorbyl palmitate in the starch matrix also occurred during spray drying, and this was observed with confocal laser scanning microscopy (CLSM) micrographs. As expected, more ascorbyl palmitate bound with high amylose maize starch than normal maize starch. Less than 40% of the bound ascorbyl palmitate to high amylose maize starch was released during pancreatic α-amylase hydrolysis suggesting that some of the complexes were indigestible and can be fermented in the large intestine. The antioxidant activities of the ascorbyl palmitate highly correlated (R = 0.97) to the amount released during enzymatic hydrolysis. It can be concluded that spray drying of maize starches can be used to encapsulate ascorbyl palmitate to form amylose-lipid complexes with a higher amount of ascorbyl palmitate bound with maize starches when spray dried compared to pasting method as previously reported.