Encapsulation and antioxidant activity of ascorbyl palmitate with maize starch during pasting

Ascorbyl palmitate can interact with amylose to form amylose-lipid complexes. This study determined the effects of ascorbyl palmitate (0, 15 and 50 mg/g starch) on the pasting properties of maize starch, amount of ascorbyl palmitate bound in the starch paste, release of ascorbyl palmitate after enzymatic hydrolysis and its antioxidant activity. Pasting of starch with ascorbyl palmitate at 91 °C for 120 min resulted in the formation of type II amylose-lipid complexes as shown by DSC melting enthalpies. About 93% and 66% of ascorbyl palmitate were encapsulated when 15 mg and 50 mg was respectively added to maize starch during pasting. Less than 50% of the bound ascorbyl palmitate was released during pancreatic α-amylase hydrolysis suggesting that some of the complexes were not hydrolysed to release the ligand. The antioxidant activities of the ascorbyl palmitate correlated (R = 0.937) to the amount released during enzymatic hydrolysis. It can be concluded that pasting of maize starch can be used to encapsulate ascorbyl palmitate by possibly forming amylose-lipid complexes.