Effect of Enzymatic Hydrolysis of Wheat Starch on Amylose-Lipid Complexes Stability

Abstract

In the process of enzymatic hydrolysis of wheat starch to glucose, the presence of amylose-lipid complexes (AML's) decreases swelling and dissolving capacity and the water binding capacity of starch, thus impeding the access of amylolytic enzymes to the starch granules. The aim of the work was to define the relationship between the stability of AML's and the conditions of the enzymatic hydrolysis of wheat starch such as the kind of enzymatic preparation (only amylolytic or both amylolytic and lipolytic) and time of hydrolysis. Hydrolysates were produced from wheat starch liquefied with bacterial α-amylase BAN 240L, subjected to further treatment with the enzymatic preparation Spezyme GA 300W, containing glucoamylase and lysophospholipase and, for comparison, only with a glucoamylase preparation (AMG 300L). The effect of amylolytic and lipolytic enzymes on the stability of AML's in the process of wheat starch hydrolysis was estimated. The amount of fatty acids released during hydrolysis was determined with gas-liquid chromatography (GLC) and by differential scanning calorimetry (DSC) measuring the enthalpy of decomposition of AML's. The investigations revealed a differentiated effect of the individual enzymatic preparations on the degree of degradation of AML's. Amylose-lipid complexes were more susceptible to the attack of preparation Spezyme GA 300W than to the digestion by α-amylase BAN 240 L and glucoamylase AMG 300L.