FOOD. Science. Technology. Quality

Food. SCIENCE. Technology. Quality

Food. Science. TECHNOLOGY. Quality

Food. Science. Technology. QUALITY




The stability of lipid-amylose complexes upon enzymatic hydrolysis of wheat starches of different chemical composition


Effect of chemical composition of wheat starches applied for glucose production on the susceptibility of lipid-amylose complexes to enzymatic digestion was studied. Influence of various types of enzymatic preparations (Termamyl S a-amylase, AMG E glucoamylase, G-zyme lysophospholipase) and temperature of hydrolysis were tested. Enzymatic starch degradation was carried out in the differential MICRO DSC III scanning calorimeter (Setaram, France) within the temperature range of 20-120°C and at the scanning rate of 1°C per minute. The scanning profile was as follows: 20-105°C, 105-105°C (5 min), 105-95°C, 95-95°C (60 min), 95-60°C, 60-60°C (48 hrs), 60-40°C , 40-120°C (I heating), 120-40°C (I cooling). The enthalpy of decomposition of lipid-amylose complexes and the filtration rate of resulting glucose syrups were taken as the measure of efficiency of wheat starches liquefaction with the a-amylase and their further hydrolysis to glucose by means of glucoamylase and lysophospholipase. Chemical composition of enzymatically digested wheat starches had an impact on the degree of the lipid-amylose complexes decomposition, and physicochemical properties of starch hydrolysates. Though one of the wheat starch preparations contained more lipids, the filtration rate of its hydrolysates exceeded that of hydrolysates produced from the starch displaying lower lipid content. It probably resulted from the higher susceptibility of the lipid-amylose complexes present in this starch, to the enzymatic degradation. DSC data suggested the possibility of dependence of pathways of the complexes decomposition on polymorphs of those complexes.