The structure property and adsorption capacity of new enzyme-treated potato and sweet potato starches

Abstract

To explore a valuable new enzyme method that effectively changes the molecular structure and absorption property of potato and sweet potato starch granules, the common combination of α-amylase (AA) and glucoamylase (GA), namely AA → GA (common method as contrast), the combination of glycosyltransferase (GT) and GA, namely GT → GA, or the combination of sequential AA, GT and GA (AA → GT → GA) treatment was utilized. The results indicated that three types of enzyme treatments increased the pore size, pore volume, specific surface area and relative crystallinity of potato and sweet potato starches, resulting in a significant increment in adsorption capacities. Compared to GT → GA or AA → GA treatment, AA → GT → GA treatment had the most significant effect on the hydrolysis of starches since a lower amylose content, higher branched degree and more amount of short side chains of starches obtained using AA → GT treatment might increase the amount of GA active sites. So, GT → AA → GA treatment had the most significant absorption impact on oil, dye and heavy metal ions of starches. Compared to native starch, the adsorption capacity of GT/AA/GA-treated starches increased by about 7–21 folds. Thus, a novel GT → AA → GA treatment may be a most effective method to prepare porous potato and sweet potato starches as desirable green adsorbents.