Cycloamylose production from amylomaize by isoamylase and Thermus aquaticus 4-α-glucanotransferase

Amylomaize (AMM) was utilized as the substrate for cycloamylose (CA) production in this study. After debranching,AMM was incubated with 10 U/g of Thermus aquaticus 4-alpha-glucanotransferase (TA 4 alpha GTase) for various reaction times in water or in DMSO reaction system. The maximum conversion yield of CA was greatly improved from 24.55% to 45.58% and from 27.40% to 47.25% after debranching in the water and DMSO reaction systems, respectively. Compared with the method that produced CA from commercial potato amylose, this method produced CA from a natural amylopectin containing starch with enhanced conversion yield after debranching. Meanwhile, we found that the minimum degree of polymerization (DP) of CA from TA 4aGTase treatment was 5, regardless of the reaction conditions. These results were different from those reported in the literature that stated the minimum DP of CA produced with a TA 4aGTase treatment was 22 regardless of the reaction conditions. (C) 2013 Elsevier Ltd. All rights reserved.