The structural characteristics of amylosucrase-treated waxy corn starch and relationship between its in vitro digestibility
2017
Park, C.S., Kyung Hee University, Yongin, Republic of Korea | Park, I., Kyung Hee University, Yongin, Republic of Korea
The glucotransferase amylosucrase (AS) influences the structural properties of starch, but its precise effects are unclear. The structural characteristics and in vitro digestibility of waxy corn starch modified by AS from Neisseria polysaccharea were examined. AS-treated starch exhibited a higher slowly digestible starch (SDS) fraction, the weak B-type polymorph, lower relative crystallinity, and lower double helix content than those of native starches based on X-ray diffractometry, solid-state 13C CP/MAS NMR, and FT-IR. AS-treated starches exhibited increased proportions of degree of polymerization (DP) 25 - 36 and DP greater thean or equal to 37 chains. Higher SDS and resistant (RS) fractions, higher proportions of DP 25 - 36 and DP greater thean or equal to 37 chains, more double helices, higher relative crystallinity, and less difference between double helix and relative crystallinity were observed for starch treated with 460 U than with 230 U of AS. AS re-built the double-helical and rearranged crystalline structure of gelatinized starch and consequently influenced the SDS and RS fractions.
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