Structures and Properties of Sago Starches with Low and High Viscosities on Amylography

Abstract

ABSTRACT Both amyloses and amylopectins from sago starches with low (280 BU, low‐v) and high (735 BU, high‐v) viscosities on amylography differed in molecular structures. The low‐v amylopectin (average chain length, c.I., 22) was a smaller molecule with a slightly higher amount of long chains than the high‐v amylopectin (c.I., 22). The number‐and weight‐average degrees of polymerization of the low‐v amylose were 2490 and 5090, respectively, which were half those of the high‐v amylose. The low‐v amylose had a lower molar fraction of branched molecules with a shorter inner chain length than the high‐v amylose, but both branched molecules had a similar number (17–19) of chains on the average. Both starch granules had the same crystalline type (C a ) and amylose content (24%).