Meeting Abstract

17
Molecular characteristics of amylose and amylopectin in buckwheat starches. M.S. IZYDORCZYK (1), S. You (2), and C. Campbell (3). (1) Grain Research Laboratory, CGC, Winnipeg, MB, Canada; (2) Department of Food Science, University of Manitoba, Winnipeg, MB, Canada; (3) Kade Research Ltd. Morden, MB, Canada.

Buckwheat is a broad-leafed herbaceous annual which produces triangular seeds resembling in composition the cereal kernels. Buckwheat has gained an excellent reputation for its nutritious qualities; however, relatively little work has been done on the physicochemical characteristics of buckwheat starches. The objective of this investigation was to enhance our understanding of the molecular characteristics of buckwheat starch and its components and to elucidate the relationships between the structure and functionality of buckwheat starch. Starch isolated from cross- and self-pollinating buckwheat lines was fractionated into amylose and amylopectin by butanol and concanavalin A precipitation. The amylose content in buckwheat starches varied from 21–27%. Gelatinization temperature of buckwheat starches was relatively high compared with other starches, but the melting enthalpy of amylose-lipid complexes was unusually low. Buckwheat starches formed stiffer and harder gels than corn, wheat or rice starches as indicated by significantly higher values of the elastic modulus of both fresh and aged gels. The molecular structure of intact and debranched amylose and amylopectin was studied using HPSEC-MALS-RI and HPAEC-PAD and the results partially explained the unusual properties of buckwheat starches.