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In Vitro Digestion Rate and Estimated Glycemic Index of Oat Flours from Typical and High β-Glucan Oat Lines
Journal of Agricultural and Food Chemistry
  • Hyun Jung Kim, Iowa State University
  • Pamela J. White, Iowa State University
Document Type
Article
Disciplines
Publication Date
5-23-2013
DOI
10.1021/jf300429u
Abstract

The in vitro starch digestion rate and estimated glycemic index (GI) of oat flours and oat starches from typical and high β-glucan oat lines were evaluated along with the impact of heating on starch digestion. Flour from oat lines ('Jim', 'Paul', IA95, and N979 containing 4.0, 5.3, 7.4, and 7.7% β-glucan, respectively) was digested by pepsin and porcine pancreatin. To determine the impact of heating on starch digestion, oat slurries were prepared by mixing oat flour and water (1:8 ratio) and heating for 10 min prior to digestion. Viscosity, as measured on a Rapid Visco Analyzer, increased with increases in concentration and molecular weight of β-glucan. The in vitro starch digestion of oat flours and a control, white bread made from wheat flour, increased as the digestion time increased. Starch digestion of oat flour was slower than that of the control (p < 0.05). Heat treatment of oat-flour slurries increased the starch digestion from a range of 31–39% to a range of 52–64% measured after 180 min of in vitro digestion. There were no differences in starch digestibility among oat starches extracted from the different oat lines. The GI, estimated by starch hydrolysis of oat flours, ranged from 61 to 67, which increased to a range of 77–86 after heating. Oat-flour slurries prepared from IA95 and N979 lines with high β-glucan concentrations had lower GI values than did slurries made from Jim and Paul lines. Starch digestion was negatively correlated with β-glucan concentrations in heated oat-flour slurries (R2 = 0.92). These results illustrate that the oat soluble fiber, β-glucan, slowed the rate of starch digestion. This finding will help to develop new food products with low GI by using oat β-glucan.

Comments

Posted with permission from Journal of Agricultural and Food Chemistry 60 (2012): 5237, doi:10.1021/jf300429u. Copyright 2012 American Chemical Society.

Copyright Owner
American Chemical Society
Language
en
Date Available
2013-10-30
File Format
application/pdf
Citation Information
Hyun Jung Kim and Pamela J. White. "In Vitro Digestion Rate and Estimated Glycemic Index of Oat Flours from Typical and High β-Glucan Oat Lines" Journal of Agricultural and Food Chemistry Vol. 60 Iss. 20 (2013) p. 5237 - 5242
Available at: http://works.bepress.com/pamela_white/1/