Figure 1. Particle size and starch digestion kinetics.
The effect of dry-milled particle size on starch digestibility in hydrothermally-cooked chickpea (a) and durum wheat (b) was investigated in chickpea cotyledon and durum wheat endosperm tissue particles and in starch extracted from these tissues. All samples were dry-milled and sieved to obtain distinct size fractions, then hydrothermally-processed at 100°C for 1 h 25 min before incubation with pancreatic α-amylase (~0.17 U per mg starch). Starch amylolysis products were quantified by Prussian blue assay and expressed as maltose-equivalents. The concentration of reducing sugars before the addition of pancreatic amylase was negligible. The legend indicates median particle size and different superscript letters indicate a significant difference in starch digestibility between particle size fractions within chickpea or durum wheat (p < 0.05, mixed-effects model ANOVA with Tukey’s post-hoc test). Values are mean of triplicates; error bars are SEM. Curves were obtained by least squares regression to two-phase association equations and 95% confidence bands show the likely location of the true curve. R 2 >0.99 for all curves.