Impact of flour particle size and origin on the bread structure and the postprandial glycemic, insulinemic and appetite responses in healthy adults

Abstract

Consumption of bakery products prepared with finely milled flour is associated with elevated postprandial glycemia, increased hunger, and reduced satiety. The milling process disrupts the plant cell walls of cereal grains and legumes, enhancing the accessibility of encapsulated starch to digestive enzymes. This study investigates the effects of flour origin (wheat and chickpea) and particle size in three wholemeal breads on physicochemical properties, postprandial glucose, insulin, glucagon-like peptide-1 (GLP-1) responses, and subjective appetite sensations in healthy individuals. In the test breads, 30% of refined wheat flour was substituted with cracked whole wheat (1.8–2.0 mm) to make whole grain bread (WGB), finely milled chickpea flour (CFM), or larger particle-chickpea flour (1.4–1.8 mm, CLP). Wheat bread (WB) served as the control. In all three test breads, 28% of refined wheat flour was substituted with wholemeal wheat flour. Compared to WB and WGB, CFM and CLP had a harder and more chewy texture, and a lower specific volume (p < 0.05). WGB, CFM, and CLP had reduced porosity and lightness (L*) compared to WB (p < 0.05). In a randomized crossover study (RCT), fifteen normoglycemic individuals participated in four separate sessions. The glucose incremental area under the curve (iAUC) was lower for CLP compared to those of both WB and CFM (p < 0.05). While insulin responses were similar across all breads, GLP-1 iAUC was significantly higher following CLP consumption compared to WB (p < 0.05), whereas no significant differences were observed among the other test breads in the postprandial GLP-1 response. CLP consumption resulted in a lower iAUC for hunger and desire to eat, and a higher iAUC for fullness, as evaluated using Visual Analogue Scales (VAS), compared to WB (p < 0.05). Incorporation of large-particle chickpea flour into bread can effectively reduce postprandial glycemia, increase GLP-1 secretion and contribute to the enhancement of satiety. Such formulations may offer promising dietary strategies for glycemic control and appetite regulation.