Kernel structure in breads reduces in vitro starch digestion rate and estimated glycaemic potency only at high grain inclusion rates

Publication date: Available online 25 April 2019Source: Food StructureAuthor(s): Akila SRV, Suman Mishra, Allan Hardacre, Lara Matia-Merino, Kelvin Goh, Frederick Warren, John MonroAbstractAlthough whole grain or wholemeal breads may be healthier than white breads because of their content of dietary fibre, vitamins and minerals, the relative glycaemic potency of New Zealand commercial breads is unknown. The contribution of grain structure to the rate and proportion of starch digested during human foregut digestion was estimated using in vitro digestion of breads differing in grain particle size and content. The bread samples were digested either as intact cubes or following homogenization to eliminate coarse (> 1 mm) grain structures. The relative glycaemic potency of the intact breads was estimated from glycaemic glucose equivalents (GGE) released during 120 minutes of digestion, and ranged from 34 GGE /100 g for white and most wholemeal breads to about 18 GGE /100 g for a rye bread containing 65% semi-intact kernels. Differences in GGE release between homogenized samples of the breads were due mainly to the wet weight proportion of digestible carbohydrate in the bread. In general, up to 35% of kibbled grain particles (>1 mm), as seen in most breads, had little effect on the rate of starch digestion whereas breads with> 65% of>1 mm particles (rye bread) significantly reduced the rate of starch digestion. It was concluded that the proportion of intact grains was i...
Source: Food Structure - Category: Food Science Source Type: research