Abstract
The hypothesis that coarse grain particles in breads reduce glycaemic response only if the particles remain intact during ingestion was tested. Three breads were formulated: (1) White bread (WB - reference), (2) 75% of kibbled purple wheat in 25% white bread matrix (PB), (3) a 1:1 mixture of 37.5% kibbled soy beans and 37.5% of kibble purple wheat in 25% white bread matrix (SPB). Each bread was ingested in three forms: unchewed (U), as customarily consumed (C), and homogenized (H). Twelve participants ingested 40 g available carbohydrate portions of each bread in each form, with post prandial blood glucose measured over 120 min. Glycaemic responses to WB were the same regardless of its form when ingested. Unchewed PB had significantly less glycaemic effect than WB, whereas the C and H forms were similar to WB. Based on a glycaemic index (GI) of 70 for WB the GI values for the C, U and H breads respectively were WB: 70.0, 70, 70, PB: 75, 42, 61, SPB: 57, 48, 55 (%) (Least significant difference = 17.43, p <0.05, bold numbers significantly different from WB). The similar glycaemic response to the H and C forms of the breads, and their difference from the U form, showed that the glycaemia-moderating effect of grain structure on starch digestion was lost during customary ingestion of bread. We conclude that kibbled grain structure may not effectively retard starch digestion in breads as normally consumed because it is largely eliminated by ingestive processes including chewing.
Application of physical and numerical simulations for interpretation of peripheral coarse grain structure during hot extrusion of AA7020 aluminum alloy
