Intact, Kibbled, and Cut Wheat Grains: Physico‐Chemical, Microstructural Characteristics and Gastro‐Small Intestinal Digestion In vitro

Abstract

AbstractIt is important to investigate the changes in the microstructure of wheat grains during processing to understand their influence on physico‐chemical properties and starch hydrolysis (SH) kinetics during gastro‐small intestinal digestion in vitro. Three differently processed formats (kibbled, cut grains, and flour) along with intact bread wheat grains are compared. Size reduction from raw intact grains to kibbled grains and flour resulted in an increase in overall SH (%) during simulated digestion and followed the order of flour>kibbled>cut>intact grains. The cooked versions of grain formats followed the similar order with a significant increase in SH observed for cooked kibbled grains and flour to 58.38±0.086% and 92.85±1.21%, respectively, whereas cooked cut grains show a lower hydrolysis of 21.56±0.39%. The expected glycaemic indices (eGI) of both cooked cut and intact grains are categorized as low glycaemic with values of 54.08±0.03 and 41.98±0.04, respectively. Scanning electron micrographs revealed the disappearance of starch granules from the grains' exposed surface areas during sequential digestion phases. The size reduction processes results in the disruption of bran and intact endosperm cells, making grain structure susceptible to digestion after cooking. The current results show the potential of differently processed grain formats to develop low glycemic wheat products.