Effect of mastication degree and eating rate on in vitro dynamic gastrointestinal digestion of rice.

The combined effect of mastication degree and eating speed on food digestion is still not clearly understood at present. This study investigated the effects of degree of crushing by mouth (strong, S or weak, W) and eating speed (high, H or low, L) on the in vitro gastrointestinal digestion of cooked Indica rice. Grain size distribution and confocal microscope obtained from volunteers showed that the bolus of S had smaller particles compared to W during dynamic gastric digestion using a model of artificial gastric digestion system (AGDS). Image scanning revealed that at the end of gastric digestion, the particle area of the retained digestive products in the stomach of S (˂ 9 mm2) was smaller than that in the W (12-15 m2). Gastric retention rate indicated that the W-L group had the highest level. During gastric digestion, W exhibited a higher starch hydrolysis rate, whereas during intestinal digestion, S demonstrated a higher level. Gastric digestion had a greater influence on the total apparent viscosity of L. This study provides practical insights into the impact of food fragmentation degree and eating speed on gastrointestinal digestion and offers recommendations for promoting digestion and supporting a healthy diet.