Some pearl millet-based foods promote satiety or reduce glycaemic response in a crossover trial.

In a previous trial in Mali, we showed that traditional pearl millet couscous and thick porridge delayed gastric emptying (about 5 h half-emptying times) in a normal-weight population compared with non-traditional carbohydrate-based foods (pasta, potatoes, white rice; about 3 h half-emptying times), and in a gastric simulator we showed millet couscous had slower digestion than wheat couscous. In light of these findings, we tested the hypothesis in a normal-weight US population (n 14) that millet foods would reduce glycaemic response (continuous glucose monitor), improve appetitive sensations (visual analogue scale ratings), as well as reduce gastric emptying rate (13C-octanoic acid breath test). Five carbohydrate-based foods (millet couscous - commercial and self-made, millet thick porridge, wheat couscous, white rice) were fed in a crossover trial matched on available carbohydrate basis. Significantly lower overall glycaemic response was observed for all millet-based foods and wheat couscous compared with white rice (P ≤ 0·05). Millet couscous (self-made) had significantly higher glycaemic response than millet couscous (commercial) and wheat couscous (P < 0·0001), but as there were no differences in peak glucose values an extended glycaemic response was indicated for self-made couscous. Millet couscous (self-made) had significantly lower hunger ratings and higher fullness ratings (P < 0·05) than white rice, millet thick porridge and millet couscous (commercial). A normal gastric emptying rate (<3 h half-emptying times) was observed for all foods, with no significant differences among them. In conclusion, some traditionally prepared pearl millet foods show the potential to reduce glycaemic response and promote satiety.

Pearl millet (Pennisetum glaucum) couscous breaks down faster than wheat couscous in the Human Gastric Simulator, though has slower starch hydrolysis.

Consumption of traditional West African pearl millet (Pennisetum glaucum) couscous delayed gastric emptying in our recent human study compared to other starch-based foods (white rice, boiled potatoes, pasta). The objective of this study was to determine whether physical properties of pearl millet couscous affect particle breakdown and starch hydrolysis during simulated gastric digestion to understand the basis of the slow gastric emptying. Starch fine structure and viscosity were analyzed for initial millet and wheat couscous samples by high performance size-exclusion chromatography and the Rapid Visco Analyzer, respectively. Couscous samples were subjected to simulated gastric digestion using the Human Gastric Simulator (HGS), a dynamic model of human gastric digestion. Digesta was collected from the HGS at 30 min intervals over 180 min. Particle size and percent starch hydrolysis of couscous in the digesta were evaluated at each time point. The number of particles per gram of dry mass substantially increased over digestion time for millet couscous (p < 0.05), while changed little for the wheat couscous samples. Millet couscous showed lower starch hydrolysis per unit surface area of particles than wheat couscous (p < 0.05). Slower starch hydrolysis was associated with smaller (p < 0.05) amylose chain length for millet (839-963 DP) than for wheat (1225-1563 DP), which may enable enable a denser packing of millet starch molecules that impedes hydrolysis. We hypothesize that the slow gastric emptying rate of millet couscous observed in humans may be explained by its slow starch hydrolysis property that could activate the ileal brake system, independent of high particle breakdown rate in the stomach.