Impact of meat cooking and masticatory efficiency on food bolus formation and amino acid absorption in human

organised by COST Action FA 1005 INFOGESTInternational audienceObjectives: Previous studies have shown that both meat cooking conditions, and chewing efficiency, can affect meat protein digestion. The objective of the present study was to try to rank these factors according to the magnitude of their effect, and to evidence potential interactions. Methods: Ten young normo-dented volunteers were invited to participate to the experiment. Pork meat was cooked 10 min at 75°C or 45 min at 90°C, leading to different meat tenderness and cohesiveness. Volunteers were invited to ingest meat in two different situations: after normal mastication, or after deficient mastication (by wearing an occlusal appliance). Meat boluses have been collected before swallowing for assessment of their physical/rheological properties. Plasma aminoacidemia was recorded after ingestion of a meal containing the pork meat as main source of protein. Results: In normal chewing condition and with comparable masticatory durations, the kinetics of matrix disruption was much faster for high cooking meat, and boli were constituted of smaller particles than in low cooking meat. Whatever the meat sample, bolus was softened along the progress of the masticatory sequence and saliva impregnation was similar at the moment of swallowing. By contrast, impaired mastication led to longer and slower sequences, but failed in softening meat samples as well as in reducing it in small fragments. With deficient mastication, the plasma amino acids concentration increases more slowly, and reaches a lower maximal value. This effect was more pronounced for the low cooking meat. Conclusions: Overall, this study showed that a decreased chewing efficiency impairs amino acid absorption, but it also evidenced an interaction between chewing efficiency, the size of swallowed particles (linked to cooking conditions), and the amino acid absorption rate. This work highlights the important but disregarded role of the masticatory function in nutrition, and brings powerful prospects in developing foods for orally impaired people