A mathematical model predicts the gastric digestion of meat proteins and quantifies the impacts of physiological factors on digestibility.

The elderly population will increase sharply in the future, along with an emerging range of specific nutritional needs that include adapted food. We aimed to develop a workflow to study the fate of a food, objectify the bioavailability of nutrients in the case of the digestive physiology of the elderly, and model the fate of proteins in the stomach. Pork frankfurters were subjected to in vitro normal and deficient mastication and gastric digestion, mimicking adult and elderly food oral and digestive processing. Swallowable food boluses were characterized for granulometric and rheological properties. Biochemical analyses were conducted on the bolus and on the digesta. Macronutrients, label-free peptide quantification and identification were performed, and modeling was applied to protein digestion kinetics. After deficient mastication, the food bolus was harder with more large particles, lower free iron release and more protein oxidation. The amount of peptides released in the stomach progressively increased, but to a lower extent for the elderly digestive condition and irrespective of masticatory efficiency. 592 peptides were identified from 67 proteins. Different trajectories were observed for adult and elderly digestive conditions, and two groups of meat proteins were identified based on the rate of hydrolysis. Designing suitable foods requires in vitro tools to evaluate the possible benefit for the elderly. Besides the well-known notion of Food Oral Processing (FOP), our work broadens the concept by extending oral activity to digestion when working in a nutritional context. This new concept is named Food Oral and Digestive Processing, FODP.

This study investigated the effect of combining tumbling and sous-vide cooking processes on the tenderness, cooking losses and colour of bovine Semitendinosus (ST) muscles sampled from Charolais-breed cows. Half of the ST muscles were tumbled for 12 h with a compression rate of 40%. All muscle samples, whether tumbled or not, were then sous-vide cooked at 50 °C, 60 °C or 80 °C for 1 h or 4 h. After cooking, we measured the shear forces (SF), cooking losses, total water content and the main colour characteristics of pre-tumbled and non-tumbled meat pieces. Pre-tumbled meat pieces had 20% lower SF values than non-tumbled meat pieces, regardless of the cooking conditions applied. All meat pieces cooked at 50 °C had significantly higher (p < 0.05) SF values and lower (p < 0.05) cooking losses than meat pieces cooked at 60 °C or 80 °C. Pre-tumbled meat pieces showed significantly lower cooking losses (p < 0.001) than non-tumbled meat pieces. Applying the tumbling process before cooking led to an increase in meat colour lightness values (p < 0.001), and the colour parameters were significantly affected (p < 0.05) by temperature, cooking time, and temperature × cooking time interaction. Combining a 12-h tumbling process with cooking at 60 °C appears to provide the best compromise between increasing meat tenderness and limiting cooking losses.