Influence of food oral processing, bolus characteristics, and digestive conditions on the protein digestibility of turkey cold meat and fresh cheese.

During mastication, foods are progressively transformed to achieve swallowable boluses and their characteristics are crucial for the subsequent digestion events. The main goal of this work was to evaluate the impact of food oral processing, bolus properties, and different digestive conditions on the protein digestibility of turkey cold meat and fresh cheese. In vivo normal and deficient masticated food boluses were prepared by a young volunteer. Besides, three digestion models were used to simulate the different physiological conditions frequently observed in adults and the elderly, presenting good or poor oral health: i) Normal Masticated-Normal Digested model; ii) Deficient Masticated-Normal Digested model; and iii) Deficient Masticated-Elderly Digested model. The oral processing behaviour (number of chews, chewing time, chewing rate, and saliva uptake), bolus particle size, textural and viscoelastic properties of boluses, and protein digestibility of samples were determined. Results showed that deficient masticated boluses exhibited lower amounts of saliva uptake and greater particle sizes, hardness, stiffness, and rigidity, notably in deficient masticated turkey cold meat boluses. Moreover, the worst digestive scenario (Deficient Masticated-Elderly Digested model) negatively impacted on the proteolysis extend of samples, especially for total soluble proteins and soluble peptides contents. The current study demonstrates that the oral processing behaviour and degree of food fragmentation impacted on the granulometric, texture, and viscoelastic properties of both food boluses, whereas the worst digestive scenario commonly observed in the elderly reduced the proteolysis extend of the products evaluated.