NMR omics approach to assess the in vitro digestion of Parmiggiano Reggiano cheese

Digestibility, the rate and extent of nutrient release from food during normal gut transit, is one of the most important properties influencing nutrient bioaccessibility. The digestibility of two different kinds of Parmiggiano Reggiano cheese, aged 15 and 30 months, has been investigated using an in vitro digestion system. To determine the entity of protein hydrolysis, low-field (LF) and high-resolution (HR)-NMR, together with other biochemical methods, were used. HR-NMR allows to simultaneously evaluate the quantity of small molecules, such as free amino acids and organic acids, as well as the presence of peptides and soluble protein fragments in the supernatant of samples collected at the different stages of digestion. The results point out that cheese with different ageing time, althought starting from different initial compositions in terms of free amino acids and small organic compounds, react to digestion in a similar overall way.