NMR comparison of in vitro digestion of Parmigiano Reggiano cheese aged 15 and 30 months

Abstract

The content of essential amino acids is an important aspect for determining the nutritional value of food proteins, but their digestibility is also a key property, deeply affected by food processing. The production of Parmigiano Reggiano cheese is closely related to the nutritional quality of the final product; in particular the high digestibility of its proteins is claimed to be proportional to cheese aging. Two different kinds of Parmigiano Reggiano, young (aged 15 months) and old (aged 30 months), were separately digested using an in vitro system that simulates digestive processes in the mouth, stomach and small intestine. Samples were collected at different stages of digestion and the process of protein hydrolysis was explored and compared by low-field (LF) and high-resolution (HR) NMR, together with other biochemical methods. HR-NMR allowed to simultaneously observe the quantity of free amino acids, peptides and proteins, also giving for these latter qualitative information about their dimension. LF-NMR, instead, gave the possibility to observe digestion with no treatments whatsoever, thus representing a technique suitable for on-line measurements. The results pointed out that cheeses with different aging times, although starting from distinct initial compositions, conclude digestion in a similar way, in terms of free amino acids and small organic compounds, but evolve with different kinetics of hydrolysis and peptide formation, discriminating the young from the old cheese.

Changes in the Amino Acid Composition of Bogue (Boops boops) Fish during Storage at Different Temperatures by 1H-NMR Spectroscopy

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The foodomics approach for the evaluation of protein bioaccessibility in processed meat upon in vitro digestion

“…All samples were prepared following the procedure described by Bordoni et al with some slight modifications: (i) a buffer solution (120 mM NaCl, 5 mM KCl, 6 mM CaCl 2 ; pH 6.9) was added in proper volumes (2, 4, and 4 mL/g dry matter (dm)) during oral, gastric, and duodenal digestion, respectively; (ii) the absolute volumes of the digestive juices were scaled to the content of food used, samples collected, and quantity of acid or base added; (iii) mastication and oral digestion were simulated grounding 50 g of Bresaola (20 g of dm) with mortar and pestle; (iv) duodenal digestion lasted 300 min.…”

“…All preprocessing steps were performed using Matlab® version R2008b (The Mathworks, Natick, MA, USA). Signals assignment was carried out on the basis of literature and by using Amix software (version 2.1.3, Bruker BioSpin).…”

Dairy products and inflammation: A review of the clinical evidence

“…Cell supplementation in in vitro studies, as well as intervention studies administering bioactives as pure compounds assume that there are no confounding effects related to the food matrix. The food matrix, as well as food processing (Bordoni et al, 2011) can, indeed modify the digestibility and bioavailability of bioactive compounds, thus introducing a fundamental bias when translating in vitro data to humans. The ideal in vitro study should thus digest food in a static or dynamic model of digestion, have the digested nutrients transported through an intestinal cellular layer mimicking the gastrointestinal barrier, ideally with a model integrating the gut microbiota, and finally measure the ability of the absorbed nutrients to modulate inflammation.…”