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

The present work describes a foodomics protocol coupling an in vitro static simulation of digestion to a combination of omics techniques, to grant an overview of the protein digestibility of a meat-based food, namely Bresaola. The proteolytic activity mediated by the digestive enzymes is evaluated through Bradford and SDS-PAGE assays, combined to NMR relaxometry and spectroscopy, to obtain information ranging from the microscopic to the molecular level, respectively. The simple proteomics tool adopted here points out that a clear increase of bioaccessible proteins occurs in the gastric phase, rapidly disappearing during the following duodenal digestion. However, SDS-PAGE and the Bradford assay cannot follow the fate of the digested proteins when the products are sized <5 kDa. Conversely, NMR spectroscopy is able to capture the overall molecular profile of small fragments and peptides, which are mainly formed during the duodenal phase, thus giving the kinetics of the whole digestion process. Time domain NMR relaxometry, finally, detects the swelling phenomenon occurring during the gastric phase, when the digestion fluid enters the meat matrix.