In vitro digestion of Bresaola proteins and release of potential bioactive peptides

Bresaola is traditionally produced by curing and air-drying entire anatomic cuts of lean bovine hindquarters. Because of its low-fat and high-protein content, Bresaola is increasingly appreciated for the nutritional properties and has become one of the best known and exported Italian meat products. Both sarcoplasmic and myofibrillar protein fractions of Bresaola are extensively hydrolyzed by endogenous proteases, since the early post mortem, releasing a large variety of peptides many of which can exert several biological activities in human body. When ingested, Bresaola proteins and (poly)peptides are further degraded by gastrointestinal (GI) proteases. With the aim to identify bovine muscle-derived proteins and peptides surviving digestion, two Bresaola samples (one with and one without the Protected Geographical Indication label) were subjected to a static in vitro model of digestion that included the sequential oral, gastric and duodenal phases. The “digestomes” were characterized by mass spectrometry-based proteomic and peptidomic strategies. Aside from slight differences, probably related to the different nature of the raw material and to different technological processes, the great part of the peptides released at the end of digestion was common to the two samples. Sarcoplasmic proteins were promptly degraded, whereas myofibrillar chains require a previous proteolytic release and are not completely hydrolyzed by gastro-duodenal proteases even after prolonged hydrolysis. More than 170 peptides liberated from the major structural (actin, myosin) and sarcoplasmic muscle proteins were identified. Several among these peptides are or are precursor of potentially antihypertensive or antioxidant sequences.