Swine plasma peptides obtained using pepsin: In silico and in vitro properties and biological activities

Abstract

The objective of this study was to perform prediction in silico of bioactivity, toxicity, allergenicity, and cell penetration potentials and evaluate, in vitro, the biological activities of swine plasma hydrolysates obtained using pepsin. The size of the peptides was determined through SDS-PAGE electrophoresis and the presence of functional groups through Fourier transform infrared spectroscopy (FTIR). Proteins and peptides were separated by online nanoscale capillary liquid chromatography and analyzed by tandem mass spectrometry with nanoelectrospray (nanoESI MS/MS). In silico potentials were obtained using digital platforms. Antioxidant activity, inhibition of α-amylase and α-glucosidase digestive enzymes, and inhibition of angiotensin-I converting enzyme were determined in vitro. The maximum degree of hydrolysis (28.44%) was obtained at 42 °C, pH 2, and 125 rpm. Peptides with sizes inferior to 10 kDa were obtained, and the FTIR spectra showed the efficiency of the enzyme. A total of 129 proteins and 376 peptides were identified, of which 72 presented bioactive potential. No bioactive peptide presented toxicity potential. However, 79.17% are possible allergens. Six bioactive peptides are cellular penetrants. The need for further in vitro evaluation is evident. The antioxidant activity values were considered satisfactory, with DPPH radical scavenging and iron-reducing power, more than 80%. All hydrolysates tested inhibited α-amylase and α-glucosidase, however, a low inhibition. The maximum inhibition of the angiotensin-converting enzyme was 15.41%. For these enzymes, the values of inhibition can be increased with the purification of peptides that have bioactivity, identified in the in silico study. Swine plasma can be a protein source with the potential to provide compounds with biological activities for functional/nutraceutical application.