Protein and Amino Acid Profile Analysis of Agri-Food Waste Biomasses

The degradation of biomasses derived from agriculture and food industry presents the double advantage of both eliminating often polluting wastes and giving the possibility of introducing novel bio-derived products into the market. The recovery of the protein component and its transformation into protein hydrolysates is generally carried out chemically or enzymatically and brings great added value to waste biomasses. The recovery of the protein component from waste products is extremely advantageous inasmuch as bio-based products can be reintroduced into the market by virtue of their high added value in full compliance with the perspective of the Circular Economy. The products obtained can be used as food supplements both in human and animal nutrition, as growth stimulants in agriculture, or as biofertilizers. The peculiar characteristics of the obtained protein hydrolysates allow their multiple applications in many industrial fields. Therefore, the aim of this work is to assess the protein and amino acid (AA) profiles of agri-food biomass, i.e. soy wastes, previously subjected to an enzymatic hydrolysis process. The protein profile of the initial biomass and the corresponding hydrolysate was analyzed by SDS-PAGE followed by Coomassie Blue staining, while the AA profile was evaluated by quadrupole time-of-flight liquid chromatography/mass spectrometry (Q-TOF LC/MS). The results indicate how the enzymatic hydrolysis process breaks down the peptide bonds of the protein component in the biomass, leading to the formation of hydrolysates rich in small peptides and free AAs.