Macro and Micro Characterization of Antioxidant Protein Hydrolysates from Hemp (Cannabis sativa L) seeds

Background and objectives: Green industries, such as industrial agricultural hemp (Cannabis sativa L.), represents a new source of sustainable plant protein and bioactive peptides that can exert biological functions and promote health. The objective of this study was to obtain bioactive peptides from hemp protein hydrolysates (HPHs), to analyse their macro- and micronutrient composition and to evaluate antioxidant activity of these functional protein by-products of agri-food industry. Methods: A hemp protein isolate (HPI), obtained from hemp defatted flour (HDF), was hydrolyzed by Alcalase and Flavourzyme enzymes, both food-grade endoproteases, under specific conditions. The resulting HPHs were chemically characterized in macro and micro-nutrients and their antioxidant capacity were evaluated by in vitro cell-free experiments owing to their measure of capacity to sequester DPPH free radical, β-carotene, and reducing power. Results: Characterization and comparison of nutritional composition (macro and/or micronutrients) between all protein products showed than the chemical composition of HPHs was like HPI. Results showed that amino acid composition of the hemp protein products broadly complies with the adult requirements established by the Food and Agriculture Organization/World Health Organization/United Nations University (FAO/WHO/UNU) for indispensable dietary amino acid. Moreover, in vitro cell-free experiments led to the identification of two bioactive HPHs, HPH20A and HPH60A+15AF, which showed an IC50 value like positive control (BHT), in order to evaluate the hemp peptides with antioxidant activities. Conclusions: Plant protein-based products supplemented in functional food and nutraceuticals are expected to grow considerably in the next years. Plant proteins, usually, present insufficient levels of at least one or even more essential amino acids thus limiting their biological value. However, antioxidant peptides in HPHs presented a balanced amino acid profile and a digestibility higher than intact proteins, hence, these results show that HPHs could be considered as an effective option within the functional food generation and would support their use in future clinical food trials.