Upcycling Almond (Prunus amygdalus) Oil Industry Byproduct into Multifunctional Peptides by Individual, Simultaneous, and Sequential Applications of Alcalase and Flavourzyme

Almond (Prunus amygdalus) deoiled meal, a byproduct of the almond oil industry, is often underutilized, especially in human nutrition despite its rich protein content, posing a challenge for its sustainable valorization. The present study demonstrated the upcycling of almond deoiled meal into value-added protein hydrolyzates with improved structural and functional properties. The almond protein isolate (API) was hydrolyzed with individual, simultaneous, and sequential applications of proteases: Alcalase and Flavourzyme (1% w/w each). Alcalase treatment was found to be the best in producing hydrolyzates with the highest degree of proteolysis (8.69 ± 0.16%), smaller particle size (240.82 nm), and stability (zeta potential of −47.66 ± 1.9); electrophoretic analysis (SDS-PAGE) confirmed the presence of small molecular weight (<40 kDa) peptides. The primary, secondary, and tertiary structural analysis revealed the unfolding of complex almond proteins and the exposure of hydrophobic residues. Alcalase hydrolyzate inhibited key enzymes like α-amylase (34.17 ± 2.27%), α-glucosidase (52.65 ± 2.13%), and pancreatic lipase (56.34 ± 2.77%), as well as demonstrated the highest in vitro protein digestibility, antioxidant (ORAC and ABTS assays), and anti-inflammatory activities. The present study is the first to reveal the multifunctional bioactivity of almond protein hydrolyzates. This study supports UN Sustainable Development Goals (SDGs) by transforming almond deoiled meal into functional ingredients, promoting sustainable production (SDG 12), improved health (SDG 3), and innovation in food processing (SDG 9).