In-vitro antioxidant activities of peptides derived from upgraded camelina seed meal using a two-phase solvent extraction system

Camelina sativa L. Crantz (Camelina/ false flax) belongs to the family Brassicaceae and is considered as sustainable, novel oilseed crop, rich in protein and lipids. While the oil is in high demand, the deoiled fraction remains underutilized. Therefore, utilizing the resultant protein-rich meal for value-added products in food and pharamaceutical applications is essential. Glucosinolates are principal anti-nutrient compounds found in high concentrations in the seed meal that limit their use in food formulations. In this study, crushed camelina seeds were treated with designed two-phase solvent extraction systems consisting of 10% NH₄OH in 95% ethanol-hexane. Interestingly, this solvent system effectively removed over 95% of glucosinolates originally present in camelina seed meal.  Furthermore, the upgraded-deoiled camelina meal so produced was hydrolyzed with Alcalase, followed by membrane ultrafiltration fractionation (3 and 10 kDa). The in-vitro antioxidant properties of camelina protein hydrolysates and yielded fractions with peptide sizes of <3 kDa, 3-10 kDa and >10 kDa which were analyzed and compared with their hexane-defatted camelina meal counterparts. Overall, low-molecular-weight peptides exhibited highest DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonate) radical scavenging activities, metal chelation and ferric reducing power than peptides with high-molecular-weight. More specifically, <3 kDa fractions derived from upgraded camelina meal were stronger scavengers of ABTS, DPPH radicals and possessed better reducing power when compared to the peptide fractions ( <3 kDa) from hexane defatted meal. The results suggest that the novel low-molecular-weight bioactive peptides derived from upgraded camelina meal may serve as potential novel dietary supplement to alleviate oxidative stress.