Phenolic profile and antioxidant activity of novel oilseed meals

Phenolic compounds in oilseeds occur in the free, esterified and insoluble-bound forms. The phenolics in seeds act as natural antioxidants by preventing deteriorative oxidative processes as well as oxidative stress and various disorders in the human body once consumed. In this work, the free, esterified and insoluble-bound phenolics were extracted from defatted camelina, chia and sophia seed meals. All samples were evaluated for their total phenolic (TPC), flavonoids (TFC) as well as procyadinin (TPC) content and the antioxidant activities of their various phenolic fractions determined. Several in vitro free radical scavenging assays, namely 2,2- diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, trolox equivalent antioxidant capacity (TEAC), hydroxyl radical scavenging capacity (HRSC), reducing power (RP) and metal chelation activity were used for all fractions. In addition, inhibition activity against lipase, α-glucosidase, low density lipoprotein (LDL) oxidation and DNA strand scission strand induced by peroxyl and hydroxyl radicals for all fractions was examined in biological systems. High performance liquid chromatography (HPLC) and HPLC-tandem mass spectrometry (HPLC-MSⁿ) led to positive identification of 34 phenolic compounds belonging to simple phenols, phenolic acids and their derivatives, flavonoids and procyanidins in the three phenolic fractions of camelina, chia and sophia. Esterified fraction was the predominant form of phenolics compared to the free and insoluble bound forms of phenolics in both defatted camelina and sophia seeds whereas the free fraction was the predominant form in defatted chia seed meal. Thus, camelina, chia and sophia seeds may serve as viable functional food ingredients with protective antioxidant potential.