Characterization of physico-chemical properties and antioxidant activity of oil from seed, leaf and stem of purslane (Portulaca oleracea L .)

Purslane (Portulaca oleracea L.) is a member of the family of portulacaceae and is a very good source of alpha-linoleic acid. Alpha-linoleic is an omega-3 fatty acid which plays an important role in human growth, development and in preventing diseases. Characterization of the physicochemical properties and antioxidant activity of oil from seeds, leaves and stems of purslane, and appraisal of its viability is the main purpose of this study. In this work, physicochemical properties of oil from seed, leaf and stem of purslane were characterized and the highest oil content was observed in seed (11.25 %) using solvent extraction method. The highest specific gravity was recorded for seed oil (1.10 w/w) followed by leaf oil (0.73 w/w) with non-significant difference. Moreover, oil extracted from purslane stem was found to be the least in oil content (2 %) and specific gravity (0.14 w/w); but the highest in acid value (13.32 w/v) and percentage free fatty acid. The peroxide value was found to be the highest for seed oil and the least for stem with significant difference. The highest ascorbic acid content was recorded for purslane seed oil (41.67 %) followed by leaf oil (32.29 %). Likewise, the highest 1, 1- diphenyl-2-picrylhydrazine activity was obtained for leaf oil (12.55 %) followed by seed oil (2.05 %). The plot for PC2 vs PC1 showed the oil content, specific gravity, peroxide value, ascorbic acid and 1, 1- diphenyl-2-picrylhydrazine having close PC1 and PC2 scores with vector angle < ${90}^0$ showing correlated effects. Characterizing physical and chemical properties and antioxidant activity of oil from seeds, leaves and stems of purslane is crucial in providing necessary information for the utilization of the oil content.

Keywords: Acid value; Alpha-linoleic acid; Antioxidant; Oil quality; Purslane.