IMPACT OF THE EXTRACTION METHOD ON PHYSICO-CHEMICAL PROPRIETIES, PHYTOCHEMICALS AND BIOLOGICAL ACTIVITY OF SESAME SEEDS OIL

Abstract

This study aimed at characterizing oil extracted from roasted and unroasted sesame seeds (Sesamum indicum L.) following either Soxhlet using hexane as the solvent or cold pressing. We obtained an inverse relationship between oil yield and seed moisture content. Seed roasting as well as Soxhlet extraction improved oil yield. Specific absorptivity (at 232 and 270 nm) increased with heating treatment. Refractive values of the different oils were about 1.464. Peroxide value was 7.6 to 9.6 meq O2/kg, iodine value was 107-109g I2/100g, saponification value obtained was 188 to 190 mg KOH/g, oleic and linoleic acids were about 42 and 40%, respectively. Total phenolic contents were 8 (USO-CE) to 17 mg/100 ml (RSO-SE). Roasting process increased the antioxidant contents and activities (DPPH scavenging and reducing power). The antibacterial activity of sesame oil revealed the inhibition of Escherichia coli and Pseudomonas aeruginosa growth. Sesame oil presents interesting physicochemical characteristics and antioxidant properties that can be improved by roasting the seeds before extraction.