Impact of Roasting on Quality and Compositional Characteristics of Fig Seed Oil

Abstract

This study investigates the effect of roasting time and temperature on the chemical parameters and bioactive compound content of fig seed oil. For this purpose, fig seeds were ground and roasted in an electrical oven at 100, 150 and 200 °C for 10 and 20 minutes. After roasting, the seeds were processed into oil using a laboratory scale mill. The obtained fig seed oil samples were evaluated for their peroxide value, K232 and K270 spectrophotometric indices; fatty acid, triacylglycerol, sterol and tocopherol profiles. That results show that peroxide values, spectrophotometric indices, α- and γ-tocopherol levels were negatively affected by the roasting process. The major tocopherol was γ-tocopherol and ranged in 3914-4016 mg kg-1. The main fatty acid was linolenic acid constituting 40% of the fatty acids; followed by linoleic (31.76-31.97%), oleic (17.06-17.30%) and palmitic (7.00-7.11%) acids. The major triglycerides were LnLO (12.27-12.46%), LnLnL (12.18-12.40%), LnLnLn (9.32-9.52%) and LnLL (9.34-9.50%) confirming the fatty acid profile. β-sitosterol was the predominant phytosterol ranging in 2985.07-3623.24 mg/kg followed by Δ-5-avenasterol (19.52-20.60%) and Δ-7-avenasterol (4.16-4.81%). The principal component analysis results enabled a clear discrimination between unroasted, mildly-roasted and intense-roasted oil samples.