The main purpose of this study was to extract the maximum amount of oil from peanuts without causing major damage and preserving their organoleptic quality after defatting. Accordingly, a successful, healthy, eco-friendly and economic defatting process for peanuts was implemented using mechanical oil expression, which was optimized by means of Response Surface Methodology. The results demonstrated that maximum extraction yields were obtained at a low initial moisture content (5-7% d.b.). Defatting and deformation ratios were mostly affected by the pressure and water content with high correlation coefficients (98.4% and 97.5%, respectively), and overall acceptability decreased following higher oil extraction yields. It was concluded that the optimum values for the product moisture content, pressure, and pressing duration were 5% d.b., 9.7 MPa and 4 min, respectively, with a defatting ratio of 70.6%. This resulted in an insignificant irreversible deformation ratio (<1%) and an overall acceptability of 7.6 over 10.
Keywords: Defatting; Oil yield; Peanuts; Pressing; Response Surface Methodology; Shape preservation.
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