Studies on method for aqueous extraction of soybean oil

Abstract

Water extraction of soybean oil was studied to find the optimal conditions for recovery of oil preenriched protein and for aqueous extraction of soybean oil. Orthogonal tests were employed in the procedures of oil pre-enrichment and aqueous extraction. Soybeans were crushed to pass a 40 mesh sieve, soaked under the optimum conditions (solid/water=1/5(w/v), 40°C, pH 10, 3 h) and water-ground to 100 mesh, stirred in 65 °C water for 20 min, and centrifuged at 1400 g to separate oil pre-enriched protein. The protein yield was 17.8 g from 100 g soybeans, which contained 62.8% oil. The oil yield was 69.0%. Optimum conditions for the aqueous extraction procedure were: solid-to-water ratio 1∶2, pH 9.0, time 30 min, stirring in boiling water bath, stationary time 10 min, centrifuge at 3600 g for 10 min. Experimental values showed that the oil yield after aqueous extraction from oil pre-enriched protein reached 88.3%, so the total oil extraction rate was 60.8%.