The effects of enzyme concentration (20-60 mg/100 g dry matter), incubation period (6-18 h), solid-water ratio (1:1.17-1:6.83), pH (3-6) during aqueous extraction, extraction time (30-70 min) and temperature (30-70°C) during aqueous extraction on oil recovery from sesame seeds were studied in enzyme assisted aqueous oil extraction process and the process parameters were optimized using response surface methodology. The process involved treating the comminuted sesame with crude enzyme from A. fumigatus, keeping it for some time (termed as wet fermentation), extraction of oil droplets in aqueous medium with continuous stirring and then separation of oil by centrifugation. Centrifugation separated the mixture into four phases viz. oil, cream, aqueous and cake. Enzyme treatment on wet ground seed increased oil recovery compared to that of aqueous extraction of with/without enzyme pretreated whole sesame seed. A second-order response surface model adequately fitted the data. All the variables, except temperature, during extraction affected the oil recovery significantly. The solid to water (SW) ratio, pH and extraction time were most significant parameters. Enzyme concentration, incubation period and extraction time had interactive effect on oil recovery. The optimum conditions were enzyme concentration (43.9 mg/100 g dry matter), incubation period (12.6 h), SW ratio during extraction (1:1.17), pH during extraction (3.8), extraction time (46 min) and extraction temperature (52°C). Under the optimum conditions, oil extracted from enzyme pretreated wet ground sesame seed was 75.23% of the total solvent extractable oil.
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