Optimization of ultrasound assisted aqueous oil extraction from (Zea mays L.) germ using response surface methodology

Abstract

Extraction of oil from Zea mays L. germ was investigated using a ultrasound assisted aqueous extraction A Box-Bhenken design for experiments were employed to study and optimize the effect of Incubation temperature, ultrasonication time and water to seed ratio on oil recovery. A quadratic polynomial model was generated to predict oil recovery. Among the process parameters studied, interaction of Incubation temperature and ultrasonication time had the most significant effect on the recovery followed by quadratic of Incubation temperature and interaction of ultrasonication time and water to seed ratio. Model validation shows no significant (p >0.05) between practical and predicted values. The optimum extraction condition for oil recovery within the experimental range of the variables researched was at 40oC incubation temperature, 60 min of ultrasonication time and water to seed ratio of 4:1. At this condition, the recovery of oil was observed to be 67±0.27%. The oil obtained was compared with the solvent extracted oil for physico chemical quality parameters. Gas-chromatography of the maize germ oil was carried out for the free fatty acid composition of the oil constituents. Both techniques yielded oil with no significant difference (P>0.05) in the percentage composition of free fatty acid and iodine value, saponification value, and peroxide value but iodine values and linoleic acid was found to be slightly highest in UAE extracted oil. From present study it can be observed that UAE method can be used as alternative to SE, to prevent high solvent consumption and prevent the release the VOCs to atmosphere.