Extraction and Demulsification of Oil From Wheat Germ, Barley Germ, and Rice Bran Using an Aqueous Enzymatic Method

Abstract

AbstractAn aqueous enzymatic method was developed to extract oil from wheat germ. Wheat germ pretreatment, effect of various industrial enzymes, pH, wheat germ to water ratio, reaction time and effect of various methods of demulsification, were investigated. Pretreatment at 180 °C in a conventional oven for 4 min reduced the moisture 12.8–2.2 % and significantly increased the oil yield. Adding a combination of protease (Fermgen) and cellulase (Spezyme CP) resulted in a 72 % yield of emulsified oil from wheat germ (both commercial and laboratory milled wheat germ). Using the same oil extraction conditions optimized for wheat germ, yields of 51 and 39 % emulsified oil were obtained from barley germ (laboratory milled), and rice bran, respectively. Three physical demulsification methods (heating, freeze‐thawing, and pH adjustment) and enzymatic methods (Protex 6L, Protex 7L, Alcalase, Fermgen, Lysomax and G‐zyme 999) were compared. After demulsification with Protex 6L, free oil yields of 63.8 and 59.5 % were obtained with commercial wheat germ and with laboratory milled wheat germ, respectively. Using the same demulsification conditions optimized for wheat germ, yields of 45.7 % emulsified oil and 35 % free oil were obtained for barley germ and rice bran, respectively.