Rice is the main staple food in Thailand and many countries in
Asia. It is also the main export product of Thailand. About 20 million
tons per year of rice are produced in Thailand, which produces about
1.6 million tons of rice bran (USDA Foreign Agricultural Services,
2010). However, only a small portion of rice bran is processed into
edible oil. Rancidity of lipids in RBO is amajor problem for utilization
of rice bran. The high lipid content and a potent enzymes result in
drastic quality reduction of rice bran. Storage of rice bran, especially
at room temperature, for extended periods leads to degradation of
triglycerides in the oil and ultimately to the formation of off-flavors
and odors. Rice bran contains active enzymes. Germ and outer layers
of the caryopsis have higher enzyme activities. Particular lipase, but
also lipoxygenase and peroxidase, are probably most important
commercially because they effect the keeping quality and shelf life
of rice bran (Orthoefer, 2005). Ramarathnam, Osawa, Namiki, &
Kawakishi (1989) also reported that lipid peroxidation by lipases