In addition to concerns over the energy consumption of and the
pollution generated by these traditional refining methods, the
methods have been shown to affect the content of unsaponifiable
matter in rice bran oil [6,12]. This crude RBO fraction includes
the major compounds oryzanol and vitamin E. This complex mixture
of antioxidants has been cited to be responsible for various
physiological functions, such as cholesterol reduction and the prevention
of cardiovascular disease and some cancers [14–16]. Alkali
refining results in nearly an order of magnitude decrease of 1.6–
0.2% (mass% in the oil) in the total oryzanol content, while the vitamin
E (tocopherols plus tocotrienols, hereafter referred as tocols)
content is drastically reduced during the steam-refining or deodorization
step [6,17]. Krishna et al. [17] suggest that although most of
the oryzanols in refined oil can be retained during steam refining,
they tend to be lost during the alkali refining process.