Effects of Crude Rice Bran Oil Components on Alkali‐Refining Loss

Abstract

The effects of minor components in crude rice bran oil (RBO) including free fatty acids (FFA), rice bran wax (RBW), c-oryzanol, and long-chain fatty alcohols (LCFA), on alkali refining losses were determined. Refined palm oil (PO), soybean oil (SBO) and sunflower oil (SFO) were used as oil models to which minor component present in RBO were added. Refining losses of all model oils were linearly related to the amount of FFA incorporated. At 6.8% FFA, the refining losses of all the model oils were between 13.16 and 13.42%. When \1.0% of LCFA, RBW and c-oryzanol were added to the model oils (with 6.8% FFA), the refining losses were approximately the same, however, with higher amounts of LCFA greatly increased refining losses. At 3% LCFA, the refining losses of all the model oils were as high as 69.43-78.75%, whereas the losses of oils containing 3% RBW and c-oryzanol were 33.46-45.01% and 17.82-20.45%, respectively.

Rice Bran Oil: A Versatile Source for Edible and Industrial Applications

“…The problems encountered and the ways to solve them during oryzanol extraction, such as prior processing and compositional variation in soapstock, resistance to mass transfer, moisture content and the presence of surface active components, which cause emulsion formation, should be examined. Engineering inputs required for solving problems such as saponification, increasing mass transfer area, and drying methods also should be carefully designed 18,19 . The TLC-densitometric and TLC-image analysis methods are useful for quantitative determination of γ-oryzanol in cold presses RBO 27 .…”

Reducing Oil Losses in Alkali Refining

“…Thus, some neutral oil is entrapped with the soap micelle, which passes into the aqueous phase and causes a refining loss [1,2]. Therefore, crude oils with high FFA contents tend to lose large amounts of neutral oil during neutralization [3,4]. When the soap is removed during centrifugation, the entrapped oil is concomitantly removed with the soap.…”

“…When the soap is removed during centrifugation, the entrapped oil is concomitantly removed with the soap. Furthermore, in case of rice bran oil, the refining loss is usually higher than other oils of the same FFA content due to the presence of surface-active compounds, such as oryzanol, waxes and long-chain fatty alcohols, in the crude oil [4,5]. These compounds stabilize the emulsions during oil refining and, thus, increase oil loss.…”

“…Separating neutralized oil and soapstock by centrifuging is one means of demulsification. However, due to the good emulsification properties of sodium soap and enhanced stabilization by other surface-active agents, the refining loss in rice bran oil is quite high when using only mechanical demulsification [4].…”

Use of colloid chemistry principles to improve efficiency in biodiesel production

“…Losses can reach the level of 20% in refining vegetable oils for food grade products [5]. Refining losses are typically 5 times the free fatty acid (FFA) content in the crude vegetable oil, mainly because of formation of emulsions in the neutralization and washing steps [6]. As a rule of thumb recommendation of Dorsa and Eiickhoff [7] Miscella refining with n-hexane solvent has been reported to reduce refining losses [8] with no record for application in practice.…”