Degumming and Neutralization of Rice Bran Oil

Abstract

AbstractThe present study aimed to perform degumming and neutralization steps of crude oil from rice bran. The degumming was studied through a central composite rotational design where the study variables were the amount of water added and temperature and the response variable was phosphorus content. In the neutralization study, a complete experimental design was used, with the study variables being temperature and amount of NaOH solution added, while the response variables were acidity and γ‐oryzanol content. The best working region for degumming was in the condition of 5% water and a temperature of 58C, under this condition the oil showed a phosphorus contentof 4.10 mg/100 g. In the neutralization step, the best condition was 60C and an addition of 20% excess soda, where an acidity of 0.41% oleic acid and γ‐oryzanol content of 1.10% was obtained.Practical ApplicationsWater degumming proves to be advantageous compared to acid degumming, commonly carried out in oil refining industries since the phospholipids obtained in this step can be dried to yield lecithin without the need of purification. The lecithin obtained from the degumming process has commercial value, especially for its emulsifying action and can be used in food industries, in products such as ice cream, milk powder and chocolates. In its composition, rice bran oil has the γ‐oryzanol compound, a natural antioxidant that is extracted during the refining process of rice bran oil, especially during the neutralization step.The refining difficulties presented by the rice bran oil reflect the high cost of the final product compared to other oils. Thus, the study of the degumming step for the use of lecithin is justified, since the lecithin obtained from water degumming can be used as a byproduct of the oil industry, generating profit. The study of neutralization to preserve the maximum γ‐oryzanol content in the rice bran oil is justified by the benefits that this can bring to the health of consumers, such as lower total plasma cholesterol and increased HDL cholesterol levels. Furthermore, the maintenance of this compound improves oil quality, since the γ‐oryzanol increases the oxidative stability of the oil occasioned for factors such as the amount of water, oxygen, process and storage temperature and time.