Outcome of Refining on the Physicochemical Properties of Cottonseed Oil

Abstract

The influence of refining processes on the physicochemical properties including fatty acid composition of cottonseed oil (CSO) was studied. Physicochemical properties were determined by standard AOCS and IUPAC methods. The obtained results of physical parameters showed that neutralization, bleaching and deodorization processes on crude CSO significantly reduced the moisture content, color, freezing point and smoke point, while slightly decrease in refractive index was observed. Similarly, in the case of chemical properties free fatty acids, saponification value and peroxide value were reduced from 1.7 to 0.15%, 175 to 173 mg KOH/g oil and 3.4 to 1.2 mEq O2/Kg oil, respectively. Refining processes did not showed significant effect on the fatty acid composition and iodine value. As, soap contents generated in the chemical neutralization step, therefore soap content were decreased from 61.0 to 15.5 ppm in bleaching and deodorization steps. Moreover, this work suggests that overall deodorization process has greater impact on physicochemical properties to improve the quality and stability of cottonseed oil.