FTIR Characterization and Physicochemical Evaluation of Cottonseed Oil

Abstract

In present study, cottonseed (Gossypium) varieties (RH-112, Lankart-57, K-25, F-20 and D-9) were evaluated for possible variation in quality attributes by using conventional and instrumental techniques. Physiochemical characteristics of seed and oils varied as: weight of individual seed (0.069-0.085 g), weight of 100 seeds (5.95-7.73 g), width (0.461-0.544 cm), length (0.736-0.915 cm), moisture (6.2-8.5%), oil content (12.01 to 14.55%), refractive index at 40^oC (1.4661-1.4665) iodine value (IV) (93.90-105.76 gI2/100g), saponification value (SV) (181.83-190.55 mg KOH/g), peroxide value (PV) (1.0-6.0 m Eq/Kg), free fatty acids (FFA) (17.30-38.80 %) and induction period (IP) (1.95 -2.65 h), respectively. Analyzed varieties showed higher level of FFA (17.30- 38.80%), while lower level of IP (1.95-2.65 h) respectively. Furthermore, GC-FID and FT-IR studies were carried out for quantitative and qualitative analysis of cottonseed oil. Analysis showed that most abundant fatty acid in each variety was linoleic acid (42.09-52.55 %) among unsaturated fatty acids, whereas palmitic acid (22.70-26.20 %) was major saturated fatty acid. Some band intensities of FTIR spectra highly correlated with the chemical properties of cottonseed oil such as IV, SV, PV, FFA and IP. In conclusion significant variation in physiochemical properties was observed among five cottonseed varieties, especially FFA and IP of cottonseed oil which is not good for the quality and edible point of view. This can be associated with the specific genetic variability and climatic conditions.