Variations in physicochemical attributes of seed oil among different varieties of cotton (Gossypium hirsutum L.)

Variation in the physicochemical attributes of the seeds and the extracted seed oils from six varieties (CIM-496, N-121, Z-33, AA-802, Desi, and CIM-534) of cotton (Gossypium hirsutum L.) were appraised. The amount of oil and protein in the tested seeds varied from 15.06 to 18.35% and 20.42 and 27.03%, respectively revealing a significant (p<0.05) differences among varieties analyzed while the contents of fiber (20.65-21.31%), ash (3.46-4.64%) and moisture (6.36-8.44%) did not vary considerably.The physicochemical properties including density (24ºC) 0.9154-0.9207 mg/mL, refractive index (40°C) 1.4607-1.4632, iodine value 100.54-108.73 I/100g of oil, saponification value 180.39-190.28 (mg of KOH/g of oil), unsaponifiable matter 0.49-0.58%, free fatty acids content 0.71-1.24% %, and color 12.01-13.04 R +63.61-68.11Yof the extracted cottonseed oils (CSOs) indicated a slight variation among varieties selected. The oxidation parameters of CSOs, as assessed by estimation of conjugated dienes, conjugated trienes, peroxide value, para-anisidine and induction period (Rancimat, 20 L/ h, 120°C), were noted to be 2.32-2.61, 0.91-0.99, 1.81-1.98 (meq/ kg of oil), 2.00-2.31and 3.19-3.61 h, respectively. The tested CSOs mainly contained linoleic acid (48.96-50.46%), followed by palmitic acid (24.42-25.80%), oleic acid (17.81-23.15%) and stearic acid (2.49-2.81%). The contents of α (125.47-296.20), γ (269.23-326.21) and δ (2.235.47 mg/kg) tocopherols among CSOs varied significantly. In conclusion, some of the physicochemical parameters of the oils varied significantly (p<0.05) among varieties selected that might be attributed to the different genetic makeup of the cotton plants. The results of this study can be useful for the selection of an appropriate cotton variety in the specified area.