Physicochemical Characteristics and Oil Keeping Quality of Two Cultivars of Sunflower (Helianthus annuus) Seeds

The work was conducted on sunflower seeds of two cultivars namely ‘Kironi’ and ‘Hysun-46’. Proximate composition of the seeds, chemical characteristics and fatty acid composition of the oils, and its keeping quality at different storage conditions were studied. Moisture content of Kironi seeds was nearly twice than Hysun-46 (8.03 vs 4.46%). Crude fat in Hysun-46 seeds was somewhat higher than Kironi. Kironi had significantly higher crude protein whereas Hysun-46 contained significantly higher percent of starch than Kironi (7.05 vs 3.90%). Physical characteristics of oil such as viscosity, colour and transparency changed with time during storage; specific gravity and smoking temperature, however, remained unchanged. Acid values of the freshly extracted oil from Hysun-46 were unexpectedly high (98.75). Iodine values were found to be higher in Kironi than Hysun-46, so the former had greater proportion of unsaturation. Saponification values of the oils decreased with the time in open vessel, in amber coloured bottle at 4°C and also in boiled oil kept at room temperature. However, these values registered an increase in oils stored in closed vessel and amber coloured bottle at room temperature. Peroxide values increased in oils under all conditions except in amber bottle at 4°C. The ratio of linoleic acid to oleic acid in Kironi (2.3:1) was higher than that in Hysun-46 (1.9:1), indicating that Kironi had more semidrying capacity and suitable for edible purpose. The freshly extracted oil had attractive appearance. Between the two oil samples, Kironi seems somewhat superior to Hysun-46.