The Effects of Dehulling on Physicochemical Properties of Seed Oil and Cake Quality of Sunflower

Abstract

This paper reports on oil yield, physicochemical properties of oil and cake quality obtained by expeller extraction of dehulled and undehulled seeds from two varieties of sunflower originated from Tanzania. The results showed significant differences in oil yield between undehulled and dehulled seeds also among the varieties. Oil yield from dehulled seeds was significantly higher (31−35.1%) than the yield from undehulled seeds (~19.7%). When compared physicochemical parameters (refractory index, saponification value, iodine value, free fatty acid value and peroxide value) of oils with standard values as recommended by Tanzania Bureau of Standard, the oil extracted from dehulled seeds were found to be within the range of values specified but the oil from undehulled was of poor quality at many instances. However, the physicochemical properties of oils from the two varieties did not differ significantly in most of the properties except for peroxide value. The cake composition from dehulled seeds was characterised by high crude protein (~44%) and low crude fibre contents (~17%), indicating improved quality. The results suggest that high yield and desired properties of both oil and cake can be achieved when seeds are dehulled, therefore, this process should be incorporated by Tanzanian sunflower processors.

Key words: Sunflower cultivar, seed oil, oil yield, dehulling, animal feed.