Studies on colour fixation of the oil of mature, immature and damaged cottonseed

Abstract

Oil was extracted from mature, inmature and damaged cottonseed with the acetone-hexane-water azeotrope (53:44:3 by volume). Mature cottonseed oil (M), 10% immature cottonseed oil in mature cottonseed oil (MIM) and 10% damaged cottonseed oil in mature cottonseed oil (MD) were subjected to some treatments e.g. refining and bleaching or the addition of sodium silicate before refining and bleaching or before colour fixation. The treated oils were spectrophotometrically studied. The presence of 10% oil from immature or damaged cottonseed in oil from mature cottonseed produced an increase in the colour and absorption spectra of most samples, resulting in an oil that could not be refined and bleached satisfactorily. Sodium silicate proved to be an effective treatment before refining and colour fixation of the oils. The study revealed gossypol pigments, carotenoids and chlorophylls present in different M, MIM and MD samples.

Keywords

• colour fixation
• dammaged cottonseed
• immature cottonseed
• mature cottonseed
• oil