Sunflower‐Oil Wax Reduction by Seed Solvent Washing

Abstract

AbstractWax distribution in sunflower seeds was determined by capillary‐gas chromatography, as well as both the wax composition in sunflower oils obtained from washed seeds and the wax composition in the solvent extracts. The dehulling efficiency was evaluated by using a laboratory centrifugal process. The washing effect on hull morphology and on wax distribution was observed by scanning‐electron microscopy. Washing preferentially removed the crystallized fraction, hexane being the most effective solvent. Short contact times (20 s) at 25–40 °C were sufficient to extract the insoluble waxes by hexane washing. The extracted material consisted of C40–C54 waxes with higher percentages of extracted C44, C46 and C48. These are superficially in the hull of sunflower seed presenting a non‐uniform distribution as observed by microscopy. Solvent washing with pre‐heating of the seeds caused a decrease in sample moisture content, which reduced dehulling ability. Ethanol‐washed seeds were the easiest to dehull, but higher production of fines was also observed. Solvent washing improves both the dehulling‐seed ability increment and the recovery of sunflower waxes as a by‐product for commercial use.