Effect of Sunflower Collets Moisture on Extraction Yield and Oil Quality

Abstract

The aim of this work was to analyse the effect of moisture content of sunflower expanded material on the quality of the extracted oil by determining its wax, phospholipids and tocopherol content and composition. Sunflower oil extraction was carried out in a batch extractor at 50 ºC using hexane and three moisture levels (5.65, 12.40 and 18.92% dry basis). The increasing moisture content caused an increment in both oil yield and total amount of minor compounds. The total wax content ranged between 808 and 1118 ppm, the wax fraction was composed mainly of esters of between 44 and 58 carbon atoms (>67%), the distribution did not change with the moisture content. In all the experiments, α- and β-tocopherols and βtocotrienol were detected, being the level of α-tocopherol higher than 93% and easier to extract at 12.40% moisture. Furthermore, the phospholipids content in the oil increased with moisture content but maintaining its profile composition. The obtained results can be explained in terms of water activity and the effect of moisture and hexane extraction on solid structure, studied by scanning electron microscopy. In brief, the moisture content of the collets not only affects the oil yield but also the content of minor compounds, the intermediate moisture rendering the better oil yield and quality.