Effect of moisture on the oil extracted from sunflower collets and its content of minor compounds

ETHEL PÉREZ; BAÜMLER, ERICA; CARRIN, M.E.; CRAPISTE, GUILLERMO; CARELLI, AMALIA

Concordia Entre Ríos

Conferencia; International Conference on Food Innovation FOODINNOVA 2014; 2014

Universidad Nacional de Entre Ríos

It is well-known that the oil yield obtained during extraction step depends on the moisture content of the oleaginous material; the oil yield increases as moisture decreases; however, a certain moisture is required because it gives the collets an elasticity, increases the bulk density and hinders percolation. Up to now, the research of the effect of moisture on oil extraction has been focused on obtaining the higher oil yield without considering minor compounds that affect oil quality. Some of these minor compounds have antioxidant properties (e.g., tocopherols) while others have to be removed in the refining process (e.g., phospholipids, waxes). The aim of this work was to analyze the effect of moisture content of the collets on the quality of sunflower oil measuring its content and profile of waxes, phospholipids and tocopherols. Low-protein sunflower collets were conditioned at three moisture levels (6, 12 and 18% d.b.), prior to oil extraction. The oil extraction was carried out at 50ºC for 2 hours using n-hexane as solvent and a batch reactor magnetically stirred. The amount of oil extracted was determined gravimetrically. The tocopherols content was measured by an HPLC instrument equipped with a fluorescence detector using AOCS method. Quantitative determination of phospholipids was carried out by enrichment with a diol solid-phase extraction cartridge and subsequent analysis by HPLC?UV. The wax fraction was isolated by column chromatography in a glass column with a solid stationary double phase of silica gel and silver nitrate-impregnated silica gel. Waxes were quantified by the internal standard method using a capillary GLC equipped with an on-column injection system and a flame ionization detector. Statistical analysis was carried out by analysis of variance (ANOVA) followed by comparisons between means with Fisher´s LSD test, at 5% significance level (n=3). The increasing moisture content caused the decrement of oil yield, they were statistically different for each sample tested (p = 0.003). The total waxes contents were between 896 and 1118 ppm, they were composed mainly by esters between 44 and 60 carbon atoms, whose distribution unchanged according to the moisture content considered. In all the experiments, - and -tocopherols and -tocotrienol were detected, being the level of -tocopherol higher than 93% and easier to extract at 12% d.b. of moisture content. Furthermore, the oil phospholipid content increased with moisture content, but maintaining their profile. In brief, the moisture content of the collets not only affects the oil yield extraction but also the content of minor compounds.