Attempts of Physical Refining of Sterol-Rich Sunflower Press Oil to Obtain Minimally Processed Edible Oil

Abstract

New phytosterol (PS)-enriched sunflower seeds, which are higher in campesterol and ∆7-stigmastenol, have recently been developed. Crude oils obtained from these new sunflower seeds in 2015 and 2017 were used in this study. Oils extracted only by press (PO) and with subsequent solvent extraction (SO) were characterized. Physical refining (PhR) was used to obtain edible PO by minimal processing and to keep the PS levels as high as possible. Oils obtained by chemical processing were also studied for comparative purposes. Different bleaching treatments were examined to reduce the contents of phospholipids in the PO to levels required for PhR (<10 mg kg−1). Phosphorous levels in PO from 2015 (9–12 mg kg−1) were reduced to optimal levels by bleaching with 0.1% Trisyl and 1% Tonsil 278 FF. Contrarily, treatments with Trisyl and Tonsil (278 FF or 114 FF) were not sufficient to reduce the higher levels in PO from 2017 (15–36 mg/kg−1), thereby they were subjected to chemical refining (ChR). The PhR applied to PO from 2015 did not lead to substantial changes in the composition and total content of PS. In contrast, losses of up to approximately 30% of total PS were found owing to ChR, although the oils preserved their unique PS profiles.

Loss in the Intrinsic Quality and the Antioxidant Activity of Sunflower (Helianthus annuus L.) Oil during an Industrial Refining Process

“…Besides, there could be an economical interest to extracting these sterols from waste products in order to use them in supplemented foods [ 66 ]. Already-developed cultivars with a high phytosterol content [ 67 ] should be largely used and improved in order to increase the content of those molecules in refined commercial oils.…”