The Effect of Processing Conditions on the Nontriacylglycerol Constituents of Sunflower Oil

Abstract

In this study samples of non-refined sunflower oils, obtained in industrial and laboratory scale by cold and hot pressing and hexane extraction, as well as sunflower oils from single refining steps were investigated. The content and composition of carotenoids, sterols, and the content of chlorophylls as well as oxidative stability were investigated. To obtain the data about the acidity and oxidative status of the oil samples, basic quality analyses of free fatty acid content (FFA), peroxide value (PV) and spectrophotometric analyses in UV area (K232, K270 and K) were used.The results showed that the predominating carotenoid in sunflower oil is lutein, and that the total amount of carotenoids during refining process was reduced to about 15% of the initial amount. The major sterol in sunflower oil (about 70%), as well as in other vegetable oils, was -sitosterol. The other important sterols in sunflower oil were 7 -stigmasterol, stigmasterol, campesterol, 5 -avenasterol and 7 -avenasterol. The composition of sterols in non-refined and refined oils was more or less the same, while the content of sterols during refining process decreased by 22%. Among all analysed sunflower oils, the laboratory extracted oil had the best oxidative stability (e.g. the longest induction period, according to Rancimat method), while cold and hot pressed oils were less stable than the fully refined one.

Effects of refining process on sunflower oil minor components: a review

“…Otherwise, sunflower oil it is not particularly rich in carotenoids with only 1-1.5 ppm of carotenoids (Gunstone, 2011). The major carotenoids in sunflower oil are xantophylls which reach up to 81% of the total (Rade et al, 2004).…”

“…• C, 0.59% w/w bleaching clay (TAIKO, type: Classic 1G, Malaysia) with mechanical stirring was used at vacuum 13 × 10 3 Pa for 30 min (Kreps et al, 2014) and carotenoids around 77% of the initial value (Rade et al, 2004). The decreases in total tocopherol contents due to bleaching step have been largely studied (Alpaslan et al, 2001;Ergönül and Köseoǧlu 2014;Kreps et al, 2014;Tasan and Demirci, 2005).…”

“…Squalene is lost up to 7% in the deodorization process (Nergiz and Çelikkale, 2011). Carotenoids suffer a supplementary reduction of between 8% and 28% of the initial content during this step, reaching a final content equivalent to 15-20% of the initial value in regular SO and 25% in HOSO (Kreps et al, 2014;Rade et al, 2004).…”

Effect of minimal neutralization at optimal conditions on minor components and oxidation stability of sunflower oil

“…Some studies have reported lower FFA contents after neutralization by NaOH. Rade et al (2004) found that FFA value of crude and alkali refined sunflower oil were 1.60 and 0.06, respectively. Kuleasan and Tekin (2008) found that the FFA content of the crude soybean oil decreased from 0.56% to 0.14%–0.2% in 60 min.…”

“…For instance, presence of tocopherols which are oil soluble natural antioxidant is important for oxidative stability while FFAs are prooxidative. Alteration of FFA concentration and addition of natural antioxidants to the oil are proven strategies for improvement of the oxidative stability of oils (Alpaslan et al, 2001; Brevedan et al, 2000; Fadda et al, 2022; Farhoosh & Pazhouhanmehr, 2009; Rade et al, 2004; Zhang et al, 2010).…”