Lipid components and oxidative status of selected specialty oils

摘要

Many vegetable oils are marketed as specialty oils udbecause of their retained flavors, tastes and distinct udcharacteristics. Specialty oil samples which were commercially produced and retailed were purchased from local superstores udin Reading, UK, and Uppsala, Sweden and profiled for detailed udlipid composition and oxidative status. These oil samples udinclude: almond, hazelnut, walnut, macadamia nut, argan, udavocado, grape seed, roasted sesame, rice bran, cold udpressed, organic and cold pressed, warm pressed and refined udrapeseed oils. The levels of PV were quite low (0.5-1.3mEq udO2ud/kg) but AV and Rancimat values at 100°C (except for udrapeseed oils) varied considerably at (0.5-15.5) and (4.2-37.0 udh) respectively. Macadamia nut oil was found to be the most udstable oil followed by argan oil, while walnut oil was the least udstable. Among the specialty oils, macadamia nut oil had the udlowest (4%) and walnut oil had the highest (71%) level of total udPUFA. The organic cold pressed rapeseed oil had considerably udlower PUFA (27%) compared with other rapeseed oils (28-ud35%). In all the samples, α- and γ- tocopherols were the major udtocopherols; nut oils had generally lower levels. Total sterols udranged from 889 to 15,106 µg/g oil. The major sterols were udβ-sitosterol (61-85%) and campesterol (6-20%). Argan oil udcontained schottenol (35%) and spinasterol (32%). Compared udwith literature values, no marked differences were observed udamong the differently processed, organically grown or cold udpressed rapeseed oils and other specialty oils in this study.ud