Abstract
The relations of the antiradical capacity to oxidative stability parameters and the contents of fatty acids, sterols, tocopherols, phenols, flavonoids, chlorophyll, Cu, and Fe were assessed in 33 cold-pressed seed oils: Walnut (7 brands of oils), rosehip (3), camelina (6), milk thistle (5), flax (6), and pumpkin (6). The antiradical capacity of oils depended strongly on tocopherol contents with a synergistic effect with polyphenols. The efficacy of tocopherols in cold-pressed oils was accompanied by a negative correlation of their antioxidant capacity with the peroxide value increase after 3 months of shelf life. This study also showed a positive correlation between the content of phytosterols and the antiradical capacity in the lipophilic fraction of cold-pressed oils rich in n-3 polyunsaturated fatty acids (PUFAs). Multiple regression analysis identified groups of antioxidants naturally occurring in cold-pressed oils in relation to their fatty acid composition, which added to the cold-pressed oils could provide possible strategies to improve their stability. Achieving high stability is primarily a result of high phytosterol content exceeding the molar ratio of 1:100 for total phytosterols to α-linolenic acid. However, the molar ratios of tocopherols to linoleic acid below 1:2000 and polyphenols to linoleic acid below 1:3000 does not prevent oxidation in oils with the predominance of linoleic acid.
Highlights
Cold-pressed oils are continuously gaining in popularity among consumers
Rosehip oil was characterized by the highest content of polyunsaturated fatty acids (PUFAs) and was one of the richest in α-linolenic acid (ALA) together with linseed and camelina oils
Analyzed rosehip oils contained the lowest level of saturated fatty acids (SFAs) (7.1%), whereas camelina oils comprised the smallest overall median quantity of monounsaturated fatty acids (MUFAs)
Summary
Cold-pressed oils are continuously gaining in popularity among consumers. The advantage of cold-pressed oils over refined ones is largely due to the numbers of bioactive substances recovered in the pressing process. These include antioxidants such as tocopherols, polyphenols, and squalene, which have been proven to retard lipid oxidation [1,2]. For cold-pressed oils rich in polyunsaturated fatty acids (PUFAs), the effectiveness of antioxidants is of particular importance, as high susceptibility of PUFAs to oxidation entails a risk of oil deterioration and, detrimental health effects when it is consumed [3].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
