COMPARISON OF THE QUALITY OF COLD PRESSED AND VIRGIN RAPESEED OILS WITH INDUSTRIALLY OBTAINED OILS
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Publication date: 2008-03-31
Pol. J. Food Nutr. Sci. 2008;58(1):85-89
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ABSTRACT
This work evaluates the quality of cold pressed rapeseed oils as well as virgin oils (from seeds heated before pressing) obtained under laboratory conditions and compares them with the quality of industrially obtained hot pressed, crude, bleached and deodorised oils. The method of obtaining oils did not affect the fatty acid composition. The composition of fatty acids in all oils was typical of the low-erucic rapeseed. The analysed oils did not contain trans fatty acid isomers, with the exception of the deodorised oils after full refining (linoleic and linolenic 1.1%). It was found that the quality of the analysed oils depended significantly on the quality of the method of their production and further processing. The quality of cold pressed and virgin oils was good and in keeping with the expectations for edible oils. Cold pressed oils differed statistically significant from both the virgin type oils and deodorised ones obtained from the same seeds in all the tested parameters: colour, acid and peroxide value, Totox, induction time and only in the case of anisidine value they showed a significantly lower value. Cold pressed oils (5.08 h) were less stable in Rancimat test in comparison with oils after full refining (5.37 h). The highest content of tocopherols was characteristic for crude oils (58.4 mg/100g). The refining process caused a decrease by over 40% of tocopherol content in fully refined oils. A higher by 25% content of tocopherols and the lack of trans fatty acid isomers speaks for the cold pressed oils.