FOOD. Science. Technology. Quality

Food. SCIENCE. Technology. Quality

Food. Science. TECHNOLOGY. Quality

Food. Science. Technology. QUALITY

Authors

MAŁGORZATA WRONIAK

Title

Nutritional value of cold-pressed rapeseed oils

Abstract

The objective of the study was to assess the quality and nutritional value of cold-pressed rapeseed oils on the basis of fatty acid composition and content of tocopherols and sterols. The scope of the study comprised the pressing of oil from rapeseed in an expeller under laboratory conditions, the analysis of quality and chemical composition of pressed oils, and comparing them with other commercial cold pressed and refined oilss. The following basic quality parameters of the oil samples were determined: acid value, peroxide value, anisidine value, Totox index, and oxidative stability in the Rancimat test at a temperature of 120 °C. The composition of fatty acids was analyzed, as were the composition and contents of tocopherols and sterols The cold-pressed rapeseed oils produced under laboratory conditions as well as other commercial oils were characterized by a high quality and a diverse oxidative stability (induction time from 3.82 to 7.32 h). The high nutritional value of rapeseed oils was confirmed owing to the optimal composition of fatty acids, i.e.: the high content of unsaturated fatty acids from 92.6 % to 93.1 %, the low content of saturated fatty acid from 6.7 to 7.3 %, and the optimal ratio of n-6 to n-3 acids, 2.1:1 on average. The oils did not contain trans-fatty acids except for the refined oil (0.8 %). Moreover, all the oils tested proved to be a valuable source of both the tocopherols from 44.82 to 57.60 mg/100 g and the sterols from 547.06 to 676.25 mg/100 g.

Keywords

rapeseed oil, cold-pressed oils, quality, fatty acids composition, tocopherols, sterols

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