Improved method for the determination of wax esters in vegetable oils

CARELLI, AMALIA; BAÜMLER, ERICA; LILIANA CECI

EUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY

WILEY-V C H VERLAG GMBH

Lugar: Weinheim; Año: 2012 vol. 114 p. 1312 - 1319

1438-7697

In this work, a modified International Olive Council (IOC) method for wax determination involving a double-adsorbent layer of silica gel and silver nitrate-impregnated silica gel is presented (SN method). Column chromatography by the SN method did not show retention of wax esters standards with an even number of carbon atoms (C34?C44), observing recovery percentages higher than 90% even for unsaturated wax esters. All wax fractions were lower by the SN method than by the IOC method, resulting in a percentage decrease in the total wax content (olive oils: 20?50%, crude sunflower oil: 38%, crude soybean oil: 58% and crude grape seed oil: 13%). Olive oils analysed by the SN method showed increases of up to 27% in C40 relative percentage with respect to the IOC method. Additionally, decreases were observed by the SN method in the relative percentages for odd-carbon atom waxes for the seed oils in comparison to the IOC method (crude sunflower oil: 27%, crude soybean oil: 28% and crude grape seed oil: 13%). The main advantages of the proposed modification consist in its easy implementation and a better determination of wax esters (C34?C60) by controlling their complete recovery and removing interfering substances. The method is suitable for quality control and for authentication of olive oil and seed oils as well as in processing monitoring.