M. Litridou et al., PHENOLIC-COMPOUNDS IN VIRGIN OLIVE OILS - FRACTIONATION BY SOLID-PHASE EXTRACTION AND ANTIOXIDANT ACTIVITY ASSESSMENT, Journal of the Science of Food and Agriculture, 74(2), 1997, pp. 169-174
The polar fraction of virgin olive oil was separated into two main par
ts (A and B) using solid phase extraction. Analysis of individual comp
onents by RP-HPLC indicated that the part (A) contained only simple ph
enols and phenolic acids. Part (B) had a complex nature. The two parts
tested for their antioxidant activity showed relatively high protecti
on factors in safflower oil stored at 80 degrees C. Part B was found t
o contribute more than part A to the stability of the oil. The antioxi
dant activity of both fractions was related to their content of total
polyphenols and o-diphenols. Acidic and alkaline hydrolysis showed sig
nificant quantitative changes in the HPLC profiles indicating the pres
ence of ether and ester bonds while high-performance anion exchange ch
romatography of sugars after hydrolysis gave evidence for the presence
of only traces of glycosides. A first attempt to identify a character
istic chromatographic peak of part B by HPLC fractionation and mass sp
ectrometry showed the presence of an ester of tyrosol most probably wi
th a dicarboxylic acid.