The differences in polyphenol content among the OPs
might be due to the observed differences in rancidity, defined as the
peroxide value. Indeed, the degree of Frantoio OP autoxidation was
higher than that of Coratina, although they both had the same proportion
of unsaturated FAs. Based on the ratio between the peroxide
value and the polyphenols, the studied OPs could be classified as
high (Coratina), medium (Frantoio) or low quality (mixture).