identified β-sitosterol oxides (hydroxide, epoxy and 7-keto derivatives),
though only the 7-hydroxy and 7-ketoderivatives were quanti-
fied. The total content, which was considered low, was 218 μg POPs/
100 g of milk in the samples enriched with free phytosterols, and
203 μg POPs/100 g of milk in the samples enriched with esterified
phytosterols — such contents being lower than those recorded in
our study. The lesser enrichment in phytosterols (0.5%) versus that
used in our study (1.77–1.84%) would justify the observed differences
in POP contents. Accordingly, Menéndez-Carreño et al. (2008)