Impact of the malaxation temperature on the phenolic profile of cv. Cobrancosa olive oils and assessment of the related health claim

Phenolic compounds contribute to the bioactive properties of olive oil. However, olive oils can only support a health claim concerning the protection against oxidative stress depending on the polyphenolic concentration, requiring effective measures during extraction to preserve/enhance their concentrations. The effect of the malaxation temperature (22, 28 and 34 degrees C) on the phenolic profile was studied for industrially extracted cv. Cobrancosa oils. Higher malaxation temperatures decreased the contents of the majority of the chromatographically detected compounds (P < 0.05, one-way ANOVA), enabling oils' differentiation. This decreasing trend was observed for hydroxytyrosol and tyrosol bound forms, determinant for the health claim, which were also negatively affected by temperature, despite revealing that all the industrially extracted oils tested supported the health claim. The observed constant free to bound forms ratio showed that the temperature range tested had a minor effect on bound-forms hydrolysis, being both free and bound forms equally affected by temperature.