Effect of an olive phenolic extract added to the oily phase of a tomato sauce, on the preservation of phenols and carotenoids during domestic cooking.

The protective effect of a phenolic extract from olive vegetation water on carotenoids and other phytonutrients has been evaluated during a home-cooking procedure to prepare tomato sauce. To specifically investigate on the complex mechanisms involved in the thermal degradation and solubilization of carotenoids, the olive phenols were added to a refined olive oil, chosen as control fat, in order to distinguish the effect of the simple oily matrix from that of the phenols occurring in virgin olive oils. Three sauces were prepared using a commercial tomato “passata”, carrots, celery and onion. Two sauces contained refined olive oil to which was added a phenolic extract at 40 or 60 mg/100 g of polyphenols, the third was the control with refined olive oil. The results revealed positive effect of the phenolic extract on the phytonutrient content of the tomato sauce. In the experimental sauces for the hydrophilic phenols, an improvement of approximately 100% was observed at both levels of phenolic extract addition in comparison to the control. There was a greater than 50% increase in a-tocopherol and a 43% increase in carotenoids with the lower level of phenols addition, and greater than 58% with the higher level of enrichment.