Enhanced cis-Isomerization of (all-trans)-Lycopene in Tomato Products with via Specific Vegetables in Home Cooking

Abstract

Lycopene is found abundantly in tomatoes and processed tomato products and exhibits a strong antioxidant capacity. However, most lycopene found in plants is present in the all-trans form, which is associated with low bioavailability. Contrastingly, cis-isomers of lycopene, which are present in considerable quantities in processed tomato products, are more bioavailable than the all-trans isomer. Recent studies revealed that thermal cis-isomerization of (all-trans)-lycopene is promoted when lycopene is cooked with edible oil and onions. In this study, we found that several vegetables such as onions, garlic, broccoli, and cabbage, which are used frequently to prepare home-cooked tomato-based dishes, promoted the thermal cis-isomerization of (all-trans)-lycopene. We also investigated the effect of onion and broccoli on the lycopene cis-isomer content in generally-cooked tomato-containing dishes. The results clearly showed that the addition of onion or broccoli promoted the cis-isomerization of (all-trans)-lycopene in the dishes.