Lycopene: effect of the heat treatment in the chemical structure and bioavailability

Abstract

Lycopene is a bioactive compound that belongs to the group of carotenoids, and is responsible for red color of many fruits. Its chemical structure is composed of isoprene units, containing 11 conjugated double bonds, which characterizes it as an antioxidant. The antioxidant capacity of lycopene is mainly due to its free radical scavenging activity, since the molecules are capable of receiving electrons of reactive species. This review aims to describe the antioxidant activity of lycopene, and the changes that occur during thermal processing of lycopene-rich foods, as well as the lycopene bioavailability. Several factors can affect the bioavailability of lycopene, and the main factor is related to its isomeric form. Although foods in natura contains lycopene mainly in the form of trans-isomer, the cis-isomers of lycopene are better absorbed by the human body, which are found mainly in heat-treated foods. This type of processing increases the bioavailability of lycopene, due to the disruption of cell walls, releasing cis isomers of lycopene; however, little is known about the amount of energy required for isomerization without compromising the total lycopene levels, since it can be degraded during thermal processing. Further studies are needed about the effect of processing on the content and the isomeric form proportion of this carotenoid, as well the antioxidant activity of the different isomers.

Keywords:Lycopene, Antioxidant, Isomerization, Bioavailability, Health, Processing