CONTENT OF HIGH BIO AVAILABLE CAROTENOIDS IN TOMATO - BASED PRODUCTS

The most abundant carotenoids present in tomato-based products were taken into account. Several samples coming from Italian stores have been analysed by using an RP – HPLC method. These products show a free carotenoids content proportional to the intensity of the manufacturing processes to which their are subjected. Among the carotenoids lycopene isomerises in various cis forms under different chemical – physical conditions. The lycopene antioxidant activity appears to be related to its trans – cis isomerisation degree, and the stability and the relative abundance of the isomers were investigated by applying heating and illumination. The cooking process seems to increase the total lycopene availabili-ty, whereas a prolonged exposure to a light source appears to be the best way to obtain the cis isomers. β-carotene is partially subjected to degradative processes, and do not shows an appreciable isomerisation degree under the same conditions. Riassunto In questo lavoro vengono studiati i più importanti carotenoidi presenti nei prodotti a base di pomodoro. I campioni dei diversi prodotti, reperiti sul mercato italiano, sono stati analizzati usando una metodica RP-HPLC. La quantità dei carotenoidi liberi riscontrata, appare proporzionale all’intensità del trattamento tecnologico impiegato. Tra i carotenoidi il licopene isomerizza in diverse forme cis a seconda delle diverse condizioni chimico-fisiche del trattamento.