LYCOPENE STABILITY DURING FOOD-PROCESSING

Accumulating epidemiological evidence continues to show that lycopene, found in tomatoes, grapefruits and watermelons, is associated with a reduced risk of developing certain chronic diseases and cancers. With respect to lycopene in tomato products, the effect of thermal processi ng on its stability has not yet been rigorously addressed. This paper assesses the effect of several different heat treatments on lycopene's isomeric distribution in a variety of tomato products, as well as in organic solvent mixtures containing all-trans lycopene. Experimental r esults indicate that in contrast to beta-carotene, lycopene remained r elatively resistant to heat-induced geometrical conversion during typi cal food processing of tomatoes and related products. The presence of fat, the change in percentage of solids, and the severity of heat trea tment were not contributing factors in the formation of lycopene isome rs in tomato products, except at extreme conditions not regularly empl oyed in the food industry or during food preparation. However, lycopen e in organic solvent isomerized readily as a function of time even in the absence of light and the presence of antioxidants. These findings suggest that while lycopene is stable in the tomato matrix, sample han dling techniques should be carefully evaluated to minimize the formati on of lycopene cis isomers in organic solutions.