LYCOPENE AND HYDROXYMETHYLFURFURAL (HMF) EVALUATION IN TOMATO PRODUCTS

Abstract

Color of tomato products is due to the pigments content of fruit together with browning compounds originated during processing. To get a final product with a good is color is necessary to use fruits with an appropriated coloration and to avoid the degradation of pigments during post-harvest and processing. Final color should be bright and characteristic of each fruit. Lycopene, a liposoluble thermostable compound, is the main carotenoid of tomato fruit and it is responsible of its red color. Although tomato concentrate, as an intermediate industrial product, has many advantages, during processing a very energetic treatment is applied, which may easily alter the product, basically by browning reactions, with the formation of hydroxymethylfurfural (HMF). Thermal treatment, together with the storage conditions and transportation can affect the chemical composition and final characteristics of the product. In this paper Lycopene and HMF content have been evaluated in commercial tomato products: juices and ketchup. Analytical methods applied were as follow: Lycopene by spectrophotometric determination at 503 nm, and HMF by a colorimetric method based on the thiobarbituric acid (TBA) color reaction with 5hydroxymethylfurfural measured at 443 nm, after clarification of samples with Carrez solutions. Lycopene concentrations in samples analyzed ranged between 6 – 15 mg/100g and HMF content ranged between 0,2 –4,0 mg/100g, with higher values for ketchups than juices in both parameters.