Effect of thermal treatment in the headspace volatile compounds of tomato juice.

Volatile compounds of tomato juice include compounds of the original fruit, such as terpenes, and other substances that are originated during processing by lipoxygenase activity, carotenoid cooxidation and Maillard reaction. This paper reports: a) a comparison between solid phase microextraction (SPME) and traditional static (SHSA) and dynamic headspace (DHSA); b) optimization of SPME; c) evaluation of the volatile compounds of tomato juice under different conditions of thermal treatment. Results were analyzed by multivariate statistical analysis. One hundred ninety and 219 volatile compounds were sampled using SPME and traditional SHSA and DHSA, respectively; these compounds belonged to the following chemical classes: ketones, aldehydes, alcohols, esters, ethers, hydrocarbons, sulfur, nitrogen and oxygen compounds, phenols, oxygen-containing heterocyclic compounds, free acids and :Lactones. The thermal treatment mainly modified saturated and unsaturated Cg alcohols and aldehydes, terpene and carotenoid derivatives.