Relationships between the volatile compounds evaluated by solid phase microextraction and the thermal treatment of tomato juice: optimization of the blanching parameters

Tomato juice contains volatile compounds that are originally detected in fruit, such as terpenes, and others that are originated during processing by lipoxygenase activity, carotenoid co-oxidation and Maillard reaction that can be activated during the thermal treatments. This paper reports the analysis of the volatile compounds of tomato juice sampled by solid phase microextraction (SPME) and the optimization of the blanching parameters in tomato juice, using the volatile compounds as markers. One hundred and ninety volatile compounds, including ketones, aldehydes, alcohols, esters, ethers, hydrocarbons, sulfur, nitrogen and oxygen compounds, phenols, oxygen-containing heterocyclic compounds, free acids and lactones, were identified or tentatively identified by the GC–MS technique. The thermal treatment mainly modifies saturated and unsaturated C6 alcohols and aldehydes, esters, ketones and carotenoid derivatives. The optimal conditions for the blanching, selected by response surface modelling (RSM), were 67°C for 24 min and 86°C for 3.5 min for the cold break and the hot break treatments, respectively.