Metabolomics of tomato fruit volatile compounds

Volatile compounds are important contributors to the tomato fruit flavour. In this study, ripe fruits of 96 tomato cultivars of three types (cherry, round and beef tomatoes) have been used. These were firstly analyzed for sensory attributes by a professional panel and then used to profile the volatile compounds using an automated SPME-GC-MS approach. After optimization of the system, this approach was shown to be a highly reproducible and reliable technique for volatile compound analysis. For an initial targeted analysis of 18 specific volatile compounds previously proposed to contribute to fragrance and taste, the ion specific peak areas were subjected to PCA. Clear correlations of known volatile compounds with the different tomato types as well as specific cultivars were identified. For an untargeted analysis “MetAlignTM” software was used for automated baseline correction and alignment of all 203 available GC-MS datasets in one automated run. The software detected over 20,000 masses. All masses appeared to cluster into about 350 mass groups, representing volatile compounds. PCA of the group-specific masses often revealed a clustering of chemically related compounds or compounds coming from the same biochemical pathway. Besides confirming the targeted approach it allowed identifying new compounds correlated to the targeted compounds and sensory attributes