Mass spectrometry-based metabolomics study for delay tomato fruit ripening by sound waves

Abstract

Tomato (Solanum lycopersicum L.) is one of the most consumed vegetables worldwide. The ripening of tomato is performed for its freshness and represented by color and gene expression. In our previous study, we performed molecular analyses on tomato ripening with and without sound-wave treatment. In the present study, we performed metabolomics analysis of ripening tomatoes with and without sound-wave treatment to expand our knowledge of tomato ripening. To achieve this goal, tomatoes at 7, 10, and 14 d of ripening were selected and analyzed via liquid chromatography–mass spectrometry (LC–MS) and gas chromatography–MS (GC–MS). A total of 33 major metabolites, including 14 LC–MS- and 19 GC–MS-derived metabolites, were assigned based on variable importance projection and p values and subjected to statistical analysis. Apparent morphology and partial least squares–discriminant analysis were consistent with the general ripening process based on color. Moreover, metabolomics analysis showed similar experimental results to those of previous studies. The quantification of metabolites with LC–MS showed decreasing levels of adenosine, tryptophan, and phytosphingosine upon sound-wave treatment. In GC–MS analysis, 4-Aminobutanoic acid and aspartic acid were decreased upon sound-wave treatment. On the other way, the quantity of malic acid, citric acid, and sucrose was increased with the treatment. The findings of this study can assist in the application of sound-wave treatment for delaying ripening in tomatoes and improving their market value.