Comparison of the nutritional as well as the volatile composition of in-season and off-season Hezuo 903 tomato at red stage

The influence of the planting season on the nutritional as well as the aromatic composition of Hezuo 903 tomato was investigated by combining use of nutrition analysis, sensory evaluation, electronic nose and electronic tongue analysis, gas chromatography–mass spectrometry (GC–MS) and GC–MS–olfactometry (GC–MS–O) method. The results suggested that in-season tomato contained higher levels of reducing sugar, vitamin C and lycopene than off-season tomato. In-season tomato showed a better overall flavor and acceptability than off-season tomato. Significant difference was observed in both composition and concentration of the typical volatile and aroma-active compounds in two samples. E-2-Hexenal and methyl salicylate were only found in off-season tomato, and phenylacetaldehyde detected merely in in-season tomato. In addition, significantly higher levels of 6-methyl-5-hepten-2-one ( P  < 0.01) and 2-isobutylthiazole ( P  < 0.01) were detected in off-season tomato than in-season tomato, which showed a negative effect on the overall flavor of tomato. Our result indicated that the planting season affected the composition and concentration of both non-volatile and volatile compounds of tomato fruit.