Abstract:To understand the quality and volatile substances in different grape varieties, the components and relative contents of volatile substances in the fresh grapes of four different varieties were measured using head space solid-phase micro extraction combined with gas chromatography mass spectrometry. An electronic nose (E-nose) was used to verify the results, and the quality characteristics were analyzed. Significant differences were found in the quality indicators among the four varieties. Among them, seedless Han Xiang-mi had a relatively high soluble solid content and titratable acidity, and Xiang Yue had high vitamin C content and fruit firmness. From the matured fruits of the four varieties, 87 volatile substances were detected and most of them were alcohols, esters and aldehydes. Differences were also found in the volatile substance content. Xiang Yue, Muscat Hambourg, Jin Shou-zhi, and Han Xiang-mi had the highest relative content of ethyl acetate, linalool, leaf aldehyde and ethyl acetate, respectively, and the corresponding flavors were strawberry flavor, rich aroma of roses, fresh green leafy aroma, and strawberry flavor, respectively. The volatile substances were also analyzed by the electronic nose, principal component analysis, and linear discriminant analysis, which could successfully differentiate the four different varieties. Therefore, the post-harvest quality differences in grapes were determined and the approach employing an electronic nose combined with GC-MS can effectively evaluate the volatile substances in grapes.
