Volatile flavor components and physicochemical indexes of Syrah grapes from Changli and Gaotai region

Using the 'Syrah' grape fruits from Changli, Hebei and Gaotai, Gansu as test materials, the changes of physicochemical indicators and volatile aroma components during the development period of 'Syrah' grape fruits in the two production areas were analyzed by conventional method and HS-SPME-GC-MS. The volatile aroma components were subjected to hierarchical clustering analysis (HCA) and principal component analysis (PCA). The results showed that the flowering period of grapes in Gaotai production area was later than that in Changli production area, and the accumulation of soluble solids and overall titratable acid content in grapes was relatively faster and higher than that in Changli production area. A total of 97 volatile aroma components were detected during the fruit development process of 'Syrah' grapes in two production areas, and the volatile substances could be divided into three categories by HCA. The first category mainly consisting of C₆ substances, the Changli production area was higher than the Gaotai production area, with contents ranging from 29.3% to 37.7% and 28.4% to 36.8%, respectively. The second category consists of some C₁₃ isoprenoids and most terpenes, with the highest content of (E)-β-sitone in the Gaotai production area (73.74 μg/L) compared to the Changli production area (53.28 μg/L). The third category consists of some terpenes and esters, and the content of these aromatic substances tends to be the same in the two production areas as the fruit matured. Principal component analysis could distinguish samples from different production areas and developmental stages. In summary, the accumulation time of volatile aroma compounds in the 'Syrah' grape fruit in the Gaotai and Changli production areas was generally earlier than that in the Changli production area, and the total accumulation amount was significantly higher than that in the Changli production area.