Analysis of the Volatile Components in Different Varieties of Dazeshan Grapes and Their Extracts

In order to explore the differences in aroma among different varieties of Dazeshan grape (a national geographical indication product) and their extracts, the volatile components of three grapes and their soxhlet reflux extracts and water extraction ethanol precipitation extracts were determined by headspace solid-phase microextraction-gas chromatography-mass spectrometry in this study. Key volatile compounds and aroma active ingredients from different grapes and their extracts were screened by orthogonal partial least squares-discriminant analysis model combined with relative odor activity values. The aroma quality of different grapes and their extracts was evaluated by principal component analysis and cluster analysis. Results showed that a total of 124 volatile components were identified in grapes and their extracts, mainly including alcohols, aldehydes, ketones and esters. The types and concentrations of volatile components were significantly different (P<0.05). Kyoho grape, Gold Finger grape and their extracts mainly consisted of aldehydes, while Muscat Hamburg grape and their extract were alcohols. Twenty-nine key volatile components with VIP>1 were screened, wherein the β-damascone was a key aroma components in three grapes and their extracts. The nonanal was a characteristic component in Kyoho grape and their extracts, while the phenylacetaldehyde was characteristic component in Gold Finger grape and their extracts. In contrast, the linalool, geraniol, and α-terpineol were characteristic components in Muscat Hamburg grape and their extracts. The above components could be considered as the key aroma components to distinguish among grapes and their extracts. Additionally, the aroma quality of Muscat Hamburg grape and their extracts were better than other grapes and their extracts. This study revealed the differences of the aroma components of different grapes and their extracts, which could provide reference for the quality evaluation of Dazeshan grapes and further development and utilization of grape extracts.