Characterization of aldehydes and hydroxy acids as the main contribution to the traditional Chinese rose vinegar by flavor and taste analyses.

The volatile aroma compounds of traditional Chinese rose vinegar were identified by headspace solid-phase micro extraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) and GC-MS-olfactometry (GC-MS-O), and the metabolites were identified by silylation-GC-MS in this study. A total of 48 and 76 kinds of flavors and metabolites, respectively were detected in this study. Quantitative analysis showed that aldehydes and acids were present in relatively high amounts. Furthermore, the data colleted by the calculated odor activity values (OAVs) suggested that aldehydes are likely to contribute greatly to the aroma of traditional Chinese rose vinegar, especially, nonanal (OAV: 133, rose), 3-methyl-butanal (OAV: 57, apple-like), decanal (OAV: 23, orange peel), heptanal (OAV: 17, fruity), and dodecanal (OAV: 4-9, violet scents). Moreover, among the detected nonvolatile acids, 14 kinds of hydroxy acids, such as lactic acid, citric acid, 3-phenyllactic acid (PLA) and d-gluconic acid were detected in rose vinegar. The acids provide a well buffer system, not only greatly reduce the irritation of acetic acid, but also improve the flavor of rose vinegar. This study suggests that the fragrance and sour notes in rose vinegar are from aldehydes and hydroxy acids.