Aroma release regularities of Rosa damascena from Xuancheng via HS-GC-IMS and P&T-GC-MS

Damascus rose (DR) is an important economic crop. In recent years, DR has been widely planted and utilized in China. In order to improve its aroma quality, the volatile releasing regularities of DR need to be studied. Therefore, HS-GC-IMS were used to examine the style of aroma release in DR under three flowering states: pre- bloom (PB), half- bloom (HB) and full bloom (FB). The results show that HS-GC-IMS detected 56 volatile compounds to investigate the changes of volatile compounds in three states of DR during the growth period. The results of PCA showed that changes in aroma substances were obvious during the growth stage of DR. In addition, FB con-tributed some key aroma molecules of DR. Thus, volatiles in DR at different times of a day (5 AM, 11 AM, 5 PM) and were further examined by using P&T-GC-MS towards FB. Finally, a total of 68 volatile compounds were identified; most of them were ter-penoids (47.83%-59.62%). Totally 21 volatiles were considered key compounds due to their high concentration (>= 1%). These key compounds showed the highest levels at 5 AM and lowest levels at 5 PM. Heat map clustering showed that most of the key compounds possessing higher levels in the flowers had maximum levels at 5 AM and compounds with lower levels peaked at 11 AM. This study will provide a theoretical understanding of the aroma generation mechanism of DR. It also helps the rose farm-ers to plant and sow rose flowers practically.