Influence of Harvesting Stage and Distillation Time of Damask Rose (Rosa damascena Mill.) Flowers on Essential Oil Content and Composition in the Western Himalayas

Abstract

Experiments were conducted to study the influence of harvesting stage and distillation time of damask rose. In the first experiment, damask rose flowers were harvested in six different stages beginning from stage 1 (HS1) where sepals were intact with dark immature petals to stage 6 (HS6) when flower opened previous day. Results revealed that stage HS4 (petal whorl opened) remained at par with HS3 (petal whorl loosened) and HS5 (fully opened flower). Furthermore, the essential oil produced in the HS4 stage recorded higher cis-rose oxide, citronellol+nerol, geraniol and lower nonadecane content than other stages. In second experiment of flower distillation time, damask rose flowers were distilled for 3 h, 4 h, 5 h, 6 h and 7 h and replicated three times. The essential oil content (0.067 %) and the concentration of citronellol+nerol (31.69±1.00 %) and geraniol (19.39±1.81 %) reached a maximum by extending distillation time up to 5 h. Linalool, phenyl ethyl alcohol, citronellol+nerol and trans-geraniol concentration increased up to 5 h of distillation and decreased thereafter. This study demonstrated that distillation time can significantly modify the essential oil yield and composition of damask rose. Moreover, distillation time could be used to obtain rose oil with targeted chemical profiles.