Preparation of Kushui Rose (Rosa setate x Rosa rugosa) essential oil fractions by double molecular distillation: Aroma and biological activities

Kushui Rose (Rosa setate x Rosa rugosa, KR) is a distinctive Chinese rose variety. Its extracts, especially essential oil (EO), showed various biological activities. In this study, double molecular distillation was used to separate different fractions from KREO. GC-MS was used to detect the composition of volatile components in different fractions. The aroma analysis of different fractions was carried out by a professional sensory evaluation team. D1 (the light phase in the first stage) and R2 (the heavy phase in the second stage) showed better biological activities, with a lower IC50 value on antioxidant ability and a higher capacity for antimicrobial. Furthermore, D1 and R2 also effectively prevented the oxidation of sunflower oil. The antimicrobial mechanism was explored by relative conductivity, the content of protein and reducing sugar, and scanning electron microscopy on Escherichia coli. In all, molecular distillation could be considered an effective way to improve the aroma and biological activity for KREO.