Subcritical Extraction of Rosa alba L. in Static and Dynamic Modes

The chemical composition of Rosa alba L. aromatic products extracted with liquified 1,1,1,2-tetrafluoroethane (freon R134a) has been evaluated in static and dynamic modes of extraction. The yield varies in the range 0.039–0.048% for the different variants. In order to reveal the chemical composition and aroma profile of the extracts, they were analyzed by means of gas chromatography-mass spectrometry (GC-MS) and gas chromatography with flame ionization detection (GC-FID). As a result of the analysis, more than 80 compounds with concentrations higher than 0.01% were identified and quantified in the extracts, representing 92.7, 88.4, and 88.0% of the total content. The study indicated that 2-phenyl ethanol (12.57–14.97%), geraniol (12.09–14.82%), nerol (5.90–6.39%), benzyl alcohol (3.63–5.34%), and citronellol (3.21–4.04%) were the main components of the aroma-bearing fraction. The solid phase consists mainly of nonadecane+nonadecene (15.21–16.85%), heneicosane (11.81–13.78%), and tricosane (2.46–2.96%). In addition, olfactory evaluation of the extracts was performed. The comprehensive assessment of the quantitative and qualitative characteristics of the extracts indicates that the static, one-stage mode is the most appropriate for the subcritical extraction of R. alba blossoms with freon R134a.