Abstract:

The free volatile compounds of wild Rosa roxburghii juice were extracted by head-space solid phase microextraction
(HS-SPME) and the O-glycosidically bound volatile compounds were released by enzymatic hydrolysis for
analysis by gas chromatography-olfactometry (GC-O) coupled with mass spectrometry (MS). The results showed that 23
free aroma active compounds and 17 O-glycosidically bound aroma active compounds were identified in R. roxburghii
juice. The major free aroma active compounds were ethyl butyrate (grassy aroma), hexyl alcohol (winy aroma), capryl
alcohol (sweet aroma), ethyl isovalerate (pineapple aroma), leaf alcohol (tea aroma), styrene (fruity aroma), β-myrcene
(sweet balsam aroma), linalool (lemon aroma), etc. The major O-glycosidically bound aroma active compounds were ethyl
3-hydroxyhexanoate (fruity aroma), ethyl 3-hydroxybutyrate (fruity or grape aroma), 2-heptanol (lemon aroma), leaf alcohol
(tea aroma), capryl alcohol (sweet aroma), phenylethyl alcohol (rose aroma) and 2’-hydroxy-4’,5’-dimethylacetophenone
(flower or sweet aroma) etc. Leaf alcohol, capryl alcohol and octanoic acid were the active aroma compounds existing in
both free and O-glycosidically- states in wild R. roxburghii juice. Both free volatile compounds and O-glycosidically bound
volatile compounds were mainly responsible for fruity/sweet fragrance. But, the overall aroma strength of the latter was
relatively weaker than that of the former.

Key words: Rosa roxburghii Tratt, gas chromatograph-olfactory-mass spectrometry (GC-O-MS), aroma active compounds, free state, O-glycosidically bound state