2.1.4. Cyclic monoterpenes
These terpenes have a single ring and are more stable with relatively
high aroma thresholds compared to their acyclic equivalents.
Limonene and p-cymene were the major cyclic
monoterpenes found in this study. Limonene alone contributed
to almost 60% of lemon–lime total volatile composition. Volkamer
lemon blossom’s monoterpene composition resembled that of
mandarins more than other lemons–limes. However, appreciable
levels of limonene (12%) further differentiated this cultivar from
mandarins. In contrast, Pummelo blossoms also differed from all
other cultivars due to high levels (13.6%) of p-cymene. No other
cultivar had more than 4.1%, with most containing between 0.6%
and 2% of total volatiles.