Volatile aroma constituents of Sri Lankan ginger

Two types of Sri Lankan ginger were examined (Sidda and Chinese varieties) and essential oils of both fresh and dried samples were prepared by standard procedures. Both varieties yielded relatively high percentages of oil (between 1.8 and 4.3%) and total aroma volatiles (ca 5 mg/g for dried samples). Analysis by GC and GC/MS showed terpenes to be the main aroma components (ca 99% for all samples). A number of the identified compounds have not previously been reported as ginger volatiles, including trans-β-ocimene, thujyl alcohol, terpinen-4-ol, myrtenal, guaiene, α-cubebene, δ-cadinene and farnesol. On drying, both varieties of Sri Lankan ginger showed considerable decrease in monoterpene content and very high increase in sesquiterpene concentration. Comparing the aroma volatiles of Sri Lankan dried ginger with those previously reported for dried ginger from some other countries, it was concluded that Sri Lankan ginger was as good as, if not superior to, other types. In particular, SriLankan dried ginger showed high levels of ar-curcumene together with reasonable levels of citral isomers and all other constituents previously claimed to be important to ginger aroma. Sri Lankan ginger would appear to be unusual in containing very low amounts of zingiberene but very high amounts of β-bisabolene.