Effects of post harvest drying on the yield of tea tree oil (Melaleuca alternifolia)

Drying tea tree leaf on the stem increased the oil content from 5.8% to 7.4% yield v/dw. This increase is not a result of changing moisture content but appears to be due to an active form of postharvest oil uptake or production. The value to oil producers of drying and storing leaf prior to distillation is a more efficient distillation system. At present, distillation occurs as close as possible to foliage harvest with the aim of reducing any chance of oil volatilization. These results show that the need for immediate distillation of cut foliage is unnecessary, as the delay would actually improve the yield rather than reduce it. For the industry these results could change the accepted methods of production. To date each producer had to have their own distillation plant as a way of avoiding distillation delays and the need for carting wet leaf material. Since drying leaves on the stems of the tree increases the oil yield and since the removal of leaves from the stem is easily accomplished when the leaves are dried, producers need only have storage and leaf stripping facilities. This would enable pure leaf to be transferred cheaply to a central distillery when a sufficient load is achieved