Yield and Composition of Oil from Japanese Cornmint Fresh and Dry Material Harvested Successively

Abstract

A field experiment was conducted to evaluate the effect of harvest time and drying on Japanese cornmint (Mentha canadensis L.) cultivars Arvensis 2 and Arvensis 3 to optimize technology. Biomass yields were comparable to those reported in the literature. Arvensis 2 had greater oil content (0.78%) than Arvensis 3 (0.59%), while Arvensis 3 had higher concentrations of (‐)‐menthol (71.9%) and (‐)‐menthone (13.5%) than Arvensis 2 (61.7 and 9.4%, respectively). Arvensis 3 had higher fresh biomass (34,289 kg ha−1) than that of Arvensis 2 (23,929 kg ha−1). Dried biomass of the two cultivars was not significantly different. Higher oil yields were achieved from the fresh biomass of Arvensis 2 (108.7 kg ha−1), and lower from the dried biomass of Arvensis 2 (78.2 kg ha−1) and the fresh biomass of Arvensis 3 (84.3 kg ha−1). The concentration of (‐)‐menthol in the cultivars was higher at harvests 4 (69.3%) and 5 (67.7%), and lower at harvests 2 (63.6%) and 3 (64.7%). The yield of (‐)‐menthol was highest in harvest 4 (116.2 kg ha−1), lower in harvest 3 (78.4 kg ha−1) and lowest in the first harvest (19.1 kg ha−1). In northern Mississippi (or in other areas with similar latitude and environment), cornmint for production of (‐)‐menthol should be harvested in late July. For highest biomass yields, Arvensis 3 should be harvested in mid‐July, whereas Arvensis 2 should be harvested in late July. The essential oil profile of M. canadensis in this experiment was more desirable (with respect to (‐)‐menthol concentration) than the profile of two commercially available M. canadensis oil samples from other countries, which should make the oil produced in southeastern United States easily marketable.