The name M. arvensis is used internationally to indicate both the plant and the essential oil. The most widespread
varieties include M. arvensis var. peperascens Holmes (Brazil, Japan) and M. arvensis var. glabrata Holmes (China). M. arvensis
is an herbaceous plant from 40 to 85 cm (16 to 33 in.) in height; it is cultivated extensively in China, Japan, Brazil and South Africa.
The plant has a long, creeping root with secondary roots, opposite leaves, slender embranched stalk and flowers growing in round
clusters at the joint of the leaves. The flowering tops are the parts used. Mentha arvensis has a fresh, strong menthol odor and a cool
mint flavor; less smooth than true peppermint oil. The oil produced in Japan, Brazil and China is put on the market partially dementholated, as the oil is used to extract menthol. The
menthol content is thus reduced by 40 to 50%. Yields of distillation vary between 0.5 and 1.0%, depending on the source of the raw
material. The oils exhibit a strong, characteristic menthol odor. Menthol is separated from the essential oil by crystallization at low
temperature and subsequent centrifugation.
物理的性質
The oil is a colorless to yellow liquid. It is soluble in most fixed oils, mineral oil and propylene
glycol. It is insoluble in glycerin.
