The Physico-Chemical Properties of Spear and Peppermint Volatile Oils

Mint is a genus of labiatae (Lamiaceae) family, which comprises a wide number of species, varieties and hybrids, that are cultivated commercially in different regions all over the world. Peppermint (Mentha piperita) and spearmint (Mentha spicata) are considered the most important species in mint genus (Salem, 2007). Mint has been used as a medicinal and aromatic plant since ancient times. Storing of volatile oil causes deterioration and reduction in the oil quality. The main processes affecting the oil quality during storage are: oxidation, resinification, polymerization, hydrolysis of esters and exchanging of the effective groups. It is clear that the oil deterioration is increased by many factors such as; temperature, light, oxygen and moisture content of the oil (Hikal and Omer, 1993). The aim of this study was to evaluate the effect of the above mentioned factors on spear and peppermint volatile oils to determine the proper storage conditions of the oils to extend its shelf life. It was also conducted to make more information available on mint essential oils storage and factors affecting it.