DISTILLATION AND PROCESSING OF MENTHA OIL IN INDIA

Distillation & Processing of Mentha

The Oil derived from the Mentha Arvensis herb (MENTHA OIL) by steam distillation, which is the basic raw material required for the Menthol Manufacture. By freezing (chilling) of Mentha oil L‐Menthol (Crystals & Flakes) are isolated. In India there is two type of Menthol ‐ CRYSTALS & FLAKES, some manufacturers are processing to their shape and size BOLD (Large crystals, Medium crystals, Small crystals, Flakes in shape of powder. Rest mother liquor by centrifuging calls De‐mentholised Peppermint oil. Menthol is main constitutent in Mentha oil Rest contains Menthone, Menthyl Acetate, Neo‐menthol, Mint terpenes, Alfa‐pinene, Beta ‐ Pinene.

L‐limonene, 3 Octanol, Pipritone are also main contents to use as raw material to produce Value added products for Flavour and fragrances Industry.

Menthol mint essential oil is the main source of natural menthol.

The dementholised oil (DMO) is reconstituted to produce oil similar to Mentha piperita oil. Several of the many dozens of terpenes present in the essential oil are valuable compounds that find uses in the cosmetic and pharmaceutical industries. Menthol itself is used as a flavouring agent mouth‐related produces such as fresheners, tooth pastes and chewing gums, etc. Menthol mint oil because of its antimicrobial properties enhances the shelf of edible products and grains. Menthol mint oil is an essential ingredient of the ointments, pain balms, lozenges and syrups. It is also used in cosmetic preparations, colognes, deodorants, cosmetics, etc. In India, menthol and mint oil are extensively used in betel (pan) related industries.

Menthol is generally obtained by chilling mint oil and subsequent centrifuging to separate out the menthol crystals. The process may be divided into two steps, firstly menthol flakes are produced by chilling mint oil and secondly menthol flakes mixed with mint oil again chilled to produce bold crystals of menthol. The total recovery of menthol in the first step is around 70% . The time cycle for first step is around 6‐7 days. In the second step, menthol flakes mixed with certain proportion of mint oil kept under temperature control for about 25 days.The mother liquor (conc. Mint oil ) is a bye product and can be used again till decolourisation of oil occurs. Total recovery of bold menthol crystals is about 50 % .

The details of cost involved in the distillation of mentha oil by farmers were also analyzed and it was revealed that, small units of mentha distillation large farmers did not go for hired distillation as all of them had their own distillation unit. The distillation cost incurred per kg of mentha oil was around Rs.58/- on overall basis. It was around Rs.43/- per kg for marginal and small farmers and a little higher cost was incurred by medium farmers (Rs. 46/kg).