Family: Labiatae
Genus: Mentha
Species: piperita
i) General background on the plant
A perennial plant growing to 30-80 cm and with a pungent taste and smell of peppermint. The flowers are lilac-pink. The plant grows in conditions such as are found on the sides of ditches and damp roadsides. The plant is cultivated as the source of peppermint and as an ornamental [1].
(ii) Details of quality characters
Peppermint oil is extracted from the plant by steam distillation.
A typical list of the constituents of peppermint oil is detailed below :
Alpha Pinene 1.4%
Beta Pinene 1.6%
Limonene 2.6%
Cineole + B. Phellandrene 7.9%
Menthone 24.1%
Mentofuran 2.4%
Iso Menthone 3.3%
Neomenthol 3.1%
Caryopyllene 2.5%
Menthol 38.7%
Pulegone 1.4%
Germacrene D 1.3%
Trans-Sabinene Hydrate 1.1%
(Aqua Oleum 1993)
(iii) Current production and yields
If the average oil yield could be raised to 60 kg/ha (possible according to Canadian work), the crop may be commercially feasible in Northern Europe. Present imports indicates home consumption could be satisfied by 12,000 ha of the crop if such a yield level could be obtained [2].
Season, soil and situation all influence the yield of peppermint oil, and its flavour and colour. When grown under ideal conditions, the yield of oil varies between 4 and 4.5 kg (0.9 kg = approximately 1 liter) per tonne of partly dried mint. A good yield would therefore be 35 to 44 kg of oil per hectare. (ADAS 1980)
English (Mitcham) peppermint oil has very variable yields, ranging from 22-44 kg/ha (Guenther, 1952)
(iv) Constraints on production
Peppermint grows well in moist soils, with the exception of heavy clays. The ground must be thoroughly cleaned to eradicate weeds, which would spoil the flavour of the oil.
Propagation is effected by means of suckers. These may be taken in the autumn, reared in cold frames and planted out in the spring, or may be planted out directly during the autumn, although the plants may be killed by frost over winter. The cuttings are placed about 30 cm apart. One hectare requires about 100,000 plants. A field is kept in mint for about four years.
(v) Markets and market potential
According to Verlet (1993) world production of peppermint oil was worth £64,000,000 in 1993. The phenomenal increase in the oral care market has enhanced the mint industry with the marketing of toothpastes, mouthwashes and related products being responsible for the increased demand.
(vi) Other information
(vii) Contacts
National
Herb Centre, Banbury Road, Warmington, Nr.
Banbury OX17 1DF, UK.
Tel: 01295 690999, Fax: 01295 690034.
(viii) References
1. Flora of the British Isles; Clapham, A. R.; Tutin, T. G. & Moore, D. M. (1987) 3rd Edition. Published Cambridge University Press
2. Smith, N. O. (1994) Department of Agriculture, University of Reading, Letter to Mrs Blackburn, Alternative crops unit, MAFF, Room 405, 10 Whitehall Place, London, SW1A 2HH.
3. Crops for industry and energy. (June 1994) Edited by Carruthers, S.P.; Miller, F. A.; Vaughan, C. M. A. Published Centre of Agricultural Strategy, University of Reading, RG6 2AT.
4.ADAS (1980) Culinary and medicinal herbs. HMSO.
5.Aqua Oleum (1993) The essential oil catalogue. Stroud, Glos.
6.Guenther, E. 1949. The Essential oils. R. E. Krieger Publishing Company, Inc. Florida. USA.
7.Varlet, N. (1993) Commercial aspects. In: Hay, K.R.M. and Waterman, P.G. (Eds.) Volatile oil crops; their biology, biochemistry and production. Longman.