Types of Turmeric

Many know turmeric only as the bright yellow powder found in their local supermarket and would be forgiven for believing that this colorful spice comes in only one variety. However, turmeric is a hugely diverse species of plant. The spice comes from a perennial plant named Curcuma Longa, which belongs to a family of ginger plants called Zingiberacae. This is native to South Asia, but around 133 species of Curcuma Longa have now been identified all over the world [1].

Turmeric can be grown in a variety of different growing conditions, making it possible for regions of many countries to produce it. It can be cultivated at up to 1,600 metres above sea level, in temperatures between 20-40ºC, and with rainfall of 1500mm [2]. These vastly different conditions produce a great variety of turmeric plants, each with unique health benefits, culinary uses and appearance.

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Picture: Different species of Curcuma that are used traditionally as a spice or as medicine [1].

Varieties of Curcuma Longa

India is the greatest producer of turmeric in the world, consuming most of what it produces and exporting its surplus to the rest of the world. The two main types consumed worldwide are ‘Madras’ and ‘Allepy’, both named after the regions of India where they are produced.

Allepy turmeric is the most popular type used in the US, as people here prefer its flavour and colour. The root is orange-yellow coloured and contains around 4% curcumin, which is the main bioactive compound in turmeric and gives the spice its colour [3]. It has an oil content of around 3-5.5% [2]. Madras turmeric is most popular in Britain and the Middle East due to its intense, light yellow colour, making it well-suited to mustard paste and curry powder. This variety contains only around 2% curcumin and 2% oils [2].

Turmeric is also produced in the Caribbean, Central and South America, though in much smaller quantities than in India. Varieties grown here tend to have a lower curcumin and oil content, making it darker in colour. This darker turmeric isn’t often found in the US. Another less common variety is Bengal turmeric, produced in South Asia, where it is usually used in dyes in India [2].

One unusual and notable variety produced by Curcuma Longa is Lakadong turmeric, produced in the Janita hills districts of Meghalaya. This type has a particularly high curcumin content of around 6-7.5% [4], making it particularly attractive to those looking to use turmeric for its health benefits. Curcumin has demonstrated anti-inflammatory, antioxidant, antimicrobial and many more beneficial effects in scientific studies, and is likely the reason for turmeric’s popularity in traditional medicine [5].

Shades of Turmeric

Even within a single type of turmeric, the shade of the root and therefore powder produced can vary as a result of growing conditions. Analysis of turmeric powder from Sri Lankan and Indian turmeric powders showed that samples with a brighter yellow colour generally contained a higher curcumin percentage, while those with a more muted orange-yellow shade contained less curcumin [6]. This is because curcumin imparts turmeric’s hallmark bright yellow colour. Turmeric grown in dark red soil usually has a deeper yellow colour and higher curcumin, protein and iron content. On the other hand, turmeric grown in gray soil usually has a greater calcium, potassium and magnesium content [7]. It contains less protein and has a lower curcumin content, giving it a duller shade. If purchasing turmeric for the health benefits imparted by curcumin, roots with a brighter yellow colour will likely indicate more beneficial soil conditions and higher curcumin content.

However, bright yellow turmeric powder is only an indicator of quality when buying from a reputable source. The FDA has issued alerts on some imported turmeric products from Bangladesh due to harmful levels of lead being present [8]. It’s possible that lead is used by traders to brighten the yellow colour of raw turmeric and hide marks of pest damage, or that another lead compound (which is red in colour) could be used to produce a darker orange or red colour [9].

Black Turmeric

One rare variety of turmeric is also a herb from the Zingoberaceae family, but is unusually blue-black in colour. It has more specific growing requirements than the more common varieties, being produced in hilly areas of India. It is classed as endangered due to its rarity. Black turmeric has been the subject of a small amount of research into its antifungal, anti-asthmatic, antioxidant, antibacterial and more possible properties, but knowledge on this topic so far is limited. For example, the oil from this variety has been shown to inhibit the activity of pathogens such as E.coli bacteria [10].

White Turmeric

Another unusual type of turmeric is produced from a variety of the species named Curcuma Zedoaria Rosc., a tropical, perennial herb [11]. Indigenous to India, Bangladesh and Sri Lanka, many parts of this plant are used in traditional medicine. Despite its unique colour it is also a good source of curcumin, as well as providing essential oils and gums. Extracts from black turmeric proved to have antimicrobial activity in one study. The root powder has been shown to reduce acid and gastric ulcers in the GI tract at doses of 200mg per kilogram of bodyweight [11]. Although much less commonly found and consumed worldwide than the yellow varieties, this plant is traditionally used to treat diarrhoea, flatulence, dyspepsia and more. If looking to purchase this, look out for its other names such as ‘zedoaria’ or ‘gajutsu’.

Table: Ethnomedicinal Uses of Curcumin Zedoaria [11].

Curcuma Aromatica

Curcuma Aromatica is yet another type of turmeric, commonly known as ‘Jangli Haldi’. It is mainly grown in the Bengal and Kerala areas of India and has a unique scent, prompting its use in traditional medicine in body deodorants and headache cures. Like other turmeric varieties, it has also shown antimicrobial, anti-tumour, anti-inflammatory and wound healing activity in scientific studies when consumed. Its roots are also commonly used in cooking in India, imparting a bitter flavour which is valued particularly for appetizers and condiments [12].

This article touches upon only a handful of the types of turmeric grown throughout the world. Turmeric is prized for its numerous uses in India yet only a couple of varieties dominate the market in the US and Europe. Search for knowledgeable, high-quality sources of this spice to explore the many flavours and benefits of these varieties.

References:

[1] Prasad, S. and Aggarwal, B.B., 2011. Turmeric, the golden spice. Herbal Medicine: Biomolecular and Clinical Aspects. 2nd edition.

[2] Lal, J., 2012. Turmeric, curcumin and our life: a review. Bull Environ Pharmacol Life Sci, 1(7), pp.11-17.

[3] Chattopadhyay, I., Biswas, K., Bandyopadhyay, U., & Banerjee, R. K. (2004). Turmeric and curcumin: Biological actions and medicinal applications. Current Science, 87(1), 44–53. http://www.jstor.org/stable/24107978

[4] PARISA, D. and BALUSAMY, A., Lakadong Turmeric.

[5] Hay, E., Lucariello, A., Contieri, M., Esposito, T., De Luca, A., Guerra, G. and Perna, A., 2019. Therapeutic effects of turmeric in several diseases: An overview. Chemico-biological interactions, 310, p.108729.

[6] Madushanka, G.D.M.P., Thilakarathne, R.C.N., Liyanage, T. and Navaratne, S.B., 2018. Analysis of curcumin content in Sri Lankan and Indian turmeric rhizomes and investigating its impact on the colour.

[7] Hossain, M.A. and Ishimine, Y., 2005. Growth, yield and quality of turmeric (Curcuma longa L.) cultivated on dark-red soil, gray soil and red soil in Okinawa, Japan. Plant Production Science, 8(4), pp.482-486.

[8] U.S. Food & Drug Administration, 2021. Import Alert 28-13. https://www.accessdata.fda.gov/cms_ia/importalert_1143.html

[9] Cowell, W., Ireland, T., Vorhees, D. and Heiger-Bernays, W., 2017. Ground turmeric as a source of lead exposure in the United States. Public Health Reports, 132(3), pp.289-293.

[10] Venugopal, A.R.Y.A., Rinu, K.A. and Joseph, D.H.A.N.I.S.H., 2017. Medicinal properties of black turmeric: A review. Innoriginal International Journal of Science, 4(3), pp.2-5.

[11] Lobo, R., Prabhu, K.S., Shirwaikar, A. and Shirwaikar, A., 2009. Curcuma zedoaria Rosc.(white turmeric): a review of its chemical, pharmacological and ethnomedicinal properties. Journal of Pharmacy and Pharmacology, 61(1), pp.13-21.

[12] Ahmed, S., Ansari, S., Ali, M., Bhatt, D. and Ansari, F., 2008. Phytochemical and biological investigations on curcuma aromatica: A review. Pharmacognosy Reviews, 2(3), p.151.