Food Product Design: Spice Rack - March 2001 - Turmeric Tales

March 2001

Turmeric Tales

Marco Polo, writing of his travels in China, reported: “There is also a vegetable which has all the properties of the true saffron, as well as the color, and yet it is not really saffron. It is held in great estimation, and being an ingredient in all their dishes, it bears, on that account, a high price.”

He was referring to turmeric, called Indian saffron in medieval times. Like saffron, turmeric is a powerful coloring agent. In the United States, it was imported and classified principally as a textile and leather dye until the development of aniline dyes in the 1930s.

U.S. turmeric consumption has increased. Part of its growing demand stems from the fact that it is an effective natural colorant; making it especially attractive to food manufacturers. Additionally, it is being used more often as a flavoring.


What is turmeric?
Turmeric comes from the roots of the perennial plant, Curcuma longa, which thrives in hot, moist tropical climates with well-drained soils. A member of the ginger family, it has long, lance-like leaves that shoot up from the rhizome to a height of 2 to 3 feet. The root consists of a central rhizome with numerous short “fingers” branching off from it. The root’s outer color is brownish-yellow, but may be lighter or darker, according to variety. The flesh inside the root is yellow to orange-yellow. When the root is dried and ground, the powder is yellow with an orange tint.
Turmeric is propagated from root cuttings; eight or nine months after planting, the roots are ready for harvest. Once harvested, they are “cured” — boiled in water or mild alkali. This procedure reduces drying time and gives the turmeric a more uniform color. The curing process differs in the various producing areas, but essentially, it is a combination of cooking and sun-drying.

Turmeric is not an aromatic spice. It has a mild odor and slight peppery flavor. A mixture of three polyphenol pigments synthesized in the plant’s rhizomes produces turmeric’s yellow hue. This collection of pigments commonly is called curcumin, and consists of curcumin (the dominant pigment), demethoxy curcumin, and bis- demethoxy curcumin.


The major types of turmeric
India is by far the world’s leading turmeric producer. Though only a small fraction of its production is exported, India supplies almost all of the turmeric used in the United States. Reportedly, 30 turmeric species grow in India, but only two designations are commercially significant: Madras and Alleppey. India keeps most of its Madras turmeric for domestic use and exports most of its Alleppey.

Alleppey turmeric has a higher color value, more flavor and is easier to grind than its Madras counterpart. Its volatile oil, or flavor principle, ranges from 3.5% to 5.5%. (Madras’ is approximately 2.0%.) Alleppey’s curcumin content, or color property, ranges from 4.0% to 6.5%. (Madras’ is approximately 2.0%.)

The Alleppey roots are brownish-yellow on the outside and deep yellow to orange-yellow internally. In contrast, the Madras roots are a lighter, brighter yellow internally, and this color difference, along with a different flavor quality, is what makes the Madras type more popular in India.

Two Alleppey grades are available on the U.S. market today: “fingers” and “splits and bulbs.” The former are the appendages separated from the main rhizome and broken into lengths of 1 to 3 inches. These are best for grinding and command a higher price. The “splits and bulbs” grade is made up of pieces from the main root that are fibrous and harder to grind.

Alleppey turmeric has a peppery, earthy odor and a slightly aromatic, bitter taste. Its flavor also is said to have gingery and nut-like undertones.

The United States also imports turmeric from the Pacific Islands and Thailand, but the total amount from these and all other sources is only about 3%.


Turmeric extractives
Curcumin delivers turmeric’s coloring strength. About 20 lbs. of dried turmeric root yields 1lb. of curcumin. Extraction is done overseas and in the United States, so there are imported, and domestic turmeric extractives found in the American market.

Turmeric oleoresin is the solvent extract of dried, ground rhizomes — the yield is about 10% to 12%. Oleoresin turmeric is available as-is, or may be mixed with solvents to make it either water- or oil-dispersible, or dispersible in both. The oleoresin also is available coated onto various dry carriers or as spray-dried product, making it easier to handle. A crystalline curcumin material may be refined from the oleoresin with a hydrocarbon solvent. This and certain other types of curcumin preparations provide coloring power without the characteristic turmeric flavor.


Buying/using turmeric
The higher the volatile-oil content, the more flavor and aroma turmeric has. The higher the curcumin content, the more coloring power it offers. Turmeric most often is used in prepared mustard — where color, flavor and aroma are important, though their relative importance differs with the mustard type. Ground turmeric finds use in curry powder by providing the characteristic color and contributing to the flavor.

Turmeric extractives are essential in many pickle, relish and sausage products. Chicken soup and broth often are colored with water-soluble turmeric. Flavor-sensitive products, such as cheese and other dairy products, use curcumin-based preparations that essentially are devoid of characteristic turmeric flavor. Flavorless product also is preferred for coloring food items, such as ice cream, lemonade, confections and baked products.

Oleoresin turmeric is blended with other coloring ingredients, such as oleoresin paprika and annatto extract, to attain various shades of yellows and reds. Natural colorants, such as turmeric, are becoming increasingly important to industrial users as safety issues arise for artificial coloring materials. Moreover, in response to consumer demand, many food manufacturers simply prefer to keep all their ingredients natural, or derived from natural sources.


How to handle turmeric
Ground turmeric should be stored in a cool, dry place protected from light. Excessive heat will volatilize and dissipate its aromatic essential oil; high humidity will cause it to cake; and sunlight will cause it to fade. Date containers when they arrive, so that older stock is used first. Tightly close containers after each use; prolonged exposure to air will cause flavor and aroma loss. Oleoresin turmeric should be stored at temperatures not exceeding 75°F.