Cumin - Cumin seed production, Functional properties

Cumin

Introduction

Cumin is a strong aromatic of dried ripe fruit (seed) of Cuminum cyminum L. (Apiaceae). It is variously known as: cumin, kummel, comino, zireh-e sabz, cumino, kemon, zira, kamun. Cumin is mentioned in Isaiah xxvi. 25 and , and Matthew xxii 2 , and in the work of Hippocrates and Dioscorides. From Pliny we learn that the Romans took ground seed medicinally with bread, water or wine. In the thirteenth and fourteenth centuries, it was much in use as a culinary spice.

Cumin is indigenous to northern Egypt, the Mediterranean region, Iran and India. Today it is cultivated in Mediterranean countries, Saudi Arabia, Iran, India, Mexico and China. Nowadays most cumin is grown in Iran, Sicily, India and Malta. Cumin is a mixture of united and separated mericarps; yellowish green or yellowish brown, elongated ovoid; 36 mm in length. The surface has five primary ridges alternating with four less distinct secondary ridges bearing numerous short hairs. Some fruits have a short attached stalk. These fruits (seeds) belong to a small annual herb 15 to 50 cm in height, with long slender and white roots, bidivaricated branching stem, long, narrow deep green slender leaves and small umbels of white or rose-coloured flower, covered with tiny hairs.

Chemical structure

Cumin has about 5% of volatile oil and about % fixed oil, together with tannins oleoresin, mucilage, gum, protein compounds and malates. The characteristic cumin odour is due to the presence of its essential oil. This odour and flavour is due principally to the aldehydes present (i.e, cuminic aldehyde) or cuminol, p-menth-3-en-7-ol and p- mentha 1,3-dien-7-ol). Studies of the chemical composition of cumin oil showed the presence of the following components: -pinene % , Myrcene % , limonene

, -cineole , p-menth-3-en-7-ol % , p-mentha-1, 3-dien-7-ol (5.6%), caryophyllene , -bisabolene , -pinene , P-cymene % , - phellandrene % , D-terpinene % , cuminic aldehyde % , cuminyl alcohol

-farnesene ) together with much smaller quantities of -phellandrene, - terpinene, cis and trans sabinene, Myrtenol, -terpineol and phellandral.

Production

Cumin seed production

Cumin is cultivated extensively as a cold-season crop on the plains and as a summer crop in the hills. In the south part of the Mashad province of Iran it is the main crop with an average production of about 2 0 tons per year. It is cultivated in northern India (the Himalayas, Punjab, Baluchistan, Kashmir) and also in eastern Europe.

For the summer crop the seeds are planted in early April. They should be sown in small pots, filled with light soil, and placed initially in a moderately warm bed to bring the plants on. They can then be hardened gradually in an open frame and transplanted into a warm border of good soil. The plants bloom in June and July, and are harvested when

of fruits are ripe. The fresh seeds are spread out on cloth to dry and, after drying, stored in cotton bags.

Cumin oil production

The ripe seeds are used for oil production, both as whole seeds or coarsely ground seeds. If a freely alcohol-soluble oil is required, the whole seed must be used. Hydrodistillation is used for essential oil extraction, producing a colourless or pale-yellow oily liquid with a strong odour. The yield for oil production varies from 5 to , depending on whether the entire seed or the coarsely ground seed is distilled. Cumin oil can be readily converted artificially into thymol. The volatile oil should be kept in well-sealed bottles or aluminium containers.

Main uses in food processing

Cumin seed is an ancient spice with a strong aromatic smell and warm, bitterish taste. It is widely used in Iran and India both as a condiment and flavouring in many eastern dishes. In Biblical times cumin seeds were valued for their digestive properties and were used for flavouring bread and other dishes during the periods of ceremonial fasting, to make up for the lack of meat.

Ground cumin can be added, for example, to lime or lemon-based marinades for chicken, turkey, lamb, and pork, or added to chilli, curries or spicy meat stews. It can be added to olive oil when stir-frying vegetables. Whole cumin is used to make various pickles in Iran, Pakistan and India. Cumin is a common flavour in confectionery, meat, sausage and bread manufacturing and as a preservative in food processing.

Functional properties

Cumin seed and distilled cumin are used as a stimulant, antispasmodic, carminative and antimicrobial agent. They are used as a carminative particularly in veterinary practice. Cumin is used widely in traditional medicine to treat flatulence, digestive disorders, diarrhoea and in the treatment of wounds.

Quality specifications

Specification for whole seeds Seeds are oblong in shape, thicker in the middle, compressed laterally, about 6 mm long, resembling caraway seeds, but lighter in colour and bristly instead of smooth, almost straight, instead of being curved. They have nine fine ridges, overlapping as many oil channels, or vittae. The odour and taste are somewhat like caraway, but less agreeable. Specific quality indices are:

 seed moisture: less than

 total ash:

 acid insoluble ash:

 volatile oil: minimum

 foreign organic matter: % (US maximum for harmless foreign matter:

Powdered seeds specification

The powdered seeds are yellowish-brown with an aromatic, slightly camphoraceous odour and taste. Distinctive characteristics are:

 The epicarp, composed of a layer of colourless cells, polygonal in surface view with thin sinuous walls and a faintly and irregularly striated cuticule; stomata are fairly frequent and, very occasionally, cicatrices may be present. Underlying the epicarps the thin-walled cells of the palisade are sometimes visible.

 The covering trichomes, which are usually found attached to small fragments of the epicarp; they are pluricellular, multiseriate and rounded at the apex, vary in length and are composed of fairly thick-walled cells.

 The sclereids from the mesocarp, of two main types: single layer and elongated cells. They are found frequently associated with the vasculare tissue.

 The fairly numerous pale yellowish-brown fragments of the vittae composed of fairly large, thin-walled cells, polygonal in surface view.

Volatile oil specification

The specific characteristics of cumin oil are:

 colourless or pale yellow

 specific gravity (25s/25sC), . 5 to

 optical rotation (20sC), + 3 to +

 refractive index, 1 to .

 solubility % ethanol), 8 vol

 aldehydes (as cuminic aldehyde) 0 to 52%. The physiochemical properties of volatile oils of cumin from various parts of the world are shown in Table . Cumin essential oil can be adulterated in several ways. One of the most difficult to detect is synthetic cuminaldehyde which cannot be detected easily, though it can affect the optical rotation of the oil. Modern analytical techniques such as stable isotope ratio analysis (SIRA) and selective ion monitoring (SIM) are

helpful in detecting adulteration of this kind.

Table 1 Physicochemical properties of volatile oils of cumin from different origins Property Mediterranean Mexico Iran India Pakistan Specific gravity at 15sC 4 6 1 5

Optical rotation at 15sC +4s22 to +5s6 +2s55 s s +4.6s Refractive index at s 4 7 8 1

Aldehyde as cuminaldehyde ) 0 0 4 0

Solubility in % alcohol (vols 5 vols 2 vols 6 vols 1 vols 8 vols required) and more

7 References

AMIN G. ), Popular Medicinal Plants of Iran, Deputy Minister of Health and

Education of Iran, p.

JACKSON, B.P. ), Powdered Vegetable Drugs, J. & A. Churchill Ltd., p.

LOEWENFELD, C. , The Complete Book of Herbs and Spice, Redwood Burn Ltd, p.1

NADKARNI, K.M. ), Indian Materia Medica, Bombay Popular Prakashan, p.132 REINECCIUS, G. (Ed.) ), Source Book of Flavours, Chapman & Hall, pp. SINGHAL, R. S. et al. Handbook of Indices of Food Quality and Authenticity,

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