Cardamom (small) - Production, Quality standards and grade specifications

Cardamom (small)

1 Introduction Small cardamom, popularly known as Queen of Spices, is the dried fruit of the tall perennial herbaceous plant, Elettaria cardamomum Maton, belonging to the family Zingiberaceae. It is a shade loving plant cultivated at an altitude of 600 to 1200 m above MSL with an annual rainfall of 1500 to 4000 mm and a temperature range of 10 to 35sC. Until recently India was the main producer and exporter of cardamom. Of late Guatemala has emerged as a keen competitor to Indian cardamom in the international spice market. Tanzania, Sri Lanka, El Salvador, Vietnam, Laos, Cambodia and Papua New Guinea are the other cardamom growing countries. In India, cardamom is cultivated in the southern states of Kerala, Karnataka and Tamil Nadu. Kerala accounts for 60% of the cultivation and production followed by Karnataka 30% and Tamil Nadu 10%. The physical and chemical characteristerics of cardamom from different growing regions in India is shown in Table 1.

Cardamom oil is used in food, perfumery and liquor and pharmaceutical industries as a flavour and a carminative. Its use in the food industry is in flavouring pickles, meat and canned soups. However, the oil is reported to develop some off flavour in a few days when it contacts with air; its use is therefore restricted to fresh meat products and foods with short shelf-life. Increasing use of cardamom oil is reported in compounded flavours for baked goods, sauces and condiments. Cardamom oil is reported to be gaining increasing use in perfumery, with a trend to spicy tones modifying the dominant lavender group perfumes for women (ITC, Markets for Essential Oils and Oleoresins 1974).

Cardamom is used as an adjuvant to carminative drugs. It is officially recognised in British and US pharmacopoeias and used as an aromatic stimulant, carminative and flavouring agent. It can be used to ease cigarette addiction. Eating a few seeds of cardamom can safely be recommended to initially minimise the number of cigarettes being smoked, and slowly the smoker may give up the chronic addiction to chain smoking.

Table 1 Composition of cardamom

Region of Weight Husk Seed Volatile NVEE* Starch Fibre Protein growth of 100 (%) (%) oil (%) (%) (%) crude (N 6.25)

capsules (%) (%)

(g)

Karnataka

Mudigere 2324 25.528.0 72.074.5 8.68.9 2.03.6 47.048.0 6.96.8 8.811.3

Coorg 2325 26.027.0 73.074.0 14 2.23.1 47.748.0 6.72.7 10.5

Kerala

Wynard 2022 28.038.0 62.072.0 7.510.0 2.22.4 3143.7 8.43 714.0

Alleppey 23 27.7 72.3 46 2.2 37.8

green

Tamil Nadu

Yercaud 2326 27.0 73.0 46 2.4 45.5 7.0 8

Nelliampathy 1218 26.031.0 74.0 8.510.5 2.53.5 43.046.0 512.8 10.711.5

* NVEE non-volatile ether extracts.

Sources: Kasturi and Iyer (1955), Krishnamurthy (1964) and Natarajan et al. (1968).

2 Description

Cardamom is indigenous to the evergreen rainforests of western ghats of Southern India from where it spread to other tropical countries such as Sri Lanka, Tanzania and a few Central American countries. Presently it is being cultivated in countries lying between

20s latitude north and south. Cardamom was an article of Greek trade during the fourth century BC. It was listed among the Indian spices liable to duty at Alexandria in AD 176

(Rosengarten 1969).

E. Cardamomum exhibits considerable variation under cultivation and the naming of commercial types after the places of production has led to confusion regarding the identity of the varieties. Two varieties based on the size of the fruits are recognized. They are : (1) E.cardamomum var. Major Thw. comprising the wild indigenous cardamom of Ceylon or Greater oblong cardamom or long cardamom and (2) E.cardamomum var. minor comprising all the cultivated races, particularly those included under the names Malabar and Mysore cardamoms. Var. major is the more primitive variety from which the cultivated var. minor is derived. All the varieties and races are interfertile and the observed variations are probably due to natural crossing. The genus belongs to the natural order Scitaminae, family Zingiberaceae under monocotyledons with diploid chromosome number, 2n = 48.

2 Production

2.1 Harvesting

The peak period of harvest is OctoberNovember. The average yield of cardamom is around 150 kg (dry)/ha; however, record yield of 695 kg/ha (average of 9 crop seasons) was obtained by adopting high production technology directly in farmers plantations

(Korikanthimath 1995). Just ripened fruits or physiologically ripened are generally harvested. More splitting of capsules was observed in over-matured capsules

(Korikanthimath and Naidu 1986). Percentage of dry recovery was highest (29%) in the fully ripened capsules followed by the one harvested at physiological maturity (24%) and in immature stage (14%). Capsules may be washed in water to remove the adhering soil and a treatment with 2% washing soda (alkali) for 10 minutes enables retention of the green colour and prevents growth of mould.

3.2 Curing

In curing, moisture of green cardamom is reduced from 80% to 12% (wet basis) at an optimum temperature (50s) so as to retain its green colour to the maximum extent.

 Natural (sun) drying. This requires 56 days and the green colour is bleached by this method.

 Electrical drier. Fifty kg capsules can be dried in 1012 hrs at 4550sC retaining the green colour.

 Flue pipe curing. This is the convenient method of curing from which high-quality green cardamom can be obtained. The structure consists of walls made of bricks or stones and tiled roof with ceiling. A pipe made of iron or zinc sheet starting from the furnace passes through the chamber and opens outside the roof. The heated air current generated in the furnace passes through the pipe and increases the temperature of the room. The fans located either sides of the wall uniformly spread the temperature. Inside the room the cardamom to be dried is kept in wooden/aluminium trays arranged in racks. The fire in the furnace is adjusted to maintain the temperature between 45

50sC. Drying takes about 18 to 22 hours (Korikanthimath 1993).

3.3 Bleached cardamom

Bleached cardamom is creamy white or golden yellow in colour. It can be done with either the dried capsule or freshly harvested capsules. It is prepared using sulphur dioxide, potassium metabisulphite (25% containing 1% HCl for 30 min) and hydrogen peroxide (46% at pH 4.0). However bleached cardamom tends to lose more volatile oil.

3.4 Ground cardamom

A large portion of the cardamom imported into western countries is to meet industrial and institutional requirements for bulk supply of ground cardamom (Survey of the World Market, 1977).

Proper maturity reflected by deep brown, shining seeds with satisfactory weight per litre specifications and good characteristic aroma are the factors necessary for making good quality ground cardamom. In cardamom, the presence of the oil cells near the surface which contains aroma-significant components like 1,8-cineole poses special problems due to the high temperatures produced in attrition and grinding. To overcome the loss of volatiles, prechilling and reduced temperature grinding are used (Anon. 1975). A new innovation for idealized grinding of spices is freeze-grinding ( 70sC) which has many advantages; increased retention of volatiles, minimizing oxidation of volatiles, increased throughput and improved functional properties of dispersability of the fine ground material in food preparation (Russo 1976).

Ground spice deteriorates in its aroma quality both by rapid loss of volatile and by the action of oxygen in the head space on the terpenic and lipid components of the spice. This

loss could be controlled by careful selection of packaging materials. Gerhardt (1972) found that of the different packaging material studied, lacquered cans, PVDC and HDPE gave the smallest loss of ethereal oils in powdered cardamom. Koller (1976) found that among several factors influencing flavour quality of vacuum-packaged ground cardamom, temperature not exceeding +5sC was the most important. Cardamom in powder form could be stored vacuum-packed in laminater such as polyamide/ polyethylene or cellophane or lacquered can for 12 months at 18sC.

3.5 Cardamom volatile oil The most functionally important constituent of cardamom is the volatile oil. The volatile oil content of seeds varies from 6.610.6% for the two types of cardamom (cv. Mysore and Malabar) grown in India (Krishnamurthy 1964; Krishnamurthy et al. 1967; Korikanthimath et al. 1999). In immature capsules the volatile oil content is low, in the order of 45%. The husk is reported to yield 0.2% volatile oil, having properties similar to those of seed oil (Rao et al. 1925). Yields of the volatile oil varied over a wide range: for seeds from 3.4 to 8.6% and for dried capsules from 5.2 to 11.3%.

Many developing countries have been producing different aromatic volatile oils by steam distillation over a long period. Among the different distillation methods, steam distillation is the preferred method. Esters have been known to be important for cardamom aroma. Other important control factors for obtaining uniform and typical aroma quality of the oil are the rate and time of distillation. Use of top grades of cardamom for distillation of oil is not economical. Lower grades which are good from the point of view of flavour, but do not command high prices as dry capsules because of defects in appearance, are generally used. The less mature, pale brown seeds contain less oil and flavour quality is also different.

The specifications of the Essential Oils Association (EOA), US, which are generally accepted by all countries are given in Table 2.

Nambudiri et al. (1968) described a stainless steel still, consisting of a material holding cage, condenser and receiver for steam distillators and the conditions of distillation for obtaining acceptable quality oil. Selected material from the lower grades containing seeds of good maturity are first dehusked by shear in a disk mill with wide distances between disks and seeds separated by vibrating sieves. The seeds are again put through the same mill, but closing the distance between the disks to crush the seeds into a coarse powder. The essential oil glands are in a single layer below the epidermal layer and fine milling will result in loss of volatile oil. Freshly powdered coarse grains of cardamom are uniformly and loosely packed into the holding chamber with a perforated bottom. When the cover of the distillation vessel is fitted securely and connected to the tabular condenser, steam at low pressure is let in through a perforated manifold. For efficient distillation, the design of the retort and packing of the powdered cardamom should ensure that the steam passes through the bed uniformly without passing the cage or channelling. Other important controls are the rate and total time of distillation. It was recommended that the distillation be continued for two to three hours.

The large volume of condensate was collected in a cylindrical oil trap which siphoned off the excess water continuously, which if allowed to accumulate, could result in loss of oil by saturation and also cause compositional variation due to differential dissolution of the components. It was found that it is better to keep the condensate warm to get a better separation of volatile oil. The oil floating at the top was collected by lapping through another conical vessel which functioned as a second separator of any residual moisture.

Table 2 Specifications for cardamom volatile oil

Definition Volatile oil distilled from the seeds E.cardamomum Maton

Source Family Zingiberaceace

Cardamom grown in South India, Ceylon, Guatemala, Indonesia, Thailand and South China.

Physical and chemical constants

Appearance: Colourless to very pale yellow liquid.

Odour and taste: Aromatic, penetrating, somewhat camphoraceous odour of cardamom:

persistently pungent, strongly aromatic taste. Specific gravity: 0.917 to 0.947 at 25^oC

Optical rotation: + 22^o to + 44^o

Refractive index: 1.463 to 1.466 at 20^oC

Descriptive characteristics

Solubility

70% alcohol: in five volumes: occasional opalescence

Benzylalcohol: in all proportions Deithyl phthalate: in all proportions Fixed oil: in all proportions Glycerine: insoluble

Mineral oil: soluble with opalescence

Propylene glycol: insoluble

Stability: unstable in presence of strong alkali and strong acids

Containers and storage

Glass, aluminium or suitably lined containers.

Aluminium cans were fitted to the top with the oil to avoid head space, closed tightly and stored in cold chambers.

4 Chemical structure

The early work of several authors, summarized by Guenther (1975), shows the presence of 1,8-cineole, d- -terphenol, terpinyl acetate, limonene, sabinene and borneol. The first detailed analysis of the volatile oil of cardamom was reported by Nigam et al. (1965). They used gas chromatography under isothermal conditions and analyzed both the total oil and fractions obtained by fractional distillation and alumina column chromatography. They confirmed and quantified all the hydrocarbon and oxygenated compounds. 1,8- cineole and -terpinyl acetate are the major components in the cardamom volatile oil. Besides the usual terpene hydrocarbon and alcohols as minor compounds and the dominance of 1,8-cineole and -terpinyl acetate, it is significant that methyl eugenol also has been identified (Lawrence 1979). The basic cardamom aroma produced by a combination of the major components, -terpinyl acetate and 1,8-cineole. The percentages of the main components given by Lawrence (1979) are as follows: - pinene (1.5%), -pinene (0.2%), sabinene (2.8%), myrcene (1.6%), -phellandrene

(0.2%), limonene (11.6%), 1,8-cineole (36.3%), -terpinene (0.7%), p-cymene (0.1%), terpinolene (0.5%), linalool (3.0%), linalyl acetate (2.5%), terpinen-4-01 (0.9%), -

terpineol (2.6%), -terpinyl acetate (31.3%), citronellol (0.3%), nerd (0.5%), geraniol

(0.5%), methyl eugenol (0.2%), trans-nerolidol (2.7%). When the spice is chewed, it does have a slight astringent and pungent taste. The astringent sensation could arise from intense release of many components of the volatile oil when seeds are chewed and or from phenolics that are usually present in seeds. Pungency stimuli have been identified in other spices belonging to the family Zingiberaceae to which cardamom belongs, e.g. gingerols and shogaols in ginger and also the saturated compound

(6)-paradol from the seeds of the related spices, the Aframomum meleguta (Connell 1970). The most significant component of cardamom, as spice, is the volatile oil with its characteristic aroma, described generally as comphory, sweet, aromatic spicy. The cardamom oil has few mono- or sesquiterpenic hydrocarbons and is predominantly made up of oxygenated compounds, all of which are potential aroma compounds. While many of the identified compounds alcohols, esters and aldehydes are commonly found in many spice oils (or even volatiles of many different foods), the dominance of the ether,

1,8-cineole and the esters, -terpinyl and linalyl acetates in the composition, make the cardamom volatiles a unique combination. The aroma differences in different sources of cardamom are attributed to the proportion of the esters and 1,8-cineole (Lewis et al. 1966; Salzer 1975; Wijesekera and Jayawardena 1973; Korikanthimath et al. 1997).

Volatile oil from cardamom (E.cardamomum Maton var. Minisula Barhill) contains few hydrocarbons and large amounts of 1,8-cineole and -cineole and -terpinyl acetate, while that from E. cardamomum Maton var, major Thewaites (the Ceylon wild cardamom) is high in monoterpenes and very poor in the above two oxygenated compounds. The oils from the Ammomum species are all much higher in 1,8-cineole, around 60 to 75%, and some have relatively large amounts of comphor and borneol. Thus, a complete dominance of 1,8-cineole, camphor, or borneol among the oxygenerated compounds could be identified with the comphory smell.

The flavour characteristics of important volatile components in cardamom are listed in

Table 3, and the structure of some of the important aroma compounds are shown in Fig.

1.

5 Quality standards and grade specifications

Dried cardamom require cleaning to remove all stalks and dried remains of floral parts. This should be done by rubbing dried cardamom over a coarse surface of wire-mesh or bamboo trays. This is best carried out while the cardamom is still hot.

Fig. 1 Structure of important aroma compounds.

Table 3 Flavour characteristics of important volatile components in cardamom

Components Flavour Effect in Use level Range of description flavour use concentration

(%) in cardamom oil

Esters

-terpinyl Mildly herbaceous, To stretch 115 ppm 34.652.5

acetate sweet spicy, cardamom, variation in odour, herbal spice, warm, mild spicy imitation taste. citrus and

cherry, peach flavours

Linalyl Sweet, floral, Fresh, sweet 215 ppm 0.76.3

acetate fruity odour and modifier in taste, poor tenacity, perfume and but stronger than berry flavours terpinyl acetate.

Ethers

1,8-cineole Fresh, comphoraceous, Refreshing 115 ppm 2351

cool odour and taste, effect and

very diffusive and lift; extensively poor tenacity. used in perfume

and flavours

Alcohol Floral, woody with Light to heavy 210 ppm 1.44.5

Linalool citrus note; perfume;

creamy floral taste peculiar pleasant at low levels. taste effect at

low levels.

-terpineol Delicately floral, Citrus and 540 ppm 1.43.3

sweet, lilac-like spice compositions

Others

Methyl eugenol Musty tea-like, Tenacious, dry,

mildly spicy, herbaceous 515 ppm 1.3

warm, slightly spicy effect earthy.

Descriptions based on Bernhard et al. (1971) and American Spice Trade Association.

With regard to the quality of the dried product, larger, round and uniform pods having a good dark green colour always fetch the highest price. The small type of cardamom with creeping panicles produces round fruits of uniform size and shape, giving a very attractive product. The largest type of bulk gives different kinds of fruits varying in shape and size, from round to longish fruits of nearly an inch in length. This results in a product of mixed quality.

The Government of India and the Indian Standards Institution (ISI) have prescribed fairly well-defined grades, popularly known as Agmark grades and Indian specifications or standards on the basis of important quality factors like colour, weight per unit volume, size and percentage of empties, malformed, shrivelled and immature capsules (Tables 4 and 5).

Table 4 Agmark grade designations of true small cardamom

Quality Grade Trade name

Alleppey Green cardamom AGEB Cardamom Extra Bold

AGB Cardamom Bold AGS Cardamom superior AGS 1 Shipment Green 1

AGS 2 Shipment Green 2

AGL Light

Coorg Green Cardamom CGEB Extra Bold

CGB Bold

CG 1 Superior

CG 2 Coorg Green Motta Green

CG 3 Shipment

CG 4 Light

Bleached and/or half BL 1

bleached cardamom

BL 2 BL 3

Bleached white cardamom BW 1 Mysore/Mangalore Bleachable

Cardamom clipped

BW 2 Unclipped

BW 3 Bulk

BW 4 Bulk cardamom unclipped

Mixed cardamom MEB Mixed Extra Bold

MB Mixed Bold

MS Mixed superior

MS 1 Mixed shipment 1

MS 2 Mixed shipment 2

ML Mixed light

Cardamom seeds CS 1 Prime

CS 2 Shipment

CS 3 Brokens

Table 5 Specifications for cardamom seeds, India (Indian Standards Institution, New Delhi)

Grade Trade Extraneous Light Weight General

name matter seeds (G/l - min) characteristics

CS-1 Prime 0.5 3.0 675 Decorticated dry seeds

CS-2 Shipment 1.0 5.0 660 of any variety of Elettaria

CS-3 Brokens 2.0 cardamomum

National and international standards are becoming more and more similar because of close association between the producer and user countries. Specifications for cardamom include the following (Wellner 1972).

1. Cardamom in capsule form should be dried, nearly ripe fruits of E.cardamomum Maton. The capsule should be from light green to brown in colour; oblong, rounded or three-cornered in shape; and have a ribbed appearance.

2. The aroma and taste of cardamom in capsules and seeds should be characteristic and fresh and free from foreign aroma and taste, including rancidity and mustiness.

3. Cardamom capsules and seeds should be free from living insects and moulds. Marks on capsules due to thrips infestation should not be counted as insect infestation.

4. Cardamom should be free from visible dirt or dust. Extraneous matter such as bits of calyx, stalks and others shall not be more than 5% by weight in cardamom in capsules and 0.5 to 2% by weight in seeds.

5. The proportions of empty or malformed capsules, from opening and examining 100

capsules taken from the sample, should not be more than 1 to 7% by count.

6. The proportions of immature and shrivelled capsules should not be more than 2 to

7% (m/m).

7. Capsules having black colour and those which are split open at the corners for more than half the length should not be found in the bold grades and not be more than 10 and 15% by count in the shipment and light grades.

8. The proportions of cardamom seeds which are light brown, broken or immature

(shrivelled), should not be more than 3 to 5% (m/m).

The importance attached to the different dimensions of quality varies with the primary raw material producer, the intermediary collector, the trader and exporter, the importer, the processor, the distributor and the final consumer. Product quality is generally related to safe moisture level and cleanliness. The content of substandard product and extraneous matter is important to the producer and trader appearance and colour also to the exporter and importer. The extraction, volatile oil, and specific ingredients are valued by the processor; the interest is sensory quality and cost to the distributor and consumer.

5.1 Adulteration

Decorticated seeds can be adulterated with seeds from lower grades and also from large cardamom as they are of similar shape, size and colour. Pale brown coloured seeds would represent immature cardamom which are low in volatiles and poor in quality and intensity. The seeds from large cardamom have lower volatile oil content, entirely different composition and aroma. Gross adulteration with seeds from large cardamom will show higher 1,8-cineole and higher terpene hydrocarbons, which are determinable by gas or thin-layer chromotography. However, examination of the surface of the seeds with a hand lens showed distinct differences: while the seed coat surface of true cardamom has clear furrows and ridges, the large cardamom has an almost smooth surface.

Adulteration of cardamom powder is possible with almost any material powdered to similar size. Cereal and pulse flours and extracted ginger have been reported as adulterants. These can be detected by microscopy by very different size and structure of the starch granules. Cardamom starch grains, unlike those of cereal and other starches, are very small (2 to 4 m). Whole cardamom powder can be distinguished from the cardamom seed powder by microscopy. The former can be recognized by the yellowish colour, abundance of pitted fibres, spiral cells of the vascular bundles, empty