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VIII. Harvesting and Processing of’Cardamom

VIII. Harvesting and Processing of’Cardamom

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334



K. P. PRABHAKARAN NAIR



when harvesting is done at immature stage. Also, essential oil content was

found to be more when harvesting was done at mature rather than immature

stage.

About 2860 ripe capsules weigh 1 kg, while it takes about 5000 physiologically immature capsules to weigh 1 kg, clearly showing that it is always

advantageous to harvest at the right mature stage. When the capsules are

well matured, the seeds inside will be black in color.

Two types of picking are practiced—light picking and hard picking. In the

first case only matured capsules are picked, while in the second case semimature

capsules are also picked. While this would reduce the curing percentage, it

would increase the picking average, secure green‐colored capsules, and reduce

fruit drop and splitting of capsules in the field ensuring minimal loss of the

produce. However, the choice of the picking type depends on the availability of

manual labor as no mechanical harvesting is practiced in India. Mostly women

laborers are employed for harvesting.

a. Postharvest Handling of Cardamom. Retention of green color: Color

of processed produce is an important factor inasmuch as the consumer is

concerned. Most markets, especially in the Middle East countries, prefer

green‐colored cardamom. The cardamom with the highest quality is ‘‘Alleppey

Green,’’ still regarded as the best. This comes from the high ranges of the Idukki

district in Kerala State, where the predominantly grown variety is Mysore.

Investigations have been carried out to understand the mechanism of color

retention during the processing of harvested cardamom capsules.

Synthesis and degradation investigations indicate that the total chlorophyll content declines after about 100 days from flowering. Comparative

evaluation of chlorophyll contents in dark green, medium and light green

capsules have shown that the depth of green color is directly proportional to

concentration of chlorophyll content of capsules (Table XXXI). Chlorophyll

a is more than chlorophyll b in fresh as well as cured capsules. In husk, 60%

of total chlorophyll is present in the surface layer. In the three clones tested,



Table XXXI

The Chlorophyll Profile of DiVerent Capsules

Chlorophyll content (ppm)

Capsule color



a



b



Total



a/b Ratio



Light green

Medium green

Dark green



509 (186)

727 (384)

1677 (446)



561 (167)

700 (349)

1890 (382)



1070 (352)

1424 (731)

3567 (828)



0.9 (1.1)

1.0 (1.1)

1.12 (1.2)



THE AGRONOMY AND ECONOMY OF CARDAMOM



335



namely, Thachangal, Mudigiri, and PV1, total chlorophyll content was more

in 100 days old capsules of Thachangal (2186 ppm) followed by that of

Mudigiri (1756 ppm) and least in PV1 (1488 ppm) (Anon, 1991). The above

investigation suggested that dry matter continued to increase until capsules

reached maturity while chlorophyll content started declining after 100 days

from flowering (Anon, 1991). The decline in chlorophyll content during

postripening period is more in Mudigiri (variety Malabar) compared to

varieties Vazhukka and Mysore indicating that delay in picking of this

clone could aVect the final greenness of capsules (Anon, 1991).

To retain the green color of the harvested capsules, various chemical treatments have been tried because the green‐colored capsules fetch a high premium

in the market. Among such treatments, soaking the green (wet) capsules

immediately after harvest in a 2% sodium carbonate solution for 10 min fixes

the green color during subsequent drying and storage (Natarajan et al., 1968).

Immature capsules retained greater intensity of the green color. Meisheri (1993)

has developed a dehydration unit, which can retain the green color and dry the

produce rapidly at ambient temperature (27–40 C).

b. Predrying Operations. Capsules after harvest are washed thoroughly

in water to remove adhering soil before taking them to drying kilns. In

diVerent trials conducted earlier, it was found that presoaking (quick dip) of

capsules in hot water at 40 C and dipping the capsules for 10 min in 2%

sodium carbonate had helped in better retention of the green color of cured

capsules. Dipping capsules in hot/warm water at lower temperatures, namely,

30 C and 35 C also was tried. Additives like 2% sodium carbonate in warm/

hot water (particularly 35 C) helped to increase the green color of the capsules. Dipping in hot water may arrest the activity of certain enzymes. Volatiles extracted from capsules presoaked in hot water and sodium carbonate

solution were subjected to GLC analysis. Results indicated that there were

no significant changes in oil profile due to hot water or sodium carbonate

treatments (Anon, 1991).

Presoaking of capsules in copper formulations and chemicals like naphthalene acetic acid, IAA and gibberlic acid, and magnesium sulfate helped

retain more chlorophyll compared to other treatments. However, when

presoaking time was extended to 60 min, significant depletion of chlorophyll

was observed in all, except in ascorbic acid treatment. Other treatments,

namely, urea, 2,4‐D, Cycocel at 100 ppm each, kinetin at 10 ppm, glycerol at

5%, and polyethylene glycol at 5% recorded either no eVect or marginal

negative eVect on stability of chlorophyll (Anon, 1991).

Chlorophyll degradation takes place on exposure to sun, and bleaching of

green color takes place. Post harvest delay prior to curing is known to cause

chlorophyll breakdown, a better storage system could help to minimize such

chlorophyll loss.



336



K. P. PRABHAKARAN NAIR



Various trials conducted to study the impact of precuring storage indicated

the following.

1. Capsule cured immediately after picking retained more of the green color.

2. Loss of the green color was more significant if capsules were stored for

more than 12 h from the time they were picked.

3. Bagging capsules helped to minimize the rate of loss of green color.

To store fresh capsules jute bag was found most ideal compared to polypropylene woven bag. Storage of fresh capsules at low temperature was found

to reduce postharvest precuring loss of the green color. Capsules stored in low

energy or zero energy cool chambers were found to be distinctly greener than

the capsules stored in the open. In large cardamom plantations, two reinforced concrete cement tanks constructed adjacent to each other are used, one

for initial washing of the capsules to remove dirt and soil particles adhering to

them and the other for washing with washing soda. Following washing,

capsules are spread in a single layer in portable drying trays for draining

water. Subsequently, the trays are arranged in kilns for drying.



B. CURING

Cardamom capsules at harvest, depending on the degree of maturity,

carry moisture levels of 70–80%. For proper storage, the initial moisture

level has to be brought down to 8–10% (on the basis of wet weight) by

curing. Curing also plays an important role in preserving green color of the

capsules since as much as 60–80% of the initial color is lost while processing.

The most widely adopted system is a slow or passive process stretching from

18 to 30 h, with an initial temperature around 50 C. The entire curing time

can be divided into four stages.

Stage

I

II

III

IV



Time lag

0–3 h

3–6 h

6–9 h

9 to final curing



Both the degree of maturity and curing temperature influence the percentage of splits in cured capsules. However, temperature has a greater influence

(Anon, 1991). During the process of curing, if the temperature exceeds the

threshold levels or the inflow of air is insuYcient, capsules develop brownish

streaks as a result of heat injury. In the case of fairly high temperature, oil

from seeds oozes out. Maintaining the temperature at 40 C in all the

four stages of curing process helps in greater retention of the green color.



THE AGRONOMY AND ECONOMY OF CARDAMOM



337



Percentage of split and discolored capsules increases with rise in temperature.

Curing at 55–60 C significantly increases the percentage of yellow capsules.

The husk of raw capsules contains about 80% water, which has to be

removed completely in the process of drying. Maximum loss of chlorophyll

occurs in the initial 6 h of curing. Higher air flow rates increase the loss of

chlorophyll. Lesser energy is required for extraction of moisture in the initial

stages when the evaporation is from the surface layers of capsules. Comparatively greater energy is required to remove the same amount of moisture

when moisture content of capsules falls in the later stages of curing. Cardamom oil extracted from samples dried at 45 C and 60 C did not show much

diVerence in the GLC profile (Anon, 1991). Cardamom capsules are moderately hygroscopic and absorb and desorb moisture depending on the changes

in the ambient relative humidity and moisture. Two types of drying are

generally adopted, namely, natural sun drying and artificial drying using

fire wood, fuel, or electricity. Drying operation demands heavy input of

energy. Energy required to dry 1 kg of green cardamom at 100% eYciency

can be used to light 250 bulbs of 100 W each for 1 h.



1.



Sun Drying



Sun drying is generally undesirable for cardamom. When cardamom capsules are sun dried, there is a bleaching eVect due to the action of UV light

present in sunlight. Sun drying requires 5–6 days or more depending upon the

availability of sunlight. As the capsules are frequently turned during sun

drying, capsules split. Cloudy atmosphere and frequent rains hinder proper

sun drying. The method of sun drying is prevalent among small plantation

owners in Sirsi district and surrounding places in the State of Karnataka.



2.



Artificial Drying



a. Electrical Dryer. A dryer having dimensions of 90 cm  84 cm is

more common. Uniform heat distribution is ensured by means of fans. In

this way 50 kg of fresh capsules can be dried in 10–12 h and medium green‐

colored cardamom can be obtained by drying at 45–50 C.

b. Pipe Curing (Kiln Drying). This is one of the best methods of

drying to obtain high‐quality green cardamom. The structure usually consists of walls made of bricks or stones and tiled roof with ceiling. A furnace is

situated on one side of the chamber and heat is generated by burning farm

waste. The fire in the furnace is maintained to maintain temperature between

45 C and 50 C and by this method high‐quality green cardamom can be

prepared in 18–22 h. A drying chamber of dimension 4.5‐m length and 4.5‐m



338



K. P. PRABHAKARAN NAIR



breadth is suYcient for a plantation producing 1800–2000 kg of raw cardamom. Some of the kilns make use of brick constructed heat conveyer lines

(Kachru and Gupta, 1993).

3. Bin Dryer

This is a dryer designed by the University of Agricultural Sciences, Bangalore,

Karnataka State, India. Drying unit consists mainly of a blower with motor,

electrical heating unit, and drying chamber. The drier is made of mild steel,

asbestos sheet, and wood. Aluminum or steel trays of 0.4 m  0.6 m size can be

arranged one over the other. Cardamom capsules are to be spread uniformly

on these trays. Hot air passing through pipes increases temperature from 30 to

80 C. Good quality cardamom can be produced by drying capsules at 55 C by

maintaining the volume of air at 3.7 m3 sÀ1. Cost of drying by this method comes

to about less than 1 cent per kg compared to about 2 cents per kg in the

conventional method (Gurumurthy et al., 1985).

4.



Melccard Dryer



This is a fire wood operated dryer commonly used in some parts of Tamil

Nadu. It consists of a fully insulated (fire bricks with mud coating) oven kept

at 3 m below the dryer. The hot flue gas from the oven is passed to an iron

tank through insulated pipes. All the trays carrying cardamom capsules

move smoothly on rails fixed inside the dryer. Trap doors attached can be

opened periodically to clean oV the soot formed in the interior of the flue

pipes (Palaniappan, 1986). Dried capsules are rubbed by hand or with coir

mat or wire mesh and winnowed to remove other plant residues and foreign

matter. They are then stored out according to size and color.

5. Cross‐Flow Electric Dryer

This is a tray‐type cross‐flow dryer having capacities ranging from 25 to

400 kg. The air is heated 15‐kW electric heaters and circulated over the

material by 0.5 hp electric fan. The drying time requirement at full loading

condition is about 18–20 h (Kachru and Gupta, 1993).



6.



Solar Cardamom Dryer



Direct type solar drier developed by Central Plantation Crops Research

Institute at Kasaragod in Kerala State, for copra (dried coconut ball without



THE AGRONOMY AND ECONOMY OF CARDAMOM



339



outer shell) drying can also be used for cardamom. The dryer has an area of

1 m2 drying surface made of black painted wire mesh tray over black painted

corrugated GI sheet inclined at 12.5 . The aluminum foil relectors of 1.5 m2

are provided from three sides of the drier. Material load density can be three

times than that used in open drying system. Complete drying of cardamom

could be achieved within 3 days using this dryer in comparison to 5 days in

the open sun. Bleaching of cardamom capsules due to the action of UV rays

in sunlight is a disadvantage of this dryer.



7. Mechanical Cardamom Dryer

Developed by the Regional Research Laboratory in Trivandrum, Kerala

State, this dryer consists of a centrifugal blower, electrical furnace, conducting arrangement for uniform hot air flow, and a drying chamber. It can be

used for cardamom drying at a load of 120 kg fresh cardamom/batch. It

takes about 22 h for complete drying at a temperature of 50 C. The final

product is claimed to possess superior green color, flavor, and appearance

(Kachru and Gupta, 1993).



8. Through Flow Dryer

This is fabricated by the Central Food Technology Research Institute,

Mysore, Karnataka State. The drier consists of a centrifugal blower, electrical

furnace ducting with arrangements to distribute the flow of hot air uniformly

and a drying chamber where 120 kg fresh cardamom capsules can be loaded to a

bed thickness of 20 cm. The air velocity at 60 cm sÀ1 and the drying temperature

was thermostatically controlled. The hot air carrying the humidity was not

allowed to recycle. It was found to take about 22 h to complete drying of 120 kg

fresh capsules at a temperature of 50 C. As the cardamom plantations are

generally located in forest areas where electricity is not available, flue pipe

dryers are more dependable and suitable to ensure continuous working.

There is still good scope in developing a dryer ideal to produce green capsules

without any volatile oil loss and with minimum expenditure for drying.



9.



Bleached Cardamom



Bleached cardamom is creamy white or golden yellow in color. Bleaching

can be done either with dried cardamom capsules or freshly harvested

capsules as starting material.



340



K. P. PRABHAKARAN NAIR



a. Bleaching of Freshly Harvested Capsules. Fresh capsules soaked for

1 h in 20% potassium metabisulfite solution containing 1% hydrogen peroxide

solution degrade the chlorophyll. Drying of these capsules yields golden

yellow color.

b.



Bleaching of Dry Capsules



Sulfur bleaching: It involves sulfur fumigation with alternate periods of soaking and drying. Capsules are soaked in 2% bleaching powder (20 g literÀ1 of

water) for 1 h and spread on wooden trays, which are arranged inside airtight

chambers. Sulphur dioxide is produced by burning sulfur (15 g kgÀ1 of

capsules) and made to pass over the trays. The process of soaking and drying

is repeated three to four times depending upon the intensity of white color

required.

Potassium metabisulfite bleaching: In this method capsules are treated with

2% potassium metabisulfite containing 1% HCl for 30 min. Further they are

transferred to a 4% hydrogen peroxide solution for 6 h.

Hydrogen peroxide bleaching: Hydrogen peroxide at low concentration

(4–6%, pH 4) can bleach capsules in 6–8 h of soaking. These capsules are

then dried to 10–12% moisture content. Bleached capsules contain sulfur

which protects cardamom from pests. However, it was found that bleaching

led to loss of volatile oil.

Conventional bleaching: In Karnataka State, bleaching of cardamom is carried out by steeping the dried capsules in soap nut water. The fruits of soap nut

(Sapindus saponaria) are mixed with water in a large vessel and stirred vigorously to produce plenty of lather. Dried cardamom capsules are then steeped

in this water with occasional stirring. After 1 h or so the fruits are collected in

wicker baskets, water is allowed to be completely drained oV, and then spread

out in mats for drying. Clean water is occasionally sprinkled over the cardamom capsules. The process of sprinkling water and drying is continued for a

couple of days till a good quality bleached product is obtained. In general,

bleaching of dried capsules lead to loss of volatile oil probably because the

bleaching process makes the husk brittle. However, bleached cardamom has

white appearance and is resistant to weevil infestation due to sulfur dioxide

content (Govindarajan et al., 1982; Krishnamoorthy and Natarajan, 1976).



C. MOISTURE CONTENT

Moisture content of commercial samples from market ranges from 7 to

20% depending on the regions and mode of curing (Varkey et al., 1980). It is

found that 10% moisture is ideal for the retention of green color, which also



THE AGRONOMY AND ECONOMY OF CARDAMOM



341



depends on the type of drying. Well‐dried capsules produce a typical tinkling

sound on shaking.



D. GRADING

The quality requirement of a produce varies with the primary raw material producer, intermediary collector, the trader, exporter, importer, processor, distributor, and final consumer. Moisture level, cleanliness, content of

sub standard product, extraneous matter, appearance, and color determine

the final quality of a product. The processor values the extractives, volatile

oil, and specific ingredients. Specifications are restricted to attributes, which

can be simply and rapidly analyzed. Many of them are related to physical

parameters, such as, color, size, weight per specified volume, freedom from

microbial, insect, and filth contaminations (Govindarajan et al., 1982b).

Specifications for Indian cardamom varieties are given in Table XXXII.

Alleppey Green cardamom is the dried capsule of E. cardamomum grown

in South India, kiln dried, which has reasonably uniform shade of green color,

three cornered and having a ribbed appearance. Coorg clipped cardamom is

the dried capsules of E. cardamomum variety Malabar grown in Coorg in

Karnataka State. Its color ranges from pale yellow to brown, global in shape,

skin ribbed or smooth. The pedides are separated. Bleachable white cardamom is the fully developed dried capsule of E. cardamomum grown in the

State of Karnataka to a reasonably uniform shade of white, light green or

light gray color and suitable for bleaching.

In India ‘‘Agmark’’ grades are commonly used to specify quality of

products. The Agmark grades of Coorg clipped cardamom and bleachable

white cardamom are given in Tables XXXIII–XXXV.



E. BLEACHED AND HALF BLEACHED CARDAMOM

Cardamom should be fully developed, dried capsules, bleached or half

bleached by sulfuring; color should range from pale cream to white, globose,

or three cornered with skin ribbed or smooth.

Allepey cardamom seeds are the decorticated and dry seeds of

E. cardamomum grown in Coorg and adjoining districts of Karnataka

State. The specifications are given in Table XXXVI.

Following are some of the general specifications for cardamom.

1. The capsules should be well formed, packed with sound seeds inside. The

cardamom may be graded on the basis of place of origin, color, size, mass

per liter, bleach level, proportion of lower grades, and extraneous matter.



342



Table XXXII

Specifications (Physical Characteristics) for Indian Cardamom Varieties



Grade



Description



Size (mm)



Weight minimum

(g literÀ1)



Color



General characteristics



7



435



Green



AGS

AGS 1

AGL



5

4

3.5



385

320–350

260



Green

Light

Green



CG, Coorg Green

CGEB

Extra bold



8



450



Golden to

light green



CGB

CG 1

CG 2

CG 3

CG 4



7.5

6.5

6

5

3.5



435

415

385

350

280



Light green

Green

Cream

Brown



Round, ribbed or smooth skin



Bleached or half bleached

BL 1

BL 2



8.5

7



340

340



Pale

Creamy



Fully developed

Round, three cornered, ribbed or

smooth skin



BL 3



5



300



Dull white



Superior

Shipment

Light



Bold

Superior

Mota Green

Shipment

Light



Source: Indian Standard Specification for Cardamom. IS: 1907–1966. Indian Standards Institution, New Delhi.



Kiln dried, three cornered, and with

ribbed appearance

Same as above



K. P. PRABHAKARAN NAIR



AG, Alleppey Green

AGB

Extra bold



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