© SANDESH PAUDEL

# Turmeric

CONTENTS
• Introduction
• Cultivation, harvesting and
production
• Chemical composition
• Postharvest processing
• Main commercial forms
• Adulteration and quality criteria
• Uses in food processing
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 # Turmeric

INTRODUCTION
 Turmeric is a dried rhizome of Curcuma longa.
 It is an herbaceous perennial plant belonging
to the family Zingiberaceae, native to tropical
South East Asia.
 Known by vernacular name besar/haldi in Nepal.
 The plant grows up to 60-100 cm high, depending on the variety.
 Leafy shoots are erect, bearing 6-10 leaves with the leaf sheath
forming a pseudostem.
 Inflorescence is a cylindrical, fleshy, central spike, 10-15 cm long,
5-7 cm wide, and arising through the pseudostem.
 Flowers are yellow or pale yellow, borne in a spike.
 Fruits are seldom. Seed set is observed in turmeric & are viable.
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 # Turmeric

INTRODUCTION . . .
 Rhizomes are formed at the base
of pseudostem, below the ground.
 They consist of mother rhizome
(thick portion of the corm known
as bulb), primary, secondary and
even tertiary rhizomes (known as
fingers); the whole forming a compact clump.
 Rhizomes have a brownish yellow skin and a bright yellowish
orange interior.
 The fresh form looks like ginger except it is thinner and its inner
flesh is yellow.
 It has a fragrant musky and earthy aroma with gingery, slightly
bitter, peppery notes.
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 # Turmeric

CULTIVATION, PRODUCTION AND HARVESTING

 Turmeric grows at all places ranging from sea level to an altitude
of 1200 m above MSL. It thrives best on well-drained, loamy or
alluvial, loose, friable and fertile soils.
 Soil should be rich in organic matter and uniform in texture.
 It is grown both under rain-fed and irrigated conditions. It
cannot withstand water stagnation or alkalinity.
 It requires a warm and humid climate, with temperature ranging
from 24-28°C and annual 70-225 cm rainfall.
 Growth ceases when temperature falls below 20°C, and hence
early-planted turmeric gives good yield.
 Turmeric is propagated vegetatively through rhizomes.
 Healthy and disease-free rhizomes with one or two sprouting
buds are generally used for planting. 5
 # Turmeric

CULTIVATION, PRODUCTION AND HARVESTING . . .

 Turmeric requires deep tilth and heavy manuring for high yields.
 Planting is done either on raised beds or ridges during May-June.
 A thick mulching with green
leaves is given immediately
after planting.
 Regular weeding and plant
protection measures should
be undertaken.
 Turmeric cultivation is
confined to South East Asian
countries such as Nepal,
India, Pakistan, China, Sri
Lanka, and Indonesia.
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 # Turmeric

CULTIVATION, PRODUCTION AND HARVESTING . . .

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 # Turmeric

CULTIVATION, PRODUCTION AND HARVESTING . . .

 The crop becomes ready for harvest in about 7-9 months after
planting (Aromatica type: 7 months, Amada type: 8 months, and
Longa type: 9 months).
 Turmeric is harvested when leaves turn yellow & start drying up.
Main harvest season begins from February & extends up to April.
 Harvesting consists of digging of underground clumps of
rhizomes with pick axe or digging fork.
 Whole clump is lifted out with the dry plant, leafy tops cut off,
roots removed, all the adhering mud particles shaken or rubbed
off and the rhizomes then washed well with water.
 Fingers, sometimes called the daughter rhizomes, are separated
from the mother rhizomes and kept in shade for 2-3 days.
 It is either harvested in a year (9 month cycle) or in two years.
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 # Turmeric

CULTIVATION, PRODUCTION AND HARVESTING . . .

 Usually when bulbs (known as mau or budi or dana) are used as
seed, harvesting is usually done in 9 months.
 If fingers (known as sella or naya) are used, harvesting is done in
2 years. The 2 years harvesting has bigger size and higher weight
and is also considered to be of better quality by the processors.
Turmeric production in Nepal
 Turmeric is an essential spice for the Nepalese households and is
listed as one of the top five major spice crops in Nepal.
 It is cultivated all around Nepal ranging from Terai to hilly region.
 It can be regarded as a good cash crop for the hilly regions as it
requires less water and less capital investment for production,
grows with comparatively less use of fertilizer, adoption of
simple technology and has low pest/disease infestation.
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 # Turmeric

Turmeric production in Nepal . . .

 Sloppy topography of hilly region and nature of soil are optimal
for turmeric cultivation as it allows no accumulation of water.

Oleoresin
level

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 # Turmeric

Turmeric production in Nepal . . .

 Turmeric cultivation in the sloppy land can be beneficial as it
prevents soil erosion. Also, cultivation involves mulching, it helps
to retain soil fertility. Usually, turmeric is grown in those lands
where other horticulture crops and grains do not grow properly.
 Major portion of production is used for domestic consumption.
 About 30% of the total production of turmeric is sold in local
markets, mostly in dried form. Two types of dried forms are
mostly found in the market: (a) sliced and dried, known as chana,
and (b) boiled and dried, known as giti.
 The demand of giti is high in the markets.
 Usually farmers are involved in producing dried turmeric,
although sometimes traders purchase fresh turmeric.

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 # Turmeric

CHEMICAL COMPOSITION
 Turmeric powder has a deep yellow color and pungent aromatic
flavor. On average, it contains:
Moisture 6% Protein 6.5%
Crude starch 50.4% Fiber 3%
Fixed oil 3.5% Volatile oil 1.5%
Oleoresin 7-8% Curcumin 3.1%

 Beside these, turmeric contains vitamin A (175 IU/100g), vitamin

B1 (0.09 mg/100 g), vitamin B2 (0.19 mg/100 g), vitamin B3 (4.8
mg/100 g), phosphorus (0.26%), calcium (0.2%), iron (0.05%),
and traces of potassium, sodium, and magnesium.
 Standards require ground turmeric to contain no more than 7%
total ash, 1.5% acid insoluble ash and 60% starch.
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 # Turmeric

POSTHARVEST PROCESSING
 The postharvest activities mainly consist of cleaning, washing,
and separation of bulb and fingers.
 Bulbs are kept for seed while fingers are processed. Storage of
seed is usually done in pit & kept for 3-4 months until plantation.

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 # Turmeric
Preliminary preparation
 Rhizomes are soaked overnight in water.
 Cleaning involves removing soil adhering to the rhizomes and
stripping of large fibrous roots.
 For processing into dried turmeric, two common methods are:
(i) cutting/slicing and drying (for household purpose), and
(ii) boiling and drying (for commercial purpose).
Boiling/Curing
 Raw turmeric rhizomes have to
be cured for color and aroma.
 For this, the fingers and bulbs
are boiled separately in water
for 30-45 min until rhizomes
become soft.
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 # Turmeric
Boiling . . .
 This procedure gets rid of the raw color, reduces drying time,
gelatinizes the starch and gives turmeric a more uniform color.
 Traditionally, boiling is done in metal or mud pots with water
level 5-7 cm above the rhizomes. For quick and proper boiling,
the rhizomes are covered with turmeric leaves; 5-7 cm thick.
 In some places, cow dung is also mixed with water, due to which,
fingers get colored with lead chromate (which is poisonous).
 In improved methods, rhizomes are boiled in lime water or 0.1%
NaHCO3 solution for 0.5-6 hrs., for imparting orange yellow color.
 Boiling is continued till froth comes out and white fumes appear
giving a characteristic odor. If rhizomes are soft & inner color has
become yellow from red, this process is said to be completed.
 Over cooking spoils the color and fingers become light and get
broken during polishing. 15
 # Turmeric
Boiling . . .
 To test proper cooking, a matchstick is pierced through the
boiled rhizomes. If it passes easily through the rhizomes, the
material is said to be cooked.
Drying
 After boiling, water is drained off and the rhizomes are stored in
heaps for overnight.
 For sun drying, the rhizomes are spread over a plain bamboo mat
or concrete drying floor, in 5-7 cm thick layers. Rhizomes are
mixed 2-3 times to ensure uniform drying.
 Drying surfaces should be clean to ensure that the product
doesn’t get contaminated by any extraneous matter.
 Drying is carried out for 10-15 days until rhizomes become dry
and hard. Excess drying results in brittle product.
 During drying, the roots and scales drop off. 16
 # Turmeric
Drying . . .
 For mechanical drying, cross-flow hot air at a maximum
temperature of 60°C is used.
 Artificial drying gives a brighter product than sun drying.
 When the dried finger breaks cleanly with a metallic sound, it is
sufficiently dry.
Polishing
 Dried turmeric has a rough appearance and dull surface color.
 Polishing removes the surface roughness by getting rid of any
remaining surface scales, small rootlets, and soil particles.
 The color of turmeric becomes bright with shiny appearance.
 Mother rhizomes and fingers if cooked together are separated
before polishing.
 Polishing can be done manually or mechanically. 17
 # Turmeric
Polishing. . .
 Polishing is not required for turmeric intended for solvent
extraction and recovery of coloring principle.
 For manual polishing, the rhizomes are rubbed against hard
surface or trampled under feet after wrapping in gunny bags.
 Shaking the rhizomes with stones in a gunny bag or bamboo
basket is also practiced.
 For mechanical polishing, a rotary polishing drum is used.

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 # Turmeric

Polishing. . .
 It is kept horizontally on a shaft and rotated by hand or motor.
 Average capacity of this machine is ~32 kg/hr. Dry turmeric is
filled and polishing is done for ~7 min.
 During this process, water is also sprinkled which causes
improvement in the color. The polished product has low
moisture content and gives a metallic sound when broken.
Coloring
 Turmeric for export is given special color by mixing yellow color
so that powder & processed materials have better look & quality.
 Coloring is done by two methods, viz. dry and wet coloring.
 In the dry method, dry powder of yellow color (middle chrome) is
sprayed on boiling turmeric and slightly mixed. Or, yellow color is
added to the polishing drum few minutes before finishing.
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 # Turmeric
Coloring . . .
 In the wet method, yellow color solution is prepared in water,
which is sprayed on rhizome and mechanically mixed.
 After coloring is completed, the rhizomes are dried for one week,
packed in sacks and sealed for exporting.

MAIN COMMERCIAL FORMS OF TURMERIC

 Different forms are used in different consumer segments.
 Households and institutions prefer the powdered form; while the
fast moving consumer goods segment prefer dry and oleoresin
type. Turmeric is mostly sold in dried or powdered form.
 The major value added products can be categorized as primary &
secondary products. Primary products are dried rhizomes and
turmeric powder. Secondary and derived products include curry
powder, turmeric oil, turmeric oleoresin, and turmeric pigment. 20
 # Turmeric

MAIN COMMERCIAL FORMS OF TURMERIC . . .

A. Dried rhizome
 Dried turmeric is mostly
traded as whole rhizome,
which is then processed
into powder or oleoresin.
 Rhizomes come as bulbs, fingers, and splits
(bulbs cut into halves or quarters before curing).
 Fingers (2-8 cm long and 1-2 cm wide) are easier
to grind than the more fibrous bulbs and splits,
and therefore, command a higher price.
 Sliced and dried turmeric is prepared for household purpose,
while boiled and dried turmeric for commercial purpose.
 Dried rhizome is lemon yellow to orange yellow in color.
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 # Turmeric
B. Turmeric powder
 It is either made at household level by farmers
for domestic consumption or is processed in
electric mills for trading purpose.
 Local traditional equipment, viz. dhiki, okhli and janto are mostly
used at home. The process is labor intensive and tedious.
 Electric mills/grinders break dried turmeric into smaller pieces,
which are sorted and taken to mill (usually flour mill) for making
fine turmeric powder, usually 60-80 mesh size.
 The powder is designated as coarse if 98% passes through a 500
μm sieve, and fine if 98% passes through a 300 μm sieve.
 Powdered turmeric is packed in bulk, in a variety of containers,
fiberboard drums, multi-walled bags and tin containers.
 The color of turmeric will not be affected for up to 6 months in
any packaging or storage conditions. 22
 # Turmeric
C. Curry powder
 Turmeric is an important ingredient in the curry powder.
 Turmeric content in curry powder blends range from 5-30%.
 Curry mixes for vegetarian dishes contain less turmeric, 5-10%,
whereas for fishes and meat dishes contain 20-30% turmeric.
D. Turmeric oil
 The volatile oil is pale yellow to orange yellow in
color with an odor reminiscent of the fingers.
 Volatile oil content of turmeric is ~1.5-6.0%.
 The essential oil contains mainly turmerone (30%), dihydro-
turmerone (25%) and zingiberene (25%), along with sesqui-
terpene alcohols (6-9%), sabinene (6%), 1,8-cineole (1%),
borneol (0.5%), sesquiphellandrene, curcumene, bisabolene, α-
phellandrene, and traces of α- and γ-atlantone. 23
 # Turmeric

Turmeric oil . . .
 The oil is highly aromatic; aroma mainly due to turmerone.
 Turmeric oil has a very limited use in food flavoring & perfumery,
and has no commercial value, as opposed to oleoresin.
 The volatile oil is obtained by distillation or supercritical fluid
extraction of dried and ground turmeric (40-50 mesh size).
 It takes 8-10 hours of distillation to recover a major portion of
the oil present. Water distillation gives a higher yield of oil than
steam distillation.
E. Turmeric oleoresin
 It is a deep red to orange red viscous
product, with various proportions of
coloring matter (curcuminoids, 40-55%), volatile oils (15-20%),
and non-volatile fatty oils and bitter principles.
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 # Turmeric
Turmeric oleoresin . . .
 Curcuminoids mostly consist of curcumin, which is the principle
coloring matter in turmeric. It is a crystalline material obtained
by further purification of curcuminoids.
 Oleoresin can be obtained by solvent extraction of the small
pieces or powdered rhizomes.
 Depending upon the solvent used,
turmeric type & cultivar, oleoresin
yield is 7.0-10.4%, in which volatile
oil is ~3.3-7.2% and curcumin
~2.2-5.4% of total oleoresin.
 About 8 lb. is equivalent to 100 lb. of freshly ground turmeric.
 For commercial use, turmeric oleoresin is generally mixed with a
suitable solubilizer like propylene glycol, polysorbate or some
fatty oil so that handling and use becomes easier. 25
 # Turmeric

E. Turmeric pigment
 Turmeric is chiefly valued for its coloring property.
 The most valued constituent of turmeric is its yellow crystalline
pigment curcumin (C21H20O6, melting point: 184-185°C).

 It dissolves in conc. sulfuric acid giving a yellow-red coloration.

 It is extracted in oleoresin, not in essential oil. Volatile oil can be
obtained as product of curcuminoids purification from oleoresin.
 Curcuminoids are extractable by solvents like methanol, ethanol,
acetine and dichloroethylene, but not by petroleum solvents.
 Curcumin content depends upon the variety of turmeric.
 It constitutes about 1/3rd of a good quality oleoresin. 26
 # Turmeric

ADULTERATION AND QUALITY CRITERIA

 Turmeric powder is adulterated with foreign starch (tapioca,
arrowroot, cereal flour), husks, lead chromate, etc.
 Some important quality checks include cleanliness, curcumin
content, microbiological contamination, pesticide residues,
aflatoxins and heavy metals.

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 # Turmeric

ADULTERATION AND QUALITY CRITERIA . . .

 Adulterated turmeric powder will have low curcumin content,
which can be determined by spectrophotometry and HPLC.
 Total aerobic bacteria, Escherichia coli, Staphylococcus aureus,
Bacillus cereus, Salmonella, and sulfite reducing clostrides are
some microorganisms of concern.
 Lead, cadmium, arsenic and mercury are heavy metals of major
concern; atomic absorption spectroscopy is used for the analysis.

USES OF TURMERIC
 Turmeric is mainly used for its coloring properties rather than its
flavor attributes. It is used in foods and other products where
rich yellow color is desirable.
 It is the major ingredient in curry powders, contributing flavor as
well as characteristic yellow color. 28
 # Turmeric

USES OF TURMERIC . . .
 In food industries, it is used in a number of products including
bakery products, dairy products (butter, cheese, yoghurt,
margarine, Vanaspati), dry seasonings, cereal based products,
sauces, ketchups, confectionaries, etc.
 Turmeric oleoresin, extracts, or curcumin (mixed with solvent
and emulsifiers) are used commercially as natural colorants.
 Curcumin is preferably used as a natural food colorant in
products where the turmeric flavor is undesirable, such as
cheese, ice cream, beverages and baked products.
 Turmeric is used in various soaps, sunscreen, fairness creams
and lotions; the anti-oxidant properties help to lighten the skin.
 Due to its strong color, it is used as a natural dyeing agent for silk,
wool, cotton and other fabrics. It is also used as a coloring
material in pharmacy, paints and varnishes. 29
 # Turmeric

USES OF TURMERIC . . .
 Turmeric has been traditionally
used for curing a number of
diseases. It is popular for its
anti-bacterial, anti-fungal, anti-
ulcer, and anti-tumoral effects.
 Its use is reputed to alleviate
asthma, cough, &
for treating skin
inflammations.
 Curcumin is also
available as food
supplement.

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QUESTION MODEL
1. Give a process outline of turmeric processing. [4]
(2066)
2. How is turmeric powder prepared? Also mention its uses. [3.5+1.5]
(2065)
3. What are the pungent principles in turmeric? Give a process outline
of turmeric processing. [2+3] (2070)
For further study