- It involves three stages viz., curing,
polishing and colouring.
- Fingers are separated from mother rhizomes and
are usually kept as seed material.
- The fresh turmeric is cured for obtaining dry
turmeric before marketing.
- Curing involves boiling of fresh rhizomes in
water and drying in the sun.
- Pests and diseases like shoot borer and soft
rot still cause havoc to the crops.
- There are no disease resistant varieties of
turmeric available in India.
Traditional method of curing is as follows
- The cleaned rhizomes are boiled in copper or
galvanised iron or earthern vessels, with water just enough to soak
- In certain places, cowdung slurry is used as
boiling medium. From hygienic point of view, such rhizomes fetch
poor market value.
- Boiling is stopped when froth comes out and
white fumes appear giving out a typical odour.
- The boiling lasts for 45 to 60 minutes when
the rhizomes are soft.
- Overcooking spoils the colour of final product
while undercooking renders the dried product brittle.
- A boiler has been developed at Tamil Nadu
Agricultural University, Coimbatore for bleaching of turmeric
rhizomes, 150 kg of fresh rhizomes could be cooked in this boiler,
which costs around Rs. 1200/-.
The improved scientific method of curing is as
- The cleaned fingers (approximately 50 kg) are
taken in a perforated trough of size 0.9 x 0.55 x 0.4 m. made of GI
or MS sheet with extended parallel handle.
- The perforated trough containing the fingers
are then immersed in the pan.
- The alkaline solution (sodium carbonate or
sodium bicarbonate at 1g/lit) is poured into the trough so as to
immerse the turmeric fingers.
- The whole mass is boiled till the fingers
- The cooked fingers are taken out of the pan by
lifting the trough and draining the solution into the pan.
- Alkalinity of the boiling water helps in
imparting orange yellow tinge to the core of turmeric.
- The drained solution in the pan can also be
used for boiling another lot of turmeric along with the fresh
solution prepared for the purpose.
- The cooking of turmeric is to be done within
two or three days after harvesting.
- The mother rhizomes and the fingers are
generally cured separately.
- The cooked fingers are dried in the sun by
spreading 5 to 7 cm thick layers on bamboo mat or drying floor.
- A thinner layer is not desirable, as the
colour of dried product may be adversely affected.
- During night time, the materials should be
heaped or covered.
- It may take 10 to 15 days for the rhizomes to
become completely dry.
- The yield of the dry product varies from 20 to
30 per cent depending upon variety, the location where the crop is
grown, cultivation practices and agroclimatic conditions.
- Dried turmeric has poor appearance and a rough
dull outer surface with scales and root bits.
- The appearance is improved by smoothening and
polishing outer surface by manual or mechanical rubbing.
- Manual polishing consists of rubbing the dried
turmeric fingers on a hard surface or trampling them under feet,
wrapped in gunny bags.
- The improved method is by using hand operated
barrel or drum mounted on a central axis, the sides of which are
made of expanded metal mesh.
- When the drum filled with turmeric is rotated
at 30 rpm, polishing is effected by abrasion of surface against the
mesh as well as by mutual rubbing against each other as they roll
inside the drum.
- The turmeric is also polished in power
- The yield of polished turmeric from the raw
materials varies from 15 to 25 per cent.
- It is done to give appearance and better
finish to the product, since the colour of the turmeric always
- This is done to half polished rhizomes in two
ways, known as dry and wet colouring.
- In dry process, turmeric powder is added to
the polishing drum in the last 10 minutes.
- In wet process, turmeric powder is suspended
in water and mixed by sprinkling inside the polishing basket.
- For giving a brighter colour, the boiled,
dried and half polished fingers are taken in baskets which are
shaken continuously when an emulsion is poured in.
- When the fingers are uniformly coated with the
emulsion, they may be dried in the sun.
- The composition of the emulsion required for
coating 100 kg of half boiled turmeric is
Castor seed oil
Concentrated hydrochloric acid
Improved methods of curing
- The Central Food Technological Research
Institute (CFTRI), Mysore has developed a simpler, hygienic and
efficient technique of curing and colouring turmeric.
- In this method, rhizomes are boiled in lime
water or sodium carbonate. A water solution containing 20 g of
sodium bisulphite and 20 g of hydrochloric acid per 45.3 kg of
tubers is recommended to give them the desired yellow tint.
Do's and Don'ts
- Choose the best suited variety to each region
for which the service of the concerned agricultural officer may be
- Seed turmeric should be immersed in suitable
solution of fungicide and insecticide after harvest for half an
hour. Then dry in shade and keep safely.
- The place selected for storage of
seed-turmeric should be free from moisture and away from sun light
- Different varieties mature at different times.
So varieties should not be mixed and cultivated together.
- Mother rhizomes are the best for seeds. Larger
rhizomes can be split and used.
- If pest infestation is noticed, follow
management practices as per the instructions of the nearby
- Remember curcumin content of the turmeric will
decrease, if harvested before maturing.
- Rhizomes should be harvested without damage
- After harvest, rhizomes may be washed by a
water jet to remove the mud and dirt adhering to them.
- Immediately after harvest, turmeric should be
boiled and dried.
- For boiling turmeric, use clean water.
- The 'bulb' and the 'finger' should be boiled,
dried and marketed separately.
- Before boiling, water should be filled to
cover rhizomes, put a gunny bag or jute bag over turmeric to
restrain the steam loss.
- Heating should be uniform.
- Turmeric should be sufficiently boiled. It
will take 45 to 60 minutes to complete the cooking of turmeric after
the first boiling. It can be tested by pressing between fingers or
by piercing a small stick through the turmeric. If it is easily
pierced, it indicates thorough cooking. The typical odour of the
vapour too indicates that it is fully cooked.
- Clean terraces of cemented yards or clean
bamboo mats should be used for drying turmeric.
- It should be heaped and covered during night
in order to protect from rain. If the turmeric happens to get wet by
rain during drying the yellow colour may change to orange red.
- Dried turmeric may be marketed after
- In order to make the produce attractive,
turmeric powder may be sprinkled during the last phase of polishing.
- After polishing, it should be marketed without
delay, if not, it should be kept in clean sacks and stored over
wooden pallets in stores.
- Stores should be kept clean, free from
infestation of pests, spiders, psocids and rodents.
- Don't cultivate turmeric at the same site
- Don't choose varieties that are unsuited to
the soil and climate.
- Pest/disease affected turmeric rhizomes should
not be used.
- Rhizomes of small size or low weight should
not be used.
- 'Bulb' and 'finger' should not be boiled
- Turmeric prepared for boiling should not
contain mud and dirt.
- Harvested turmeric should not be delayed more
than 2 days to boil.
- Disease or pest infested turmeric should not
be used for processing.
- No chemical or other materials should be added
to the water used for boiling,
- Cow-dung pasted floor or mats should not be
used for drying.
- Cow-dung pasted containers should not be used
to handle turmeric.
- Extraneous matters should not be allowed to
get contaminated with turmeric.
- No colouring materials should be added while
polishing other than turmeric powder.
- Pesticides should not be applied on the
dried/polished turmeric to prevent storage pests.
- Properly dried and half dried turmeric should
not be mixed.
- Turmeric should not be stored in dirty sacks,
bags or containers.
- The assembling markets in Erode stock the
rough dried turmerics in underground pits made in elevated ground.
- The polished turmeric is stored in double
gunny bags in ware houses.
- Well dried turmeric (< 5% moisture) is not
susceptible to any mould growth/disease problem.
Storage pest management
- Insects feed on stored dried turmeric and thus
account for serious damage and loss.
- The important insect species responsible for
loss in stored turmeric are as follows:
Cigarette or tobacco beetle
Drug store or spice beetle
Red flour beetle
Saw toothed grain beetle
Meal snout moth
- Cigarette beetle and drug store beetle are
very important insect pests attacking dry turmeric in storage.
tobacco beetle, Lasioderma serricorne
- As the name indicates, it is primarily a pest
of stored tobacco.
- The grub feeds on stored turmeric by making
circular pinhead sized bore holes.
- Infestation by this pest resulted in a weight
loss of 39.78 per cent.
- Sixty eight per cent of turmeric samples
collected were infested with L.serricorne
- The light brown round beetle has its thorax
and head bent downward and this presents a strongly humped
appearance to the insect.
- The elytra have minute hairs on them.
- Antenna is of uniform thickness.
- The whitish hairy grubs feed on stored
tobacco, ginger, turmeric and chillies.
- The creamy white oval eggs are laid on the
surface of stored material.
- The incubation period is 9 to 14 days.
- The larval and pupal periods range
respectively from 17 to 29 days and 2 to 8 days.
- The beetles live for 2 to 4 weeks and during
that period, the females lay as many as 100 eggs each.
- Fumigation with phosphine gas from Aluminium
Phosphide (celphos) tablet at 3 to 4 tablets/tonne in an air tight
store for 2 to 3 days resulted in total mortality of the pest.
Drug store beetle,
- It is a very general feeder and gained its
common name from the frequency with which it was found feeding on
drugs in pharmacies.
- The grub feeds on dry turmeric by making
circular pin head sized bore holes.
- The reddish brown small beetle has striated
elytra and measures 3mm long.
- Antenna is clubbed.
- It lays the eggs in batches of 10 to 40.
- Grub is not hairy but is pale white, fleshy
with the abdomen terminating in two dark horny points.
- It tunnels into stored products like turmeric
ginger, coriander and dry vegetables and animal matter.
- The larval and pupal periods occupy
respectively 10 to 20 days and 8 to 12 days.
- Similar to that of cigarette beetle.
- The other storage pests viz., red flour
beetle, saw toothed grain beetle, arecanut beetle, cadelle fig moth
and meal snout moth are of minor importance in turmeric. Fumigation
of the stored material will take care of all the storage pests.
- Decide the need for shed fumigation (entire
store house or godown) or cover fumigation (only selected blocks of
- Check the store house/godown and the black
polythene sheets or rubberised aluminium covers for holes and get
them ready for fumigation.
- Choose the fumigant and work out the
requirement based on the following guidelines.
- For cover fumigation: 3 tablets of 3 g each
per tonne of grain/dry turmeric.
- For shed fumigation: 21 tablets of 3 g each
for 28 cubic metres.
- Period of fumigation: 5 days
- In case of cover fumigation, mix clay or red
earth with water and make it into a paste form and keep it ready for
plastering all round the fumigation cover or keep ready sand-snakes.
- Insert the required number of aluminium
phosphide tablets in between the bags in different layers.
- Cover the bags immediately with fumigation
- Plaster the edges of cover all round with wet
red earth or clay plaster or weigh down with sand-snakes to make
- Keep the bags for a period of 5-7 days under
fumigation based on the fumigant chosen.
- Remove the mud plaster after specified
fumigation period and lift cover in the corner to allow the residual
gas to escape.
- Allow aeration and lift cover after a few
- Follow similar steps to ensure leak proof
condition, fumigation period, aeration etc., in case of shed
- Fumigants are used for curative treatment and
they have no residual action on new immigrant insects which can
- Sample periodically and fumigate stored
material based on need.
- Handle fumigants with utmost care as per
- Fumigation should be carried out only by