Turmeric

Harvesting And Storage

Harvesting

  • The crop is ready for harvest when the leaves turn yellow and start drying up.
  • Usually harvesting begins from January-February and continues till March.
  • The crop becomes ready for harvest in seven to nine months after sowing depending upon variety, fertility status of soil and moisture availability.
  • Early varieties mature in seven to eight months, medium varieties in eight to nine months and late varieties after nine months.
  • The general practice in conventional method of harvesting is to wet the crop after removal of the cut foliage and the turmeric rhizomes are dug out after a week by skilled labour with a special fork type of spade/pick axe.
  • Normally turmeric digging is done by contract labour who demand very high wages during peak season.
  • The damage caused to rhizome by fork type spade is more because the labourer has to dig out the clump all around and in doing so, the fork bruises the rhizomes every time it hits the rhizome.

Turmeric harvester

  • A power tiller operated turmeric harvester has been developed by TNAU for harvesting turmeric rhizomes to avoid several losses due to delayed harvesting

Description of the unit

  • The unit consists of a curved blade with three bar points for easy penetration into the soil.
  • The blade is fixed at an inclination of 25 degrees to the horizontal.
  • To the rear end of the blade, two oscillating sectors with six slats spaced at 25 mm apart are hinged at both ends.
  • The oscillating motion for the slats is obtained through eccentric provided on either side of the unit.
  • The eccentrics are connected to the main shaft provided at the top portion of the unit.
  • The power is transmitted from the clutch pulley of the power tiller to a reduction gear box mounted near hitch bracket assembly of the power tiller.
  • From the gear box, the power is transmitted to the main shaft of the turmeric harvester unit through V belt transmission.
  • The eccentrics mounted on both the ends of the main shaft provide oscillating motion to the two slat portions through suitable linkages.
  • The unit is attached to the rear of the power tiller through hitch bracket assembly.
  • For digging, the bar points with the blade penetrate into the soil and lift the turmeric rhizomes along with the soil.
  • When the dug rhizomes with the soil travel along the slots, the oscillating motion of the slats separates the rhizomes from the soil.
  • The soil slip back to the ground and the dug out rhizomes get deposited on the soil surface.
  • For controlling the depth of operation, wheels are provided on either side of the unit.
  • The pneumatic wheels of the power tiller are replaced with a pair of special type cage wheels to accommodate the height of ridges.
  • The cost of the unit is Rs. 7000.

Tractor Drawn Turmeric Harvester

  • The unit consists of a blade with five bar points for easy penetration into the soil. The blade is fixed at an inclination of 20° to a cultivator frame with straight tynes at both ends.
  • It can be hitched to the tractor through three point linkage connection provided in the front portion of the unit. The rake angle of the blade can be adjusted by moving the blade through a clevis provided at the bottom of the two tynes. At the rear end of the clevis two converging slats are fixed to convey the harvested turmeric with the soil on to the lift rods without spilling to the side ways. To the rear end of the blade seven lift rods of 250 mm length are provided.
  • For digging, the bar points with the blade penetrate into the soil, lift the turmeric rhizomes from the soil. The soil slip back to the ground and the dug out rhizomes deposited at the centre of the unit.
  • The cost of the unit is Rs. 8000/-
  • Results in 70 per cent saving in cost and 90 per cent in time when compared to manual digging.
  • Extent of damage caused to the rhizomes is very much less (2.83 per cent).

Turmeric digger

The specifications of the turmeric digger are as follows:

Blade width (mm) 250
Blade inclination, (deg.) 25
Source of power 7.45 kw power tiller
Weight (kg) 44
Overall dimensions (L x B x H) (mm) 730 x 830 x 610
Depth of operation (mm) 200
Draft, N 850

Salient features

  • Harvesting turmeric rhizomes with power tiller based harvester is highly economical as about 65 per cent saving in cost is achieved when compared to manual digging.
  • This will alleviate the high labour requirement during the peak season.
  • Power tiller operated harvester ensures timeliness of harvesting, since 90 per cent of saving in time is obtained.
  • Extent of damage caused to the rhizomes is very low (0.5 per cent) as compared to 3.0 per cent observed in case of manual harvesting.
  • The undug rhizomes left in the field is minimum (0.8 per cent) when compared to a maximum of 4.9 per cent in the case of manual harvesting.
  • The harvesting efficiency is 99 per cent.

Preservation of seed rhizomes

  • Rhizomes for seed purpose are generally stored after heaping under the shade of a tree or in well ventilated shed and covered with turmeric leaves.
  • Sometimes, the heap is plastered with earth mixed with cowdung.
  • The seed rhizomes can also be stored in pits with saw dust.
  • The pits can be covered with wooden planks with one or two holes for aeration.
  • At Bhavanisagar, storage of seed rhizomes in open sand media with partial closed pandal system recorded the highest percentage of germination (96 per cent), less weight loss (4.1 per cent) and high seedling vigour (22.8 cm).

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Processing

  • It involves three stages viz., curing, polishing and colouring

Curing

  • 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 them.
  • 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 follows

  • 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 become soft.
  • 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.

Improved Turmeric Boiler

  • It will boil the turmeric rhizomes under hygienic condition
  • It consists of one rectangular, larger size, solid outer container, made out of 20 SWG thick galvanized iron sheet to hold water and two to three inner containers to hold rhizomes. Washed rhizomes are loaded in the inner cylinder and required quantity of water is added in the outer cylinder. Rhizomes are boiled by the steam liberated from the boiling water.
  • Sodium bicarbonate is added in the boiling water to add colour. The inside containers which hold turmeric can easily be taken out without wasting boiling water, which can be reused and thereby fuel requirement can be considerably reduced.
  • The cost of the unit is Rs.6,000/-
  • Salient Features:
    • Enhanced boiling and improvement in colour.
    • Less fuel requirement. Reduces drying time.

Polishing

  • 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 operated drums.
  • The yield of polished turmeric from the raw materials varies from 15 to 25 per cent.

Colouring

  • It is done to give appearance and better finish to the product, since the colour of the turmeric always attracts buyers.
  • 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

Alum 0.04 kg,
Turmeric powder 2.00 kg,
Castor seed oil 0.14 kg,
Sodium bisulphate 30.00 g
Concentrated hydrochloric acid 30.00 ml.

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 in processing

Do's

  • Choose the best suited variety to each region for which the service of the concerned agricultural officer may be sought.
  • 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 and rain.
  • 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 agricultural officer
  • Remember curcumin content of the turmeric will decrease, if harvested before maturing
  • Rhizomes should be harvested without damage and cuts.
  • 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 polishing.
  • 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.

Dont's

  • Don't cultivate turmeric at the same site continuously.
  • 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 together.
  • 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.

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Storage

  • 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:

Common Name Scientific Name
Cigarette or tobacco beetle Lasioderma serricorne
Drug store or spice beetle Stegobium paniceum
Red flour beetle Tribolium castaneum
Saw toothed grain beetle Oryzaephilus surinamensis
Arecanut beetle Araecerus fasciculatus
Cadelle Tenebroides mauritanicus
Fig moth Ephestia sp.
Meal snout moth Pyralis manihostalis

  • Cigarette beetle and drug store beetle are very important insect pests attacking dry turmeric in storage.

Cigarette or tobacco beetle,Lasioderma serricorne

  • As the name indicates, it is primarily a pest of stored tobacco.

Symptom

  • The grub feeds on stored turmeric by making circular pinhead sized bore holes.

Loss

  • 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

Biology

  • 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.

Management

  • 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,Stegobium paniceum

  • It is a very general feeder and gained its common name from the frequency with which it was found feeding on drugs in pharmacies.

Symptom

  • The grub feeds on dry turmeric by making circular pin head sized bore holes.

Biology

  • 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.

Management

  • 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.

Fumigation

  • Decide the need for shed fumigation (entire store house or godown) or cover fumigation (only selected blocks of bags)
  • 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.

Aluminium phosphide

  • 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 cover.
  • Plaster the edges of cover all round with wet red earth or clay plaster or weigh down with sand-snakes to make leak proof.
  • 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 hours.
  • Follow similar steps to ensure leak proof condition, fumigation period, aeration etc., in case of shed fumigation.
  • Fumigants are used for curative treatment and they have no residual action on new immigrant insects which can infest grain.
  • Sample periodically and fumigate stored material based on need.
  • Handle fumigants with utmost care as per specifications.
  • Fumigation should be carried out only by trained persons

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Biotechnology Research in Turmeric

  • Biotechnology has opened up entirely new vistas in crop improvement including spice crops.
  • Tissue culture is the most important biotechnological tool being used in spices, especially for the large scale propagation.
  • Tissue culture propagation would be useful
  • When the existing methods of vegetative propagation are too slow or non-profitable
  • When conventional methods of vegetative propagation are not successful
  • When plant breeders need several plants of a selected genotype without delay and
  • When plant materials free from plant pathogens are desired.
  • Successful micro propagation of turmeric has been reported.
  • This technique could be used for production of disease free planting material of elite plants.
  • Micropropagation of turmeric was standardized at National Research Centre for Spices (NRCS), Calicut using young vegetative buds as explants.
  • They responded to culture conditions producing 8-10 adventitious shoots in 40 days of culture.
  • Organogenesis and plantlet formation were achieved from the callus cultures of turmeric.
  • Variants with high curcuminn content were isolated from tissue cultured plantlets.

Micropropagation and organogenesis of turmeric

Explant used Media composition Morphological response
Vegetative buds, rhizome sets with axillary buds MS + 1 mg/l. NAA liquid medium from second subculture Multiple shoots and in-vitro rooting
Vegetative buds MS + 10% coconut milk, 0.1 mg/l kinetin, 0.2 mg/l BAP Plant let formation
Red flour beetle Tribolium castaneum Stegobium paniceum
Vegetative buds, rhizome sections, pseudostem tissues MS + 2 mg/l, 2-4 D Callus
Callus derived from vegetative buds MS + 10% coconut milk 2.5 mg/l BAP Shoot regeneration
Cadelle Tenebroides mauritanicus Stegobium paniceum
Callus derived from vegetative buds, leaf Modified MS Organogenesis and plant regeneration

Turmeric propagation through tissue culture

  • The use of rhizome as seed material has the following problems.
  • The dormancy of rhizomes is about two months and this makes the process of cultivation slow.
  • The cost of cultivation is also increased as only a few plants can be obtained from a rhizome. The requirement of seed material is nearly 1800-2000 kg/ha if propagated through rhizome.
  • Diseases like rhizome rot (Pythium sp.) and soft rot (Pseudomonas sp.) are transmitted through rhizomes and treatment with fungicides causes yield and quality reduction.
  • Tissue culture technique has the potential to accept the above challenges to produce high quality material.
  • Thousands of disease free plantlets can be produced from a single plant part in a small unit area and time.
  • This technique also offers good opportunities for long term storage of germplasm, cheap handling and transportation of propagating material.

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