Karaya Gum

Gum Karaya Lumps

Sterculia or Karaya or Thapsi tree is a native of dry deciduous forests of dry rocky hills lands having tropical climate. Gum Karaya is an exudate of gum obtained from the trees of Sterculia Urens one of the most important forest products of our country.

In India, the species of sterculia are found in tropical Himalayas, west and central India, throughout eastern and western ghats. In Andhra Pradesh, Gum Karaya trees are found in Adilabad, Khammam, Warangal, Karimnagar, Mahabubnagar, Kurnool, Vishakhapatnam, East/West Godavari and Chittoor districts. Gum Karaya trees are also found in Australia, Pakistan, Panama, Phillippines, Indonesia, Senegal, Sudan and Vietnam.


1) Botanical Characters: Distinguishing features of the Genus Sterculia are:

  • Leaves alternate, Stipulate, hairy. Flowers unisexual and polygamous, petals absent, anthers 10 and more, fruit follicle.
  • Bark - White, papery
  • Flowering - December, February
  • Flowers - Unisexual to Bisexual
  • Calyx - Companulate
  • Seeds - Oblong / Dark brown


2) Trade Name: Gum Karaya

3) Common Names:

Gum Karaya, Thapsi Gum, Gum Kadaya, Kullo, Karei, Kandol, Katilo, Gulu, Katera, Katiera, Indian Tregacanth.

In Andhra Pradesh in different regions Gum Karaya is called under different names.

1) Telangana - Tapsi, Tabsigum
2) Rayalaseema - Yerra poliki, Tella poliki
3) Coastal Andhra
a) Vishakapatnam, East and West Godavari - Kovela
b) Vizianagaram and Srikakulum - Konda tamara


4) Season: Through out the year. Best season to collect quality material is January to June.


5) Production:

Annual World Production is estimated at 5500 Tons, while India’s
share is around 3000 - 3500 tons. Senegal, Sudan and Pakistan are emerging as other important suppliers.


6) Producing States:

1) Andhra Pradesh
2) Maharashtra
3) Gujrat
4) Orissa
5) Rajasthan
6) Karnataka
7) Bihar.

Though MP has abundant potentiality of gum,its tapping is banned since 1981; however in Bastar abd Sirguja districts it is
allowed.

7) Potentiality: Once its annual potential was around 5000 mts. but its present potential is estimated around 3000 tones per annum.

Sterculia Urens

Scientific methods of Tapping:

The ideal season for tapping is from October to June depending upon locality. For tapping gum, the Gum Karaya tree should be of at least 3 ft. in girth and blazing should be confined to main stem above 3 ft. from the ground level.

The number of blazes that can be made, depends on the girth of the tree as detailed below. Girth (in inches) Number of blazes

1) 36-48 2 blazes equally spaced
2) 48-60 3 blazes equally spaced
3) 60-72 4 blazes equally spaced
4) 72 and above 1 blaze at every 18 inches


The blazes of the rows should be alternate. The depth of the blaze should not exceed 1/2” till second layer is exposed and each blaze should be a semicircle with 6” wide base. Blazing too deeply, a horizontal excessive blazing,exposing the wood leads to borer attack and may also result in the death of the tree.

In the 2nd and 3rd year, tapping can be continued by extending the 1st years blaze, 5 cm, above the previous years treated area. Old wounds should not be reopened. In order to keep the longivity of the tree and for better quality of gum, tapping should not be done continuously and trees should be given long periods of rest before retapping so that the blazed portion gets enough time to heal and resume normal activity. Excessive tapping of the tree may also deteriorate the gum quality.


Gum Yield: The yield of gum will vary depending on the locality, time of collection, age of the tree, trunk girth, number of blazes etc. The yield of a single tree has been calculated to be 0.5 to 4.5 kg per season. The yield of gum for 100 blazes varies from 7.5 to 10.0 kg per tree with girth of 0.9 to 1.35m with 2 blazes may vary from 2.5 to 5 kg. As per the study made in Gujarath, the yield per tree of different girth is 1 kg per girth of tree 0.12m, 1 to 5 kg per girth of 120-150 cm. and above 2 kg per girth of 150cm., and above. It was noticed that two forms of trees i.e., Red bark and white bark – Red barked tree yielded more gum than 3’
6”3’ 3 white barked one. It was also noticed that trees growing on hill-slopes yield more and quality gum than others. Collection of gum per one person one blaze would be around 30 – 50gms.


Post Harvest Technology and Grading:

Freshly collected gum is thoroughly dried in sun for 5 to 15 days depending on the climate to reduce the moisture content and also to bleach the colour to some extent, grading in the initial stages is based on purity, colour. The grading and processing / purification is done manually or mechanically in processing plant. Gum processing, purification involves in removal of adhesive bark, wood, dust and sand etc., by physical means and by blowing air.
After removal of the impurities to the extent possible, the gum is graded into different categories based mainly on colour and then impurities, then sized into different grades i.e., HPS, grade I, II, III, siftings.


Quality Specifications:
Bureau of Indian Standards laid down the following specification on gum grading:

  • Grades Colour Bofm Viscosity
  • HPS Pure White 0.3% - 0.5% 1200-1500cps
  • I White to amber 0.5% 1000 cps
  • II Reddish pale yellow 1.5% 600-1000cps
  • III Brown to Black 3% 200-600 cps
  • Siftings - 1 Brown 6%
  • Siftings – 2 Brown and dark 8-10%
  • Crude Gum Karaya is in the form of tears of variable size or in broken irregular pieces.
  • The colour varies from pale yellow to pinkish brown translucent and hornand occasionally admixed with a few darker fragments.
  • The crude Gum Karaya also contains plant debris such as bark, wood, sand, dust and also rodent hair andinsect fragments etc.,

Gum Karaya (Sterculia urens)

Industrial Applications:
  • In petroleum and gas producing industries the Gum Karaya is used in formulations of drilling fluids in removing calcareous deposits in the wells. Gum Karaya added to the lime-base drilling fluids to prevent water loss after reducing its viscosity by heating at 90oc. for 10 hrs.
  • Paper and Pulp: Gum Karaya is used in the paper industry for the manufacturing of certain special quality papers. It deflocculates the fibres and serves as binder for fibres. Use of Gum Karaya results in light weight sheets of improved formation and strength.
  • Leather and Allied Products: In leather industry it is employed as an ingredient of dressing compositions and in proportions for accelerating the tannin action weighing compositions. Gum Karaya is also used in the manufacture of collagen fibre material.
  • Miscellaneous Industrial Products: Low grade gum served as a more efficient binder in the briquette (a block of compressed coal dust).

Food Industry Applications:

1) Sugar: Acceleration of settling rates of first carbonation juice in beet sugar manufacture can be accelerated by the addition of small amount of a dilute solution of a natural gum such as Gum Karaya. The addition of gum / stabilizer improves the quality of juice.

2) Meats:
Gum Karaya serves as a less adhesive water absorber in the final ground meat products and as an emulsifier and binder during meat processing. Gum also gives the product a smooth appearance. During meat processing such as chapping, curing, smoking, cooking, chilling, the added Gum Karaya acts as an emulsifying and binding agent by absorbing moisture and stored product.

3) Salad dressings: In salad dressing Gum Karaya is used as a stabilizer byincreasing the water, oil emulsion and thereby preventing or slowing separation.

4) Sauces, Condiment Bases, Ketchups, Sweet pickle & liquor: In the above items Gum Karaya acts as a stabilizer on 0.1% to 1% by increasing the viscosity. It retards the movements of solid particles or liquids of different density.

5) Baked Foods:
A mixture of karaya and arbic gums gave some good results as an emulsifying agent, Gum Karaya mixture & biscuits improves the appearance, symmetry, grain and tenderness whereas in bread it increases the volume and improves the softness, symmetry, extreme, cream color, taste, odour.

6) Karaya gum can be used in making synthetic pulp for fruit juices because of its cold water swelling property.
 
7) Medicinal Uses: Gum Karaya also used for constipation, liverticular disease and as laxative. Also used to osmotic aids through gum which is from powder,paste, ring, disk, a sheet board advantageous only the other adhesive plasters and cements specially immediately after post surgical core of skin / sensitive skins or in soothing to skin, less likely to produce softness, darker support microbial growth.
Sores and Wound: It found that the application of powdered Gum Karaya stimulated granulation and healed the resistant bed sores in few patients. Gum Karaya powder packed in to open wounds increased the normal granulation tissue and also resulted in good epidermal in growth.
Gum Karaya is also used in dentine adhesive, medical adhesive tapes for the treatment of stomatities and also used in preparation of pressure-sensitive masking tapes, medical jellies, pastes.

8) Cosmetics:
The film forming property of Gum Karaya makes it useful in the hair setting preparations of hair dressing lotions and finger wave lotions for the beauty trade.

9) Other Uses: Also used in linoleum, Ice creams, Jellies, Varnishes, Inks,Rubber compositions, Oil cloth, Paper coating, Polishes and Engraving process.

Gum Karaya Powder

Uses:

The major use of Gum Karaya is as a bulk laxative in view of its ability to form a mucilaginous gel on contact with water. For their use, the Gum is ground to a granule size of 8-30mesh. These granules have a capacity to absorb and after and swell to 70-100% times their original value. The Gum is neither digested nor absorbed by the body . The Gum has also been used in a limited way as a wet end additive in paper manufacture in conjunction with starches.


Gum Karaya is used extensively in various totally unrelated industries because of the properties such as water absorbing / moisture absorbing, gel and film forming,adhesiveness abilities. It is highly resistance to hydrolysis by mild acids and degradation by most of the microorganisms.

Storage: Most of the uses of Gum Karaya in various industries is based on its property to form a viscous or colloidal solution. Powdered gum should be stored in air tight containers. Since viscosity of Gum Karaya especially urns if it is in powdered form, is greatly reduced, when stored in aerable containers in dry/hot environment. Therefore, cold storage i.e., temperature on exceeding 25oC. under humid conditions is necessary to inhibit the decrease in viscosity of Gum Karaya. Gum should be dried (sun / tray drying) properly before putting in bags. Excess
moisture in the stored material may lead to change in colour from white to dark and also fungus attack resulting in poor demand and low price.

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