2.2.2.3 Locust Bean Gum
Synonym Carob Flour; Arobon; Carob Gum; Ceratonia; Johannisbrotmehl;
Biological Source The Gum essentially consists of the hydrocolloid from the powdered endosperm of tree pods of Ceretonia siliqua Linn, belonging to the family Leguminoseae (St. John’s bread). It normally takes about 15 long years for a full-grown tree to yield seeds which , therefore, restricts the provision of a regular production of the gum to cater for the ever-expanding needs for the hydrocolloids.
Geographical Source The tree is found in abundance in Egypt, Cyperus and Sicily. It is very sensitive to low temperature. It is also commercially grown in countries like: Algeria, Greece, Israel, Italy, Morocco, Portugal and Spain.
Preparation The locust bean pods comprise of about 90% pulp and 8% kernnels. The kernnels are separated from the pods mechanically by means of Kibbling Machine. The kernnels comprise of mainly the endosperm (42-46%), husk (30-33%) and germ to the extent of 25%. First of all the seeds are duly dehusked and splitted lengthwise the seeds are duly dehusked and splitted lengthwise to facilitate the separation of the endosperm from the embryo* (i.e., the yellow germ). The dried gum is pulverised and graded as per the mesh-size e.g., 150, 175 and 200 mesh sizes available in the European market.
Description
Colour : Translucent white, yellow green
Odour : Odourless
Taste : Tasteless and mucilaginous. Acquires a leguminous taste when boiled with water
Solubility : Insoluble in alcohol. Dispersable in concentration upto 5%
Viscosity : As it is a neutral polysaccharide, hence pH has no effect on viscosity between
3-11.
Chemical Constituents Locust bean gum comprises of proteins, for instance: albumins, globulins and glutelins; carbohydrates, such as: reducing sugar, sucrose, dextrins, and pentosans; besides ash, fat, crude fiber and moisture.
* Embryo enhances the rate of fermentation of gum solutions and hence it must be removed as completely as possible.
Chemical Tests The mucilage of this gum when gently boiled with 5% KOH solution it yields a clear solution; but agar and tragacanth gives rise to a yellow colour, whereas karaya gum produces a brown colour.
Substituent Adulterant In food industry it is employed as a substitute for strach.
Uses
1. It is used as a stabilizer, thickner and binder in foods and cosmetics.
2. It is widely employed as a sizing and finishing agent in textiles.
3. It finds its abundant use as fiber - bonding in paper manufacture.
4. It is used as an adsorbent - demulcent therapeutically.
5. It is employed as drilling mud additive.
