Depending upon the requirement of the end product, various techniques are used for processing guar. In India, commercial production of guar gum is normally undertaken by using the process of roasting, differential attrition, sieving and polishing. The stage-wise process of manufacturing food grade guar gum is as follows: Selected guar split is screened to clean and then soaked to prehydrate in a double cone mixer. Prehydrating stage is very important in the process as it derives the rate of hydration of the final product. Soaked splits, which have reasonably high moisture content, are passed through a flaker. The flaked guar split is ground to the desired particle size, followed by drying of the material. The powder is then screened through rotary screens to deliver required particle size. Oversized material is either recycled or reground, as per viscosity requirement. The soaked splits are difficult to grind. Direct grinding of such splits generates more heat in the grinder, an undesirable process, as it results in insoluble or reduced hydration in the end product. Using heating, grinding and polishing process, the husk is separated from the endosperm halves and the refined guar gum split is obtained. Through grinding process, the refined guar split is then
treated and converted into powder. During the split manufacturing process, husk and germ are obtained and these are widely used as cattle feed, as they are rich in protein. It is widely sold in the international market as guar meal and contains oil and lbuminoids, about 50 per cent in germ and about 25 per cent in husks. Quality of food grade guar gum powder is defined from its particle size, rate of hydration and the microbial it contains
Guar Seed: The pods are sun dried, manually separated from the seeds and the seeds are supplied to the industry for processing. Guar by-products, churi and korma, are used as cattle feed.
Undehusked Guar Splits: A mechanical process of roasting, differential attrition, sieving and polishing, commercially extracts the gum from the seeds. The seeds are broken and the germ is separated from the endosperm. Two halves of the endosperm are obtained from each seed and are known as undehusked guar splits.
RefinedGuar Splits: When the fine layer of fibrous material, which forms the husk, is removed and separated from the endosperm halves by polishing, refined guar splits are obtained.
Guar Powder: The refined guar splits are then treated and grounded into powders by a variety of routes and processing techniques, depending upon the end product desired.
Guar Meal: A by-product of guar processing, guar meal (mixture of husks and germ) is rich a source of protein. It is used for cattle as well as poultry feed. Toasting of guar meal improves its nutritive value. It can be used up to 10 per cent in poultry diet and can replace up to 100 per cent protein supplements, such as groundnut cake, in cattle feed.
