The German word Starch means strong or hard or hard or rigid. Starch is a complex homopolysaccharide. Its molecular symbol is (C6H10O5)n. Carbohydrates or sugars produced in the process of photosynthesis are converted into starch and stored. Rice, wheat, potato, sorghum, banana, barley etc. are the main sources of starch. All these ingredients contain 70-80% starch. Round potato starch particles are the largest and 100µm. Rice starch particles are smallest and 2µm. The first reference to the extraction of starch from plants is found in the Natural History of Pliny the Elder (77-78 AD). Dr. Siddiq Publications
Properties of Starch /Religion
(i) Starch is tasteless, odorless and colorless substance.
(ii) It is a white granular powdery organic chemical substance.
(iii) It is insoluble in water, alcohol and ether.
(iv) Starch turns blue in iodine solution.
(v) It breaks down at high temperature into large dextin particles.
(vi) Starch cannot oxidize Fehling’s solution.
(vii) Iodine reacts with amylose of starch to produce black or black-blue color.
(viii) Iodine reacts with amylopectin of starch to produce red or purple color.
Chemical structure of starch
Starch is a complex polysaccharide. Starch is made up of amylose and amylopectin. It contains 22% amylose and 78% amylopectin. Amylose is composed of 200-1000 molecules and amylopectin is composed of 2000-200,000 molecules of glucose. Numerous glucose molecules are linked by α-1-4 glycosidic bonds to form starch. However, glucose molecules can be joined by α-1-6 bonds. Starch is hydrolyzed to glucose.
Use of starch
(i) Stored food: Starch is stored in the plant body as stored food. Starch in plant seeds, fruits and tubers serves as stored food. Starch stored in rice, wheat, bhutra, cassava, corn and round potato is used as human food.
(ii) Source of energy: It acts as a source of energy in the organism. Starch is converted into glucose to provide energy and carbon molecules to the body. Dr. Siddiq Publications
(iii) Respiration: It generates heat and energy in respiration.
(iv) Research: Starch is used in the laboratory to produce glucose and alcohol.
(v) In Paper Industry: Starch is the main ingredient in paper industry.
(vi) Preparation of glue: Pure starch is mixed with hot water to make glue. It is used to make corrugated board glue.
(vii) In titration: Starch is used as indicator during titration.
(viii) Textile use: Warp seizing agent is produced from starch. Warp shrinking agents reduce the rate of yarn tearing during fabric weaving. Starch is used for beating (laundry) cloth. Dr. Siddiq Publications
(ix) Oil exploration: Starch is used to increase the viscosity of drilling fluids, which are slippery fluids in oil exploration.
(x) Manufacture of cosmetics: Starch is used in the manufacture of talcum powder and other cosmetics.
(xi) Food processing: Starch is used to increase the density of food during food processing.
(xii) Production of Polymers: Starch is used to make eco-friendly bioplastics and other synthetic polymers.
(xiii) Fuel production: Biofuel corn ethanol is produced from starch in a fermentation process.
(xiv) Reproduction: Starch stored in the fruits, seeds, rhizomes and corms of the plant participates in the production of offspring in the next season.
(xv) In pharmaceutical industry: Starch is used as active ingredient carrier, tablet disintegrant and binder in pharmaceutical industry.
(xvi) Clothing starch: Liquid clothing starch is prepared by mixing pure starch with water. It is used in garments and laundry.