A Brief Introduction to Starch

                                     INTRODUCTION TO STARCH 

1.1 MOLECULAR STRUCTURE

Chemical formula- (C6H10O5)n

Molecular weight - 162gm/mol

Starch contains both Amylose

                                 Amylopectin

Amylose-

 -is a linear polymer of short 1,4 linked glucose chains.

 -Typically the amylase fraction is about 20-25% of starch molecules found in corn & has a molecular weight of about 250,000. The percentage of amylase in the starch is genetically determined. Genetic modification producing high amylose (50-70%).

Amylopectin-

 - is a branched polymer of the basic repeating units of 1,4 linked glucose with branches of 1,6  linked glucose. The branching occurs approximately one per twenty-five glucose units.

 -comprises about 75-80% of starch and has a molecular weight of about 50-550 million.

1.2 SOURCES OF STARCH

The main sources of starch are staple food as Maize (corn), wheat, rice, potatoes, cassava,

Arrowroot and Sago, etc.

1.3 RAW MATERIALS

-Dry maize -moisture 11-15% by weight

-Plant capacity 150 Ton per Day

-Process water- 6-8 m

-SO2 water – 160-180 grams sulfur per day

-prepared concentration nearly 3600 ppm

-Electricity – 2500 units per ton of grinding

1.4 SPECIAL STARCH PROPERTIES

COMPOSITION

Moisture – (11-15%)

Carbohydrates – (98-99%)

Protein- (0.5-0.7%)

Fiber- (0-0.5%)

Sulfated ash – (0-0.2%)

1.5 APPLICATIONS

Maize starch in its biological function, is used as an anti-agent and a chemical catalyst. The world mohas been aware of the physical properties of the maize starch for a while now, but researchersand scientists all over the world are paying a great deal of the interest to biological aspects of thecomplex carbohydrates, polymers.

Textile Industry

Maize starch has an extensive use in the Indian cotton textile industry. Out of all starches maize starch has the quality to be removed in the first wet process. It therefore can have an individual function at every stage of textile manufacture.

a) It is used as an adhesive to strengthen the wrap yarn by improving its resistance to abrasion while weaving.

b) Maize starch is immensely useful in printing to increase the consistency of the printing paste.

c) It is used as finishing of the material, to change the appearance after it has been dyed, bleached and printed.

d) Thread owes its glaze and bright shine to maize starch

e) Starch solution has very good penetration power and is used as laundry stiffening agent.

Modified starch for the textile industry sizing

During weaving process, yarn is subjected to two kinds of stresses. One is external frictional

stresses and shearing stresses and second is inner structural stresses. An inadequately sized wrap can very often hinder the productivity of even the most efficient automatic loom.

Among sized agent starch maintains its pre-eminence inspire of the development of the synthetic products, starch keeps abreast of all new changes.

Application of sizing grade starch

All staple fibers, be they cotton polyesters mixtures, spun rayon or wool, use sizing grade starches modified starches during the weaving process.

Food Industry

80% of the food diet is supplied by carbohydrates, and starch is rich in it. Food starch manufacture is separation process to obtain powdered starch, which is further used in sweeteners and modified starch products. Food starch therefore plays:

a) They are nutritive stabilizers

b) They are the processing aids used in the manufacture of food stuffs.

c) Modified starches provide uniformity in filling operations for liquid and particulate formulations.

d) The use of pre-gelatinized starches controls the spread of cold flow products in extrusions.

     Examples- gravies, sauces, puddings, chocolates, spreadable salad dressing, canning   diary,confectionary baking, packaged mix, frozen food.

  

Paper Industry

The very crispness of good quality paper depends on maize starch. Besides accounting for a smooth surface texture, stiffness and rattle it increase the paper strength so necessary for the printing.It is needed as ink penetration, sizing purposes, and as a adhesive for coating of pigmented paper.

Adhesive Industry

High strength adhesives, paper glue, wood adhesives, label adhesives, wall paper paste, etc all have a maize starch component. Gelletinized starch is used as binder agent, while a number of adhesives such as dextrin’s and modified starches are used in specific purposes.

Pharmaceutical Industry

Edible starch is being used as binding agent in tablets, etc. besides this physical function it simultaneously acts as a dispersant agent. Starch granules are very easily metabolized in the human body, so even a small amount of medicine absorbed by the granules is quickly dispersed