Characteristics of Starch

Characteristics of Starch

Storage form of carbohydrates in plants

Sources:

Cereal endosperm

Wheat

Corn

Roots and tubers

Cassava

Potatoes

Hot water + Starch = Lump formation

Starch granules must first be separated

4 ways:

Coat starch granules with hot fat

Coat starch granules with cold fat

Disperse starch in cold water

Separate granules using sugar

Gelatinization

Starch heated with water

Viscosity increases

Maximum viscosity occurs @ 194°C

Pasting

Occurs when heated beyond gelatinization

Becomes pasty and swollen

Composition of Starch

Amylose

Linear chain of glucose molecules

Source: Cereal starches

Include wheat and corn

Thicken near boiling point

Retrogradation occurs when chilled

Becomes rubbery

Loses water

Composition of Starch

Amylopectin

Branched chain of glucose molecules

Source: Roots and tubers

Include potato and tapioca

Thicken at lower temp.

Becomes clear

No retrogradation occurs

Starch principles

Browning

Dextrinization produces pyrodextrins

Reduced thickening ability occurs

Factors affecting properties of starch

Temperature

Length of treatment

Agitation


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