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Starch and Starch Granules

  1. Alison M Smith

Published Online: 19 MAY 2010

DOI: 10.1002/9780470015902.a0001294.pub2

eLS

eLS

How to Cite

Smith, A. M. 2010. Starch and Starch Granules. eLS. .

Author Information

  1. John Innes Centre, Norwich, UK

Publication History

  1. Published Online: 19 MAY 2010

Abstract

Starch is the main form in which plants store carbon. It occurs as semi-crystalline granules composed of two polymers of glucose, called amylose and amylopectin. Depending on the plant organ, it can act as a store of carbon for lengths of time as short as a day (e.g. in leaves) or as long as many years (e.g. in dormant seeds). Starch granules are characterised by internal growth rings. There is enormous variation in granule size and shape between plant organs, and between species. Starch is the major carbohydrate of nutritional importance in the diet: it is degraded to glucose by amylases in the mouth and small intestine. When cooked in water, starch forms gels or pastes that have a wide range of industrial applications in both food and nonfood industries.

Key Concepts:

  • Starch is the main form in which plants store carbon.

  • Starch occurs as semicrystalline granules, composed of branched and linear polymers of glucose.

  • Starch granules vary in size and shape between plant organs and between species.

  • The distinctive morphology and anatomy of starch granules enables the identification of plant remains in food, forensic and archaeological samples.

  • Starch is the main component of the harvested parts of many crops, including cereals, peas and beans, potatoes and cassava.

  • Starch is the main carbohydrate of nutritional importance in the human diet.

  • When cooked in water, starch granules swell to form gels or pastes that are widely used in food and nonfood industries.

  • Major uses for starch include a thickener in processed foods, and in the manufacture of paper, biodegradable plastics and adhesives.

  • Starch is often modified after extraction to generate properties desirable for specific industrial purposes: there is interest in breeding new crops in which the native starch already has these properties.

Keywords:

  • starch granule anatomy;
  • starch granule morphology;
  • industrial uses of starch;
  • starchy foods;
  • starch properties