Starch granules organization

Starch occurs as highly organized structures, known as starch granules. Starch has unique thermal properties and functionality that have permitted its wide use in food products and industrial applications. When heated in water, starch undergoes a transition process, during which the granules break down into a mixture of... 

Birefringence (or double refraction) is the decomposition of a light ray into two rays when it passes through certain types of crystalline material. This occurs only when the material is anisotropic, that is, the material has different characteristics in different directions. Amylose and amylopectin polymers are organized into a radially anisotropic, semicrystalline unit in the starch granule. This radial anisotropy is responsible for the distinctive... 

In these plant organs, starch is present in the form of microscopically small granules in special organelles known as amyloplasts. Starch granules are virtually insoluble in cold water, but swell dramatically when the water is heated. Some 15-25% of the starch goes into solution in colloidal form when the mixture is subjected to prolonged boiling. This proportion is called amylose ( soluble starch ). 

Gallant, D. J., Bouchet, B., and Baldwin, P. M. 1997. Microscopy of starch Evidence of a new level of granule organization. Carbohyd. Polymers 32 177-91. 

French, D. (1984). Organization of starch granules. In R. L. Whistler (Ed.), Starch Chemistry and Technology (pp. 183-247). Academic Press, New York. 

Starch granules are composed of two different polysaccharides, amylopectin and amylose the former constitutes about 80 % of the most common starches. Separation of the two components can be achieved by selective precipitation involving the formation of an insoluble complex of amylose with polar organic substances. 

Microscopic Examination.—50 grams of the honey are dissolved in about 150 c.c. of hot water and the solution filtered through a dry filter into a 250 c.c. flask. The filter is washed with small quantities of hot water and the solution made up to volume when cold and shaken this is used for tests 4, 6 and 9. The residue on the filter is usually small in amount and is examined microscopically under low and high powers to ascertain if pollen, starch granules, residues of the different organs of the bee, vegetable elements, etc., are present. 

Microscopic test. Pollen grains, starch granules and organs of the bee may be present. 

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