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Under the microscope in polarized light starch loses its birefringence and its extinction cross. [ 2 ] Amylose leaching: Penetration of water thus increases the randomness in the starch granule structure, and causes swelling; eventually amylose molecules leach into the surrounding water and the granule structure disintegrates.
The International Commission for Uniform Methods of Sugar Analysis (ICUMSA) is an international standards body, founded in 1897, [1] [2] that publishes detailed laboratory procedures for the analysis of sugar. The ICUMSA Methods Book [3] contains detailed instructions for analyzing raw, cane, white, beet, molasses, plantation white and ...
Extinction is a term used in optical mineralogy and petrology, which describes when cross-polarized light dims, as viewed through a thin section of a mineral in a petrographic microscope. Isotropic minerals, opaque (metallic) minerals, and amorphous materials (glass) do not allow light transmission under cross-polarized light (i.e. constant ...
The multiple crystals on the right were grown from a sugar cube, while the one on the left was grown from a single seed taken from the one on the right. Red dye was added to the sugar solution before growing the large crystal, but was insoluble with the sugar in its solid state, and all but small traces of the dye was forced to precipitate out ...
In chemistry, fractional crystallization is a stage-wise separation technique that relies on the liquid–solid phase change. This technique fractionates via differences in crystallization temperature and enables the purification of multi-component mixtures, as long as none of the constituents can act as solvents to the others.
From aqueous solutions, the three known forms can be crystallized: α-glucopyranose, β-glucopyranose and α-glucopyranose monohydrate. [54] Glucose is a building block of the disaccharides lactose and sucrose (cane or beet sugar), of oligosaccharides such as raffinose and of polysaccharides such as starch, amylopectin, glycogen, and cellulose.
A crystal's crystallographic forms are sets of possible faces of the crystal that are related by one of the symmetries of the crystal. For example, crystals of galena often take the shape of cubes, and the six faces of the cube belong to a crystallographic form that displays one of the symmetries of the isometric crystal system. Galena also ...
A petrographic microscope, which is an optical microscope fitted with cross-polarizing lenses, a conoscopic lens, and compensators (plates of anisotropic materials; gypsum plates and quartz wedges are common), for crystallographic analysis. Optical mineralogy is the study of minerals and rocks by measuring their optical properties.