Phosphorus starch granules

Kasemsuwan, T., and Jane, J. 1994. Location of amylose in normal starch granules. II. Location of phosphodiester cross-linking revealed by phosphorus-31 nuclear magnetic resonance. Cereal Chem. 71, 282-286. 

Starch granules have been cross-linked with phosphate by the reaction of an aqueous alkahne (pH 8-12) suspension reaction with phosphorus oxychloride [161]. Trimetaphosphate has also been used to produce phosphate cross-linkages. These reactions are primarily with the C-6-OH groups and only a minimal number with the C-3-OH groups [162]. Starch phospho esters can be obtained by phosphorylation with sodium triphosphate at pH of 8.5 [163]. 

Similar behavior was found when starch granules were dehydrated under diminished pressure over phosphorus pentaoxide there was a loss of x-ray diffraction pattern, but, in this instance, the pattern could be brought back by re-hydrating the starch. Katz therefore assumed that loss of water was responsible for the characteristic diffraction pattern of the pyrodextrins, and he suggested, without any experimental evidence,... 

The hydroxyl groups of polysaccharides can be phosphorylated by reaction with tripolyphosphate at pH 5-6.5 the reaction is conducted at 110-130°C in the dry state and creates products containing 0.07-0.1% phosphorus [15] (reaction 7.14). Reaction of starch granules with tripolyphosphate at 150°C resulted in 0.3% covalently linked phosphorus that was distributed 9% at 0-3, 28% at 0-2, and 63% at 0-6 [19]. 

Granular starch has been cross-linked with phosphate by reaction of an aqueous alkaline suspension at pH 8-12 with 0.005-0.25% phosphorus oxychloride [15] (reaction 7.15). If starch granules are treated with 1% or higher concentrations of phosphorus oxychloride, the granules become very resistant to gela-tinization. Trimetaphosphate has also been used to produce phosphate cross-linkages [15] (reaction 7.16). Phosphorylation of 0-6 is predominant, and that of 0-3 is minimal [19]. 

If the fused element be shaken up with a warm liquid until cold, it furnishes the so-called granulated phosphorus. J. L. Casaseca recommended alcohol of sp. gr. 085 in preference to water R. Bottger, human urine, or an aq. soln. of urea N. Blondlot, soln. of various salts, or sugar and H. Schiff, methyl alcohol, actone, aq, ammonia, soln. of gum, dextrine, glue, starch, ammonium carbonate, etc. 

Starch is a glucan and is present in many plants as a reserve carbohydrate. It is most abundant in seeds, fruits, tubers and roots. Starch occurs naturally in the form of granules, whose size and shape vary in different plants. The granules are built up in concentric layers, and although glucan is the main component of the granules they also contain minor constituents such as protein, fatty acids and phosphorus compounds, which may influence their properties. 

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