Starch Complexes with Other Nonmetallic Guests

Starch Complexes with Other Nonmetallic Guests 1. Introduction 

As with iodine, starch forms an inclusion complex with bromine vapor.205 Depending on the starch variety, different colors are developed by the complex. Maize and wheat produce an ochre color, rice produces a light-buff color, potato and sago develop a pale-yellow color, and cassava forms a cream color.69 Iodine cyanide (and bromine)-amylose complexes are brown-black and dark brown, respectively.206 The adsorption of chlorine and iodine proceeds according to the Freundlich isotherm. A discontinuity on the Freundlich isotherm plot is reported, which possibly results from the swelling of starch granules454 

Sorption of various gases (02, N2, C02, and He) on wheat flour, soybean flour, potato starch, and wheat starch has been investigated in order to study the effect of those gases on the functional properties of processed food products. Results indicate that such properties improved only after flour and starch were treated with chlorine.455,456 The adsorptivity of various gases by starch has been reexamined.457 Liquid ammonia quickly forms a gelatinous paste with starch.458 Tomasik et al.459 attempted to prepare inclusion complexes of starch with colloidal sulfur. A key result was that inclusion inside the starch matrix was only possible in small amounts because of the large relative size of the sulfur micelles. 

It has been discovered that starch adsorbs onto graphite, a phenomenon that is employed in processing sulfide ores containing graphite.460 The adsorption of starch on quartz and hematite has been studied in more detail.461 In this case, adsorption is related to the balance between electrostatic interactions and hydrogen bonding. Interparticle bridging is also observed as a result of the adsorption of starch molecules at the interface (flocculation). 

Reychler independently presented a similar suggestion.469 The following complexes with sodium hydroxide and starch have also been characterized in solution (2C6H10O5 NaOH)n (C6H10O5 NaOH) and (C6HiO05 2NaOH) 470,471 

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