Derivatization potato starch

Physico-chemical properties of derivatized potato starch... 

Com and rice starches have been oxidized and subsequently cyanoethylated (97). As molecular size decreases due to degradation during oxidation, the degree of cyanoethylation increases. The derivatized starch shows pseudoplastic flow in water dispersion at higher levels of cyanoethylation the flow is thixotropic. Com and rice starches have been oxidized and subsequently carboxymethylated (98). Such derivatives are superior in the production of textile sizes. Potato starch has been oxidized with neutral aqueous bromine and fully chemically (99) and physically (100) characterized. Amylose is more sensitive to bromine oxidation than amylopectin and oxidation causes a decrease in both gelatinization temperature range and gelatinization enthalpy. 

In this chapter, we have presented a great deal of information on important physicochemical and functional characteristics of native potato starch in comparison with some cereal starches. In addition, we have also discussed various modification techniques being used to modify potato starch, with an emphasis on the post-modification changes (particularly after derivatization)... 

Modification, which involves the alteration of the physical and chemical characteristics of the native potato starch to improve its fimctional characteristics, can be used to tailor it to specific food applications. The rate and efficacy of any starch modification process depend on the botanical origin of the starch and on the size and structure of its granules. This also includes the surface structure of the granules, which encompasses the outer and iimer surface depending on the pores and channels, which cause the development of the so-called specific surface (Juszczak, 2003). Potato starch modification can be achieved in three different ways physical, conversion, and chemical (derivatization) (Table 10.6). 

AVEBE, the starch producers cartel declined rapidly. Their companies were either closed or taken over by the farmers. In 1948, it was decided that AVEBE should increase its market base and derivatization of potato starch was started. Today, AVEBE modifies about 70% of the potato starch it produces. 

Anionic starches are obtained by reaction with phosphoric acid and alkali metal phosphates or by derivatization with carboxymethyl groups.30,31 This modification is primarily used to introduce amphoteric properties into cationic com starch for application on the wet end of the paper machine. Anionic starches with carboxymethyl substitution are used as thickeners in coating colors or as binders in coatings for specialty paper grades. Oxidized starches are inherently anionic but without thickening action. Potato starch already carries sufficient natural anionic charge to provide amphoteric properties after cationization.32... 

P. F. Tankam, R. Muller, P. Mischnick, and H. Hopf, Alkynyl polysaccharides Synthesis of propargyl potato starch followed by subsequent derivatizations, Carbohydr. Res., 14 (2007) 2049-2060. 

The major starch sources are corn, potato, waxy maize, wheat and tapioca. Refined starches are supplied in powder form or as slightly aggregated pearl starch.16 Unmodified (native) starch is rarely used in the paper industry, except as a binder for laminates and in the corrugating process. Most starches for use in papermaking are specialty products that have been modified by controlled hydrolysis, oxidation or derivatization.17... 

Hydroxypropylstarehes are derivatized starches from waxy maize, eom, potato, or tapioca starch. They are often crosslinked to change texture, as well as to improve temperature and pH resistanee (14,19). Hydroxypropylstarehes are used for viscosity stabilization for both water and milk based products. They improve freeze-thaw and water holding eharaeteristics of produets. 

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