Ageing starch

Furunori is a modified wheat starch made in Japan by ageing starch paste under water for years. The molecular weight of the starch is reduced considerably by microbial action and the amylose is almost totally retrograded (Daniels, 1988 Hayakawa et al., 2002). It has less tack and greater gel stiffness. 

Daniels, V. (1988). A study of die properties of aged starch paste (furu-nori). In J. S. Mills, P. Smith and K. Yamasaki, (Eds.), The conservation of Far Eastern art, Kyoto Congress, 19-23 September 1988 Preprints 5—10, International Institute for Conservation. 

The differential scanning calorimetry (Figure 15.3) is a thermoanalytical assay in which the difference in the amount of heat required to increase the temperature of a sample is measured as a function of temperature (temperature increases linearly as a function of time). In cereals, DSC analysis of starch-rich and starch-water slurries have been used to determine quantitatively starch gelatinization as an enthalpy (-AHg) of gelatinization (Table 15.3). Enthalpy measurements also can be used to measure the return to crystallinity in aged starch gels. The endotherm excursions... 

Retrogradation characteristic is a visual finding of starch aging. Starch paste can appear stratification phenomenon after the gelatinized starch places a period of time. The upper transparency increases, but the lower layer transparency decreases. This is the aging characteristic of starch. 

The synthetic approach is very simple and does not require any special set up. In a typical room temperature reaction, 1.0 mL aqueous solution of cadmium chloride was added to 20 mL aqueous solution of soluble starch in a 50 mL one-necked round-bottom flask with constant stirring at room temperature. The pH of the solution was adjusted from 6 to 11 using 0.1 M ammonia solution. This was followed by a slow addition of 1.0 mL colourless selenide ion stock solution. The mixture was further stirred for 2 h and aged for 18 h. The resultant solution was filtered and extracted with acetone to obtain a red precipitate of CdSe nanoaprticles. The precipitate was washed several times and dried at room temperature to give a material which readily dispersed in water. The same procedure was repeated for the synthesis of PVA and PVP - capped CdSe nanoparticles by replacing the starch solution with the PVA and PVP polymers while the synthesis of elongated nanoparticles was achieved by changing the Cd Se precursor ratio from 1 1 to 1 2. The synthesis of polymer capped ZnSe nanoparticles also follows the same procedure except that ZnCb solution was used instead of CdCb solution. 

Viscometer test. Typical crosslinked starches are obtained when the initial rise of the viscosity of the product is between 104° and 144° C, and the viscosity of the product does not rise above 200 Brabender units at temperatures less dian 130° C. The crosslinked starch slurry is then drum-dried and milled to obtain a dry product. The effectiveness of the product is checked by the API Fluid Loss Test after static aging of sample drilling fluids containing the starch at elevated temperatures. The milled dry product can then be incorporated into the oil well drilling fluid of the drill site. 

The ethyl alcohol fermentation is of course an age-old process and is so well known that little need be said about it here. The acetone-butanol fermentation is perhaps the next most important industrial fermentation process, although starch in the form of maize has been largely used as the basic material more recently suitably treated molasses has been used. The fermentation, a relatively rapid process requiring about thirty hours, produces about 60 parts of butanol, 30 parts of acetone and 10 parts of ethyl alcohol. These products already have large uses in industry and other uses are being explored. One possibility is the use of butanol in motor fuel. Jean has described a fuel, called Jeanite, consisting mainly of butanol and ethyl alcohol, which shows some promise. Of course the admixture of ethyl alcohol with petroleum is well known and an increased use of this mixture is probable. 

Mita, T. (1992). Structure of potato starch pastes on the ageing process by the measurement of their dynamic moduli. Carbohydrate Polymers, 12,269-276. 

Historical. Accdg to Kirk Othmer(Ref I2,p 245), the fact that a chem reaction can be aided by the addn of certain substances was known to the alchemists in the Middle Ages and by the end of 18th and beginning of 19th century several industrial processes were known such as hydrolysis of starch by acids(Parmentier, 1781) and the lead-chamber sulfuric acid manuf... 

Aging of gelatinized starch was studied by cross-relaxation NMR method [99]. Relatively immobile starch components increased and components with liquid-like mobility decreased during aging. Two spectral components were observed in cross-relaxation spectra. According to the theory mentioned above(5.5.1.), the broader one correlates with the degree of crystallinity and the narrower one with starch chains having mobility intermediate between... 

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