Rice starch paste

The functionality of rice starch depends on the amylose amylopectin ratio. Differences among rice starches made from long-, medium- or short-grain rice are insignificant relative to the amylose content. Rice starches made from common rice tend toward higher peak, cooked and cooled viscosities, as well as paste textures that are short and pasty. The texture of waxy rice starch pastes tends to be long and stringy (Table 13.3). 

Gelatinization of sweet potato, tania, and yam tuber starches. Starch/Starke. 47, 298-306. Varavinit, S., Shobsngob, S., Varanyanond, W., Chinachoti, P., and Naivikul, O. (2003). Effect of amylose content on gelatinization, retrogradation and pasting properties of flours from different cultivars of Thai rice. Starch/Starke 55,410-415. 

Lim, S. T, Lee, J. H., Shin, D. H., Lim, H. S. (1999). Comparison of protein extraction solutions for rice starch isolation and effects of residual protein content on starch pasting properties. Starch, 51, 120-125. 

Almost all the starches investigated contain some phosphorus.124-126 In addition to phospholipids, phosphorus is also commonly found in starch as monostarch phosphate esters.6,7 Inorganic phosphate is present in some starches.124-126 Monostarch phosphate esters and phospholipids have different effects on starch paste properties.133,135 Monostarch phosphate esters, found in potato, shoti and other starches,6,7,136-140 increase paste clarity and paste viscosity.79 Little phosphate monoester is found in cereal starch.121,124,141,142 Phospholipids, found in normal cereal starches (e.g. wheat, rice and maize) decrease paste clarity and viscosity.133 31P-nmr spectroscopy has... 

Rice starch from common rice contains 0.3%-0.4% lipids, while waxy rice contains considerably less (0.03%). Complexes of these lipids are not easily removed from the starch, and are presumably responsible for the lack of paste clarity and the difficulty in clarification of starch hydrolyzates. 

RVA curves compare commercial rice starch prepared by traditional alkali methods and rice starches prepared by the mechanical method. In the case of common rice starches, the onset of pasting appears to occur earlier (at lower temperature) and the final cooled viscosity appears to be lower for the starches prepared using alkaline conditions. The latter differences may be due to either rice type or the effect of alkali on granules. In the case of waxy rice starches, mechanically produced starches, in... 

Properties of rice starches are changed by chemical modification in the same way as the properties of other starches (see Chapter 18). Starches prepared via the alkali method have been modified to provide additional pH and shear stability. In general, hypochlorite-oxidized rice starch has a lower gelatinization temperature and lower maximum paste viscosity producing a softer, clearer gel. Hydroxypropylated rice starches have lower gelatinization temperatures, whereas crosslinked rice starch has an increased gelatinization temperature, increased shear resistance and acid stability. 

This cohesive nature of glutinous rice starch is quite important especially for preparing round stars, because the essential point of the process lies in that the composition must be pasted in a wet state on the core using as little paste as possible Accordingly a paste which has a strong cohesive power satisfies the requirement well. For this reason glutinous rice starch is quite superior for manufacturing round stars. 

However the cohesive power of the paste of glutinous rice starch generally changes as the time passes when it is mixed with chemicals or compositions. For example, an experiment in the summer season is set out in Table 16. 

The decrease in the viscosity caused by sodium oxalate or black powder, which are the most powerful, was more precisely observed. In the first one or two hours it looks as though there is an increase in the viscosity, and then the viscosity slowly decreases after five or six hours the viscosity is not so different as that at the beginning. This property of glutinous rice starch does not cause any trouble in manufacturing stars, but the paste of a composition which contains glutinous rice starch must not be left more than half a day. 

I and II use a white smoke generated from the flame. White willow uses the smoke formed by the condensation of sulphur vapour without flame. The realgar allows the composition to burn smoothly. The stars of I and II are coated by an ignition composition. The white willow is manufactured as follows Form the composition into cut stars. Dry them well. Place them in a coating tub. Add to it slurry paste of soluble glutinous rice starch and shake the tub so that all the surfaces of the... 

Tukomane, T., and Varavinit, S. (2008). Classification of rice starch amylose content from rheological changes of starch paste after cold recrystallization. Starch/Stdrke, 60, 292-297. 

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