Corn-starch gel

In a current rheological study [296], the galactoxyloglucan from Hymenia courbaril was mixed with starch containing 66% amylose and with waxy corn starch (amylopectin). The gel mixtures showed, under static rheological conditions, an increase in paste viscosity compared to those of the polysaccharides alone. Dynamic rheometry indicated that the interactions resulted in increased thermal stability of the gel formed in comparison to that of the starch alone. 

Pure starch is not much used in bakery products. Some maize starch goes into a few types of biscuits or cakes under the heading of corn flour . A few starch gels are applied on bakery flans. 

The first thing you need is an adsorbant, a porous material that can suck up liquids and solutions. Paper, silica gel, alumina (ultrafine aluminum oxide), corn starch and kitty litter (unused) are all fine adsorbants. Only the first three are used for chromatography. You may or may not need a solid support with these. Paper hangs together, is fairly stiff, and can stand up by itself. Silica gel, alumina, corn starch, and kitty litter are more or less powders and will need a solid support to hold them. 

Other methods, alternative methods of producing lump-free CWS starch have been described. One employs heat-moisture treatment of a mixture of granular starch, a surfactant containing a fatty acid moiety and (optionally) a gum.214 A process for making a corn starch product giving a uniform viscous dispersion when added to boiling water employs heating a mixture of starch, surfactant and water, followed by microwave radiation.215 Compositions that gel at low solids concentrations were prepared by complexation of starches of moderate (20-30%) amylose content with emulsifiers.216... 

Starches with high amylose content, such as corn starch (28% amylose) retrograde more than starches with lower amylose content, such as potato starch (20% amylose). Redispersion of retrograded starch is energy-intensive due to extensive bonding. Temperatures of 115° to 120°C are required to solubilize amylose gels or crystals. Amylopectin gels can be redispersed at temperatures above 55°C. 

Cooking is traditionally done in kettles with acid-thinned corn starch chosen for its shorter texture and reduced hot viscosity, allowing more starch to be used for greater gel strength. With jet or tubular cookers, high-amylose starches are favored because... 

This general purpose, unmodified corn starch is basic to a large number of food and industrial applications. It is most used in neutral pH systems in which the properties of a low cost, thick boiling, high gel starch are advantageous. 

Boiled starch pastes tend to gel on cooling. This action must be attributed primarily to the linear A-fraction which has been partially leached from the swollen granules and which subsequently sets up an interlacing network within and about the granules. The various starches exhibit different gelation tendencies thus, corn starch (especially when defatted) gives a firm gel, while potato and tapioca pastes are weak and slimy. These variations may be due in part to differences in content... 

There are about 4 parts of cordierite powder for 1 part of organics. The 18 wt% of organics is composed as follows 4 wt% of gel of corn starch as binder. 

Dextrins obtained on y-irradiation of starch have been found to contain appreciable proportions of unidentified carbonyl residues. The properties of starch for starch-gel electrophoresis were improved by y-irradiation. The decreases in viscosity and iodine-absorption values, as well as the increased reducing properties, indicated that amylose and amylopectin are degraded by y-irradiation in the same way as native starches. Although each of the amylose and amylopectin components of amylomaize starch in y-irradiated and untreated samples was hydrolysed by a-amylase to the same extent, y-irradiated amylose had a low p-amylolysis limit. /-Irradiated amylomaize and com starches were hydrolysed to greater extents by a-amylase as the radiation dose was increased, and differences were detected in the products of enzymic degradation of amylomaize and corn starches following y-radiolysis. The water-soluble dextrins formed on y-irradiation of maize starch have been examined. ... 

Other applications of the technique include the use of immobilized glucose isomerase for the enrichment in fructose of corn starch hydrolysates and the use of immobilized pectinases for the clarification of fruit juice and wine. Immobilized enzymes have also been used as sensors for particular substrates. For example, a glucose-specific electrode has been developed which consists of glucose oxidase (page 94) entrapped in a polyacrylamide gel which is layered over a conventional polarographic oxygen electrode. 

Malate Enzyme. Malate enzyme, as well as the other enzymes of the pathway, is known to exist in multiple forms. In apple fruit, Dilley (1966) isolated and purified a form which ran as a single band on acrylamide gels. In corn root tissue, we were able to locate a single isoenzyme (by starch gel electrophoresis) and reported evidence that it was a soluble or nonparticulate protein (Danner and Ting, 1967). Hence, it was concluded that dark CO2 metabolism, insofar as it is mediated by this particular malate enzyme isoenzyme, is in the cytosol. 

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