Starch different concentrations

In industrial production of acid-modified starches, a 40% slurry of normal com starch or waxy maize starch is acidified with hydrochloric or sulfuric acid at 25—55°C. Reaction time is controlled by measuring loss of viscosity and may vary from 6 to 24 hs. For product reproducibiUty, it is necessary to strictly control the type of starch, its concentration, the type of acid and its concentration, the temperature, and time of reaction. Viscosity is plotted versus time, and when the desired amount of thinning is attained the mixture is neutralized with soda ash or dilute sodium hydroxide. The acid-modified starch is then filtered and dried. If the starch is washed with a nonaqueous solvent (89), gelling time is reduced, but such drying is seldom used. Acid treatment may be used in conjunction with preparation of starch ethers (90), cationic starches, or cross-linked starches. Acid treatment of 34 different rice starches has been reported (91), as well as acidic hydrolysis of wheat and com starches followed by hydroxypropylation for the purpose of preparing thin-hoiling and nongelling adhesives (92). 

Cucumber cotyledons were inoculated with purified tobacco mosaic virus (TMV) 20 to 24 hours before vacuum infiltration with different concentrations of crude water extracts of plant leaves (4). After 7 days, inoculated leaves were harvested and stored 24 hours in the dark in a moist chamber to remove excess starch. Starch lesions were counted after clearing with alcohol and staining with an iodine-potassium iodide-lactic acid mixture. The inhibitory effects of various extracts were demonstrated by comparing lesion counts of treated cotyledons to counts on control cotyledons. 

Lesion formation represents a host response to virus infection. Factors preventing the formation of starch lesions incited by the virus do not necessarily mean that virus replication is inhibited at the same time. Therefore, the total virus titer in cotyledon samples treated with different concentrations of tannic acid was determined (Figure... 

Fig. 15. TGA curve of pure waxy starch and Ag-waxy starch nanocomposites with different concentrations of silver ion precursor (moles of AgN03)...

The data show that the extent of the hydrolysis of starch by the amylase of Aspergillus oryzae depends within wide limits upon the concentration of amylase used. Like those for pancreatic amylase already discussed (Figure 2), these hydrolysis curves show a change from a rapid to a slow phase of the reaction and tend to flatten at higher values as the concentration of amylase is increased. Again, with different concentrations of the amylase of Aspergillus oryzae there is no evidence of a common limit such as is observed with different concentrations of beta amylase (Figure 1). 

These data with arrowroot starch are similar to those reported by many previous investigators for the action of different concentrations of malted barley alpha amylase on other substrates.1-8 19-81 It is evident... 

It has been shown also that the concentration of sucrose is a critical factor and that to obtain the highest yields very dilute solutions are necessary. Thus Fig. 1 shows the relative yields at different concentrations of sucrose heated with hydrobromic acid, all experiments being carried out under similar conditions. The highest yield of levulinic acid, weighed as crude material, was 79% of the theoretical and was obtained when the concentration of sucrose was 3%. Ploetz has also used the hydrobromic acid method to make levulinic acid and records a yield of 69% of the theoretical from crude sugar, 75% from glucose and 64 % from starch. 

Figure 1-1 First Normal Stress Coefficient Data of Starch Dispersions with Different Concentrations as a Function of Shear Rate (Genovese and Rao, 2003). Abbreviations cwm, cross-linked waxy maize tap, tapioca gran, granule.

In the experiment, the concentrations of the reactants are given in terms of drops of Solution A and drops of Solution B. Solution A contains Na2S205, the starch-indicator solution, and dilute sulfuric acid to supply the hydrogen ions needed to catalyze the reaction. Solution B contains KIO3. You will run the reaction with several different concentrations of the reactants and record the time it takes for the blue-black color to appear. 

Figure 1 Coefficient of viscosity fi/,) as a function of thickness of cassava starch films at different concentrations...

Starch is a white powder, having a peculiar slippery feel, or it appears in short columnar masses. The granules of starch differ in size and appearance according to the kind of plant from which they have been obtained. They are rounded or egg-shaped masses, having at the centre or toward one end a spot, called the hilum, around which are a series of concentric lines more or less well marked. Differences in size, shax)e, and markings of starch granules are shown in Pig. 40. 

Digital oscillator densimeter techniques have been used to determine the density of dispersions of starch, glycogen, dextrin, amylopectin, and amylose in water at 40 C but at different concentrations. ... 

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