Effect of Acid and Sugar on the Rheology and Flow Properties of Corn Starch Paste

The results for Benedict’s test for reducing sugars before hydrolysis, the control dH2O had no color change, as well as sucrose and raffinose. Gelatin became a dark blue and egg albumin a light greyish blue. Glucose yielded a dark orange, milk albumin turned orange, and starch had a yellow precipitate. In the Benedict’s test for reducing sugars by hot acid hydrolysis, the control dH2O was blue or no reaction. Glucose turned a brownish-orange; sucrose, a reddish-brown, raffinose, light pink; starch, a dark yellowish-orange; gelatin, violet; milk powder, a light yellow; and egg albumin, a greyish-violet. In the Lugol’s test for polysaccharides, the control dH2O turned yellow or no reaction, as well as glucose, sucrose, raffinose, milk powder and albumin. Starch was clear with blue-violet on the bottom (precipitate) and gelatin turned a slightly opaque white. In the test for polysaccharides remaining after hydrolysis with Lugol’s solution the control dH2O was yellow or no reaction. Glucose, sucrose, raffinose, starch and gelatin also had no reaction. Milk powder had a white precipitate and particle suspension. Egg albumin had an even greater white precipitate and particle suspension. In Biuret’s test for proteins there was no reaction for dH2O, glucose, sucrose, raffinose, and starch. Gelatin, milk powder and egg albumin all turned slightly violet with bubbles.

Cornstarch was the next powder experiment on. Cornstarch is a white, soft powder generally used as a thickening agent in liquid-based foods such as soups or sauces. When mixed with lower temperature liquids, it forms a past/slurry. As the starch is heated, the molecular chains unravel, allowing them to collide with other starch chains to form a mesh, thickening the liquid (Starch gelatinization). When mixed with a fluid, cornstarch can make a non-Newtonian fluid, for example, adding water creates Oobleck while adding oil creates an Electro rheological fluid (a suspension of extremely fine non-conducting particles which can be up to 50 micrometers in diameter) (Cornstarch).

The purpose of this experiment was to find out the nutrient content of unidentified food samples and to use chemical reagents to see if the unidentified foods for sugar, starch, protein and fat (lipid) content. After comparing the color changes in each unknown substance then you will be able to see the amount of sugar, starch, protein or fat there is in the unknown substance.

2) The control here was to use a solution containing no starch to show that it was the presence of starch itself that was needed for the reaction to proceed and not something inherent in the liquid or the towel itself.

In order to test the predictions of the hypotonic, hypertonic, and isotonic hypothesis for the solution  made during the study,  four samples of sucrose were taken and placed into two different beakers each containing a different concentration. Beaker 1 is  250- mL and contained 150-mL of 10% sucrose with dialysis tubing A, while beaker 2 (a large bowl) contained 1% sucrose, with dialysis tubing  B, C, and D. Tubing A contained 10-mL with 1% sucrose. Tubing B

In conclusion what makes Oobleck act like both a liquid and a solid? In your mind think that you can see the individual molecules of corn flour and water then think about how they might act when being pushed and pulled. The corn flour and water mixture will act like a solid and a liquid this type of mixture is an example of suspension. The particles stay undissolved in a liquid and corn flour molecules are dispersed into the water. If the cornstarch mixture is pinched, it causes the molecules to go closer together. The effect of the force traps the water between the flour molecules to form a solid shape. When you let go the pressure of your fingers the corn flour will be able to flow like liquid. Viscosity is the resistance for a liquid to

Also by using the molecular weight of glucose (342.3) it can be determined that the average degree of polymerization of the corn syrup solids is 2.669. These numbers were calculated based on boiling point data. A freezing point experiment was not conducted. This data makes sense, for corn syrup solids are created via hydrolysis of starch and consist of a mixture of glucose, maltose, and small glucose oligomers. The molecular weight/average degree of polymerization determined via this experiment directly correlates with that

An enzyme also known as a protein, is a biological catalyst which speeds up chemical reactions by lowering the activation energy to increase the rate in which the reaction occurs. The enzyme used was amylase, which breaks down starch molecules into maltose. PH, substrate concentration, salt concentration, and temperature. When enzymes reach a low temperature, the activity is slowed down of molecule movement, but the enzyme is not destroyed. Once enzymes are placed in optimal temperatures once again, it will restore its activity to a normal rate. When enzymes reach too high above optimal temperature, the enzyme is denatured and cannot be restored. In the experiment performed the activity of breaking down starch in fungal and bacterial amylase was being tested at a range of temperatures and time. The fungal and bacterial amylase work best at optimal temperature. Amylase will function best at sixty degrees Celsius at 10 minutes when starch had been one hundred percent hydrolyzed. Hydrolyzed is the breakdown of molecules through addition of water. The experiments independent variables were the time, temperature and enzyme used. The dependent variable was the enzyme activity that broke down the starch into maltose. The controlled variables were the temperature baths, the iodine drop amount, the mixture drop amount, and location of experiment. The control group was the zero minutes without amylase at

The students first prepared to construct a standard curve. To do this, each group measured the absorbance of starch solutions of unknown concentrations treated with IKI (General Biology I, Martineau, Dean, Gilliland, & Soderstrom, Lab Manual, 2017, 45). The absorbance values were determined for a range of samples, and plotted on a graph. A line of best fit was then used as a reference to determine the amount of starch present in unknown samples.

2. What effect did boiling and freezing have on enzyme activity? Why? How well did the results compare with your prediction?__Boiling caused amylase to be denatured, thus inactivating the enzyme. Freezing has no effect. The function of an enzyme is directly related to its environment, like temperature.__

We then recorded the initial color. We placed each tube in boiling water for one minute and recorded the color results and gave our conclusion. To test for starch using Lugol’s solution, we reused the test tubes and added a squirt of the solution. We recorded the final color and then our conclusion for each content. To test for lipids using paper towels, we placed a drop of solution and we let it stand for one minute. We then recorded our observation, if it was dry or not dry and wrote our conclusion for each sample. To test for proteins using Biuret’s reagent, we added a squirt of stock solution plus a few drops of Biuret’s solution. We wrote the initial color. We then shook the solution and waited for two minutes before recording the results. After the two minutes, we wrote the final color and conclusion for each content. For the unknowns, we wrote the odor and appearance of each content and then tested the benedict’s, starch, lipid, and protein test and wrote our conclusion.

This experiment consisted of setting up a control group of starch in various temperature and then placing both fungal amylases and bacterial amylases in a mixture of starch and placing the solution of amylase and starch in various temperatures of water. After a certain amount of time- different amount of time needs to be used in order to have reliable results- iodine is added in a well on spot plates, then two drops of the mixture of amylase-starch is added from each temperature used, by adding iodine into the plates the mixture will show how much starch was hydrolyzed, this is used to calculate the amount of

1. 5 sucrose solutions were made of increasing molarity: 0.2 M, 0.4 M, 0.6 M, 0.8 M, 1.0M. 2. 50 mL of each unknown solution were poured into 5 separate cups. A slice of potato was placed into 5 equal cylinders. 3. The mass of the 5 potato cylinders were then recorded. 4. The cylinders were placed into the foam cups with solution and covered with plastic wrap. It is to be left overnight. 5. The room temperature was recorded in Celsius. 6. The cylinders are then to be removed from the cups and carefully blotted of any excess solution. 7. The mass of the potato cylinders were recorded afterwards.

(6.2)Material and Methods in the process or exercise of measuring the starch we were used the following material and how we used them to conduct the experiment. Obtain seven tubes the material to be tested table 6.1 and then add seven to ten drops of iodine to each tube, and then record the color of the tubes contents in table 6.1

Iodine was used to test for the presence of starch, remaining yellow for its negative control and becoming a blue-black colour if a reaction occurred;