Molisch test is one of the useful qualitative test for presence of carbohydrates in solution. The three glucose solutions all have a violet colored ring formed at the junction between the two layers. This showed that carbohydrates are present in these sugar solution. This test involved the addition of concentrated sulphuric acid which causes dehydration of all carbohydrates to give ‘furfural’ compound, where pentoses are dehydrated to furfural, and hexoses are dehydrated to 5-hydroxymethylfurfural (Molish's reagent, 2009). These compounds will later react with – naphtol which is Molisch reagent to give a purple colored complex. The test has to be carried out slowly as the violet colour formed at the surface of contact of concentrated sulfuric …show more content…
Tollens' reagent is an alkaline solution of ammoniacal silver nitrate. There is brown precipitate which is the silver hydroxide present and it will dissolves in aqueous ammonia, forming the diamminesilver(I) ion, [Ag(NH3)2]+. Aldehydes is then reduce the diamminesilver(I) ion to metallic silver and is oxidised to a salt of the corresponding carboxylic acid. Similar to Fehling’s test and Benedict’s test, Tollen’s reagent test will not react with ketones (Baker, 2007). The wall of glucose and fructose solution are deposited by layer of silver mirror while maltose solution has grey precipitate of silver within the solution. Even grey precipitate is shown in maltose solution instead of silver mirror layer, the result is still positive. This is because glucose, fructose and maltose are reducing sugar that contain of free aldehyde sugar which can reduce the diamminesilver(I) ion to metallic silver(Clark, 2004). The electron-half-equation for the reduction of of the diamminesilver(I) ions to silver …show more content…
Starch consist of mainly two parts, which are amylose and amylopectin. Amylose in starch is the main cause for the formation of a deep blue color in the presence of iodine as the iodine molecule will slips inside of the amylose coil. Iodide molecules is dissolving in water with potassium iodide because iodide is not so soluble in water. This makes a linear triiodide ion complex with is soluble that slips into the coil of the starch causing an intense blue-black colour. In this test, blue-black colour is shown and this indicates the presence of starch. Starch amylopectin does not give the blue-black colour, nor does cellulose, nor do disaccharides such as sucrose in sugar (Orhardt,
Data from Table 1. confirms the theory that as the concentration of glucose increases so will the absorbance of the solution when examined with the glucose oxidase/horseradish peroxidase assay. Glucose within the context of this assay is determined by the amount of ferricyanide, determined by absornace, which is produced in a one to one ratio.1 Furthermore when examining the glucose standards, a linear calibration curve was able to be produced (shown as Figure 1). Noted the R2 value of the y = 1.808x - 0.0125 trend line is 0.9958, which is statistically considered linear. From this calibration curve the absorbance values of unknowns samples can be compared, and the correlated glucose concentration can then be approximated.
Solid A was identified to be sodium chloride, solid B was identified to be sucrose, and Solid C was identified to be corn starch. Within the Information Chart – Mystery White Solid Lab there are results that distinguishes itself from the other 4 experimental results within each test. Such as: the high conductivity and high melting point of sodium chloride, and the iodine reaction of corn starch. Solid A is an ionic compound due to its high melting point and high electrical conductivity (7), within the Information Chart – Mystery White Solid Lab there is only one ionic compound which is sodium chloride, with the test results of Solid A, it can be concluded that is a sodium chloride. Solid B was identified as sucrose due to its low electrical
These labels indicated the lactose solution that was be placed into the mini-microfuge tubes. The varying lactose ph solutions were obtained. The four miniature pipets were then used, (one per solution,) to add 1mL of the solution to the corresponding mini-microfuge tubes. When this step is completed there were two mini-microfuge tubes that matched the paper towel. Then, once all of the solutions contained their respective lactose solutions, 0.5mL of the lactase enzyme suspension was added to the first mini-microfuge tube labeled LPH4 on the paper towel, and 4 on the microfuge tube. As soon as the lactase enzyme suspension was added to the mini-microfuge tube, the timer was started in stopwatch mode (increasing.) When the timer reached 7 minutes and 30 seconds, the glucose test strip was dipped into the created solution in the mini-microfuge tube for 2 seconds (keep timer going, as the timer is also needed for the glucose strip. Once the two seconds had elapsed, the test strip was immediately removed, and the excess solution was wiped gently on the side of the mini-microfuge tube. The timer was continued for 30 addition seconds. Once the timer reached 7:32 (the extra two seconds accounting for the glucose dip), the test strip was then compared the glucose test strip color chart that is found on the side of the glucose test strip
The independent variable for this experiment is the enzyme concentration, and the range chosen is from 1% to 5% with the measurements of 1, 2, 4, and 5%. The dependant variable to be measured is the absorbance of the absorbance of the solution within a colorimeter, Equipments: Iodine solution: used to test for present of starch - Amylase solution - 1% starch solution - 1 pipette - 3 syringes - 8 test tubes – Stop clock - Water bath at 37oc - Distilled water- colorimeter Method: = == ==
The progress of this reaction was monitored using Dinitrosyl alcohol. (DNS) as the reagent reacts with the reduced sugar products. The The colour of DNS changes from yellow to varying shades of red depending on the color of the DNS. on the on the reducing sugars product being found with time. The light absorption from the varying colours of solutions can then be measured calorimetrically.
Glucose, fructose, and galactose are examples of single or simple sugar molecules or monosaccharides. Maltose, sucrose, and lactose are examples of two sugar molecules linked, also known as disaccharides. Starch, glycogen, and cellulose are examples of many sugar molecules linked. They are also called polysaccharides. If you wanted to test if there were carbohydrates in something, you could do the sugar or the starch test.
Carbohydrate Utilization: The test result for the phenol red lactose broth was positive for acid and negative for gas. The positive result for the acid means that the organism is able to ferment the particular sugar lactose. The Durham tube did have gas in it which means the organism produced gas in the lactose broth. The rest result for the phenol red sucrose broth was negative for both acid and gas. This means the organism was not able to ferment in sucrose. The organism was also not able to produce gas in the sucrose broth.
Before reading A DIFFERENT MIRROR by Ronald Takaki, the title probably illustrates an issue about images of people and where they come from, but what sets them alike is being human and the blood flowing though their veins. The book starts off of with Takaki going to Norfolk for a multiculturalism conference. He first starts off talking to taxi man who questions him ‘“How long have you been in this country?”’ and he answers “All my life” (1). Takaki gives the taxi man a preview about how he came to live here in the United States. Based off of that conversation, it seems that the taxi man who is in his late forties thought that he was not born in America due to his appearance. He judge Takaki as one who couldn’t understand nor speak english that well. In response humans shouldn't judge a book by its cover. The taxi man judged him as one who isn’t from the United States and couldn’t speak. At this point he realized that there was an “uncomfortably conscious of a racial” division ( Takaki 1).
A bar graph was created using Excel and the percent of sugar in each substance was compared. The graph was included in the lab report.
Another chemical property that is important is that saliva is an enzyme amylase that helps breakdown starch into sugars. Starch plus water with amylase goes into maltose. During digestion the glands secrete enzymes and hydrochloric acid. This is why hydrochloric acid is used to lower the pH level. Pepsin catalyzed the reduction of proteins into polypeptides and amino acids. A temperature of approx. 37 degrees is required. Hydrochloric acid is what gives a lower pH and this kills any harmful microorganisms that may be present in the food being digested. Pancreation has an amylase just like saliva does. This is why it was used in part five of the lab to break down starch. It is just like saliva and breaks starch down into the component sugar. Our bodies cannot absorb any protein, starch or fats if they are not broken down into their component. Another chemical property is that starch is identified by using iodine-potassium iodide. The iodine changed from yellow to blue or black when starch is present. This is because the iodine binds to the starch molecules. Biuret reagent was used to be able to distinguish between proteins and polypeptides and amino acids. The reagent will turn purple when a protein is
I used Cheerios, distilled water, and a pestle and mortar. I ground the Cheerios until they had a fine, sand-like texture and consistency. I then added distilled water and mixed until I was left with a thin, runny solution, that was beige in color. Once I had the stock solution made, I was able to perform my first experiment, beginning with Benedict’s reagent. For this experiment I used a hot plate, beaker, and three test tubes, one labeled + (positive control), - (negative control), and Cheerios. Two milliliters of each solution was then added to the tubes they were labeled to go into. In this experiment, the positive control was a glucose solution. I then added two milliliters of Benedict’s reagent to each tube. Once a boiling bath had been made using water, the beaker, and the hot plate, each of the three test tubes were places, sitting upwards, into the boiling bath. A timer was set for three minutes, and I recorded the color
By taking a Carbon Dioxide, rich substance and mixing it with a yeast, solution fermentation will occur, and then it could be determined if it is a good energy-producer. In this study glacatose, sucrose, glycine, glucose, and water were used to indicate how fast fermentation occurred. The overall result shows that monosaccharides in particular galactose and glucose were the best energy source for a cell.
However, in order to measure the rates of reaction, sodium thiosulphate and starch are added. Sodium thiosulphate is added to react with a certain amount of iodine as it is made. Without the thiosulphate, the solution would turn blue/black immediately, due to the iodine and starch. The thiosulphate ions allow the rate of reaction to be determined by delaying the reaction so that it is practical to measure the time it takes for the iodine to react with the thiosulphate. After the all the thiosulphate has reacted with the iodine, the free iodine displays a dark blue/black colour with the starch. If t is the time for the blue/black colour to appear, then 1/t is a measure of the initial rate.
The salivary glands secret high quantities of α- amylase which allows the enzymatic process of digestion of starch beginning in the oral cavity and can also be found in the pancreas (Witts 2005). α - amylase catalyses hydrolysis of starch reaction 1-4 glycosidic to yield maltose which is a reducing sugar from 3- 5 dinitrosalicylic acid. The Benedict’s test is used when reducing sugar are tested they continue to colour change from green to yellow, orange, brown and red depending on the quality of reducing sugar (Toole and Toole,
of sucrose, 88.5 lb. of allyl chloride, 46.2 lb. of sodium hydroxide and 23.1 lb. of water by Griffin, Willard, Sinnamon, Edwards and Redfield, Ind. Eng. Chem., 43, 2629 (1951) [5].