BENEDICT’S TEST – REDUCING SUGARS
Benedict’s test for reducing sugar results in colour changes from blue to green precipitate and lastly forms brick-red precipitate. In this case, Benedict’s solution which is aqueous solution of copper (II) sulphate, sodium carbonate and sodium citrate, used as a test of the presence of reducing sugar. Glucose is one of the reducing sugars. Functional group of aldehyde (CHO) and keto (C=O) are found in glucose. Benedict’s test will detect on functional group of aldehyde and keto. As glucose has this functional group, the Benedict’s test shows positive results by changing the colour of Benedict’s reagent from blue colour to green then to brick red precipitate. Therefore this test is semi quantitative. This is due Benedict’s reagent reduces copper (II) sulphate forming a precipitate of copper (I) oxide upon heating. Blue colour means no reducing sugar, green precipitate represents less sugar and brick red precipitate means more sugars form. Hence, intensity of colour indicates amount of sugar.
Cu2+ (blue) ...
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.
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
To uncover organic compounds like carbohydrates, lipids, proteins and nucleic acid, by using tests like Benedict, Lugol, Biuret and Beta Carotene. Each test was used to determine the presents of different organic molecules in substances. The substances that were tested for in each unknown sample were sugars, starches, fats, and oils. Moreover, carbohydrates are divided into two categories, simple and complex sugars. Additionally, for nonreducing sugars, according to Stanley R. Benedict, the bond is broken only by high heat to make make the molecules have a free aldehydes (Benedict). As for Lipids, there are two categories saturated and unsaturated fats. One of the difference is that saturated fats are mostly solids and have no double bond (Campbell Biology 73). The Beta Carotene test works by dissolving in a lipid, thus giving it color to make it visible. Moreover, proteins are made out of amino acids that are linked by a polypeptide bond (Campbell Biology 75). The purpose of this experiment was to determine whether an unknown class sample or food sample had any carbohydrates, lipids, or proteins in it. The expected result of the lab was that some substances would be present while other would be absent.
The unknown substance is probably a carbohydrate because it tested positive for starch which is a polysaccharide. This reaction also had very similar results as the Lugol’s test for potatoes which is a polysaccharide. Although the colors from the test for potatoes were not the same colors as the test for the unknown; the Biuret test had a slight color change and the Lugol’s test had a dramatic color change for both the unknown and potatoes. I am sure that the unknown was a starch, but the Benedict’s test for sugar was positive for the potatoes while the Benedict’s test for the unknown didn’t have a color change. The unknown probably did not have a color change for the Benedict’s test simply because there were not enough sugar present in the unknown for it to test positive. The Sudan IV Test for Lipids did not test positive for the unknown nor the potatoes because there isn’t a trace of lipids in starch. Based on my results, the unknown has a little protein, a lot of starch and no traces of lipids or
This lab used many test to determine which functional groups were present in certain substance. The Benedicts test was used to identify reducing sugars (glucose and fructose) based on their ability to reuce the Capric ions to cuprous oxide at high pH. The Cuprous oxide is reddish orange in color when shown to be at high levels by the test, and greenish when at low levels. In both the onion juice and glucose solution the reducing sugar levels were very high, because the test came back dark orange. The starch solution had relatively low levels of reducing sugar present and this was seen by the test coming back cloundy blue, green and brown.
The sugar test is conducted like this: Step 1. Place a small amount of your sample in a test tube. Step 2. If the sample is not a liquid already, add a little
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.
Secondly, the protein test was held by using the Biuret Reagent to indicate whether the substance contains proteins. The positive test result will show the color change to pink or purple. When Biuret was added into the substance, its colour
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
Methyl Red: One can identify an organism’s ability to conduct the mixed acid fermentation of glucose in a positive test. The fermentation of glucose will lower the pH to less than 5 by overcoming the phosphate buffer that is in the medium6. The lowered pH will allow the indicator, methyl red, to turn the medium red.
The Sugar Busters diet claims that sugars, such as refined sugar and sugar processed by the body-starches and complex carbohydrates, are toxic to the body. The Sugar Busters diet operates under the belief that only a certain amount of insulin is necessary for survival, and too much will have a negative impact on the body. The intent of the Sugar Busters diet is to lower cholesterol level, obtain weight loss, increase energy, and improve the body’s health; the diet achieves this by eliminating food high in sugar from the diet. Sugar is eliminated from the diet because it stimulates excess insulin to be produced by the body, which increases cholesterol level and allows the body to store fat. By controlling the insulin, the body can use stored
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.
Determining the Effect of Different Sugar Concentrations on Benedict's Solution PLANNING: Hypothesis and prediction: My hypothesis is that the sugar solution with the highest concentration will turn the precipitate the darkest colour. This will be the 10% sugar solution. This is because the more amount of sugar it contains the more it will reduce the Copper. It will be a much darker precipitate compared to the other two. Background theory: Benedict's solution is an aqueous solution of Copper (II) Sulphate, Sodium carbonate and Sodium citrate.
Over the last 50 years, sugar has become a staple in the American diet and can be found virtually anywhere. In fact, it is often hiding where you would least expect it. Sugar is no longer found only in sweet treats, but in many of the basic meals we eat on a daily basis. In saying this, it isn’t surprising that many adults and children are consuming more sugar than our bodies can process. Growing up in a very health conscious family, the notion that sugar is addictive and unhealthy has always been stressed in my household. While some kids would flaunt their candy bar at lunch, I was left eating an apple. At a young age, I was resentful of the lack of sugar in our cabinets. However, as I’ve grown older I have realized that my parents did me
First is the Benedict’s test for reducing sugars which determines if a carbohydrate contains a free aldehyde or ketone group. When Benedict’s reagent is heated with a reactive sugar the color of the reagent changes. The initial solution color of the Benedict’s regent is sky blue. Depending on the number of available sites for the reaction to occur, the reaction will result in a solution that may range from green to yellow to orange to brick red, a red precipitate may form if more time is allowed. The test will only show a positive reaction for starch if the starch has been broken down to maltose of glucose. ("BIO 1510 Laboratory Manual," 2016)