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Benedict's test for reducing sugars a level essay report
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Title : Comparison of Chemical Composition of Various Food Stuff
Introduction
Carbohydrate is a macromolecule that consists of atoms of carbon, hydrogen & oxygen. The carbohydrates or saccharides exists in 4 groups, monosaccharides, disaccharides, oligosaccharides and polysaccharides. Starch is among one of the polysaccharides and it consists of a large number of units of glucose molecules joined together by glycosidic bonds. Starch consists of two types of molecules , the linear and helical amylose and the branched amylopectin. Potatoes have large amount of starch as it is a staple food. The starch in potato can be tested by the iodine test. When starch is present, the iodine will turn purplish black in colour.
Benedict’s solution is used to test the presence of reducing sugar. All monosaccharides are reducing sugars since all of them have an active carboxyl group. The example of reducing sugars are glucose, fructose, lactose and maltose. Some disaccharides that are exposed to a carboxyl group are also reducing sugar, but less reactive than monosaccharides. By mixing the sugar solution solution with Benedict’s solution and heating them under water bath of 80℃, a redox reaction will occur. The copper(II) sulphate present in Benedict’s solution which exists as light blue in colour reacts with electron from aldehyde or ketose group of reducing sugars to form copper oxide, which is a brick-red precipitate.
The purpose of doing Benedict’s test is to detect the presence of reducing sugar in a substance. Benedict’s solution, which is the reagent for the test will detect the presence of aldehydes and alpha-hydroxy-ketones. If positive result is shown when Benedict’s test was conducted, the substance will change in colour from c...
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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.
Miller, K. R., & Levine, J. S. (2010). Miller & Levine biology. Boston, Mass.: Pearson.
3 Leicht B. G., McAllister B.F. 2014. Foundations of Biology 1411, 2nd edition. Southlake, TX: Fountainhead Press. Pp 137, 163-168, 177-180,
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: = == ==
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)
All monosaccharides are reducing sugars because they all aldehydes. Different monosaccharides contain different number of carbon atoms. There are three types of monosaccharides, trioses, pentose and hexose. They generally contain three (trioses), five (pentoses) or six (hexoses) carbon atoms. Triose is used as a product in biochemical pathways of respiration and photosynthesis.
Freedman convincingly argues that hitting the drive-thru may be a better choice for you and your pockets, rather than spending hours and all of your hard earned cash at a whole foods store. That may sound ridiculous to most people because they’re under the impression to not eat fast food because it is not good for you, while that may be true, neither is the advertised “healthy” foods.
Miller, K. R., & Levine, J. S. (2010). Miller & Levine biology. Boston, Mass: Pearson
The Benedict's Test is used to test the presence of simple sugars in a sample. If sugars are present, a color change will occur from blue to red. However, although the Benedict's test shows the presence of sugars, it cannot accurately determine the concentration of sugar in a sample solution. In our method, we added specific concentrations of glucose to the Benedict's test to use as a chart to estimate the glucose concentration of an unknown solution X. Although this gives a rough estimate of the concentration, it is very inaccurate. For example, the mystery solution X was a pale orange color, which was between the colors in my first and second test tube.
Cain, M. L., Urry, L. A., & Reece, J. B. (2010). Campbell Biology. Benjamin Cummings.
... The Web. 4 Feb. 2014. Campbell, Neil A., and Jane B. Reece. Biology.
== § Test tubes X 11 § 0.10 molar dm -3 Copper (II) Sulphate solution § distilled water § egg albumen from 3 eggs. § Syringe X 12 § colorimeter § tripod § 100ml beaker § Bunsen burner § test tube holder § safety glasses § gloves § test tube pen § test tube method = == = =
A dehydration synthesis reaction forms a bond between carbon atoms in two monosaccharides, sandwiching an oxygen atom between them and releasing a water molecule.” (https://dlc.dcccd.edu/biology1-3/carbohydrates). Carbohydrates are composed of carbon, hydrogen, and oxygen in a ratio of one carbon atom to two hydrogen atoms to one oxygen atom. Carbohydrates exist as monosaccharides, disaccharides, and polysaccharides. A monosaccharide is a monomer of a carbohydrate. A monosaccharide is a single sugar that contains carbon, hydrogen, and oxygen. When two monosaccharides join, they form a double sugar called a disaccharide. “This image shows disaccharides joined by a glycosidic bond. A glycosidic bond to the anomeric carbon can be either a or B. For example maltose, is the disaccharide gained by enzyme-catalyzed hydrolysis of starch, consists of two D-glucopyranose units joined by a 1,4’-a-glycoside bond. The “prime” indicates that C-4 is not the same ring as C-1. Unlike the other disaccharides, sucrose is not a reducing sugar and does not exhibit mutarotation because the glycosidic
I was born in one of the countries in Asia, and our staple food is rice. Rice is always at the center of the table, and the rest of the viand surrounds it. Here in the United States, my household still eat rice every day, accompanied by cooked vegetables and meat. My food choices are influenced by culture and family. Vegetables and fruits of my choice are abundant at the International Market and other Asian grocery stores. Vegetables are also available for a cheaper price at the farmers market. I myself buy these foods to ensure its freshness, prepare and cook them for my entire family. Inspired by Asian and American cuisine, our food is prepared with variety of cooking styles; such as dry like barbecues, baked and fried, with sauce
Complexity of compounds is the reason they must be absorbed long before the physical activity. Starch a main area of complex carbohydrates. It has several bonds. Starches are tightly bound carbon molecules and have several attaching elements. This bonding complexity is the reason starches are capable of retaining large amounts of energy. These compounds should be taken into an athlete's body prior to intense physical activity because an energy storage supply is necessary when simple compounds are completely oxidized.