Distilled water is not reducing sugar also shows negative result. Once all the copper sulfate in solution has reacted, any further addition of reducing sugars causes the indicator to change from blue to white. Cellulose only digested by cellulase enzyme. Dietary fibers can be separated from other components in aqueous solutions by adding different concentrations of ethanol to cause selective precipitation. Its main disadvantage is that it tends to overestimate the fiber content of foods containing high concentrations of simple sugars, e.
The concentration of carbohydrate can be determined gravimetrically, spectrophotometrically or by titration. Place the beaker on a hot plate or Bunsen burner and stir constantly over a high heat until bubbles form all around the edge. A polarimeter consists of a source of monochromatic light, a polarizer, a sample cell of known length, and an analyzer to measure the angle of rotation. All incarcerations are reducing sugars. If it reacts in the Iodine test it is a polysaccharide. The solubility of monosaccharides, oligosaccharides and polysaccharides depends on the ethanol concentration.
Fatty acids are what make lipids non-polar and unable to dissolve in water. When comparing the difference in arrangement or bonding of the functional group in glucose, we are able to see that adehyde and ketone are vital components of glucose. Bacteria, Bacteriology, Gram staining 2100 Words 6 Pages percentage of sugar will produce more fermentation. The fiber is then hydrolyzed using a concentrated sulfuric acid solution to break it down into its constituent monosaccharides, whose concentration is determined using the methods described previously, e. This can be achieved by adding chemicals that form an insoluble complex with one of the components, but not with the other, e. Most polysaccharides contain somewhere between 100 and several thousand monosaccharides.
In unknown 1, sugar was the only substance that was present. Our teacher provided us with three unknown solutions, A,B, and C. Them, we labeled each of the test tubes with the appropriate label: glucose, sucrose, maltose, starch, ribose, galactose, and distilled water. These antibodies can then be extracted from the animal and used as part of a test kit for determining the concentration of the specific carbohydrate in foods. The blue-black colour is due to the formation of starch-iodine complex.
The amylose and amylopectin concentrations in a sample can be determined using the same methods as described for starch once the amylose has been separated from the amylopectin. The test tube is inclined. I review the procedure in a whole-class discussion by demonstrating the procedural and investigative expectations for both stations. Questions 1 It could be a Polysaccharide or a Disaccharide. Introduction: This experiment was centered on metabolic and biochemical testing.
Once the students have completed the data collection, they will return to their seats to collaboratively complete the conclusion questions from the Student Answer Sheet. In a graduated cylinder, measure 60 mL of water. That the purpose of heat it in longer time compare to sucrose. The methods that have been learned thus far for identifying bacteria have been applied to this unknown. The glucose concentration is then analyzed using methods described previously e. However, sucrose, in which the anorexic carbons of the two units are linked together, are non-reducing disaccharide since neither of the rings is capable of opening. Test the effect on blood glucose levels You will find that the effect on the blood glucose level is very different, depending on the composition of food.
Without the addition of acid to sucrose solution, starch solution, the test given is negative. Either of these aldehydes, if present, will condense with two molecules of naphthol to form a purple-colored product. Indigestible carbohydrates form part of a group of substances known as dietary fiber, which also includes lignin. In addition, little sample preparation is usually required. For this reason many food scientists believe that its use should be discontinued. Two categories of amylases, denoted alpha and beta, differ in the way they attack the bonds of the starch molecules.
All incarcerations are reducing sugars; they all have a free reactive carbonyl group. The terminal carbon either carries either an alder or a ketene functional group. If you bond one glucose molecule with a fructose molecule you get a sucrose molecule. This step is performed inside the fume cupboard. As we all know, enzyme amylase can only catalyzes the breakdown of starch into simpler sugars, but not cellulose. After 5 minutes, the students record their observations on their Student Answer Sheet. We labeled each test tube with the name of the solution that the test tube contains.
The starch concentration is calculated from the glucose concentration. Carbohydrates can be separated on the basis of their partition coefficients, polarities or sizes, depending on the type of column used. This method is quick and simple to carry out and can be performed with simple hand-held instruments. Starch and cellulose are two very similar polymers. Since the unknown also tested positive to these three tests and negative to all other tests that we ran, this means the unknown is a reducing sugar, a pentose, and a monosaccharide. Prevent eye, skin clothing, and combustible material contact. Timing is important since a false positive test can be obtained for monosaccharides with disaccharide, if the disaccharides are heated for more than 3.
If no reaction occurs in either test the carbohydrate is a disaccharide. Sucrose is found in table sugar, and is often formed as a result of photosynthesis sunlight absorbed by chlorophyll reacting with other compounds in plants. Pectins are another form of heteropolysaccharides found in cell walls that are rich in uronic acids, soluble in hot water and that are capable of forming gels. Monosaccharides give a rapid positive test. However, the solubility will increase when these complex carbohydrates are broken down into its monomers where the hydroxyl groups can form hydrogen bonds with other water molecules easily due to the reduced molecular weight and size that affects the affinity for water.