University:
Buffalo State University
Course:
CHE 111 | Fundamentals of Chemistry
Academic year:

2024
Views:

55

Pages:

1
Author:

ethan vicor

EXPERIMENT V CHEMICAL HYDROLYSIS OF STARCH Starch (starch) as a type of polysaccharide that is abundant in nature, is a polymer composed of glucose units the monomers are bonded via -glycosidic bonds. Through a hydrolysis reaction perfect, both chemically and enzymatically, the glycosidic bond broken down to form monomer units. In this practicum, changes that occur during the hydrolysis process over time can be observed using the Iodine test (positive for starch) and the Benedict test (positive for reducing sugars such as maltose and glucose). Apart from that, in this practicum it is hoped that significant comparisons can be made from various aspects between the chemical and enzymatic starch hydrolysis processes. 1. Chemical Hydrolysis of Starch (Acid Hydrolysis) Reactor : - 1% Starch Solution - Iodine solution (0.05 M Iodine, namely: dissolve 10 grams of KI in one liter of water. Then add 2.5 grams of Iodine and stir). - Benedict's reagent - Concentrated HCl Procedure: - Provide 25 mL of 1% starch solution in a beaker. Add 10 drops of HCl concentrated, then mix, shake and boil in a water bath (calledSolutionI). Solution IThis remains heated in a boiling water water bath for up to 45 minutes, and don't move it from the water bath during this time occasionally shaken. - To observe the starch hydrolysis process and the changes that occur during it If the time goes up to 45 minutes, it will be doneiodine test AndBenedict's testat the same time every 5 minutes interval to solution I. - Iodine testcarried out in a drop plate or petri dish, by: Take one drop of sample from Solution I, and add one drop iodine solution. After stirring, observe the color changes that occur. Note the changes in color intensity that occur with increasing time warmup! - WhereasBenedict's testThis is done by: Prepare 9 test tubes each containing 5 mL of Benedict's solution, add to Each test tube contains 3 dropsSolution I(do this with 5 minute intervals for each tube, because the hydrolysis time is up to 45 minutes then 9 Benedict's tests are needed). The tubes that have been containing the mixture is then heated in a water bath oiling water and observe the color change. After cooling, compare the colors. The green color indicates a glucose content of 0.25% , orange yellow color indicates 1% glucose content and color red indicates a sugar content of more than 2%. Observation result recorded in the observation table.