Saliva EXPERIMENT 1. Nature and Composition of Saliva Chew a piece of wax or paraffin to stimulate water excretion saliva. Collect 50 mL of saliva in a beaker. Determine weight the type with a urinometer. Filter some and do the following experiment. a. Unfiltered saliva. 1) Test pH with litmus, phenolphthalein, Congo red or indicator universal. 2) Biuret, Millon, and Molisch tests. b. Filtered saliva. 1) Add 2 mL of saliva with 1 drop of dilute acetic acid. is what forms this amorphous precipitate? 2) Perform a phosphate test. Add 1 mL of solution with 10% urea and 10 mL of reagent special molybdate. Mix, then add 1 mL of special FeSO4 solution. The blue color which becomes clearer after being left alone, indicates its presence orthophosphate. Explain the results obtained. 3) Perform a sulfate test. Acidify the solution with dilute HCl and add 2% BaCl2. White precipitate indicates the presence of sulfate. Explain the results obtained. 2. Nature and Composition of Saliva Add 5 mL of filtered saliva to 5 mL of 1% starch solution, stir, and place in a water bath at 370 C. Note if the opalescence disappears and the viscosity changes. Meanwhile, fill it all in indentation of the reaction plate with 1 drop of iodine solution. Every 1 minute, Take a little of the mixture with a glass stirrer and drop it in on the iodine in the indentation of the reaction plate. Determine when the iodine solution is not again provides a color change. This time is called the achromic point. Remember that the starch solution itself is brown-yellow. At the end of the experiment, compare the time you obtained with the time that your friend got. If the experiment is carried out well and the same way, then the time difference obtained shows differences in amylase activity in each saliva. Note that the opalescence of the starch solution has disappeared before the reaction with iodine stopped (showing negative results). If the achromic point has achieved, check the solution with Benedict's reagent. Note whether it is reduced has occurred. 3. Effect of pH on the Action of Saliva Amylase Provide 4 tubes and fill them with: 1) Tube I : 2 mL of 0.4% HCl solution with pH 1 2) Tube II : 2 mL of 0.1% lactic acid solution with pH 5 3) Tube III : 2 mL of distilled water with pH 7 4) IV tube: 2 mL of 1% Na2CO3 solution with pH 8. Add 2 mL of 1% starch solution and 2 mL of unfiltered saliva to in each tube. Stir well and place in a water bath at 370 C for 15 minutes. Lift and divide the contents of each tube into 2 parts the same one. Add 1 drop of iodine solution to the first part and do Benedict's test on the second part. Explain the results.