P ractical 2 · Part 3

cream Chemicals: Iodine solution Procedure: . In a test tube, add approximately ml of milk or melted ice cream. . Add iodine solution, drop by drop. . Mix the contents of the test tube. Observation: Observe for appearance of blue colour. Interpretation: Development of blue colour indicates the presence of starch in the sample. . Test for the presence of colophenial resins in asafetida (hing) Chemicals: . per cent copper acetate solution in water Petroleum ether Procedure: . Take about - g of asafetida sample in a test tube. Add approximately ml of petroleum ether. . Shake the test tube well. . Filter the contents of the tube. . To ml of the filterate add ml of copper acetate solution. . Shake and allow the layers to separate. Observation: Note whether a blue or green colour develops in the ether layer. Interpretation: Development of blue or green colour denotes the presence of colophenial resins that are not permitted.