P ractical 2 · Part 2

To each test tube, add ml of per cent sucrose solution. Then to each test tube, add 1ml of concentrated hydrochloric acid. Shake each test tube well. Observation : Note if a pink colour develops. Development of pink colour indicates presence of sesame oil. Interpretation : Are the ghee samples pure or adulterated? Test for presence of excessive amount of stalks in tea leaves Procedure: . Weigh gm of tea leaves into a conical flask or a beaker. Label the container. . To this add ml of water and boil the flask/beaker for minutes. . Filter out the water. . Transfer the tea sample to a flat white plate and with a forceps, pick out the stalks and place them in a preweighed petridish or crucible. . Dry the stalks at degrees until all the moisture has evaporated. . Weigh the stalks. . Calculate the percentage of stalks in the tea. Interpretation: The proportion of stalks in the tea should be less than per cent. . Test for detecting Light berries in Black Pepper Chemicals: Alcohol water mixture (sp.gr . to . ) Procedure: . Take about 10g of the pepper sample in a ml beaker. . Add approximately – ml of the alcohol water mixture. . Pick out the berries which rise to the top and float. . Dry the berries and weigh them. . Calculate the percentage of dried berries. Interpretation: The higher percentage of light berries, suggests that the berries have been extracted from the black berries. . Test for the presence of metanil yellow in turmeric Chemicals: Hydrochloric acid concentrated Procedure: . Take about g of turmeric sample in a test tube. . Add 5ml of distilled water. . Mix well. . Add concentrated hydrochloric acid (about ml to ml) slowly into the tube. Observation: Observe the test-tube for development of pink to magenta colour. Interpretation: Development of pink to magenta colour denotes the presence of metanil yellow which is a toxic adulterant. . Test for the presence of starch in milk and ice