The document describes a procedure to test food samples for starch and quantify vitamin C content in juices. It involves: 1. Preparing an iodine solution to test food samples for starch and calibrate the solution by titrating it against a vitamin C standard. 2. Titrating juice samples using the iodine solution and starch indicator. The volume of iodine used is measured to calculate the amount of vitamin C in each sample. 3. Recording observations of starch presence in foods and the initial/final iodine volumes and calculations to determine the average mg of vitamin C per 20mL of juice samples.