You will know a test is positive for glucose and starch when Benedict's reagent will give a positive test result for glucose but not for starch.
Step-by-step explanation:
- Benedict's Test is used to test for simple carbohydrates. The Benedict's test identifies reducing sugars which have free ketone or aldehyde functional groups.
- Food scientists can test for starch in food using iodine solution. If starch is present, the iodine will turn dark blue. Testing for sugar can be performed with Benedict's solution.
- The Benedict's solution is added to the sample, and heated for five minutes.
- The test involves heating a solution of the sugar to be tested with Benedict's reagent and observing the colour change of blue to orange. Benedict's reagent will give a positive test result for glucose but not for starch.
- Benedict's solution can be used to test for the presence of glucose in urine