Nutrients in Food
Lab Report (C1)
Positive test – Tests that will determine if certain substances are present in many ‘complex’ foods:
Starch: Iodine turns blue black when added
Protein: Biuret test - If the foodstuff contains soluble protein, the reagent turn from light blue to purple
Fat: Reagent forms a white cloudy precipitate
Simple Sugars: Benedict's solution – when added, and once heated, Benedict’s will turn dark orange-red
Below is the data collected; if a certain substance such as starch, protein, fat or sugars are present, then in the table, it will be marked positive (+ve), and will have a remark, ‘yes’, next to it. If a substance is not present, then it will be marked negative (-ve) with a remark of ‘no.’ Though in some cases, there will be a trace of some substances, meaning there was a slight formation of the precipitate or the substance was slightly present, in extremely small amounts. This, on the table will be marked as “–ve though a slight trace”