Food tests
Method overview
Prepare a food solution. For reducing sugar add Benedict’s and heat in a water bath; for starch add iodine; for protein add Biuret reagent; for lipid use the ethanol emulsion test where appropriate. Record the positive observation and use known controls.
Apparatus set-up
Diagramfood samples; test tubes; pipettes; Benedict’s solution; iodine solution; Biuret reagent; ethanol; water bath
Independent variable
food sample or known nutrient concentration
Dependent variable
qualitative colour/result
Control variables
sample volume; reagent volume; heating time and temperature
Apparatus
food samples; test tubes; pipettes; Benedict’s solution; iodine solution; Biuret reagent; ethanol; water bath
Safety
Wear eye protection; use a water bath for Benedict’s; keep flammable ethanol away from flames.
Scientific rationale
Controls confirm reagents work and show the negative colour; crushing/dissolving exposes molecules; the water bath heats samples safely and evenly.