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Food Tests. Grade8. Test for starch. Collect the food sample (liquid) in a test tube. Add few drops of iodine solution.(yellowish brown) If the colour changes from yellowish brown to blue black then this substance contains STARCH. Test for fat.
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Food Tests Grade8
Test for starch • Collect the food sample (liquid) in a test tube. • Add few drops of iodine solution.(yellowish brown) • If the colour changes from yellowish brown to blue black then thissubstance contains STARCH
Test for fat • Collect the food sample (liquid) in a test tube. • Add ethanol and shake well. • Add water. • If a cloudy mixture appears then the food sample contains FAT.
Test for protein • Collect the food sample (liquid) in a test tube. • Add 5 drops of copper sulphate. • Add 5 drops of sodium hydroxide. • If the colour changes from blue to purple then the food sample contains PROTIEN.
Test for sugar (glucose) • Collect the food sample (liquid) in a test tube. • Add few drops of Benedict’s solution. • Place the test tube in a boiling water bath. • If the colour changes from blue to green to orange to a red deposit, then the sample contains SUGAR (GLUCOSE) • The colour change depends on the concentration of sugar in the sample.
Substance tested Test Result Starch Iodine Turns blue-black Sugars Benedicts solution Turns red Proteins Biuret test Turns purple Fats Emulsion test Turns cloudy white Food tests These are some of the most common food tests: