To find out the food substance in food sample X,Y and Z. Biological Principle: Test for lipids using the grease spot test Test for glucose using Clingiest paper Test for reducing sugars using Benedicts test Test for starch using the iodine test Test for proteins using Albumin paper Test for vitamin C using DUCKPIN solution A control using distilled water instead of the sample should be included. Independent: different types food samples Dependent: different types of food substance presence in food sample Assumption: Controlled: using the same amount of food sample in different test
Procedure: Solid: Grind the food with distilled water. Squeeze the ground materials through layers of muslin. Liquid: Put 1 CM of the liquid food sample into test tubes. -grease spot test: C] A drop of liquid food sample was added to a filter paper and was let to dry for 5 minutes. 0 The filter paper was held up to the light and any translucent spot was observed. 0 The filter paper was put into an organic solvent. It was taken out and let to dry [l The filter paper was examine against light again. (positive result – translucent spot disappears) -Clingiest paper:
C] A drop of liquid food sample was added to the well of a spot plate D The Clingiest paper was dipped into the sample and any color change was observed. (positive result -change from pink to purple) -Benedicts test: C] Equal volumes of liquid food sample and Benedicts solution were mixed. O The mixture was boiled for 5 minutes and any change in it was observed. (positive result – brick-red precipitate forms) -iodine test: C] A drop of liquid food sample was added to the well of a spot plate A drop of iodine solution was added to the sample and any color change was observed. Costive result – change from brown to blue-black) – Albumin paper A drop of liquid food sample was added to the well of a spot plate t] The Albumin paper was dipped into the sample and any color change was observed. (positive result – from yellow to green) -DUCKPIN solution 1 CM of DUCKPIN solution was added to a test tube. C] liquid food sample were added in drop by drop and any color change was observed. (positive result – DUCKPIN solution becomes colorless) Precautions: Boiling destroy the reducing property of vitamin C DOD not boil [overheat the food sample before testing.