Food Tests

Elena Cade
Flashcards by Elena Cade, updated more than 1 year ago
Elena Cade
Created by Elena Cade almost 6 years ago
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Description

Part of unit 1 1.2 Enzymes for AS Biology AQA, will be updated to include more of the topic asap.

Resource summary

Question Answer
Name the food test for Reducing Sugars (Glucose, Fructose, Maltose etc.) Reducing Sugar Test (Benedict's Reagent)
How would you prepare this test? 1) Dissolve food sample in water 2) Equal volume of Benedict's reagent added 3) Heated in water bath Colour change from blue-green-yellow-brown-red shows positive result... stays blue if negative
Name the food test used for Protein: Biuret test
How would you prepare this test? 1) small amount of food in test tube 2) add 2ml of Biuret solution A purple or violet colour shows a positive test, stays blue if negative. The presence of peptide bonds is indicated by the solution going purple
What food test would you use for a fat/lipid: Emulsion test
How would you prepare this test? 1) small amount of food in tube 2) 2ml ethanol added 3) pour the ethanol off into another tube 4) add a little water and shake gently A milky colouring shows a positive test
What food test would you use for starch: Starch test
How would you prepare this test? 1) small amount of food in test tube 2) 2 drops of potassium iodide Blue-black colouring shows positive test stays yellow if negative
Name the test used for Non-Reducing Sugar (sucrose): Non-Reducing Sugar test/ Benedict's Reagent
How would you prepare this test? 1) Check there is no reducing sugar by heating part of the sample with benedict's R 2) Hydrolyse the rest of the sample by heating with dilute hydrochloric acid 3) test sample again with B-R Orange-Red precipitate formed if positive result
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