Flashcards
Biology Food Tests
Cards in this deck (8)
- 1Testing for fatsAdd the food sample to 2 cm3 of ethanol, shake well.
Allow to settle in a test tube rack for 2 minutes for food to dissolve in ethanol.
Empty any clear liquid into a test tube containing 2 cm3 of distilled H2O.
A MILKY-WHITE EMULSION is a positive result: lipid is present.
If the mixture remains clear, there are no fats present in the sample - 2Starch Testadd Iodine solution to a solution or directly onto materials such as bread, potato, crackers...
a BLUE-BLACK COLOR is a positive result: starch is present - 3Biurets Test (Protein)add an equal amount of NaOH to a solution of the food, mix carefully.
add a few drops of 1% CuSO4, do not shake the mixture.
a PURPLE/MAUVE COLOR is a positive result: protein is present. - 4Benedict's Test (reducing sugars)add a few drops of Benedict's solution
heat the mixture for 2-3 minutes in boiling water bath
a BRICK RED/ORANGE COLOR is a positive result: glucose is present
The closer the color is to brick red, the more reducing sugar is present. - 5Benedict's testadd a few drops of Benedict's solution
heat the mixture for 2-3 minutes in boiling water bath
a BRICK RED/ORANGE COLOUR is a positive result: glucose is present
The closer the colour is to brick red, the more reducing sugar is present. - 6Starch Testadd Iodine solution to a solution or directly onto materials such as bread, potato, crackers...
a BLUE-BLACK COLOR is a positive result: starch is present - 7Emulsion (ethanol) test for FatsAdd the food sample to 2 cm3 of ethanol, shake well.
Allow to settle in a test tube rack for 2 minutes for food to dissolve in ethanol.
Empty any clear liquid into a test tube containing 2 cm3 of distilled H2O.
A MILKY-WHITE EMULSION is a positive result: lipid is present.
If the mixture remains clear, there are no fats present in the sample - 8Biuret test for Proteinsadd an equal amount of NaOH to a solution of the food, mix carefully.
add a few drops of 1% CuSO4, do not shake the mixture.
a PURPLE/MAUVE COLOUR is a positive result: protein is present.
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- GCSE Useful Flashcards on Biology Food Tests, created by Emma Barrett on 17/03/2015.
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- Emma Barrett
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