2295320
Description
Flashcards by Emma Barrett, updated more than 1 year ago
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Created by Emma Barrett
about 9 years ago
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| Question | Answer |
| Testing for fats | Add 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 |
| Starch Test | add 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 |
| Biurets 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. |
| Benedict'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. |
| Benedict's test | add 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. |
| Starch Test | add 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 |
| Emulsion (ethanol) test for Fats | Add 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 |
| Biuret test for Proteins | 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 COLOUR is a positive result: protein is present. |
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