Food Tests Flashcards
what is the test for starch in food
add red iodine unto food with a pappette
what is the test for reducing sugars in food
the benedicts test
what is the test for lipids and how is it done
- shake the test substance with ethanol for about a minute until it dissolved
- pour the solution into water
what is calorimetry
amount of burning energy transferred from food to water. temp of water is calculated
what is the result of the starch test if starch is present
the sample changes from browny-orange to a blue-black colour
what is the result for the benedicts test if sugar is present
the food turns an orangy-red colour
what is the result of the bivet test if protein is present
the food turns purple
what is the result of the lipids test of lipids are present
they will precipitate out of the liquid and show up as a milky emulsion
what is 1 calorie defined as
the amount of energy it takes from food to raise 1kg of water by 1 degree
what is the test for proteins in food and how is it done
- the biuret test
- add a few drops of potassium hydroxide solution to make solution alkaline
- add some copper sulfate solution
what is the result for the protein test
- if there’s no protein the solution will stay blue
- is there is protein the solution will turn purple
what is the equation for working out how many joules of energy are in food
energy in food = mass of water x temperature change x 4.2
what is the equation for working out the energy per gram in food (J/g)
energy per gram of food = energy in food / mass of food
