food tests Flashcards
what do we do at the start of food tests?
grind food sample with distilled water using mortar and pestle
after grinding food sample, what do we do?
transfer paste to a beaker and add more distilled water, stir so chemicals in food dissolve with water
after stirring in a beaker, what do we do?
filter solution to remove suspended foot particles
when testing for starch, what solution is used?
iodine
what colour is iodine?
orange
if starch is present, what colour does iodine solution turn?
blue-black, if not it remains orange
when testing for sugars, what solution is used and how many drops?
benedicts solution and 10 drops
what colour is benedicts solution?
blue
when testing for sugars, what do you do with the test tube?
place test tube in a beaker, half fill beaker with hot water from kettle and leave for 5 min
what does a green colour tell us when testing for sugars?
small amount of sugar
what does a yellow colour tell us when testing for sugars?
more sugar is present then green, but less then brick red
what does a brick red colour tell us when testing for sugars?
alot of sugars are present
testing for sugars only works on what?
reducing sugars like glucose
when testing for protein, what solution is used, and what colour is it?
biuret solution, which is blue
if protein is present, biuret solution is what colour?
purple
