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biology
PAGs
PAG 2: food tests
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Created by
lucy dock
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Cards (5)
describe how you would prepare a sample of food to be tested
grind up
food
samples using
pestle
and
mortar
mix with
water
filter with
funnel
and
filter paper
describe how you would test for the presence of starch in a sample
add
iodine solution
to a sample
if
starch
is present, solution turns from
brown
to
blue-black
describe how you would test for the presence of reducing sugar in a sample
add
benedict's reagent
to sample
boil
test tube in a
hot water bath
if reducing sugar is present, a
brick red
precipitate forms. if not, the solution remains
blue
describe how you would test for the presence of starch in a sample
add
biuret reagent
(
potassium hydroxide
and
copper
(II)
sulphate
)
shake mixture
if protein is present, solution turns from
blue
to
purple
describe how you would test for the presence of lipids in a sample
add
ethanol
to sample
add
water
to sample
shake
test tube
white emulsion
formed if lipid present