Soaps, detergents and emulsifiers Flashcards
Emulsifiers for use in food are commonly made by reacting what
edible oils with glycerol
What is formed when a long chain carboxylic acid is neutralised by an alkali
soap and water
What are emulsifiers
compounds added to prevent emulsions from separating
What doe soap ions have
a long non polar hydrocarbon tail and an ionic carboxylate head
What does hydrophilic mean
water loving
What does hydrophobic mean
water hating
Explain fully how emulsifiers prevent non-polar and polar liquids from
separating into layers.
has a hydrophilic polar head and hydrophobic non polar tail
hydrophobic part dissolved in non polar liquids while the hydrophilic part dissolves in polar liquids
Explain why glycerol is able to form fats and oils.
Glycerol has 3 hydroxyl groups.
State the advantage that soapless detergents have over soap when
used with hard water.
dont form scum
What is hard water
water containing high levels of dissolved metal ions
What happens when soap is used in hard water
scum, an insoluble precipitate it formed
Describe soapleess detergents
remove oil and grease in the same way as soap
do not form scum with hard water
How are soaps produced
alkaline hydrolysis of edible oils and edible fats
What does the hydrolysis for soaps produce
three fatty acid molecules and one glycerol molecules
What happens to the fatty acids during hydrolysis
are neutralised by the alkali forming water soluble ionic salts called soaps
dishwasher tablets produce the bleach hydrogen peroxide one action of this oxidising agent is to oxidise food suggest another action of the bleach
kill bacteria/ remove stains
What does soap contain
esters
Describe fatty acids saturation
can be saturated or unsaturated
State the role of an emulsifier in food
to prevent oil and water molecules from separating into layers
What is an emulsion
contains small droplets of one liquid dispersed in another liquid
State the function of an emulsifier
to prevent non polar and polar liquids separating into layers
How does soap work
soap is made of a hydrophobic non polar tail and a hydrophilic polar head
the tail dissolves in the grease and the head in the water
agitation causes ball like structures to form
the negatively charged ball like structures repel each other and the oil or grease is kept suspended in the water
