Download Milk - Home Economics

Milk
A near perfect food
© PDST Home Economics
% Composition of Milk
90
80
70
60
Whole milk
Low fat milk
Skimmed milk
50
40
30
20
10
0
Pro.
Fat
Carb.
Water
Nutritive/Food Value
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Protein: 3.5%, HBV,
caseinogen, lactalbumin,
lactoglobulin
Carbohydrate: 4.5%,
disaccharide lactose,
lactic acid bacteria
change lactose to lactic
acid when milk goes
sour
Fat: 4%, saturated, in
fine emulsion, easy to
digest
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Minerals: calcium, 500mls
of milk 100% of RDA,
Phosphorus, trace of
sodium and potassium
Vitamins: good source
vitamin A especially
summer milk, also has
some vitamin D, good
source Vitamins B1 and
B2, only trace Vitamin C
Water 87% very dilute
food therefore easy to
digest
Dietetic Value
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Easily digested nutrients, useful for
invalids, elderly, infants.
Assists growth - protein, Vitamin A,
Calcium, Phosphorus, Vitamin D - good for
children, adolescents and pregnant women.
Due to saturated fat and cholesterol
people on low cholesterol, low fat diets
should use skimmed milk.
Milk lacks fibre, Vitamin C, Iron so infants
need other food in their diet after 6
months.
Cheap food available in a variety of forms.
Culinary Uses
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Drinks
Sauces, white roux & custard
Enriching dishes, soup, mash
Milk based dessert, milk
puddings, custard dishes
In baking, bread, scones etc.
Batters, pancake, coating,
yorkshire pudding
Glazing baked goods
Effects of Heat on Milk
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Protein coagulates, forms skin, milk boils over
Change of colour (caramelisation of lactose + maillard
reaction)
Change of flavour
Loss of Vitamin B1
Micro-organisms killed
Buying & Storing
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Check the best before
date
Store in fridge @ 2ºC
Once opened use quickly
Store in its own sterile
carton, resealable
carton best
Don’t mix milk of
different dates
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Use in rotation
Away from strong
smelling food
Don’t expose to
sunlight, destroys
vitamin B2
Homogenised milk can
be frozen for one
month
Processing Milk
Homogenised:
 Means to make the same
 Heated to 60ºC, forced through tiny holes
to break up fat globules
 Tiny globules stay spread through the milk
 Effect: Milk has smoother creamier taste
Pasteurisation:
 Heated to 72ºC for 25 seconds then cooled
quickly
 All pathogenic bacteria killed, safer
 Some souring bacteria killed, keeps better
Processing Milk
Ultra heat treatment(UHT):
 Long life milk
 Heated to 132ºC for 1 second
 Cooled quickly and sealed in sterile
containers
Effect:
 Kills all micro-organisms
 Milk keeps for several month unopened
 Destroys vitamin C & B group
 Change of flavour
Processing Milk
Evaporated milk:(e.g. Carnation)
 Pasteurised, evaporated to 50%, homogenised
 Sealed in tins and heated to 115 ºC for 20 min
 Keeps indefinitely
 Vitamins B & C lost
 Flavour change
 Not suitable for children
Condensed milk:(e.g. Nestle)
 Pasteurised, evaporated to 33%, homogenised, 40%
sugar added.
 Sealed in tins, heated 115 for 15min
 Vitamins B & C lost
 High in calories
Processing Milk
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Dehydrated milk (Marvel)
Homogenised, evaporated to
60%, then spray dried or roller
dried
Handy in emergencies or when
camping
Reconstituted with water
Flavour changed
Vitamins and some amino acids
lost
Safety of Milk
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Milk is ideal place for bacteria to grow
Controls inspection and testing of herds for TB etc.
Registration of farms
Guidelines for milking, transportation, bottling &
storage of milk
Sampling of raw milk for bacterial contamination
Pasteurisation of milk for human consumption
Controlled by Milk and Dairy Acts and Food and Drugs
Acts
Classification of Milk
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Whole milk - 4% fat
Low fat (semi-skimmed)
- 1.5% fat
Skimmed - 0.1% fat
Fortified ‘supermilk’ low
fat with extra vitamins
and minerals added
Soya made from soya
beans suitable for
vegans & those allergic
to cows milk
Buttermilk, soured by
lactic acid bacteria, for
baking