Milk
Milk may defined as the whole, fresh, clean, lacteal secretion obtained by
the complete milking of one or more healthy milch animals, excluding that
obtained within 15 days before or 5 days after calving or such periods as
may be necessary to render the milk practically colostrum –free, and
containing the minimum prescribed percentage of milk fat and milk solids
not fat.
Milk, liquid secreted by the mammary glands of female mammals to
nourish their young for a period beginning immediately after birth.
The term “market milk” refers to fluid whole milk that is sold to
consumers usually for direct consumption. It excludes milk consumed on
the farm and that used for the manufacture of dairy products.
, Sources
• Almost all the milk now consumed in Western countries is from the
cow.
• Other important sources of milk are the sheep and goat, which are
especially important in southern Europe and the Mediterranean area;
the water buffalo, which is widely domesticated in Asia; and the camel,
which is important in the Middle East and North Africa.
,Physical properties of Milk
• Milk is a white opaque fluid in which fat is present as an emulsion
(O/W), protein and some mineral matters in colloidal suspension and
lactose together with some minerals and soluble proteins in true
solution.
• The opacity of milk is due to its content of suspended particles of fat,
proteins and certain minerals.
• The colour varies from white to yellow depending on the carotene
content of the fat.
• Milk has a pleasant, slightly sweet taste, and pleasant odour.
, Colour and optical properties
• Milk appears turbid and opaque owing to light scattering by fat globules and
casein micelles.
• Optical properties are influenced by the manner of scattering of light by the
molecules.
• Skim milk appears slightly blue because casein micelles scatter the shorter
wavelengths of visible light (blue) more than the red.
• Beta-carotene, the carotenoid precursor of vitamin A, is responsible for the
creamy colour of cow milk.
• The greenish tinge in whey is due to the presence of riboflavin.
• Refractive index of milk is an optical property and ranges from 1.3440 to 1.3485
at 20 °C
Milk may defined as the whole, fresh, clean, lacteal secretion obtained by
the complete milking of one or more healthy milch animals, excluding that
obtained within 15 days before or 5 days after calving or such periods as
may be necessary to render the milk practically colostrum –free, and
containing the minimum prescribed percentage of milk fat and milk solids
not fat.
Milk, liquid secreted by the mammary glands of female mammals to
nourish their young for a period beginning immediately after birth.
The term “market milk” refers to fluid whole milk that is sold to
consumers usually for direct consumption. It excludes milk consumed on
the farm and that used for the manufacture of dairy products.
, Sources
• Almost all the milk now consumed in Western countries is from the
cow.
• Other important sources of milk are the sheep and goat, which are
especially important in southern Europe and the Mediterranean area;
the water buffalo, which is widely domesticated in Asia; and the camel,
which is important in the Middle East and North Africa.
,Physical properties of Milk
• Milk is a white opaque fluid in which fat is present as an emulsion
(O/W), protein and some mineral matters in colloidal suspension and
lactose together with some minerals and soluble proteins in true
solution.
• The opacity of milk is due to its content of suspended particles of fat,
proteins and certain minerals.
• The colour varies from white to yellow depending on the carotene
content of the fat.
• Milk has a pleasant, slightly sweet taste, and pleasant odour.
, Colour and optical properties
• Milk appears turbid and opaque owing to light scattering by fat globules and
casein micelles.
• Optical properties are influenced by the manner of scattering of light by the
molecules.
• Skim milk appears slightly blue because casein micelles scatter the shorter
wavelengths of visible light (blue) more than the red.
• Beta-carotene, the carotenoid precursor of vitamin A, is responsible for the
creamy colour of cow milk.
• The greenish tinge in whey is due to the presence of riboflavin.
• Refractive index of milk is an optical property and ranges from 1.3440 to 1.3485
at 20 °C
