This document discusses butter and dairy spreads. It defines butter as a fat spread made from milk that typically contains 80% fat and 16-18% moisture. The key steps in butter production are described as: preparing cream through centrifugal separation, aging the cream to promote fat crystallization, churning the cream to cause an emulsion inversion from oil-in-water to water-in-oil, and working the butter grains to create a homogeneous butter mass while removing buttermilk. Factors like cooling rate during cream preparation and churning temperature can impact butter texture and properties.

1. Butter and dairy spreads
Dr AYSHA SAMEEN

3. • Fat spread:
A fat spread is a food in the form of an
emulsion (mainly of the water-in-oil type),
comprising principally an aqueous phase
and edible fats and oils.
• Edible fats and oils:
Foodstuffs mainly composed of
triglycerides of fatty acids. They are of
vegetable, animal, milk or marine origin.

4. Types of “spreadable fats”
• Milk fat products such as “butter” and “dairy
spreads”;
• Vegetable and/or animal fat products such as
“margarine” and “fat spreads”; and
• Mixed fat products (milk fat/ vegetable/animal
fats), such as “blends” and “blended spread

5. Butter
• Butter is usually divided into two main
categories:
• Sweet cream butter
• Cultured or sour cream butter made from
bacteriologically soured cream
• Butter can also be classified according to
salt content: unsalted, salted and
extra salted.

6. • Variations in the composition of butter are due to
differences in production.
• butter contains 80 % fat and 16 – 18 % moisture,
• Butter also naturally contains the Vitamins A and D.
• The colour of butter varies with the content of
carotenoids, which makeup from 11 to 50 % of the total
vitamin A activity of milk.
• As the carotenoid content of milk normally fluctuates
between winter and summer,
• Butter produced in the winter period has a brighter colour
• In this context it might be mentioned that butter made of
cream from buffalo milk is white,

7. PRINCIPLES OF
BUTTERMAKING
• Preparation of cream by centrifugal separation of
liquid milk to a fat content typically 40%.
• Cream ageing to promote crystallization of milk fat
• Emulsion destabilization and phase inversion
from an oil/water cream emulsion to water/oil
butter emulsion achieved by physical agitation
• Physical working of butter grains to form larger
granules, expel buttermilk, distribute moisture,
and create a homogeneous butter mass.

8. Key processing steps involved in
commercial manufacture of butter

9. Phase
separation
Creaming
Coalescence
Homogenisation
(stabilisation)
Milk fat
Instabilities of
dairy fat
Difference of density
Difference of density
Density =
Density =
If milk is left to stand for a
while in a vessel, the fat will
form a layer cream on the
surface.
Difference of density
Difference of density
Density =
Density =
Density =
Density =
If milk is left to stand for a
while in a vessel, the fat will
form a layer cream on the
surface.

10. Fat Globule after heat
treatment
Adsorption of whey proteins at the
membrane surface of fat globules
0.2 – 20 µm
Formation of fat globule aggregats in
cream
Heat treatment of fat globules

11. Creaming Maturation
Phase
Inversion
Manufacture of cream and butter
Skim milk Butter milk
Whole milk
(Fat  4%)
Cream
(Fat  40%)
Maturated
Cream
Butter
(Fat > 82%)

12. Butter manufacture

15. Components Values
Water 16 % maximum
Defatted dry matter
(lactose, proteins, minerals)
2 % maximum
Proteins 0.6 %
Carbohydrates 0.4 %
Lipids 82 %
Cholesterol 220-280 mg
Calcium 16 mg
Carotene 0.3-0.9 mg
Vitamin A 0.4-1.05 mg
Energy 755 kcal = 3 150 KJ
Butter composition (for 100 g)

16. Separation and Cooling
•The first step of the butter making process requires
the separation of the milk fat from the serum phase.
•Milk fat droplets are less dense than the aqueous
phase, and therefore over time will tend to separate
out due to creaming.
• Creaming rate is partly dependent on droplet size,
larger droplets may cream over a few days, it can take
considerably longer for smaller droplets
•Early butter manufacturing relied on acidification
through addition of cultures to assist in separating the
cream

17. •Acidification causes precipitation of the
proteins in the milk
• entrapment of fat globules within the
protein matrix.
• The resulting coagulum can then be
more readily separated from the milk.

18. • After a pasteurization step, the cream is
cooled and starter cultures may be added
to lower the pH and develop flavor.
• pre-requisite concentration of solid fat is
necessary to develop butter grains during
the churning process

19. Churning
• After the initial cooling step the cream is
transferred to an ageing tank
• The ageing step may take up to 15 hours to
insure that fat crystallization has reached
equilibrium.
• Churning is the mechanical agitation of the
cream at10–15◦ C.
• Significant changes to the microstructure
of the dairy emulsion take place during this
process,

20. • emulsion undergoes a process of phase
inversion from the initial cream oil-in-
water-type emulsion to a water-in-oil-type
emulsion.
• shear-mediated aggregation of fat droplets
through a process of partial coalescence
• Partial coalescence requires that the
droplet interfaces between colliding
droplets are ruptured, leading to wetting,
fusion, and sintering of droplets

21. step of interfacial rupture, wetting, fusion,
and sintering

22. •In the case of full coalescence, the mechanism
of instability is caused by rupture of the interface
between two colliding droplets.
•In this case, the interior of the droplets is en
tirely liquid, and consequently collision and
rupture of two approaching droplets will lead to
the formation of a single larger combined droplet.
•partial coalescence of fat during the churning
process is in fact greatly accelerated by the
incorporation of air while beating, which is why air
is incorporated as part of aerated (flotation)
churning (Frede and Buchheim,1994).

23. • Firstly, the incorporation of air into the
emulsion greatly increases the local shear
rate, leading to more frequent droplet
collisions with greater force.
• Secondly, adsorption and wetting of fat
droplets to the surface of bubbles during
the churning process allows the spreading
of liquid oil at the air–water interface.

27. • factor affecting fat agglomeration is the
relative solid fat content of the emulsion
droplets.
• A certain liquid content is required in order
for spreading and wetting to take place,
while a
• certain degree of solid fat is necessary to
maintain rigidity of the butter granules.

28. • Variations in solid fat content have
significant impact on the material
properties of the final product.
• either as a consequence of the particular
triglyceride composition of the milk fat, or
• through the temperature treatment of the
emulsion prior to churning, as well as the
churning temperature itself

29. • fats comprising higher levels of saturated
fatty acids can result in firmer butters due
to a higher solid fat content,
• while fats containing higher levels of
unsaturated fatty acids (or those to which
unsaturated vegetable oils have been
added) may produce softer, more
spreadable butters.

30. • the solid fat content can be manipulated using
appropriate temperature treatment
• After pasteurization, emulsion droplets will be completely
liquid in composition.
• However, during subsequent cooling of the cream a
proportion of the fat will crystallize
• If cooling is rapid, there will be extensive nucleation of
the fat, leading to the formation of many, small crystals.
• However, a slow cooling process will result in fewer
nucleation sites thereby:
• yielding fewer, but larger crystals.

31. • Generally, increasing the rate of cooling
will result in increasing the relative solid fat
content of the droplets.
• So by modifying the thermal treatment of
the cream, it is possible to regulate the
size of the crystals in the fat globules and
in this way influence both the magnitude
and the nature of the fat
• structuring processes during both churning
and subsequent kneading stage, as a
means of controlling the textural properties
of the butter.

32. Working
• After churning, the buttermilk is drained from
the fat granules. Salt is added (1–3%) and
the granules are then worked.
• During working, fat moves from globular to
free fat, completing the inversion process
from initial oil-in-water cream emulsion to the
final water-in-oil butter emulsion.
• During this process, the water droplets
decrease in size becoming small enough so
as not to be visible in properly worked butter.

33. • Overworked butter will be too brittle or
greasy depending on whether the fat is
hard or soft.
• The moisture content should be checked
regularly during working, adjusted so that
it complies with the requirements for the
finished butte

34. The raw material
• The cream must be of good bacteriological
quality, without taste or aroma defects.
• The iodine value is the deciding factor in
the selection of manufacturing parameters.
• fat with a high iodine value (high
unsaturated fat content) will produce
greasy butter.
•

35. Iodine value
• The iodine value states the percentage of
iodine that the fat can bind.
• Iodine is taken up by the double bonds of
the unsaturated fatty acids.
• Since oleic acid is by far the most
abundant of the unsaturated fatty acids,
the iodine value is largely a measure of
the oleic-acid content and thereby of the
softness of the fat.

36. • The iodine value of butterfat normally
varies between 24 and 46
• The variations are determined by what the
cows eat.
• Green pasture in the summer promotes a
high content of oleic acid, so that summer
milk fat is soft (high iodine value).

38. • Cream containing antibiotics/disinfectants
is unsuitable for the manufacture of
acidified butter.

39. Pasteurisation
• Cream is pasteurised at a high
temperature, usually 95 °C or higher,
• The heat treatment should be sufficient
to result in a negative peroxidase test.
Vacuum deaeration
cream is first heated to 78 °C and then
pumped to a vacuum chamber where the
pressure corresponds to a boiling
temperature of 62 °C.

40. • Cream cooled to ripening temperature (20–27C)
and inoculated with starter culture (1–2%).
• Normally, a mixed culture of lactic
microorganisms
• Lactococcus lactis subsp. cremoris
• Lactococcus lactis subsp. lactis
• Lactococcus lactis biovar.
• Streptococcus diacetylactisis
• to insure acid (pH 5.3–4.7)

41. • The primary aroma producers:
• Lactococcus lactis biovar. diacetylactis
and
• Leuconostocmesenteroides subsp.
cremoris.