Butter and Butter Products 2015 ° C to 8 ° C (41 ° F to 46.4 ° F), causes the rapid
formation of many small milk fat crystals,
leading to a high solid fat content with less
liquid oil available due to its entrapment
within the crystal network and adsorption at
the crystal surfaces. When the cream is gently
heated in the warm phase (14 ° C to 21 ° C;
57.2 ° F to 69.8 ° F), partial melting of these
crystals takes place, followed by a period of
slow reformation of high - melting - point fat
into larger crystals. Reducing the tempera-
ture again (second cold phase) causes some
additional crystallization of lower melting
point fractions, resulting in the growth of
larger crystals, but with minimal entrapment
of liquid oil within the fat crystal structure.
By maximizing the relative amount of liquid
oil within the emulsion, a softer butter can be
produced.
More recently, fractal studies (studies of
crystal microstructure geometry and dimen-
sions) have been employed to determine
quantitative parameters that characterize the
milk fat crystal microstructure, which
changes in response to processing variables.
These parameters can then be used to predict
the texture of butter and may be applied by
butter manufacturers to control processing
conditions such as cooling rate to derive the170.6 ° F) for 15 seconds for most countries,
but higher temperatures up to 95 ° C (203 ° F)
are frequently used. Flavor taints from animal
feed can be removed at the cream pasteuriza-
tion stage by carrying out the heat treatment
under vacuum (vacreation) before cooling
the cream. Vacreation, however, can increase
fat loss into the buttermilk.
Cooling and aging of cream are important
because this part of the process affects the
number and size of fat crystals formed and
ultimately affects the spreading characteris-
tics of the butter. Cream for traditional sweet
cream butter is cooled after pasteurization to
5 ° C to 10 ° C (41 ° F to 50 ° F) to encourage
nucleation of the fat crystals and then aged at
a similar temperature for 7 to 12 hours before
churning, usually around 10 ° C to 13 ° C (50 ° F
to 55.4 ° F). The appropriate cream tempering
regimes to modify fat crystal size and number,
and hence spreading properties, can be
selected based on melting and solidifi cation
curves for milk fat (Precht et al. 1981 ) or by
identifying hard and soft milk fats from
iodine values.
The cold - warm - cold cream tempering
procedure was developed to improve the
spreadability of hard winter butter (Figure
9.1 ). An initial low temperature, for example,
Figure 9.1. Temperature - time curve for cold - warm - cold treatment of cream. Adapted from GEA Westfalia
Separator, Germany.51015202530Crystallization time°C PasteurizationChurning
temperatureTime (h)Min 2
Min 2 Min 12