7/28/2019 CrystallizationMechanismsOfCream_PABU.pdf
1/1
Cr stallization Mechanisms of Cream
[email protected]. Aarhus University, Department of Food
Science, Blichers All 20,a r z a u o ars ng
P. O. Box 50, 8830 Tjele, Denmark
n ro uc on onc us ons
steps in butter production. These steps vary during the year
basedon the fatty acid composition of the cream.
Viscosity measurements can be used to monitor partialcoalescence
formation of butter rains durin churnin in
A better understanding of the mechanisms leading to
partialcoalescence, such as fat crystallization during butter
manufacturing,will contribute to o timization of the roduction
rocess.
a starch cell
pen ng t me n uences ot t e c urn ng t me an naviscosity
Longer ripening time results in larger butter grains
To examine the mechanisms of cream cr stallization durin
Crystallization behavior changes just before butter grain
aggregation occurs
churning, including the effect of ripening time and thereby
understand how churning time and partial coalescence are.
10
12
14
After 1h of ripeningAfter 5h of ripening
After 5min of churning
After 14min of churning
10
12
14
After 1h of ripening
After 5min of churning
Just before butter grains aggregation
-0.2
-0.1
End of ripening (1h)Coalesced milk fat globulesJust before
butter rains a re ationV
olume(%)
4
6
8
Jus e ore u er grans aggrega on
Volume(%)
4
6
8
-0.3
- .
ow(W/g)
0
2
0
2
-0.5
-0.4HeatFl
85h of ri enin
Processing time (min)
0 50 100 150 200 250 300 350 400
Processing time (min)
0 100 200 300 400c
-0.6
- .
10 20 30 40 50
Temperature(C)ExoUp
sec)
6
No ripening
1h of ripening
30min of ripening
10
12
14
After 5min of churningAfter 10min of churning
After 15min of churning
Just before butter grains aggregation
iscosity(Pa*
2
4
Fig. 2: Melting behavior during ripening and churning of
cream.Volume(%)
4
6
8
00
2
ripening is the high melting fraction (HMF) During churning the
HMF melting peak shifts fromFig. 1: Viscosity during churning of
cream ripened at 10C for 5, 1, 0.5, and 0 hours (a).
Churning Time (min)
0 5 10 15 20 25 30aProcessing time (min)
0 50 100 150 200
During ripening, no changes in viscosity nor in milk fat globule
size were observed
. o . , an s area ncreases as e
churning proceeds A new HMF crystallized just before butter
grain
, , .
(15min), while, when no ripening treatment was applied to the
cream, thechurning time was 23 min, and the final viscosity was
significantly lower
aggregation occurs
Coalescence of milk fat globules begins right after that the
churn starts The final size of coalescence of milk fat globules was
approximately 100m (5h),70 m 1h , 60 m 30min and 53 m 0min
Butter manufacturin in a lab scale Rheomether- starch cell :
Milk fat lobule size: coalesced milk fat lobule size was
pasteurized milk cream (38% fat) was supplied by ARLA FOODS
(DK).After erasing the crystal history of the cream by heat
treatment, the
investigated as function of ripening and churning time by a
laser lightscattering (Malvern Hydro 2000S; Malvern Instrument,
UK).
, , . , .After that, the cream was churned at 13C, at 100
rad/sec, untilrequired.
Melting profile of cream during butter processing: the
meltingprofile was analyzed as function of ripening and churning
time by Q
Oscillation Rheology: during the entire butter processing,
theviscosit was followed as function of ri enin and churnin time b
a
2000 Differential Scanning Calorimeter (DSC; TA Instrument,
US-based). The cream samples were heated to 60C at 5C/min.
rheometer (AR-G2, TA Instrument) supplied with a starch
cellgeometry.
AcknowledgementThe authors wish to thank ARLA FOODS FOOD Denmark
and theMinistry of Food, Agriculture and Fisheries for financing
the PhDproject.
