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The comminution of spices is one of
the most difficult size reduction tasks, on the one hand because
spices vary so much both in structure and grindability, and
on the other hand because the quality of some spices such as
curcuma, for example, can vary widely as a function of the planting
method and time of harvesting.
Regardless of whether the spices are going to be used for sauces,
soups, milk products, cheese, sausages or bakery products, Alpine
delivers complete systems for every kind of spice and for every
fineness requirement. Dependent on the problem specification,
we have plants and systems for all the necessary process steps,
i.e. cleaning, crushing, cutting, fine grinding, cryogenic grinding
with LN2,
sieving, sorting, mixing, and packing, etc. Either tailored
to individual products or designed as universal systems.
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Chilli
Coriander
Rosemary |
| Aniseed (seeds) |
100-150 |
1000 µm |
| Chillis (entire pods) |
120-150 |
750 µm |
| Fennel (seeds) |
80-100 |
1500 µm |
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100 |
600 µm |
| Ginger |
60-80 |
300 µm |
| Cardamom |
100 |
400 µm |
| Caraway seeds |
70-100 |
700 µm |
| (2nd grinding pass) |
70-100 |
420 µm |
| Coriander |
200 |
630 µm |
| Mace |
150-200 |
1000 µm |
| Nutmeg |
100-200 |
1200 µm |
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150-200 |
800 µm |
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150-200 |
600 µm |
| Cloves |
70-100 |
500 µm |
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100 |
850 µm |
| Paprika |
200 |
400 µm |
| Paprika seeds |
200 |
650 µm |
| Pepper |
100-150 |
200 µm |
| Pimento |
150 |
500 µm |
| Mustard seeds |
200-250 |
500 µm |
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100-150 |
400 µm |
| Star aniseed |
150 |
400 µm |
| Juniper berries |
150-200 |
1500 µm |
| Cinnamon |
150 |
200 µm |
Contraplex – wide
chamber mills CW
Scale-up factors of the most common models:
Type 250 CW = 1
Type 400 CW = 2.5
The speed and rotational direction of both pin discs can be
selected such that the grinding is gentle with optimum preservation
of the essential oils despite a high end-product fineness.
Example
graph
Machine: type 250 CW
Spice: mustard seeds, oil content approx. 20 - 35%
Curve 1: approx. 200-250 kg/h
Curve 2: approx. 100-150 kg/h |
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Because the grindability of individual
spices varies so considerably, it is only possible to quote
reference values. The climatic conditions and provenance of
the spices also play a role.
Cryogenic grinding of spices with
the Contraplex® wide-chamber mill CW
The heat which develops during grinding leads on the one hand
to evaporation of the essential oils and on the other hand,
heat-sensitive fats are melted. This in turn can lead to the
grinding elements become greasy and clogged or even to machine
blockages.
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Drawing:
Design of a cryogenic grinding system in circuit-gas mode
1 = Feed metering unit: channel, screw, rotary valve,
etc.
2 = Eddy-current screw cooler with LN2
supply
3 = Impact mill, Contraplex, fine impact mill UPZ, etc.
4 = Automatic filter, frequently in quick-change design
T = Temperature sensor |
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Cryogenic grinding optimises product
properties and process control:
Cryogenic grinding:
Improves the aroma by minimising the loss of essential oils
(approx. 3-10% loss) when compared with grinding at normal temperature
(approx. 15-43% loss)
Approx. 2 - 3 times higher grinding capacity
Eliminates fire risks
Essential oil content compared with original unground spice
| |
weight by volume
(= ml/100g) |
% |
weight by volume |
% |
weight by volume |
% |
| Pepper, white |
3.38 |
100 |
1.95 |
57.8 |
3.19 |
94.5 |
| Pepper, black |
3.37 |
100 |
2.21 |
65.7 |
3.09 |
92.0 |
| Pimento |
3.19 |
100 |
2.71 |
85.0 |
3.08 |
97.0 |
| Mace |
16.1 |
100 |
9.10 |
56.5 |
14.5 |
90.0 |
| Cloves |
17.3 |
100 |
11.5 |
66.0 |
16.5 |
95.0 |
Consumption in kg of LN2
per kg of material
(non-binding reference values)
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- 10 ° C |
0 ° C |
+ 10 ° C |
| 0.02 kWh/kg |
0.25 |
0.2 |
0.15 |
| 0.05 kWh/kg |
0.5 |
0.45 |
0.4 |
| 0.1 kWh/kg |
1.0 |
0.9 |
0.85 |
| 0.15 kWh/kg |
1.45 |
1.4 |
1.35 |
Empirical values for spices:
Temperature at mill outlet approx. 0°C, sometimes also -5°C
to -10°C.
Consumption dependent on spice and fineness approx. 0.2 - 0.8
kg LN2/kg
product
Scale-up factors of the most common
models:
Type 315 UPZ = 1
Type 500 UPZ = 2
Type 630 UPZ = 3.6
The material properties, especially the wear characteristics,
dictate the type of mill. UPZ mills are ideal for root spices,
seeds, fruit peel with a high ash content, extremely hard pips
and kernels such as rose hips.
| Basil with 50% marjoram |
140 |
600 µm |
| Curcuma |
150 |
180 µm |
| Curry |
200 |
450 µm |
| Ginger |
100 |
220 µm |
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200 |
400 µm |
| Cardamom (pods) |
80 |
180 µm |
| Garlic |
200 |
160 µm |
| Coriander |
150 |
450 µm |
| Caraway |
100 |
700 µm |
| Marjoram |
150 |
600 µm |
| Paprika |
250 |
550 µm |
| Pepper |
250 |
550 µm |
| Thyme |
80 |
130 µm |
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800 |
2000 µm |
| Cinnamon |
160 |
150 µm |
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Just about all of the above-listed
spices can be processed with this system. The great advantage
of this particular system concept is that individual system
sections or components can be switched in to or out of
circuit when and as needed.
For example, if the leaves do not need to be ground extremely
finely, then only the classifying step to separate coarse
materials such as stones, etc., the coarse cutting-grinding
step and the second classifying step (e.g. for the stem
waste) are necessary (pos. A – E). The first and/or
second classifying step can also be bypassed if required.
For a finer end product and dependent on the grindability,
the cleaned leaves are ground with either an Ultraplex
UPZ fine impact mill or a Contraplex CW pin mill (pos.
E1 – F).
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Spices which require neither
cleaning nor preliminary grinding can be charged direct
to this fine grinding step. The processing steps that
are not required are simply switched off.
To permit production of different fineness qualities,
the finely ground product can be fed to a screening machine
for fractionation (pos. G – H). The system is also
equipped with a mixing system to permit the production
of spice blends (pos. J – K). The entire system
is dedusted by means of an automatic filter (pos. L).
The system is controlled from a central control cabinet. |
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Spice processing sequence
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| A = |
Feed point for spices
in the form of leaves,
e.g. oregano, parsley, bay leaves, dill,
tarragon, sage, thyme, etc |
| B = |
Coarse materials such as stones,
wood chips,
bits of metal, etc. |
| C = |
Cleaned leaves |
| C1 = |
Feed point for paprika, ginger,
turmeric, cinnamon,
garlic, etc. |
| D = |
Waste such as stems, sand, etc. |
| E = |
End product, i.e. clean leaves |
| E1 = |
Feed point for cleaned spices
such as pepper,
pimento, caraway, paprika, mustard, aniseed, etc. |
| F = |
End product |
| G = |
Fractionated end product after
first screening step |
| H = |
Fractionated end product after
second screening step |
| I/J = |
Feed point for mixer |
| K = |
Blended end product |
| L = |
Waste from the central dedusting
system |
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Spice processing system
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| 1 = |
Feed bin for leaves |
| 2 = |
Rotary valve |
| 3 = |
Multiplex
MZM Zigzag Classifier |
| 4 = |
Suction-side
silencer |
| 5 = |
Cyclone |
| 6 = |
Air flaps,
electropneumatically controlled |
| 7 = |
Fan |
| 8 = |
Change-over
flap |
| 9 = |
Feed metering
unit |
| 10 = |
Fine impact
mill UPZ or CW |
| 11 = |
Automatic
reverse-jet filter |
| 12 = |
Screening
machine |
| 13 = |
Feed bin
for mixed product |
| 14 = |
Mixer |
| 15 = |
Control
cabinet |
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