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Background/Requirement
Salad dressings and many similar sauces are simple oil-in-water
emulsions with additional liquid and powdered ingredients.
These other ingredients may include acidifying agents such
as vinegar, lemon juice, stabilizers & thickeners such as
xanthan or carrageenan gum and a host of other additives for
flavor & color such as salt, sugars, eggs, tomato products,
etc. Salad dressings are available in a variety of flavors
and variations including, regular, low calorie and low fat.
Most salad dressings and sauces are produced in the following
manner:
| 1. |
Water (the continuous phase) is added to the batch tank
and the in-tank mixer is started. |
| 2. |
Powdered ingredients such as stabilizers, thickening agents,
flavorings, preservatives and coloring are added to the tank
and dispersed in the water. In some cases, these are pre-mixed
in dry form and then added to the water in the batch tank. |
| 3. |
The oil phase (the dispersed phase) is added to the tank
with the mixer running and an emulsion is formed. |
The
Challenge
Several difficulties arise when using conventional
mixers and agitators:
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| • |
Additives designed to thicken the product are by
nature liable to form lumps, which a conventional mixer
cannot easily break down. |
| • |
Partially hydrated ingredients can build up on the
vessel walls and mixer shaft. |
| • |
Inconsistent product, batch-to-batch. |
| • |
Emulsions are not easily formed using conventional
agitators. |
| • |
Long processing times are often required to achieve
a satisfactory consistency. |
| • |
Significant air entrainment occurs as a by-product
of the incorporation of powders from the liquid surface. |
Quadro's Approach
Quadro Ytron Mixers are designed to overcome all the
aforementioned difficulties. Batch size, formulation,
type of ingredients, and viscosity of the end product
dictate the ideal choice of equipment (Jet Mixer, ZC
Powder Disperser, Z Emulsifier or a combination of equipment)
that is best-suited to the specific process requirements.
For batches smaller than 500 gallons (1900L), Quadro
recommends the Y Jet Mixer. The Y Jet Mixer delivers
a purely axial flow pattern without the need for tank
baffles to provide instant, homogeneous blending of
the oil and water mixture. The addition of a bypass
tube assembly in combination with the high-speed rotor
provides for rapid, sub-surface, air and agglomerate
free dispersion of powders into the liquid phase.
Our 3 stage, high shear, in-line Z Emulsifier can be
added to the discharge should a high shear in-line mixer
be required to finish the product (additional emulsifying
and/or texturizing).
For larger batches, Quadro recommends our inline powder
disperser to incorporate the powders in a single pass
without agglomerates. The inline powder disperser can
also be used in a re-circulating mode to provide additional
shearing if required to create the desired properties
(additional emulsifying and/or texturizing). In this
set-up, the Ytron Y Jet Mixer is used as a tank mixer
providing good top to bottom turnover of the tank ingredients
and ensuring homogeneity.
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