APPLICATION
Coating of pet food with digest and palatant
Pet food is generally a cereal-based, protein-enriched, ready-to-eat feed for cats and dogs. Palatability is critical to the acceptance of demanding pets.
BASE
Core products
The core is made of a pre-cooked and expanded cereal and protein mix (corn, wheat, rice, potato, meat meal, fresh meat, and fish). Expansion is direct (high-pressure, short-time extrusion). The resulting bulk density is medium: 0.2 to 0.5.
RECIPE
Ingredients
The liquid coating is prepared with the following:
- Vegetable oil
- Digest (resulting room the microbial digestion of meat by-products)
- Minerals and vitamins
A dry seasoning can be further applied:
- Cereal carrier
- Flavour mix
RECIPE
Ingredients
The liquid coating is prepared with the following:
- Vegetable oil
- Digest (resulting room the microbial digestion of meat by-products)
- Minerals and vitamins
A dry seasoning can be further applied:
- Cereal carrier
- Flavour mix
PROCESS
How does it work?
Upstream. The core products are formed by extrusion or, for more sophisticated treats, through a bakery process. Drying is compulsory.
The coating relies on the dispersion of the liquid and powder ingredients first and then on the mechanical friction caused by mixing.
Liquid and powder ingredients can be added separately. One option is to mix finely ground spice powder into the oil and carry out just one application. This ‘slurry’ needs to be constantly agitated until it is applied.
Downstream. After the coating, the product is ready for packaging.
Step 1.
Consistent dosing of the pet food.
Step 2.
Liquid dosing and dispersion, often air-assisted, + 5 – 30%.
Step 3.
Powder dosing, +1 – 10%.
PROCESS
Coating system
The operation usually occurs in a rotary tumbler or rotating screw whose length and diameter are calculated to accommodate the product flow.
The ingredient’s dispersion can be enhanced by blowing air. Dedicated spraying systems best disperse liquid ingredients. The powder can be distributed with a vibratory tray. It is a continuous operation.
Rotation speed (and tumbler tilt angle) are adjusted to achieve the required friction and residence time. The residence time is relatively long to absorb a large quantity of liquid and powder ingredients.
For the same reason, an alternative technique requires a dual-shaft paddle mixer. The sequence runs as previously described but as a batch operation. Due to the efficiency of the mixing, a whole cycle from loading to discharge takes a few minutes.
PROCESS
Coating system
Given the enormous volume processed, the coating system combines the central coating system with liquid and powder applications devices fed with preparation, mixing, and handling assemblies.
PRODUCT EVALUATION
How do you measure your success?
Key quality features
The accurate evaluation is reverted to the pet consumer and assessed by physical values.
Core
Crunchiness vs. softness measured by instruments and sensory evaluation.
Flavour
Appealing formula vs. cost, completed with sensory evaluation tests with pets.
Stability
Absence of residue, fine or off-flavor over time.
Key quality parameters
Pet food coating is a specific domain of food processing.
Ingredients
Flavour selection is a matter of specialized suppliers.
Design
Machine design, volume, accessories.
Operation
Mechanical energy is used for mixing and dispersion—residence time for impregnation.
APPLICATION
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