APPLICATION
The very light texture of expanded corn seeds – popcorn – makes them sensitive to moisture. Only high solid-content sugar syrup can be applied. The alternatives are 100 % fat-based ingredients such as a savoury slurry or chocolate.
BASE
Core products
The core is the result of the sudden expansion of corn seed. The minute water content evaporates, leaving a hollow texture. The starchy material and fine texture tend to draw moisture and spoil the surface. There are different sorts of maize: butterfly or mushroom variety.
RECIPE
Ingredients
The ingredient is sugar diluted in water, heated to a boiling point, and cooked until it reaches the appropriate concentration. The addition of an oil or emulsifier prevents agglomeration and eases the dispersion.
PROCESS
How does it work?
Upstream
The maize cores popped with the intense heat. The water inside reaches a boiling point, and the cores expand brutally under the build-up pressure.
Coating
The coating involves applying a dense and hot sugar syrup that disperses partially. It leaves parts of popped corn apparent, white flesh and yellow skin, in a mesh of yellow sugar. Syrup preparation by dissolution, cooking, vacuum EV.
Downstream
The highly concentrated syrup sets by cooling, with nil moisture left in it. Conversely, the coated product must be packed and protected from water to soften the inner and melt the syrup.
1.
Product dosage
2.
Syrup dosage 10-20 %
3.
Cooling and setting
PROCESS
Coating system
The operation occurs in a rotary tumbler whose length and diameter are calculated to accommodate the product flow. Baffles inside enhance the tumbling action.
The coating relies on the dispersion of the liquid ingredients first, then on the mechanical friction caused by tumbling. Liquid and powder ingredients can be added separately.
One option is to mix the finely ground powder into the syrup (cocoa, cinnamon) and carry out just one application. However, this ‘slurry’ must be constantly agitated until it is applied.
Dedicated spraying systems best disperse the 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. After coating, the product must be thoroughly dried in 2 or 3-tier driers for packaging.
PROCESS
Coating system
Syrup application drum.
PRODUCT EVALUATION
How do you measure your success?
Key quality features
Coated popcorn is the unique combination of a crunchy and soft bite.
Aspect
The balanced colour contrast of the popped product and its coating texture.
Texture
The crispy texture of the hard syrup and the soft bite of the popcorn flesh. No stickiness.
Product integrity
No broken product nor fine dust.
Key quality parameters
A controlled combination of material (water evaporation, syrup application), mechanical (application and dispersion) and thermal (boiling, cooling) transfers.
Temperature
Critical syrup preparation, handling, dosing, dispersion, and setting are essential parameters.
Motion
Thorough mixing to disperse the syrup while gentle enough to preserve the fragile popped structure.
Dosage
Balance the dosing of the low-density popped cores and the syrup.
How to tackle a project?
Do you want to develop or improve the coating of a food product? Or do you have a problem that we can solve with a coating application?
First, write the brief, and define the purpose of the coating: aspect, texture, taste, flavour, preservation, and functionality.
Core product
What is the core centre to coat? Composition, size, shape, texture, moisture, bulk density.
Ingredients
Are they specific ingredients to apply, or are you looking for the right ingredients?
How does it work?
Upstream
Where does the core product come from? How is it shaped?
Coating process
Is there an existing process, or are you seeking a technical solution?
Downstream
A finishing step is probably required to stabilize and give its characteristics to the coated product.
Step 1
Upstream
Forming process
Step 2
Syrup dosage 10-20%
Step 3
Downstream
Finishing process
Coating system
The challenge is to reproduce at a larger scale what has been done manually in the kitchen or at the bench scale. What operating principle to choose: band, pan, tumbler with dipping, dribbling, dispersing, spraying.
Coating system
If existing, what are the coating system characteristics? Type, capacity, making. Any picture, documentation, or reference of it? Where to source it?
How do you measure your success?
Key quality features
Coated popcorn is the unique combination of a crunchy and soft bite.
Aspect
The balanced colour contrast of the popped product and its coating texture.
Texture
The crispy texture of the hard syrup and the soft bite of the popcorn flesh. No stickiness.
Product integrity
No broken product nor fine dust.
Key quality parameters
A controlled combination of material (water evaporation, syrup application), mechanical (application and dispersion) and thermal (boiling, cooling) transfers.
Temperature
Critical syrup preparation, handling, dosing, dispersion, and setting are essential parameters.
Motion
Thorough mixing to disperse the syrup while gentle enough to preserve the fragile popped structure.
Dosage
Balance the dosing of the low-density popped cores and the syrup.