The optimization of "fast setting" versus "slow drying" in a cooling tunnel is a delicate balance achieved through precise engineering and process control. At KorNutra, we approach this by designing tunnels with multiple temperature zones that can be independently adjusted, allowing the product to undergo a rapid initial set in the first zone to solidify its shape-which enables higher line speeds-while then transitioning to a slower, more controlled drying or cooling phase in subsequent zones to develop the desired texture.
Key factors in this optimization include:
- Temperature profiling: Using a gradient from cold to warmer or vice versa, depending on the product. For example, a sharp cold blast at the start sets the exterior quickly, while a moderate zone follows to allow internal moisture to escape without cracking.
- Airflow control: Adjusting both velocity and direction. Higher airflow accelerates surface setting, but lower, more laminar flow in later stages prevents over-drying and maintains a soft or chewy texture.
- Belt speed and tunnel length: KorNutra designs tunnels with variable-speed belts and sufficient length to accommodate the required residence time. This ensures the line speed doesn't outpace the necessary drying phase for optimal texture.
- Product-specific parameters: We calibrate each tunnel based on the supplement's formulation-ingredients like binders, moisture content, and fat levels dictate how quickly it can set without compromising quality.
Ultimately, the goal is to achieve a rapid enough set to maintain throughput without sacrificing the final product's mouthfeel or stability. At KorNutra, we rigorously test these parameters in our pilot tunnels to fine-tune the balance for each client's unique product line.