How to Apply Fat, Palatants, and Enzymes Uniformly to Feed Pellets

A feed pellet can carry far more than its basic nutritional formulation. Fats contribute energy, palatants influence acceptance, and enzymes may support specific nutritional functions, yet each liquid ingredient brings different coating challenges. Uniform distribution depends on more than simply spraying an additive over moving pellets. A vacuum coater can create a different pressure environment that supports liquid penetration, while FAMSUN approaches coating as a process involving pellet movement, atomization, and ingredient characteristics.

Why Liquid Properties Matter in Pellet Coating

Fat, palatants, and enzyme preparations rarely behave in exactly the same way. Fat may become more viscous as temperature changes, while enzyme solutions can be sensitive to processing conditions. Palatants may also contain combinations of oils, flavor compounds, or other liquid carriers. These differences affect how easily each ingredient can be pumped, atomized, dispersed, and transferred onto the pellet surface.

Viscosity is particularly important because it influences nozzle performance and droplet formation. A liquid that is too viscous may resist fine atomization, whereas excessive dilution can change the intended formulation. Temperature control may therefore become part of the coating strategy for certain fats, while enzyme-containing liquids may require attention to conditions that could affect their activity.

The practical objective is not simply to achieve a high application rate. Instead, the process should provide a controlled relationship between liquid flow, pellet movement, and droplet distribution so that individual pellets receive a reasonably consistent amount of the target ingredient.

Nozzle Design Shapes Liquid Distribution

Nozzle geometry has a direct effect on how liquid enters the coating chamber. Spray angle, atomization method, flow rate, pressure, and nozzle placement all influence the size and trajectory of droplets. If the spray pattern does not match the movement of the pellets, some material can receive more liquid than other areas, even if the total addition rate is correct.

For this reason, pressure-atomizing systems are often assessed together with the internal circulation pattern. The powder coating vacuum concept is not simply about pressure reduction; in liquid-feed applications, the pressure environment and spray system must work together. A suitable arrangement gives droplets an appropriate opportunity to contact the moving pellet stream instead of concentrating application in one region.

At FAMSUN, our PTZL Series Vertical Vacuum Coater uses a 360° all-round pressure atomizing nozzle without a dead angle. The equipment also uses a vertical double-screw lifting mechanism and spiral casing to circulate material rapidly. FAMSUN specifies a coating homogeneity coefficient of variation of CV ≤7% for this model.

Mixing Intensity and Pellet Movement

Even a well-designed nozzle cannot compensate for poor material circulation. Pellets need sufficient movement through the coating zone so that their surfaces repeatedly encounter the liquid spray. Excessive mechanical action, however, can create unnecessary stress on fragile pellets. The appropriate intensity therefore depends on pellet durability, size, density, and the characteristics of the coating material.

Different feed types create different process requirements. Pelleted aquafeed, for example, may include floating, sinking, shrimp, or micro-feed products, each with distinct physical characteristics. A coating system should consequently be evaluated according to the specific pellet rather than assuming that one circulation pattern works equally well across all products.

Pressure conditions can add another dimension to the process. With powder coating vacuum, pressure reduction may assist the movement of liquid into accessible spaces within compact pellets, but the actual effect depends on pellet structure and liquid properties. Vacuum should therefore be considered as one part of the process rather than a standalone solution.

Controlling Viscosity for Consistent Application

Liquid viscosity affects pumping resistance, nozzle flow, droplet formation, and the way additives spread after contacting the pellets. Fat is a clear example: its flow behavior can change considerably with temperature. A coating system that handles the same material at different temperatures may therefore produce different spray characteristics unless operating conditions are properly controlled.

Enzyme and palatant preparations introduce their own considerations. A producer may need to balance concentration, carrier selection, temperature, and application rate while protecting the functional characteristics of the ingredient. The process should also account for interactions between multiple liquids when more than one additive is applied.

At FAMSUN, we consider these relationships when developing coating solutions for feed-processing applications. Rather than treating the spray stage independently, we look at liquid characteristics together with pellet movement, atomization, pressure conditions, and the desired addition rate. This process-oriented view can be especially useful when a formulation contains several liquid ingredients with different physical properties.

Conclusion

Uniform coating is ultimately a matter of controlling several variables at the same time. Nozzle design determines how the liquid enters the process, circulation influences pellet exposure, and viscosity affects how readily an ingredient can be transported and atomized. The formulation itself adds another layer of complexity, particularly when fats, palatants, and enzymes have to be handled under different conditions.

Our work at FAMSUN reflects the need to consider these factors together rather than relying on a single equipment parameter. A vacuum coater can provide pressure-assisted processing for suitable pellet structures, while the spray arrangement and liquid-handling conditions remain essential to the final distribution.

Whether the process involves conventional spraying or powder coating vacuum terminology appears during equipment evaluation, the same principle remains useful: start with the ingredient and pellet characteristics, then establish the operating conditions around them. That approach gives feed producers a more practical basis for achieving consistent additive distribution without treating every formulation as if it behaved the same way.