Case Study: Preserving the Quality Activity of Spray Dried Enyzmes

Jeffrey Bernstein, Research Scientist / Arslan Ijaz, Process Engineer


Many specialty food ingredients are temperature sensitive and have specific processing requirements. One such class of ingredients, enzymes, are biologically active proteins whose function can be greatly affected by temperatures. At American Custom Drying (ACD), we understand the sensitivity of these ingredients and have a process solution to help. Our Specialty Ingredients Dryer (Dryer-5) is the best option to process and spray dry enzymes for the following reasons:


  • Compared to other spray dryers it can be dried – at lower-than-typical temperatures which preserve enzyme activity;
  • Consistent, year-round control over final product’s moisture ensuring the maximum shelf life of the final product;
  • Higher product recovery, and
  • Safe and controlled environment to handle enzymes.
Temperature Control

Maintaining enzyme activity is critical to processing as most are temperature sensitive. Temperatures that exceed critical levels (enzyme dependent) run the risk of deactivating the enzyme’s active site.  Dryer-5 has a fluid bed at its bottom, which provides a secondary source of heating that removes excess moisture from the product.  This fluid bed also allows us to operate the dryer at lower temperatures as compared to other dryers that do not have this option.  Thus, running at absolute minimum temperatures required for drying the product maximizes the enzyme activity.

Moisture Control

Final product moisture is a critical food quality attribute as it determines the overall risk of microbial growth, which directly impacts long term safety and shelf life.  At different times of the year, the ambient humidity is different and affects the finished product’s moisture. In traditional spray dryers, drying temperatures need to increase to compensate for higher ambient humidity: however, this is not an option when drying temperature-sensitive materials.  Fortunately, Dryer-5 uses a dehumidifier that removes the moisture from the incoming air before it enters the dryer.  This way, it allows the production of a consistent quality product with moisture control regardless of the time of year, and without the need to increase the drying temperature.

Product Recovery Yield

Product recovery yield is critically important for enzymes as they fall under the umbrella of specialty products and carry a high dollar value per pound.  Due to the cost, even a slight loss in yield impacts the overall profit margin for our customers.  Dryer-5 is specially designed in a way to provide a higher yield for these products in the following ways:

  • A smaller dryer requires less material to coat the system, meaning less product will be wasted as compared to a larger scale dryer.
  • It is equipped with high-efficiency pneumatic impactors that periodically knock off the powder from the walls of the system, minimizing any sort of buildup and increase productivity.
  • For enzymes, PTFE Membrane bags are used to collect and separate the powder in the baghouses. These bags have 99.98% collection efficiency, which significantly improves the product recovery.
  • Dryer-5 can collect the dust from the packaging station and recycle it back to the product conveying line. By recycling these dust particles, Dryer-5 improves the overall yield.

Enzymes are also hazardous for material handlers without proper personal protective equipment. Since Dryer-5 is a newly installed dryer it was designed to minimize dust exposure by recycling dust back into the product collection line from the packaging station. When dealing with enzymes, Dryer-5 operators are provided with Powered Air Purifying Respirators (PAPR) units; these are used while wearing Tyvek suits to ensure that the operators are safe and decrease the risk of dust exposure. In the event of a dust exposure, the operators are trained on how to wash the affected body part with cold water as soon as the exposure occurs to stop any further reaction of the enzymes on the body.


It is evident that ACD’s Dryer-5 is properly equipped to effectively and economically handle spray drying enzymes. We have taken into consideration temperature requirements to spray dry with minimal effect on enzyme activity, how to maximize production yield by recycling and collecting particles that may have been lost to the air column, controlling environmental moisture by use of a dehumidifier and have even put into place more effective dust collection to help protect the material handlers operating the equipment. We are here to provide top of the line service and effective manufacturing and even have the ability to customize and determine the right parameters for your specialty products.