Application Example: Accurate Transfer, Feeding and Batch Weighing of Probiotics into Blending and Packaging Operations


According to both the Food and Agricultural Organization (FAO) as well as the World Health Organization (WHO), probiotics are defined as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". These food supplements help to improve the intestinal microbial balance within any host animal, whether it be pets, livestock, or human beings.  Global use of  probiotics has steadily increased over the last 10 years, mainly in dairy products such as yogurts and yogurt beverages.  However, even more recently, the introduction of probiotics in a powdered microencapsulated form for nondairy foods such as infant formulas, health food bars, breakfast cereals, snack foods, and even chocolate has appeared in the food marketplace.  This growing trend in the use of probiotics can be attributed to the increased media exposure which emphasizes that intestinal balance is critical to obesity management, cancer prevention, as well as improved overall immune system health.

Introduction of Probiotics Direct to the Packaged Product:

Due to the delicate nature of the probiotic organism, the introduction of probiotics to the food processing or packaging stages requires special attention.  The probiotic  must be treated carefully during all stages of  food processing to ensure that the probiotic viability is not affected ,and the overall efficacy is still maintained. Coperion Coperion K-Tron loss-in-weight Feeders and Sanitary Vacuum Conveying systems are used both in the highly accurate introduction of probiotic powders to continuous mixers as well as  for the contained transfer and loss in weight batching to the final packaging container.

In the case of batch weighing of the probiotic to the final package, such as a supersack or flexible container,  the use of loss in weight batching is employed. As explained below, the Coperion Coperion K-Tron loss-in-weight batching system utilizes high accuracy Coperion Coperion K-Tron load cells to ensure the required accuracy of introducing an exact and controlled amount of product to the process or package below. In addition, depending upon the room and space requirements, a specialized Coperion Coperion K-Tron glovebox/ bag dump station is used to introduce the probiotics to either the feeder directly or to a pneumatic conveying system to transfer the product to a receiver mounted directly above the feeder hopper. In both cases, the system is completely contained, in order to avoid any outside contaminants from interacting with the probiotic powder.

Batch Weighing Principles

When delivering a powdered ingredient to a process, two separate modes of batch weighing can be utilized. In Gain-in-Weight (GIW) batching, the system usually includes volumetric metering devices, such as a screw feeders or valves, which deliver the product to a hopper on load cells. Alternatively, the batching system can include gravimetric feeding devices, such as screw feeders, mounted on load cells or scales which deliver the product to the process by means of loss-in-weight (LIW) Batching.

Loss-In-Weight Batching Principle

In the case of probiotics addition LIW batching is used because the accuracy of individual ingredient weights in the completed batch is critical and the percentage of the probiotic to the overall size of the final batch is very small. For example, if one were to use gain in weight batching – the complete bulk bag or FIBC containing the major ingredients must be mounted on load cells. Most load cell devices would not be able to detect the typicaly small amount (ie grams) of the probiotic which needs to be added to such a large batch. Therefore, the use of a feeder which will accurately weigh and deliver a minute amount to the container directly is utilized.

Loss-in-weight batchers also offers additional versatility in batching multiple ingredients. For example, when delivering ingredients to a process, several gravimetric feeders operating in batch mode can simultaneously feed multiple ingredients into a collection hopper. Since the whole feeder is mounted on a scale or load cells, the load cells are weighing the actual amount of product which leaves the feeder.

A batch cycle includes two phases. During the first phase, 90% of the batch weight (as determined by the preprogrammed recipe) is fed as fast as possible. During the second phase the last 10% is fed in a slower “dribble” mode to ensure an accurate batch weight equal to +/- 0.1% of desired setpoint.  Adjustment of the delivery speed (on/off, fast/slow) as well as the ability to quickly change batch setpoints based upon the packaging requirements is set within the Coperion Coperion K-Tron Loss-in-Weight Batcher  controls.This method of batching is often used for micros, (such as vitamins and probiotics) due to the highly accurate requirement of their weight in the mix as well as their ingredient cost.  

Introduction of Probiotics to a Continuous Mixing Process via Loss-in-Weight Feeders

When the probiotics can be added and blended directly into the mixer via a continuous process, Loss in Weight feeders are also used. During this type of application, Coperion Coperion K-Tron feeder configurations are specifically chosen to accurately and gently feed the viable probiotics into the mixer,  In addition, Coperion Coperion K-Tron sanitary pneumatic receivers are used for the refill of these feeders, which is critical for maintaining the accurate and consistent delivery of the probiotic material to the process.

Continuous LIW Feeding: Principle of Operation

Due to the high accuracy requirements of feeding for the continuous blending process, the gravimetric feeding principle of loss in weight feeding is utilized. Coperion Coperion K-Tron’s gravimetric feeding utilizes the same load cells outlined above to constantly measure the weight of the ingredient delivered to the process below. Loss in weight feeding affords broad material handling capability and thus excels in feeding a wide range of materials from low to high rates. In operation, the entire feeder, hopper, and material are continuously weighed, and the feeder’s discharge rate (which is the rate at which the feeding system is losing weight) is precisely controlled to match the desired feed rate. Gravimetric feeders have low fluctuations in feed rate because variations in the filling degree of the screws and in the bulk density of the feed material are compensated by modulation of the screw speed. With this technology, a constant mass flow is ensured, thus also ensuring for consistent product output from blender.  

Designing for Probiotic Handling

Whether designing forbatching or continuous feeding ,the probiotics system is carefully engineered to ensure that the efficacy of the probiotic be maintained, that the probiotic is not subject to outside contaminants, and that the complete system can be easily taken apart and cleaned after operation.

In the case of the feeder, a sanitary design is used,complete with a closed hopper which includes specialized reverse pulse venting in order to avoid any contaiminants from entering the product. In addition, the  conveying and transfer system is designed for ease in access and cleanability. Specialized filter media,high polish material contact surfaces and toolless design for dismantiling are all available dependent upon the specifics of the installation.

The Coperion Coperion K-Tron Advantage:


  • Coperion Coperion K-Tron’s patented SFT III digital weighing technology delivers the high accuracy requirements needed for maintaining control of the addition of costly and delicate ingredients such as probiotics. SFT III ‘s weighing technology features a resolution of 1:4,000,000 in 80 ms, as well as built in immunity to fluctuations in plant vibration and temperatures.
  • The Coperion Coperion K-Tron  Control Module (KCM) provides integrated control of motor, loadcell and drive fuctions for both batch weighing and continuous feeding applications. Integration with the Series 4 Controller for the automated refill by Coperion Coperion K-Tron sanitary pneumatic receivers optimizes the system operation.
  • All components in the system include a quick clean, easy disassembly design complete with fully welded and polished housings and triclover clamps/ferrules. All product contact parts  are constructed to conform with strict cGMP and FDA standards. 
  • The Coperion Coperion K-Tron pneumatic receivers are also designed for cleanability and ease of access, with all materials of construction FDA approved.
  • Coperion Coperion K-Tron is able to provide a wide variety of auger and agitator designs, in order to give best results for the  high variety of ingredients ,inclusingthe gentlehandling required for theviable probiotic materials
  • Whether batching or continuous feeding, the  Coperion Coperion K-Tron Systems Group can supply integrated systems of Coperion Coperion K-Tron and ancillary products, with one source management to  ensure thedelicate viability of the probiotic is maintained.