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Microencapsulation is a process by which we apply a protective coating called a matrix around a small particle called the core or active. The matrix keeps an active ingredient locked in and stabilized until the release of the material is desired.

microencapsulation diagram

There are many benefits to the food or supplement manufacturer that can be achieved through encapsulation.  

  • Reduce Overages: To ensure label claim is met, often higher levels or “overages” must be added to compensate for expected losses in nutrient potency that occur during processing. Given the high costs of many vitamins, these overages can eat into your profit margins over time. Encapsulation protects these nutrients, reducing losses and minimizing overages. The result is significant cost savings.
  • Protection: From moisture, acids, ingredient interactions, heat, and exposure to oxygen.
  • Release Parameters: Engineered so that the nutrient is released when desired, for instance at a specified temperature or in the stomach for digestion.
  • Flavor and Odor Masking: Increase consumer acceptance by minimizing unpleasant tastes and odors associated with certain nutrients.
  • Ease of Handling: Encapsulated ingredients are dry and free-flowing.
  • Precision: The stability afforded by encapsulated ingredients allows measuring and delivery of precise levels of the desired nutrient.
  • Effectiveness: Encapsulation is critical to such products as medical foods, nutraceuticals, and meal-replacement products where characteristics such as stability, bioavailability, delivery, and effectiveness are closely regulated.

Microencapsulation Methods

Hot Melt Microencapsulation Process diagram

Hot Melt Microencapsulation Process

Hot Melt encapsulation utilizes fluid bed technology to apply a molten coating to a substrate.

In the fluid bed microencapsulation process, atomizing air breaks a molten solid into droplets, which hit the substrate particle and spread on the surface of that particle. The droplets are applied layer by layer until they coalesce into one integral film.

One of the important parameters is the selection of the coating material. At what temperature do you want it to melt? What is the application? Are there any GMO restrictions or other requirements on it? All of these things need to be considered when selecting the coating material.

Other important product variables that need to be considered are the size and morphology of the substrate. The surface area and shape of the particle will ultimately determine how much material needs to be applied in order to fully encapsulate the substrate. Finer particles will have much more surface area than a larger particle, and thus will require more coating to encapsulate.

In hot melt encapsulation there are many choices of coating or matrix material:

Lipid Encapsulation Matrix Melting Range  
Paraffin Wax 55℃ 131℉
Fractionated Palm Oil 55℃ – 60℃ 131℉ – 140℉
Fully Hydrogenated Palm Oil 58℃ – 63℃ 136℉ – 145℉
Mono and Diglycerides 60℃ 140℉
Fully Hydrogenated Cottonseed Oil 61℃ – 65℃ 142℉ – 149℉
Fully Hydrogenated Soybean Oil 67℃ – 71℃ 153℉ – 160℉
Distilled Monoglycerides 72℃ 162℉
Carnauba Wax 84℃ 183℉
Fully Hydrogenated Castor Oil 85℃ – 88℃ 185℉ – 190℉

Microencapsulation applications for hot melt encapsulation:

  • B vitamins for flavor masking chewable tablets
  • Nutrients for cold form sports nutrition or meal replacement bars
  • Powdered beverages with enough viscosity to suspend the particles
  • Release of antimicrobials in baking application

Aqueous Coating Microencapsulation Techniques

Aqueous Coating Microencapsulation Techniques

Microencapsulation with a water-soluble (aqueous) coating material can be done using top spray fluid bed coating methods.

You might want to encapsulate a hygroscopic ingredient but not affect its release characteristic greatly. By encapsulating (or agglomerating) with a water-soluble material, we can reduce the substrate’s hygroscopicity, while not greatly impacting its release rate. Film-coated tablets are an example of applying a water-soluble coating to change the surface of an ingredient to mask its flavor.  Once the tablet is swallowed and past the consumer’s taste buds, the coating dissolves quickly and the active ingredients are released. We can spray this type of coating onto powders, crystals, and granules.

Sometimes an ingredient is coated to change the color or appearance, to make it shinier for example.

Aqueous coatings are often used as a prefill for particles with a lot of surface irregularity that needs to be smoothed before another coating is applied.

Examples of aqueous coatings matrix materials:

  • HPMC
  • Gums

Micro-encapsulation applications for aqueous coatings:

  • Pre-coating to fill crevices in a particle before next layer is applied
  • Change appearance or color of a particle
Solvent Coating Microencapsulation Technology

Solvent Coating Microencapsulation Technology

A solvent coating is another fluid bed process used to apply a water-insoluble coating (such as ethylcellulose dissolved in alcohol) onto a particle substrate.
Solvent coatings are often used when the substrate is incompatible with water, or extremely fine.
 

Microencapsulation applications for solvent coatings:

  • Gummy vitamins
  • To protect sensitive ingredients incompatible with certain pH ranges
  • To protect sensitive ingredients incompatible with extreme heat

Encapsulation by Spray Drying

Spray drying can also be a form of microencapsulation. Learn more on our spray drying page.

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