Supplier sign in
Home
STAY INFORMED
Subscribe to our monthly newsletter.
Your email address will never be disclosed to any third party.
Read our privacy notice.

       

Specialist article
21.07.2021  |  5564x
Share this item
Allow (tracking) cookies from YouTube and Vimeo to watch videos
matrix system - drying and solidification, basic formulation concepts

Spray (micro) encapsulation of sensitive substances in matrix form

An overview of essential oil and vitamin case studies

Phytochemicals are increasingly found in many food, chemical and agricultural items. Product and process optimization is becoming ever-more important in all of these industries, with a focus on quality, manufacturing efficiency, stability and formulation costs.

Essential oils are volatile substances with a relatively high vapor pressure; they are susceptible to oxidation and light and may change or may even lose their properties when directly exposed to stressors. Like other sensitive, volatile, odor- or taste-intensive liquid active ingredients, they must therefore be protected from the environment or vice versa.

For this protection and to simplify handling — as well as for better dosage and targeted release — these substances are therefore progressively offered and used in encapsulated and/or free-flowing forms.

Various processes can be used to deliver products with a compact structure. During process development, the most suitable procedures and equipment must be selected, considering the specific project conditions. Such factors are, for example, the raw material properties, the availability of approved additives for the formulation, the application area of the product and the specification of the product itself.

Supplementary regulations, guidelines and functionality are just as important as product and plant safety. In all instances, the project must be specified as comprehensively as possible to evaluate various process designs and options. The inherent considerations of the individual industries, be it pharmaceutical or food, for example, must also be taken into account.

Microencapsulation, based on fluidized bed technology, is the inclusion of an active substance in a solid matrix. Microcapsules provide an ideal vehicle to control and protect vitamins, flavors or polyunsaturated fatty acids (PUFAs), as well as volatile essential oils. Selecting the right matrix materials makes the targeted release of these active substance possible. The matrix material forms the carrier and the active substance is physically embedded in the solidified particle structure.

The basic principle of fluidized bed-based spray granulation involves spraying a liquid onto fluidized particles to wet their entire surface area. By simultaneously drying and hardening the liquid film, the particles increase in size, layer by layer. Compared with other drying-based encapsulation processes, such as conventional spray drying, the particle and bulk properties can be adjusted quite easily. Thus, depending on the properties of the liquid, the particle size and structure, the spraying conditions and the residence time can all be modified. With this process, almost spherical particles can be produced in a size range of 100 µm up to a few millimeters. The mass fraction of the encapsulated component can also be adjusted. Microcapsules produced in this way have a closed surface and a compact structure, resulting in the stable, long-term inclusion of the active substance.

To optimize product performance and process efficiency, both formulation and operating parameters should be considered during process development. This is key for customized properties and is illustrated in the following case studies. All experimental work was done using a laboratory scale unit from Glatt.

The ProCell LabSystem is modular by design and suitable for a wide range of process development and evaluation applications. Various inserts are available for batch and continuous processing, fluidized and spouted bed operation and any kind of liquid spray.

Based on various laboratory experiments, statistical models were derived from artificial neural networks. A parameter study and sensitivity analysis were performed to determine the main process conditions and formulation variables. The multidimensional model of the process supported the optimization of product properties and the associated process conditions. In general, two basic concepts were available for formulation (Figure 1). The choice depended on the final application and the material properties of the substances to be encapsulated.

The water-based microencapsulation of water-insoluble substances utilizes emulsification to form a liquid matrix system as a preprocessing step. The emulsion must be stable and droplet size distribution must cover an appropriate range to ensure high recovery rates and product stability. Using a matrix containing an oil-in-water emulsion as a raw material, continuous spray granulation in fluidized or spouted beds yielded solid particles of a defined size in which the oil was very finely distributed.

By contrast, lipid-based microencapsulation uses the lipid solubility of substances to be encapsulated. No emulsification step is required. In these instances, lipid carriers are transformed into a liquid state by melting; then, the active substances are added, mixed and dissolved. The thermal stability of the ingredients is a critical consideration during product development. Data analysis is the method of choice when assessing the influence of parameters such as product composition (formulation) and processing (operating conditions).

In a case study involving the encapsulation of volatile oils (orange, bergamot, mint, eucalyptus), an artificial neural network (aNN) was created and used as a statistical process model. Here, various input parameters (spray rate, product temperature, air flow rate, particle residence time, etc.) and output parameters (yield, mean particle size, particle sphericity, product moisture) were used. The method allows the relationship between process variables, formulation options and product properties to be assessed.

The parameter study and sensitivity analysis provided knowledge about the effects of individual process parameters and allowed for complex multiparameter analysis, enabling the formulation and process conditions to be optimized. The case study also examined the capability of using process models for product and process optimization. In the case of spray (micro) encapsulation, very valuable information regarding different formulations could be demonstrated.

For example, it could be seen that process units that offer low residence times are advantageous when sensitive substances have to be incorporated into a granular structure. Here, the Glatt ProCell apparatus delivers significant benefits regarding product quality and processing.
Owing to the specific fluidization behavior and the associated principle of particle movement inside the process chamber, the spouted bed system ProCell offers certain procedural advantages compared with standard fluidized beds. The ability to operate at low residence times and minimize the thermal stress applied to the particles in situ means that the ProCell can be used for encapsulation purposes. Moreover, the high shear forces in the spout zone support uniform film formation and minimize agglomeration.

As an alternative to water-based processing, lipid-based encapsulation offers a way to stabilize sensitive ingredients. In this instance, both conventional fluidized bed systems and spouted beds can be used.
As well as the process parameters discussed previously, the principle of atomization (pressure nozzle versus binary nozzles) and the composition of the spray liquid also influence particle morphology and product stability.

To cite another example, when working with sensitive vitamins such as fat-soluble vitamin A acetate and vitamin E acetate, it’s crucial to granulate them before they oxidize and, in particular, develop a stable formulation and appropriate process parameters. A stable emulsion is critical. Film-forming and surface-stabilizing agents such as modified starches facilitate the preparation of stable emulsions that are unaffected by pumping and atomization. During the granulation process and depending on the emulsion, solid particles with a very fine distribution of trapped oil can be obtained.

In one series of water-based microencapsulation experiments, various spray emulsion formulations and aqueous solutions with different mass fractions of hydrolyzed and modified corn starch and microcrystalline cellulose were studied. Each vitamin was dispersed into these solutions in different proportions as a fine, discontinuous phase. By adjusting the product temperature, spray rate and spray pressure in the fluidized bed, it was possible to influence the shape, structure and size of the resulting particles. As such, and because of the formula, the recovery rate could be optimized. The recovery rate represents the ratio of theoretically achievable active substance from the formulation to reality. The objective is always to obtain the maximum yield of the active substance in the product.

The reasons for possible losses are multifaceted. For example, an encapsulating material might decompose or become volatile during certain process steps. This starts with the formulation of the raw materials and ends with storage. Another reason could be that a matrix material only provides a limited barrier to the active substance. A good formula, targeted process management and optimized process steps help to reduce the loss of valuable materials to a minimum and increase the overall recovery rate.
High recovery rates of more than 80% are possible, depending on the essential oil, because of the thermodynamic equilibrium conditions that exist, whereby some of the oil to be encapsulated is discharged from the granulation zone by the fluidization air. Furthermore, the choice of fluidization medium — ambient air or nitrogen — has a significant impact on the recovery rates.

Based on Glatt’s long experience, it’s always recommended to start any project with experimental studies. As explained before, formulation and process conditions have to be chosen depending on actual substance. Of course, standards are available; but, a better understanding of the material to be encapsulated — in relation to the equipment configuration and process parameters — increases the potential to ensure optimal performance.

In general, it’s most economical to start small and do laboratory tests with minimal quantities of raw materials. Glatt provides test facilities with various process operations, system configurations and, just as important, a well-equipped laboratory at its Technology Centre. With the help of in-process analyses the content of the active substance or other important particle characteristics — such as size and bulk density — processes can be quickly adapted to obtain the desired product properties. A team of experienced food and process engineering experts is available to help and advise. For reliable scale-up to production scale, Glatt also has local pilot lines for both batch and continuous processing.

Based on all the information collected and analyzed during the product and process development phase, optimal production lines can subsequently be designed. Proven procedures and methods ensure the scalability of the system. Moreover, modern approaches such as flow-sheet-simulation and process modeling allow different plant configurations to be compared in terms of energy consumption or emission.

For instance, closed loop operation has been shown to be particularly economical and safe during various granulating applications, especially with oxygen-sensitive and explosive materials. In these instances, granulation is done under a nitrogen atmosphere and needs considerably less nitrogen than open system operations. In applications that do not utilize a fresh gas flow, the required process humidity must be maintained by using a condenser.

Optimal encapsulation conditions to produce a closed particle surface with a uniform structure were discovered in experiments by varying the spray rate, product temperature and condenser settings. For example, in experiments with carvacrol as the active substance, the recovery rate could be increased to more than 90%. Thanks to the condenser and a comparatively low exhaust gas mass flow, the loss of carvacrol within the process air could be reduced by up to 99%.

As an option, particles produced by encapsulation can be further modified by spray coating them. Depending on the application requirements, one or more coating layers can be added to the core as a moisture barrier or protective layer, to add ingredients, for masking (taste, odor) or to modify the release characteristics.

Case studies, as discussed, can help process engineers and product developers to assess plant configurations in an efficient manner to meet a customer’s specific project requirements. Based on the outcomes from these case studies, its own research projects and scientific work on encapsulation, Glatt offers a unique portfolio of process knowledge and formulation know-how. During the development phase, everyone involved should discuss the pro and cons of all the available options. Plus, the evaluations should not be limited to the formulation, process and core equipment, up- and downstream steps such as liquid preparation, handling, in-process analysis and control, as well as heat recovery and zooning, should also be included.

Author: Dr.-Ing. Michael Jacob, Glatt Ingenieurtechnik

Originally published in the magazin ’Innovations in Food Technology’, issue Nov. 2019

Company information

Glatt Ingenieurtechnik GmbH
Glatt Ingenieurtechnik GmbH
Glatt is specialized in intelligent particle design for the generation and functionalization of powders and granulates with defined, adjustable properties. The focus is on particles and powders for pigments, catalytic, ceramic or battery materials as well as for granules and pellets as additives for e.g. industrial salts, detergents and cleaning agents, fertilizers, pesticides, food, feed, dietary supplements and pharmaceuticals. Encapsulation of flavors, enzymes, vitamins, microorganisms, probiotics or fatty acids (PUFA) is just as possible as encapsulation of essential oils and other active, sensitive substances to be protected. With Glatt APPtec®, a unique technology for spray calcination, it is possible to generate, coat and then calcine particles in a pulsing hot gas stream in a single process step. As a pioneer in fluid bed and spouted bed technologies, Glatt masters these important processes for the formulation and optimization of particle properties through defined spray agglomeration, spray granulation, spray coating or (micro)encapsulation as well as through combinations of these processes. Also in the high temperature range. Glatt supports the product idea from the early phase of product formulation through process development to scale-up to production scale. Under the leadership of the Glatt Process & Plant Engineering teams, customized production plants for nutrition, fine chemicals, pharmaceuticals, and biotech applications are successfully planned and commissioned. Worldwide. Whether based on powder synthesis, fluid bed or spouted bed technology, Glatt also offers certified contract manufacturing for customers without their own production capacities.
Last update: 27.02.2024

Related trade show

Related articles

Wirbelschichtsysteme: Konti, Batch, oder doch ein Hybrid?
Wirbelschichtsysteme: Konti, Batch, oder doch ein Hybrid?

This item is only available in German
15.07.2021  |  3810x  |  Specialist article  |   | 
Optimising functional ingredients for enhanced nutrition  Fluidised bed and spouted bed processes offer manufacturers almost unlimited possibilities in terms of optimised particle design and the functionalisation of ingredients, the properties of which can be fine-tuned
Optimising functional ingredients for enhanced nutrition
Fluidised bed and spouted bed processes offer manufacturers almost unlimited possibilities in terms of optimised particle design and the functionalisation of ingredients, the properties of which can be fine-tuned Fluidised bed and spouted bed processes by Glatt offer manufacturers almost unlimited possibilities in terms of optimised particle design and the functionalisation of ingredients, the properties of which can be fine-tuned using spray granulation, agglomeration, microencapsulation and coating. The consumer demand for fortified products is constantly growing and has been well received by end users. The form in which health-promoting probiotics, dietary fibres or antioxidants are consumed depends on both the preferences and everyday habits of the individual: some prefer sports drinks, protein bars or enriched iced tea, whereas others favour more direct dosage forms, such as effervescent tablets, sachets or capsules. However, although the manufacturing processes associated with these products present numerous challenges, a universal requirement is that functional ingredients must be stable during storage, precisely dosed, dissolve quickly or have a depot effect. Key
12.05.2021  |  6370x  |  Specialist article  |   | 
The gentle processing of highly volatile oils by fluid bed technology Sensitive raw materials, especially those that are volatile or of natural origin, require particularly gentle process conditions.
The gentle processing of highly volatile oils by fluid bed technology
Sensitive raw materials, especially those that are volatile or of natural origin, require particularly gentle process conditions. Spray granulation, spray coating and (micro)encapsulation procedures have proven to be methods of choice, as they enable high yields, low temperatures and bespoke properties. When it comes to cosmetics, product development often focuses on proven, multifunctional ingredients. This is in addition to the ongoing demand for natural ingredients, as consumers increasingly look for effective cosmetic products that neither harm their health nor the environment. Glatt Ingenieurtechnik, the German expert in particle design, process development and plant engineering, offers unique particle processing solutions based on fluidised bed and spouted bed technologies for essential oils, collagens, active substances, stabilizers, enzymes, fragrances, aromas, vitamins and controlled release products, all of which can be optimally produced, protected and refined. Efficient fluidised and spouted bed processes Unique flow, mechanical and thermodynamic properties make fluid bed technology
03.11.2020  |  3542x  |  Specialist article  |   | 

More items

First German plant for recycled phosphate fertilizer in operation Glatt PHOS4green plant for fertilizer production with phosphorus from sewage sludge ash at Seraplant in Haldensleben, Saxony-Anhalt, Germany started up
First German plant for recycled phosphate fertilizer in operation
Glatt PHOS4green plant for fertilizer production with phosphorus from sewage sludge ash at Seraplant in Haldensleben, Saxony-Anhalt, Germany started up Residue-free production of ready-to-use fertilizer from phosphate-containing sewage sludge ash is now possible, thanks to plant manufacturer and process expert Glatt Ingenieurtechnik, and fertilizer specialist Seraplant. After a 20-month construction period, the first production plant for phosphate-containing mono and complex fertilizers made from recycled sewage sludge ash is now in operation. Seraplant operates the new plant at its headquarters in Haldensleben, Saxony-Anhalt, Germany. Glatt Ingenieurtechnik, a globally active plant engineering company, was responsible for the process development and construction. The official commissioning on May 31, 2021, was attended by Prof Dr Armin Willingmann, Saxony-Anhalt’s Minister for Economics, Science and Digitalization. Seraplant invested more than 20 million euros in the new production facility, with the support of the state of Saxony-Anhalt. As a result, more than 20 new jobs have been created in the southern
08.06.2021  |  3977x  |  Product news  |   | 
Creating dustfree granules by drying + granulating liquids Webinar-Recording of POWTECH Virtual Talks Volume 7.0 | Handling of sensitive bulk products before and after production processes
Creating dustfree granules by drying + granulating liquids
Webinar-Recording of POWTECH Virtual Talks Volume 7.0 | Handling of sensitive bulk products before and after production processes Glatt fluidized bed spray granulation was part of POWTECH Nuremberg Virtual Talks “Processing fragile bulk materials”. Missed the webinar? You can now re-watch - free of charge - the recording of Didier Schons’ presentation and discussion on the topic of "Producing dust-free granules by drying and granulating liquids in just one process step". Powders and liquids can be granulated, coated, encapsulated, dried and functionalized by fluidized bed and spouted bed technology in only one step. Learn more about intelligent particle design to generate and functionalize powders and granules with adjustable properties. Product properties such as freedom from dust, particle size and particle size distribution, porous or compact structure, particle density, bulk density, homogeneity, hygroscopicity, surface quality, abrasion resistance, solubility, shelf life, dosing, flowability, flow behaviour, optical attractiveness, taste or smell, release behaviour/depotting
29.04.2021  |  3578x  |  Product news  |   | 
Glatt Ingenieurtechnik celebrates continued business success  Plant engineering expert Glatt Ingenieurtechnik marks its 30th anniversary with an investment in the future of its headquarters
Glatt Ingenieurtechnik celebrates continued business success
Plant engineering expert Glatt Ingenieurtechnik marks its 30th anniversary with an investment in the future of its headquarters From vitamins in animal feed and enzymes in detergents to powder materials for high-performance batteries, Glatt, the Germany-based plant manufacturer and process expert, is working on all of these in close cooperation with renowned research companies. In spring 2021, Glatt will expand its technology center in Weimar for the third time in twelve years. Precision landing: Special plant engineering For more than three decades, Glatt Ingenieurtechnik has been by its customers’ side, from laboratory through to production. These collaborations sometimes lead to ground-breaking new systems that have never previously been considered or designed. Some of these are available at the company’s headquarters in Weimar, which is why the plant manufacturer has expanded its technology center several times in recent years. The latest developments include, for example, a fluid bed system made entirely of glass for processing special materials with the highest purity demands
23.03.2021  |  3905x  |  Press release  | 

Related categories

PORTALS
BulkSolids-Portal Schuettgut-Portal Recycling-Portal
Related
Bulkgids.nl
SIGN UP FOR OUR NEWSLETTER
Newsletter archive
Service and contact
ContactDisclaimerPrivacyAdvertising
FOLLOW US
Linked