Page 93 - FoodFocusThailand No.238 January-February 2026

whey protein, and sodium caseinate, which help protect conducted under either aerobic or anaerobic conditions, avoids the
target microorganisms from environmental factors, maintain use of harsh solvents, and produces microcapsules of various sizes
viability, and control the release of active compounds in the depending on nozzle diameter and extrusion parameters. These
body. First, a solvent or emulsion is prepared in which the characteristics make extrusion a suitable method for producing
core materials are dispersed and homogenized within a probiotic capsules that require high safety and stability.
polymer solution. The mixture is then fed into an atomizer
through a high-pressure pump to produce fine droplets, EMULSION TECHNIQUE uses hydrocolloids and surfactants to
which are sprayed into a drying chamber filled with hot form a stable emulsion system. Each emulsion droplet acts as a
gases (typically hot air). The droplets may be sprayed in protective microenvironment for probiotics, shielding them from heat,
the same or opposite direction to the gas flow, thereby oxygen, and pH fluctuations. This enhances their viability during
promoting rapid moisture evaporation and forming dry storage, facilitates compound transport through the digestive tract,
particles containing encapsulated bioactive compounds and improves the targeted delivery of probiotics to specific sites
(Figure 3a). Probiotics or prebiotics are enclosed within in the intestine. The types and amounts of surfactants used in the
the wall materials, preventing damage during processing formulation are critical determinants of the overall efficiency and
and storage, improving delivery to targeted sites in the stability of the encapsulated probiotics.
gastrointestinal tract, and supporting overall health.
COACERVATION is a physical technique that relies on cooperative
COOL SPRAY DRYING differs from conventional spray electrostatic interactions between biopolymers with opposite electric
drying in its processing conditions. It converts dispersant charges. It can be divided into two types: simple coacervation
matrices into fine particles under cold conditions controlled and complex coacervation. Simple coacervation occurs through
by chilled air or liquid nitrogen, with temperatures kept electrostatic interactions between electrically charged bioactive
below the melting points of the carrier materials and compounds, such as probiotics or prebiotics, and oppositely
bioactive compounds (Figure 3b). Lipid-based materials charged biopolymers that act as encapsulating carriers. Complex
are commonly used as wall matrices; the core materials coacervation, on the other hand, results from electrostatic
are uniformly dispersed within the lipid phase before being interactions between two biopolymers bearing opposite charges
transformed into fine particles in the cold chamber. In the (Figure 3f), which then form encapsulating matrices around the
gastrointestinal tract, these lipid particles remain intact until targeted bioactive compounds. This process generates a coacervate
they reach the intestine, where they are hydrolyzed by lipase. phase characterized by high viscosity and density due to the
Because lipids melt only at their specific melting points, this aggregation of oppositely charged proteins and polysaccharides.
mechanism allows precise control over the targeted release Factors that may influence the quality of the resulting microcapsules
of probiotics in appropriate regions of the gastrointestinal include pH, temperature, and polymer concentration. Following
system. Additional advantages include cost-effective coacervate formation, additional steps, such as hardening, filtration,
manufacturing, higher yield, suitability for both continuous and drying, are required to ensure that the microcapsules achieve
and batch production, and improved environmental optimal stability for storage and subsequent use.
sustainability, as the process requires neither high heat
nor substantial energy input, thus helping to safeguard the GELATION forms a three-dimensional polymer network that
viability of probiotics and prebiotics. encapsulates probiotic and prebiotic cells, using materials such
as alginate, carrageenan, sodium carboxymethylcellulose (CMC),
FREEZE-DRYING OR LYOPHILIZATION is a highly and polysaccharide-based organogels or hydrogels (Figure 3g).
efficient technique widely used across fields ranging from This technique produces a robust structural matrix that protects
biopharmaceuticals to food science, particularly in the microorganisms from undesirable environmental conditions and is
production of health foods. The method relies on sublimation, well suited for applications in both food products and pharmaceuticals.
in which frozen water transitions directly from solid to vapor
under high-vacuum conditions. First, solvents or dispersions ELECTROHYDRODYNAMIC (EHD) ENCAPSULATION uses
containing probiotics, prebiotics, other bioactive compounds, an external electric field applied between two oppositely charged
and carrier materials are frozen before undergoing the electrodes and a biopolymer solution containing probiotics and
drying process (Figure 3c). Cryoprotectants such as prebiotics. The solution is injected through a syringe at a constant,
oligosaccharides or proteins are added to prevent cellular stable rate, and once the electric potential reaches approximately
damage during freezing and sublimation. Key advantages 5–30 kilovolts, it is transformed into micro- or nanodroplets through
include excellent preservation of probiotic viability, high electrospraying, a process that fuses polymers and bioactive
functional effectiveness, and strong retention of prebiotic compounds into unified capsules. Because EHD does not require
properties, as the low-temperature process minimizes the high heat, it is well suited for thermo- or photosensitive compounds
degradation of bioactive compounds and enhances the and is compatible with biodegradable materials. As a result, it is
functional quality of health food products. increasingly used in the food industry to efficiently encapsulate
probiotics, control capsule characteristics, and enhance functional
EXTRUSION is a physical method widely used for both properties.
encapsulation and co-encapsulation due to its ability to Encapsulation technology helps protect the viability and
maintain high probiotic viability under mild processing effectiveness of microorganisms in the body’s challenging
conditions. The process consists of three main steps: environments. These technological advancements also enhance
(1) preparing an aqueous hydrocolloid solution (the matrix the quality of health products containing probiotics and prebiotics.
material) in which probiotics and prebiotics are uniformly The choice of encapsulation technique depends on factors such as
dispersed; (2) precisely extruding this suspension through the properties of the food and its interactions with the surrounding
a nozzle into a cold gelling bath or anti-solvent solution, matrix; selecting a compatible method ensures optimal absorbability
where stable microbeads are formed; and (3) subjecting the and functional activation.
microbeads to controlled dehydration. Typically, alginate is
employed as the primary wall material, while calcium chloride
serves as the cold-gelling solution. The process can be More Information Service Info C016

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