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Ciência Rural
ISSN: 0103-8478
cienciarural@mail.ufsm.br
Universidade Federal de Santa Maria
Brasil
Teixeira da Silva, Pablo; Martins Fries, Leadir Lucy; Ragagnin de Menezes, Cristiano; Tasch Holkem,
Augusto; Schwan, Carla Luisa; Francine Wigmann, Évelin; de Oliveira Bastos, Juliana; de Bona da
Silva, Cristiane
Microencapsulation: concepts, mechanisms, methods and some applications in food technology
Ciência Rural, vol. 44, núm. 7, julio-, 2014, pp. 1304-1311
Universidade Federal de Santa Maria
Santa Maria, Brasil
Available in: http://www.redalyc.org/articulo.oa?id=33131561028
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Ciência Rural, Santa Maria, v.44, n.7, p.1304-1311, jul, 2014 http://dx.doi.org/10.1590/0103-8478cr20130971
Silva et al.
1304
ISSN 0103-8478
Microencapsulation: concepts, mechanisms, methods
and some applications in food technology
Microencapsulação: conceitos, mecanismos, métodos
e algumas aplicações em tecnologia de alimentos
I* I I
Pablo Teixeira da Silva Leadir Lucy Martins Fries Cristiano Ragagnin de Menezes
I I I
Augusto Tasch Holkem Carla Luisa Schwan Évelin Francine Wigmann
I II
Juliana de Oliveira Bastos Cristiane de Bona da Silva
- REVIEW -
ABSTRACT material with thin polymeric coatings, forming small
Microencapsulation is a process in which active particles called microcapsules (GHARSALLAOUI
substances are coated by extremely small capsules. It is a new et al., 2007). The polymer acts as a protective fi lm,
technology that has been used in the cosmetics industry as well as in isolating the core and avoiding the effect of its
the pharmaceutical, agrochemical and food industries, being used inadequate exposure. This membrane dissolves itself
in fl avors, acids, oils, vitamins, microorganisms, among others. through a specifi c stimulus, releasing the core in the
The success of this technology is due to the correct choice of the
wall material, the core release form and the encapsulation method. ideal place or at the ideal time (SUAVE, 2006).
Therefore, in this review, some relevant microencapsulation Microencapsulation has numerous
aspects, such as the capsule, wall material, core release forms, applications in areas such as the pharmaceutical,
encapsulation methods and their use in food technology will be
briefl y discussed. agricultural, medical and food industries, being
Key words: microcapsules, microencapsulation, controlled widely used in the encapsulation of essential oils,
release. colorings, fl avorings, sweeteners, microorganisms,
among others (AZEREDO, 2005).
RESUMO Recently, the food industry has
A microencapsulação é um processo em que demonstrated increasingly complex formulations:
substâncias ativas são revestidas por cápsulas extremamente as microorganisms in fermented meat; the addition
pequenas. É uma tecnologia nova, a qual tem sido empregada na of polyunsaturated fatty acids that are susceptible
indústria de cosméticos, farmacêutica, agrotóxicos e alimentícia to auto-oxidation in milk, yogurts or ice creams;
e, nesta, é utilizada em aromas, ácidos, óleos, vitaminas, micro- and the use of fl avor compounds that are highly
organismos, entre outros. O êxito nessa tecnologia deve-se à
correta escolha do material encapsulante, da forma de liberação do volatile in instant foods, which often can only be
núcleo e do método de encapsulação. Dessa forma, nesta revisão, checked by microencapsulation (KHAN et al., 2011;
serão abordados, sucintamente, alguns aspectos relevantes da GHARSALLAOUI et al., 2012).
microencapsulação, como a cápsula, o material encapsulante, as
formas de liberação do núcleo, os métodos de encapsulação, assim Microencapsulation can serve as an
como sua utilização na tecnologia de alimentos. effective means of creating foods that are not only
Palavras-chave: microcápsulas, microencapsulação, liberação a source of nutrients with sensory appeal but also
controlada. a source of well-being and health for individuals,
such as by increasing the level of calcium to prevent
INTRODUCTION osteoporosis, using microorganism-produced lactic
acid to decrease cholesterol and adding phenolic
Microencapsulation may be defi ned as the compounds to prevent heart problems (OLIVEIRA
packaging technology of solids, liquid or gaseous et al., 2002; SANGUANSRI & AUGUSTIN, 2006).
I
Departamento de Tecnologia e Ciência dos Alimentos, Universidade Federal de Santa Maria (UFSM), Avenida Roraima, nº 1000, 97105-900,
Santa Maria, RS, Brasil. E-mail: pabloteixeiras@hotmail.com. *Autor para correspondência.
II
Departamento de Farmácia Industrial, UFSM, Santa Maria, RS, Brasil.
Received 07.20.13 Approved 12.09.13 Returned by the author 05.09.14
CR-2013-0971.R1 Ciência Rural, v.44, n.7, jul, 2014.
Microencapsulation: concepts, mechanisms, methods and some applications in food technology. 1305
In this review, some relevant aspects from the external environment until release is
of microencapsulation, such as the capsule, wall desired. Therefore, the release at the appropriate time
material, core release forms, encapsulation methods and place is an extremely important property in the
and some of their uses in food technology will be encapsulation process, improving the effectiveness,
briefl y discussed. reducing the required dose of additives and expanding
the applications of compounds of interest. The main
Capsule factors affecting the release rates are related to
Generally, capsules can be classifi ed interactions between the wall material and the core.
according to their size: macrocapsules (>5,000μm), Additionally, other factors infl uence the release, such
microcapsules (0.2 to 5,000μm) and nanocapsules as the volatility of the core, ratio between the core and
(<0.2μm). In terms of their shape and construction, wall material, particle size and viscosity grade of the
capsules can be divided into two groups: wall material (ROBERTS & TAYLOR, 2000).
microcapsules and microspheres. Microcapsules are The main mechanisms involved in the core
particles consisting of an inner core, substantially release are diffusion, degradation, use of solvent, pH,
central, containing the active substance, which temperature and pressure. In practice, a combination
is covered with a polymer layer constituting the of more than one mechanism is used (DESAI &
capsule membrane. Mononuclear and polynuclear PARK, 2005). Diffusion occurs especially when
microcapsules can be distinguished by whether the the microcapsule wall is intact; the release rate is
core is divided (FAVARO-TRINDADE et al., 2008). governed by the chemical properties of the core and
In contrast, microspheres are matrix the wall material and some physical properties of
systems in which the core is uniformly dispersed and/ the wall. For example, some acids can be released
or dissolved in a polymer network. Microspheres during a process step but protected by another step.
may be homogeneous or heterogeneous depending on In some cases, some preservatives are required at the
whether the core is in the molecular state (dissolved) product surface, but their spread to other parts must
or in the form of particles (suspended), respectively be controlled (AZEREDO, 2005).
(SILVA et al., 2003). According to ROSEN (2006), degradation
release occurs when enzymes such as proteases
Wall materials and lipases degrade proteins or lipids, respectively.
The correct choice of the wall material is An example is reducing the time required for the
very important because it infl uences the encapsulation ripening of cheddar cheese by 50% compared with the
effi ciency and stability of the microcapsule. The ideal conventional ripening process (HICKEY et al., 2007).
wall material should have the following characteristics: In contact with a solvent, the wall material
not reactive with the core; ability to seal and maintain can dissolve completely, quickly releasing the core
the core inside the capsule; ability to provide maximum or start to expand, favoring release. For example,
protection to the core against adverse conditions; lack microencapsulation of coffee fl avors improves the
an unpleasant taste in the case of food applicability and protection from light, heat and oxidation when in the
economic viability (GHARSALLAOUI et al., 2007; dry state, but the core is released upon contact with
NAZZARO et al., 2012). water (FRASCARELI et al., 2012).
According to FÁVARO-TRINDADE The pH release occurs because pH changes
et al. (2008), most wall materials do not have all can result in alterations in the wall material solubility,
the desired properties; a common practice involves enabling the release of the core. For example,
mixing two or more materials. Such materials can be probiotic microorganisms can be microencapsulated
selected from a wide variety of natural and synthetic to resist the acid pH of the stomach and only be
polymers, including the following that we highlight: released in the alkaline pH of the intestine (TOLDRÁ
carbohydrates: starch, modifi ed starches, dextrins, & REIG, 2011).
sucrose, cellulose and chitosan; gums: arabic gum, Changes in temperature can promote
alginate and carrageenan; lipids: wax, paraffi n, core release. There are two different concepts:
monoglycerides and diglycerides, hydrogenated oils
and fats; inorganic materials: calcium sulfate and temperature-sensitive release, reserved for materials
silicates; proteins: gluten, casein, gelatin and albumin. that expand or collapse when a critical temperature is
reached, and fusion-activated release, which involves
Controlled core release melting of the wall material due to temperature
According to GOUIN (2004), increase. An example is the fat-encapsulated cheese
encapsulation should allow the core to be isolated fl avor used in microwave popcorn, resulting in the
Ciência Rural, v.44, n.7, jul, 2014.
Silva et al.
1306
uniform distribution of the fl avor: the fl avor is core and wall material, followed by nebulization
released when the temperature rises to 57-90°C in a drying chamber with circulating hot air. The
(PARK & MAGA, 2006). water evaporates instantly in contact with the
Pressure release occurs when a pressure hot air, and the material encapsulates the core
is applied to the capsule wall, such as the release of (LAOHASONGKRAM, 2011). Atomization has some
some fl avors during the mastication of chewing gum advantages over other methods: large equipment
(WONG et al., 2009). Some wall materials and the availability, possibility of employing a wide variety
possible mechanisms for the microcapsules release of encapsulating agents, potentially large-scale
are listed in table 1. production, simple equipment, good effi ciency,
reduced storage and transport costs and low process
Some encapsulation methods cost. The main disadvantage of atomization is
The choice of the most suitable method the production of non-uniformly sized materials
depends on the type of core, the application for the (MADENE et al., 2006).
microcapsule, the size of the particles required, The spray drying technique is the most
the physical and chemical properties of the core common microencapsulation method, has been used
and the wall, the release mechanism required, the for decades to encapsulate mainly fl avors, lipids, and
production scale and the cost (SUAVE et al., 2006). pigments, but its use in thermo-sensitive products,
According to CABALLERO et al. (2003), the main such as microorganisms and essential oils, can be
encapsulation methods are: spray drying, spray limited because the required high temperature causes
cooling, extrusion, coacervation, lyophilization and volatilization and/or destruction of the product
emulsifi cation. (GHARSALLAOUI et al., 2007).
Spray drying The sumac fl avor has been successfully
This process involves the formation of encapsulated by spray drying in sodium chloride in
an emulsion, solution or suspension containing the salted cookies, salads and crackers (BAYRAM et al.,
Table 1 - Wall materials and their potential release mechanisms.
Wall Materials -----------------------------------------------Release Mechanisms-----------------------------------------------
Mechanic Thermal Dissolution Chemical
Soluble in water
Alginate x x
Carrageenan x x
Caseinate x x
Chitosan x
Modified cellulose x x
Gelatin x
Xanthan gum x x
Arabic gum x x
Latex x x
Starch x x
Insoluble in water
Ethylcellulose x
Fatty alcohols x x x
Fatty acids x x x
Hydrocarbon resin x x
Mono, di and triacyl glycerol x x
Natural waxes x x
Polyethylene x x
Source: adapted from FAVARO-TRINDADE et al. (2008).
Ciência Rural, v.44, n.7, jul, 2014.
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