POTENTIAL APPLICATION OF MICROENCAPSULATION IN THE FOOD INDUSTRY

Dayane de Melo Barros 1 , Erilane de Castro Lima Machado 2 , Danielle Feijó de Moura 1 , Maria Heloisa Moura de Oliveira 3 , Tamiris Alves Rocha 4 , Silvio Assis de Oliveira Ferreira 4 , Roberta de Albuquerque Bento da Fonte 2 and Ranilson de Souza Bezerra 5 . 1. Mestre em Saúde Humana e Meio Ambiente – Centro Acadêmico de Vitória, Universidade Federal de Pernambuco, CAV/UFPE – Pernambuco. 2. Doutora em Nutrição – Universidade Federal de Pernambuco – Pernambuco. 3. Discente de bacharelado em Nutrição – Centro Acadêmico de Vitória, Universidade Federal de Pernambuco, CAV/UFPEPernambuco. 4. Mestre em Bioquímica e Fisiologia – Universidade Federal de Pernambuco – Pernambuco. 5. Doutor em Ciências Biológicas – Universidade Federal de Pernambuco – Pernambuco. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History Received: 16 October 2018 Final Accepted: 18 November 2018 Published: December 2018

In the food sector, encapsulation is a process of coating one or more food ingredients through an edible capsule. This is a relatively new technology that has been used successfully in the food industry. Several techniques have been used in the production of microparticles, such as: extrusion, spray drying, complex coacervation, fluidized bed, lyophilization, internal and external ionic gelation, liposomes and molecular inclusion. Microencapsulation, in addition to increasing the performance and availability of active agents, has solved limitations in the use of food ingredients, since it can suppress or attenuate undesirable organoleptic characteristics (flavors, odors and color) of some compounds, reduce volatility and reactivity and increase their stability under adverse environmental conditions (oxygen, light, moisture, pH and incompatible agents).The present study presents a review of the literature on encapsulation in food technology -history of encapsulation/microencapsulation, encapsulating agent, encapsulated agent, controlled release mechanisms, techniques used in microencapsulation and potential application in the food industry.
In this scenario microencapsulation has applicability in several areas, such as pharmaceutical, cosmetic and agrochemical, being also used in the alimentary area (REBELLO, 2009;PHISUT, 2012;NESTERENKO et al., 2013).

ISSN: 2320-5407
Int. J. Adv. Res. 6 (12), 956-976 957 In the segment of technology associated with the encapsulation of food products, in an environment of competitiveness, the innovation factor is paramount. The technological innovation in the systems of encapsulation of ingredients allows creating differentials in products that can provide the most varied sensations for the consumer. The encapsulation technology is in increasing expansion and constant evolution, being of competence of the scientific community of the science and technology of food and of the industries to be kept abreast both in relation to the use of new materials, as in the techniques employed, that transform ideas products with high added value ( In the food industry, encapsulation has been used as a way to enable liquid and solid ingredients to effectively barrier against environmental and/or chemical interactions, until the desired release (CARMO et al., 2015).One of the major advantages of microencapsulation technology is the controlled release, whose technique allows extending the spectrum of applications of the compounds of interest, being considered not only an additional, but also a source of new ingredients with unique characteristics (GOUIN, 2004).
The present study aimed to identify available evidence on the potential application of microencapsulation in the food industry. The present study aimed to identify available evidence on the potential application of microencapsulation in the food industry.
History about encapsulation/microencapsulation: the encapsulation consists of a technology of packaging of particles (liquid, gaseous or solid) in edible capsules being considered a favorable tool to optimize the release of molecules and living cells through particles (kailasapathy and masondole, 2005; nedovic et al., 2011).the carrier material forming the capsule is known as encapsulant, wall material or cover and the encapsulated material may be called encapsulated agent, active agent, core or fill (azeredo, 2005; suave et al., 2006).
The first studies of the use of the microencapsulation technique were verified in the 30's mediated by the US National Cash Register, which became a pioneer in the commercialization of carbonless copy paper (in the 1950s).This paper was covered by a thin layer of colorless ink microcapsules.This paper was covered by a thin layer of colorless ink microcapsules. When writing with a pen, that is, by pressing under the surface of the paper, there was the rupture of the microcapsules leading to the release of the colorless ink that, when interacting with the reagent, became colored, generating on the sheet underneath a copy of what was being written in the first role (FIB, 2017).
The distinction between encapsulation, microencapsulation and nanoencapsulation is basically the size of the capsule.According to Rebello (2009) the capsules can be classified according to the diameter into three categories: macrocapsules (>5000μm), microcapsules (0.2-5000μm) and nanocapsules (<0.2μm).
The microparticles are subdivided into microspheres and microcapsules ( Figure 1), according to their structure, so that capsules where the nucleus is evenly dispersed in a matrix result in so-called microspheres and capsules in which the nucleus concentrates in the central region, wrapped by a defined and continuous film of the wall material characterize the microcapsules.The most relevant difference between the microspheres and the microcapsules is that in the microspheres a small fraction of the "encapsulated" material remains exposed on the surface, which is prevented by the true encapsulation (AZEREDO, 2005;SUAVE et al., 2006).  Although there are several techniques of microencapsulation, the biggest challenge is to choose the most efficient and appropriate method, taking into account the application to be used and the type of coating material (ANAL and SINGH, 2007).

Description of the main techniques and potential application in the food industry:
The main techniques used in microencapsulation of active agents in food (  In the extrusion method, the molten or solution liquid core material is poured through the bore of a thin tube or syringe to form microdroplets, the size of which is dependent upon the orifice diameter and the material exit velocity.The drops contain the coating material or this is added when the drops fall or is injected. Solidification of the coating material may occur by solvent evaporation, solvent diffusion or chemical reaction (KRASAEKOOPT; BRANDARI and DEETH, 2003).
This method has been widely used for the microencapsulation of probiotics and volatile oils. It is emphasized that, one of the disadvantages of this technique is the formation of large particles, which limit the use of flavorings in applications where the taste is a determining factor (ETCHEPARE et al. Spray drying includes: the preparation of the dispersion or emulsion to be processed, the homogenization of the dispersion and the atomization inside the drying chamber (GHARSALLOUI et al., 2007). During spray drying, the 962 temperature of the droplets increases slightly, while its water content decreases, so, through the differences between the molecular weight of the water and the volatiles, the reduction in the diffusivity of the volatiles is greater than in the water, allowing, but good retention.
This common and low-cost technique is considered to produce microencapsulated food materials, equipment is readily available and production costs are relatively small. It has been used for decades to encapsulate mainly flavors, lipids and pigments, but its use in thermosensitive products such as microorganisms and essential oils can be limited due to the use of high temperatures which causes product volatilization and / or destruction (GHARSALLOUI et al., 2007).
Pereira (2007) investigated the efficiency of chitosan as a wall material in the microencapsulation process of the phyto-constituent eugenol by means of the spray drying method and verified that the biopolymer was efficient in the microencapsulation process, and this technique could be considered as a viable alternative in the encapsulation of volatiles.
Santos, Favaro-Trindade and Grosso (2005) evaluated the microencapsulation of paprika oleoresin by spray drying using encapsulating agents (gum arabic and porous starch / gelatin granules). The production of microcapsules of paprika oleoresin with the encapsulating agents was successful as it was able to protect the carotenoids against factors that cause oxidation of this pigment.
Carmona (2011) confirmed in his study that the process of obtaining orange oil microparticles by spray drying was fast and simple to perform.
Felix (2014) sought to evaluate the efficiency of the microencapsulation of cinnamaldehyde (cinnamaldehyde major essential phytoconstituent) with wall materials (gum arabic and protein isolate). All wall materials and combinations thereof associated with maltodextrin proved to be amenable to the microencapsulation of the volatile compound.
In the study by Carvalho (2009), when evaluating the encapsulation of oregano essential oil, it was able to confirm that the spray drying process was effective in the retention of the active compound, referring it as a viable technique.
According to Garcia (2013), there was an expressive increase in retention of basil essential oil by the microencapsulation technique in question, taking into account all wall materials (a combination of gum arabic, maltodextrin plus soy protein isolate and maltodextrin more whey protein concentrate) used, it is emphasized that this retention was optimized with increasing homogenization pressure.
Müller (2011) showed high efficiency of encapsulation in orange essential oil (99.32%), even after 10 months of storage, the microcapsules kept the oil concentrations stable.
In agreement with Garcia (2013), Frascareli (2010) to microencapsulate the coffee essential oil under high pressure in the homogenization, verified that the emulsions fed in the spray drying were stable, with smaller particle diameter and with less dispersion of the distribution.

Complex Coacervation:
Complex coacervation can be defined as a process in which a polyelectrolyte complex is formed.This process requires the mixing of two colloids, with pH adjustment. The two oppositely charged polymers are driven to a phase separation and formation of solid particles or closed liquid droplets (CHÁVARRI, MARAÑÓN and VILLARÁN, 2012).
In the food industry, this technique has been used for the encapsulation of several active food components such as: flavorings, probiotics, oils, nutrients, vitamins and enzymes The coacervation technique was performed by Yang et al. (2015). This study aimed to improve the stability of poppy seed oil and used gum arabic and gelatin as wall materials. The microcapsules showed good performance for the incorporation of the oil of poppy seeds, which possibly can be used in the food industries.  2015) opted for the coacervation technique to produce and characterize xylitol microcapsules for use in foods in order to prolong the sweet and refreshing effect provided by this ingredient and found that the encapsulation efficiency was relatively good in the case of a hydrophilic core , in addition, more than 70% of microencapsulated xylitol was released in artificial saliva over a period of 20 minutes.
Souza (2016) chose to encapsulate the cinnamon extract by the same technique and concluded that the encapsulated extract particles showed resistance when subjected to stress conditions and provided good stability of the encapsulated phenolic compounds during drying.In addition, the encapsulation process was able to mask undesired sensory characteristics, such as strong taste and astringency sensation caused by proanthocyanidins. Fluidized bed encapsulation also has other advantages such as: high degrees of contact between the two phases, heat and mass exchange, and degree of mixing within the dryer.In addition to ease of process monitoring, being considered an economically viable technique and ideal for thermosensitive products (LEE and SHIN, 2009).
However, there are some difficulties with this technique, among the main ones are: the defluidization, which occurs due to the formation of large particle agglomerates, drastically altering the dynamic activity of the system, and the phenomenon of friction that can generate losses of the material reducing the efficiency of the encapsulation (HEMATI et al., 2003).

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There are several fluidized bed configurations for the atomization of the feed composition: the air suspension system or Wurster system, with bottom-spray feed, top-spray system) and system with tangential feed to the particle bed (BENELLI et al., 2015). A study by Benelli et al. (2015) analyzed the coating/agglomeration process of rosemary(Rosmarinus officinalis) extract in fluidized bed with top spray atomization using particle seeds of natural origin (cassava flour and sugar pellets).Granules with excellent fluidity and high retention of phenolic compounds were obtained, confirming the viability of the fluidized bed as a promising method for the production of herbal compositions with appropriate physicochemical and pharmacotechnical properties.
In the application of the fluidized bed to coat the carnauba wax particles, Paulo (2017) used the following polysaccharides as a wall material: sodium alginate, gum arabic, chitosan, maltodextrin and Eudragit® L30-D55 and emphasized the importance of evaluating parameters as contact angle and viscosity for the selection of wall materials when using this type of technique, since only the suspensions containing Eudragit® L30-D55 and sodium alginate had the lowest contact angle (θ≅ 40°), low viscosity and were able to cover the carnauba wax particles (coating efficiency ≅ 55%).
Cardoso, Grosso and Vitali (2001) prepared microcapsules containing fish oil coated in a fluidized bed, and the encapsulation yields of the retained oil were high, being 88.9% in the particles covered with gelatin and 85.9% in the particles coated with calcium pectate.The highest yield obtained for gelatin coverage is possibly due to the use of only one spray system.

Freeze-drying:
Freeze-drying, also known as cryosecting or freeze-drying, is a process characterized by dehydration, so that the water or other solvent of the previously frozen product passes from the solid to the gaseous state (sublimation) in conditions of temperature and pressure. In this technique, in order for the water to pass directly from the solid to the vapor phase, the temperature and the partial pressure of water vapor must be lower than the triple point, ie 0.0099 °C In the first stage, freezing of the product to be lyophilized, should generally be below a temperature of -18°C. This phase is of paramount importance for the quality of the final product and the performance of the lyophilization, since the size and homogeneity of the formed ice crystals characterize the shape, distribution, size and connectivity of the formed dry layer by sublimation, thus influencing the parameters that define heat transfer and mass in the product during primary and secondary drying (PEREDA, 2005; MARQUES, 2008).
In the primary drying, the frozen water is removed by sublimation, giving empty spaces inside the lyophilized product that were previously occupied by the ice.For this to happen, it is necessary to keep the frozen material below -10ºC and absolute pressure of 2mmHg or less. At this stage, most of the water is removed, around 90% of the initial content (MARQUES, 2008; PEREDA, 2005).
And in secondary drying, after sublimation, significant amounts of bound water can still be left inside the product, requiring an additional potential. The driving force of this stage is heating (the temperature increases between 20 and 50ºC), where the desorption of water occurs, with the final humidity reaching 2 to 10% (SNOWMAN, 1997; PEREDA, 2005; MARQUES, 2008).
Lyophilization has several advantages when compared to other drying processes which also use drying, i.e., drying at high temperatures, at ambient pressure and without prior freezing. The advantages include: lower product 965 contraction, higher solubility (due to the spongy structure left by the water outlet), avoids decomposition by heat, promotes the reduction of volatile loss without influencing product quality, as well as reduces enzymatic actions of microorganisms, prevents protein denaturation, and preserves the initial morphology of the material (ORREGO, 2008).
Despite the numerous advantages, this drying system also has some limitations, such as its long life The causes of this limitation are mainly due to the low heat transfer performance inside the product and the reduced working pressures, which make the radiation the main mechanism of heat transfer, since, there is little convection and a low conduction between the surfaces of vacuum contact (HAMMAMI and RENÉ, 1997).
Another limiting factor is the high cost to use this technique, since it has a relatively low drying rate, generating high energy consumption for sublimation and for the removal of water vapor from the chamber (KOROSHI, 2005).
As for indications, this technique is commonly indicated for thermosensitive materials such as: biological materials (fungi, enzymes, tissues), pharmaceutical materials (antibiotics, vaccines, serums) and foods (juices, meats, vegetables, fruits) temperatures and basically work under vacuum, promotes the generation of products with superior quality when compared to those obtained through other drying techniques (MARQUES, 2008).
In the food context The researchers found that among the independent variables, the bran content had a greater effect on the emulsion properties, although there was a reduction in viscosity and homogenization pressure.With this result, it could be stated that the modified oat bran has an excellent ability to form stable emulsions which may be suitable for this microencapsulation technique.
In the study by Sarkar et al. (2012), microcapsules of mint oil with gum arabic and guar gum (irradiated) were produced by emulsification followed by spray-dryer. The microcapsules were analyzed for retention of mint oil over the 8 week period. The results obtained demonstrated that guar gum irradiated at 50kGy can be used in the partial substitution of gum arabic for encapsulation of sensitive food ingredients, since in this condition there was greater retention during storage period.
Lupo et al. (2014) microencapsulated polyphenols extract by internal ionic emulsification / gelation and reported that the microcapsules of citrate and carbonate salts had a smaller diameter and an encapsulation efficiency of 60%.They concluded that the microparticles of cocoa could increase the daily intake of antioxidants when implemented in a food product.
Holkem, Codevilla and  have stated that the emulsification using double emulsion is being used extensively in the encapsulation of oils since it favors a better protection for the active agents. The emulsions may be water-oil-water (w/o/w) or oil-water-oil (o/w/o).

External Ionic Gelation:
In the external ionic gelation a solution of biopolymer containing the material of interest is dripped onto an ionic solution at appropriate concentrations and considerable levels of encapsulated active agent and particles of different shapes and sizes can be achieved (Figure 3).The interactions of the ions with the carboxylate groups of polysaccharides lead to the formation of insoluble gels (ARANHA, 2015).
The hardening of the particles occurs rapidly, starting at the surface, in which the divalent ions react with the negatively charged biopolymer chains, this results in the formation of a rigid three-dimensional structure, with high water content, through which the ions diffuse into the particle, providing the cross-linking from the outer part to the inner part (  Ionic gelling is a simple technique, which does not require the use of organic solvents, pH or extreme temperature, making it low cost when compared to other encapsulation systems.In addition, it enables the encapsulation of hydrophilic or hydrophobic substances (MCCLEMENTS, 2005). In contrast, although the ionic gelling particles are suitable for encapsulation, they are sensitive to extreme pH values. There is also another limiting factor which is the porosity of the matrix which generates the release of the encapsulated substance. In order to overcome this drawback, the structure of the gel can be changed by combining various types of biopolymers in order to assure the advantage of the chemical composition of each compound or to promote its interaction with polyelectrolytes, the proteins (PATIL et al., 2010).
Gelling/emulsification is applied in various fields such as: pharmaceutical, medical and agronomic. In the food sector it is considered promising and several studies have been carried out (LAM and GAMBARI, 2014).
A study carried out the microencapsulation by external ionic gelation associated with the electrostatic interaction of the dye extracted from the buriti pulp, using the alginate coating materials: whey proteins (WPC) and pectin: whey proteins (WPC). The gelation process was effective in the encapsulation of buriti oil, although the alginate: WPC particles presented a more regular shape and a smoother surface when compared to those of pectin: WPC, which showed more rough surfaces and elongated forms (ARANHA, 2015).

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Silva (2016) produced alginate and gelatin microgels by ionic gelation to protect probiotics (Lactobacillus acidophilus) and also evaluated the influence of the addition of Fructooligosaccharides (FOS) on the encapsulation matrix.The study revealed that microgels were efficient against the protection of microorganisms, the survival and viability of probiotics during the microencapsulation process, resistance to digestive fluids by in vitro simulation and stability to storage under controlled conditions. Rocha (2017) produced microparticles containing tomato juice via external ionic gelation in order to evaluate the combination of carrier materials (inulin and maltodextrin together with sodium alginate). Through the results, it was concluded that the wall material, alginate and inulin provided better protection over time, demonstrating the possibility of producing alginate microparticles containing tomato juice.

Liposomes:
Liposomes The use of liposomes as a way of controlled release of flavorings, pigments and natural active agents through the liposomes is considered a promising alternative because of its protection capacity, against several conditions associated with the food matrices and elaboration processes involved, besides to increase the availability and bioactivity of these compounds (CHAPAL, 2017).
Several studies have reported the importance of using liposomes as a food encapsulation technique, with the encapsulation of ascorbic acid and tocopherol that were loaded into liposomes and then incorporated into apple juice, orange juice and dairy products improving its bioactivity ( The inclusion of quercetin in liposomes made from soybean phospholipids and coated with Isolated Whey Protein (WPI) was evaluated for application in a functional milk beverage, revealing that the coated liposomes allowed to mask the undesirable sensory characteristics of the active compound in addition , the coating allowed a greater stability of the liposomes by protecting them from the osmotic forces arising from the significant amounts of sugars and salts present in the beverage, preserving the stability under refrigeration temperature in the course of three months(FRENZEL and STEFFEN-HEINS, 2015).
The encapsulation of polyphenols obtained from grape seed extract in chitosan-coated liposomes provided greater control in the release of polyphenols, retaining their bioactivity for a prolonged period when compared to the encapsulation in simple liposomes and with the free compound, these liposomes originated a system with greater stability, which allowed its use in food of high water content (GIBIS et al., 2016).
Liolios et al. (2009) evaluated the antioxidant capacity, antimicrobial activity (on Gram negative and positive bacteria) and pathogenicity against Listeria monocytogenes (present in some foods) of a liposomal system based on phosphatidylcholine of carvacrol and thymol (compounds obtained from the essential oil of Origanum dictamnus L.).The results showed higher antioxidant capacity and antimicrobial activity of these encapsulated compounds when compared to their pure form.It should be noted that thymol was a more potent antimicrobial than carvacrol against most of the microorganisms tested. The same result was obtained with the use of clove essential oil encapsulated in liposomes made from soy lecithin and cholesterol.This system improved the chemical stability of the essential oil, thus increasing its antimicrobial action time against Staphylococcus aureus in tofu (CUI et al., 2015). These results contribute to the promising use of this type of compound as a preservative in the food industry (CHAPAL, 2017). 969

Molecular inclusioncyclodextrins:
This process occurs at the molecular level, unlike the other described techniques, generally using the cyclodextrins (CD) as encapsulating material.The CD are cyclic carbohydrates consisting of 6 (α-CD), 7 (β-CD), 8 (γ-CD) or more α-(1,4) linked glycopyranic units. In general, this technique is used to encapsulate compounds like vitamins, aromas, essential oils, dyes, among others (MARTIN DEL VALLE, 2004; BRASILEIRO, 2011). The oligosaccharide commonly used in these complexes is β-cyclodextrin, which in turn acts as a molecular capsule, with a polar outer surface and an apolar cavity, which makes it capable of playing the role of "host molecule", forming inclusion complexes with large variety of low polarity "guest molecules" (MARTIN DEL VALLE, 2004).
Molecular encapsulation is based on the substitution of water molecules that have high enthalpy, by smaller enthalpy molecules. It is an energetically viable process, because it allows the favorable alteration of enthalpy, increase of entropy and reduction of the total energy Studies have shown that CD not only masks the taste of essential oils to be used as antimicrobial agents, but also protects against the oxidation triggered by high temperatures, which allows the use of these oils, preserving their effectiveness as an antimicrobial agent in a wide variety of environmental conditions and for long periods of time (DUCHÊNE, 1987;SZEJTLI, 1998).
According to Szente and Szejtli (1986), the molecular inclusion in β-CD was efficient in reducing the loss of coffee volatiles. Matioli and Rodriguez-Amaya (2003), when encapsulating a pigment (lycopene), found that the higher the ratio of γ-CD, the greater the color intensity of the final product. And even in the presence of light, the stability of the complex was considered excellent.
Lying, Passos and Fontana, (2005) carried out a study in order to form an inclusion complex between β-cyclodextrin and bixin (carotenoid) and to define its stability under different established conditions.The results evidenced that the pure bixin extract lost 26% of the color being protected from light and in contact with oxygen for six weeks, while the encapsulated sample obtained a reduction of only 1.4%, which allowed greater protection of the pigment.
Kuck (2016) microencapsulated polyphenols extracted from the bark of the Isabel and Bordô grapes, using different wall materials.The extracts were submitted to atomization to obtain the microparticles, using gum arabic, βcyclodextrin and hydroxypropyl-β-cyclodextrin as encapsulating agents, combined in maximum concentrations of 5%.The results showed that the treatment prepared with 3% gum arabic and 2% β-cyclodextrin was considered the best, with a higher retention of flavonoids (67.2%), showing that the inclusion complexes present good retention capacity volatile agent.

Conclusions:-
The technology of microencapsulation of food ingredients and other substances has been shown to be highly employable, since it is an effective strategy and of great relevance in the conservation of various nutritional components, microorganisms, enzymes, colorants, flavorings, sweeteners, among others, protecting them from degradation and increasing stability, due to its advantageous characteristics which consequently results in products with superior quality.Thus, it can be considered that microencapsulation has a high potential to expand the market for high value-added products, producing foods that are not only a source of nutrients with sensory appeal, but also a means of well-being and health for consumers. 970