The study results of
Microencapsulation is a technique or process of wrapping very small gas particles, gases, or active solid content with a coating material/membrane to protect the active particles (core) from environmental influences like unwanted effects such as light, moisture, and oxygen to increase shelf life of the product. Microencapsulation proposes to protect sensitive food components, reduce nutritional losses, expand the usefulness of sensitive food components, add certain food to other food, protect flavors and fragrances, convert liquid food components to more convenient solids handled, and protect materials from environmental influences. Product microcapsulation can be used as raw material for the food industry, cosmetics, and pharmaceuticals using bioactive compounds. From the results of the curcuminoid content testings, it can be observed that an increase of drying temperature produces lower amount of curcuminoid contents, which is caused by the inability of curcuminoid compounds to be preserved by maltodextrin, as the microencapsulant. The best temperature to preserve curcuminoid compounds is at 110°C, in which 10.52% is preserved. Hence, for Aloe vera processing, the optimum drying temperature was 120°C which maintained the active component of Aloe vera powder such as Aloenin (B), Aloeresin A, and Chrysophanol.
- herbal compounds
- Aloe vera
Microencapsulation is an encapsulation technique or process of very small gas particle, gas, or active solid substance with coating/membrane materials with the purpose of protecting the active particle (core) from unwanted environmental influences, such as radiation, humidity, and oxidation to increase shelf life . These capsules are measured in one (1) micron (1/1000 mm) to seven (7) mm, and release their contents at a measured time according to their applications .
Microencapsulation aims to protect sensitive food particle, reduce loss of nutrition, expand the uses of sensitive food material, add certain food particles into other food materials, protect tastes and aroma, modify the state of food material from liquid to solid for ease of handling, and protect food particles from environmental effects. Protection provided by microencapsulation can also prevent degradation caused by radiation or oxidation, and also slow down evaporation on volatile compounds .
The results of a microencapsulation process are microcapsules containing an active compounds or raw materials surrounded by membrane or cell. The material encapsulated is usually referred to as the core, internal phase, or insert. The coating material is called coat, encapsulant, or shell with varied number and thickness. Coat, shell, encapsulant, or wall is designed to protect the core from destructive factors such as radiation, oxygen, and humidity. In microencapsulation, capsule is designed and prepared to achieve all the needs considering the natures of the core or coating materials, the desired usage of the material, and storage condition .
Encapsulants from carbohydrates, such as maltodextrin, starch, and arabic/acacia gum are widely used. However, these materials generally have weak surface tension and require modification or are used with agents with active surface tension to encapsulate oil-based substances .
There are four mechanisms of core release from microcapsules: degradation, dissolution, and melting of capsule walls, and diffusion of core materials through broken shell. Abrasion (slow erosion of capsule shell) and biodegradation are two other mechanisms that are less frequently employed .
The use of microencapsulation technology has been applied in many fields, such as drug encapsulation in the pharmaceutical industry, adhesive materials, agrochemicals, live cells, catalysts, vitamin storage, and so on. The advantages of microencapsulation are handling liquid as solid, preserving aroma or taste effectively in the food industry, protecting core substances from detrimental effects of the environment, safe handling of toxic materials, and controlling the delivery of drugs .
The benefits of microencapsulations are preserving the functions of active compounds, extending shelf life, covering unpleasant taste or aroma (unpleasant taste but high benefits), facilitating handling, facilitating control, improving appearance, and improving taste and colors. Microencapsulation can be prepared by emulsified coating or fluidized bed coating. Microencapsulation process with spray dryer method consists of two phases: oil emulsification in polymer solution and solvent removal using hot air. The polymers used are from many kinds of polysaccharides and proteins, such as starch, arabic gum, gelatin, albumin, and casein .
In an emulsification, emulsion is formed when minute oil droplets are dispersed in an emulsifier, in this case a polymer. Emulsion is a mixture system containing two immiscible liquid phases, in which one phase is dispersed in the other phase in the form of droplets. Almost in all food products, the diameters of the droplets range from 0.1 to 100μm. Emulsion is an unstable system in which the phases tend to separate. In an emulsion system consisting of pure oil and pure water, it is easy to for two layers based on the difference in densities. This phenomenon is caused by the tendency of the droplets to combine with nearby droplets and often produce a perfect separation. As such, stability is one of important factors in the encapsulation process using spray dryer. The process to make two immiscible solutions form an emulsion is called homogenization and the mechanism to perform this process is called homogenizer. To differentiate between the natural state from the initial components, homogenization can be more appropriately categorized as primary (emulsion formation) and secondary homogenizations (droplet size reduction) .
In almost all microcapsules, the coating materials are usually made of organic polymers, although wax and fats have been used, especially in the uses for food and pharmaceutical products, the coating materials have to meet the specifications required by the FDA .
Microencapsulation process can be performed with several techniques, such as spray drying, spray cooling, extrusion, and coacervation . Out of those four methods, spray drying is most frequently employed. Spray drying has become the most important method in the water removal process (dehydration) for liquid food products in the western world. This dehydrator is a diabetic dehydrator, and there are many considerations on solid-state diabetic dehydrator that can be applied. This process is a conversion from a liquid state into dry particles by spraying materials into the hot dehydrating medium. The dry products from this dehydrating process can be in the forms of powder, granules, or clumps. In this drying process, the products are not placed in drying cabinets or shelves, but dispersed as fine droplets suspended in the air inside the dryer. The advantages of this method are that the technology is well known thus easily obtained; it can be used to produce capsules in large quantities, the coating materials for spray drying are approved as food products, and the coating materials dissolve in water and can release the core without leaving residue. Efendi stated that microencapsulation with spray dryer should utilize encapsulant materials with high solubility, emulsion-forming capability, layer-forming capability, dry, and low viscosity . Even though several encapsulants can be used in nonfood materials, those for food products are limited to natural gum, carbohydrates, maltodextrin, wax, and several proteins.
Drying with spray dryer is performed by spraying the materials to be dried as mists, which increases the surface area of the materials to be in contact with the drying medium, thus the water evaporation process can proceed well. The spraying process is influenced by the form of the sprayer, speed of product flow, and product characteristics .
The spray dryer process consists of four stages: (1) atomization, in which liquid or paste is converted into mists, (2) contact between the atomized materials with hot air, (3) water evaporation from the materials to reach the desired moister content, and (4) product collection in a powder form. In the stages of spray drying process, there are several operational units consisting of preconcentrated solution, atomization (mist formation), drying using dry and hot air, separation of powder from water vapor, cooling, and product packaging.
2. Microencapsulation process of
turmeric( Curcuma domestica Val.)
Microencapsulation is a coating technology for solid, liquid, and gas using capsules in minute form, in which those capsules can release the core under specific conditions. Microencapsulation aims to protect sensitive components, reduce nutrient loss, and add food products in liquid form to solid form for ease of handling .
In this study, the microencapsulation process uses spray drying, which is the most frequently employed in the food industry because of its relatively lower cost. The advantages of this process are flexible and can be used for a variety of materials in microencapsulation because the equipment can be applied to process various materials and produce good quality particles with a consistent distribution of particle size. The food materials that can be applied in this method include fats, oils, and flavor enhancers. The coating can be from carbohydrates, such as dextrin, sugar, starch, and gum, or proteins, such as gelatin and soy proteins. Microencapsulation process includes emulsion formation or suspension on the active compounds and coating, and atomization of the emulsion into circulated dry and hot air inside drying chamber using an atomizer or a nozzle. The water contents inside emulsion droplets evaporate. The solid left over from the coating material traps the core material. Spray drying is useful for food materials that are sensitive to heat because the drying process occurs very fast. The other advantages of spray drying are the variety and availability of equipment, microcapsule quality that stays high, variety of particle size that can be produced, and good dispersibility in liquid media. However, loss still happens to active compounds with low boiling point. Physical characteristics of microcapsules depend on hot air (about 150–200°C), degree and uniformity during emulsion atomization, degree of emulsion density (30–70%), and emulsion temperature. The other disadvantages are the loss of bioactive compounds with low boiling point, oxidation in flavor enhancer substances, and limited options for shell materials, in which these materials can dissolve in water in an adequate amount. The flow diagram for microencapsulation process for
This study was conducted to determine the optimal temperature of the inlet (T
|No.||Samples for varied T||T||Drying time (s)||Yield (w/v) (%)|
In this study, the
Based on the results shown in Table 1, the increased drying temperature (T
This outcome is caused by higher the drying temperature, faster the water evaporation from the materials. The result of this study is supported by Estiasih et al. , where there is a difference of temperatures between heating medium and materials, in which the faster the heat transfers to the materials, the faster the water evaporates from them. As such, it can be understood that the higher the temperature used in the drying process, the shorter the drying time. However, it takes longer time for the spray dryer to reach higher temperatures.
|No.||Samples from different T||T||Water content (w/v) (%)||Dissolving time (s)|
Water content analyses are performed to determine the water content of the powder produced from the spray dryer because water content influences shelf life, appearance, and water solubility. An increase of drying temperatures will reduce water content in the product. Water content testing is a part of quality testing on the
Based on Figure 2, an increase of drying temperature would reduce the water content of the product. This is because drying temperature has a role in water evaporation from the materials. And thus, the higher the temperature, the more water will evaporate, and the less water is left in the product.
Solubility is an important factor in powder product testing. Powder solubility is determined by composition, conditions during drying process, solvent temperatures, and mixing method. The higher the drying temperature, the less the water content in the products. The solubility testing is conducted by dissolving the
As shown in Figure 3, the yields from a drying process are determined by the amount of the resulting products. In this study, the yields range from 1 to 4.42%, which means that the yields are relatively low compared to the initial dry materials that are inserted in the spray dryer in liquid forms. In a drying process, free water molecules on the surface of the material particles can be easily evaporated, which produce low yields. However, based on the drying temperature variables, as presented in Table 4, the higher the drying temperature, the higher is the yield. It can be noted that the highest yield is found at the temperature of 150°C, and the effect of different T
|Sample code||T||Bis-demethoxycurcumin content (%)||Demethoxycurcumin content (%)||Curcumin content (%)||Total curcuminoid content (%)|
|Sample III [*13]||130||0.09||0.70||2.22||3.01|
Based on Figure 4, the effects of drying temperatures can be explained by an increase of temperatures causing dryer particles, which leads to less materials sticking inside the dryer and more getting collected in the cyclone vacuum collector. With an increase of temperatures, the yields obtained increase, and in this study, the highest yield is obtained from 150°C drying temperature at 4%. At the drying temperature of 100°C, the yield is relatively low at only 2.64%. The results of this study show that the drying temperatures have a positive correlation with the yields, such that when temperature is raised up to 150°C, the yields also increase because more materials are collected in the cyclone vacuum collector.
The results from HPLC testing are used to show curcuminoid contents in the
From the results of the curcuminoid content testing, it can be observed that an increase of drying temperature produces lower amount of curcuminoid contents, which is caused by the inability of curcuminoid compounds to be preserved by maltodextrin, as the microencapsulant. The best temperature to preserve curcuminoid compounds is at 110°C, in which 10.52% is preserved, although the yield was lower and drying timer was longer than 150°C.
Based on research results,
The following figure shows the resulting chromatograms from the HPLC testings on sample V.
3. Microencapsulation process on
Aloe vera( Aloe chinensis Baker)
The highly perishable nature of
Furnawanthi  stated that
The procedures to produce
To obtain the optimum drying temperature, the optimization was conducted to preserve the active compounds corresponding to commercial
|1||Water content (% w/w)||2.88||4.04||4.89||4.89||8% max|
|6||Color||Beige white||Beige white||Beige white||Beige white||Beige white|
In general, the resulting product has met most of the parameters and specifications of commercial
While the product is almost the same density compared to available commercial products, this might be due to the method of testing using different methods, so the result is somewhat different. The testing methods used packed density. In the drying process (spray dryer), the decreasing of hot air inlet temperature did not affect the increase of water content significantly. In fact, water content tended to be stable of 2–5%. This has a positive effect for the quality of product in which the active component microencapsulated was relatively stable for lower temperature of dryer.
The results of chemical and content analyses of active compounds in
|No||Specifications||Spray-dried aloe gel powder||No||Specifications (amino acid contents)||Spray-dried aloe gel powder, ppm|
|1||Amylase activities||0.024 unit/gr sample||1||Aspartic acid||131.71|
|4||Saponin||Confirmed presence (qualitative test)||4||Glycine||72.78|
|9||Lead (Pb)||<0.02 ppm||9||Proline||132.11|
|10||Arsenic (As2O3)||<0.005 ppm||10||Tyrosine||242.98|
Microencapsulation proposes to protect sensitive food components, reduce nutritional losses, expand the usefulness of sensitive food components, add certain food to other food, protect flavors and fragrances, convert liquid food components to more convenient solids handled and protected materials from environmental influences. Product microcapsulation can be used as raw material for the food industry, cosmetics, and pharmaceuticals, using bioactive compounds. From the results of the curcuminoid content testings, it can be observed that an increase of drying temperature produces lower amount of curcuminoid contents, which is caused by the inability of curcuminoid compounds to be preserved by maltodextrin, as the microencapsulant. The best temperature to preserve curcuminoid compounds is at 110°C, in which 10.52% is preserved. Hence, for
Thanks to Universitas Muhammadiyah Jakarta and Directorate of Research and Community Service, Directorate General for Research and Development, Ministry of Research and Technology Higher Education on the Research Grant PTUPT in 2018, Contract number 006/KM/PNT/2018, 06 March 2018. Thanks to Rector of Universitas Muhammadiyah Jakarta and Dean of Engineering Faculty, Universitas Muhammadiyah Jakarta.