Impact of Wall Materials on Physicochemical Properties of Microencapsulated Fish Oil by Spray Drying

Application of structurally modified WPC in combination with maltodextrin for microencapsulation of Roselle (Hibiscus sabdariffa) extract as a natural colorant source for gummy candy

The aim of this work was to improve the stability of Roselle extract (RE) by spray-drying using maltodextrin (MD) alone, and in combination with WPC in the forms of unmodified and modified (via ultrasonication, UWPC, or enzymatic hydrolysis, HWPC). Enzymatic hydrolysis by improving the surface activity of WPC increased spray-drying yield (75.1 %), and improved physical (flow) and functional (solubility, and emulsifying) properties of obtained microparticles. Degree of hydrolysis of the primary WPC (2.6 %) was increased to 6.1 % and 24.6 % after ultrasonication and hydrolysis, respectively. Both modifications caused a significant increase in the solubility of WPC, in a way that initial solubility (10.6 %, at pH = 5) was significantly increased to 25.5 % in UWPC, and to 87.3 % in HWPC (P < 0.05). Furthermore, emulsifying activity (20.6 m²/g) and emulsifying stability (17 %) indices of primary WPC (at pH = 5) were significantly increased to 32 m²/g and 30 % in UWPC, and to 92.4 m²/g and 69.0 % in HWPC, respectively (P < 0.05). FT-IR analysis indicated successful encapsulation of RE within carriers' matrix. According to FE-SEM study, the surface morphology of microparticles was improved when modified HWPC was used as a carrier. Microencapsulation of RE with HWPC showed the highest contents of total phenolic compounds (13.3 mg GAE/mL), total anthocyanins (9.1 mg C3G/L) as well as a higher retention of antioxidant activity according to ABTS⁺ (85.0 %) and DPPH (79.5 %) radicals scavenging assays. Considering all properties of microparticles obtained by HWPC next to their color attributes, it can be concluded that HWPC-RE powders could be used as natural colorant and antioxidant source for the fortification of gummy candy. Gummy candy obtained using 6 % concentration of the above powder gave the highest overall sensory scores.

Microencapsulation of Yerba mate extract: The efficacy of polysaccharide/protein hydrocolloids on physical, microstructural, functional, and antioxidant properties

Effects of hydrolyzed whey protein concentrate (WPC) and its combination with polysaccharides as wall material in spray-drying microencapsulation of Yerba mate extract (YME) have not been investigated yet. Therefore, it is hypothesized that the surface-active properties of WPC or WPC-hydrolysate may improve different properties of spray-dried microcapsules (such as physicochemical, structural, functional and morphological properties) compared to neat MD and GA. Thus, the objective of current study was to produce microcapsules loaded with YME by different carrier combinations. Effect of maltodextrin (MD), maltodextrin-gum Arabic (MD-GA), maltodextrin-whey protein concentrate (MD-WPC), and maltodextrin-hydrolyzed WPC (MD-HWPC) as encapsulating hydrocolloids was studied on physicochemical, functional, structural, antioxidant and morphological characteristics of the spray-dried YME. The type of carrier significantly affected spray dying yield. Enzymatic hydrolysis by improving the surface activity of WPC increased its efficiency as a carrier and produced particles with high production yield (about 68 %) and excellent physical, functional, hygroscopicity and flowability indices. Chemical structure characterization by FTIR indicated the placement of phenolic compounds of the extract in the carrier matrix. FE-SEM study showed that the microcapsules produced with polysaccharide-based carriers were completely wrinkled, whereas, the surface morphology of particles was improved when protein-based carriers were applied. Among the produced samples, the highest amount of TPC (3.26 mg GAE/mL), inhibition of DPPH (76.4 %), ABTS (88.1 %) and hydroxyl (78.1 %) free radicals were related to microencapsulated extract with MD-HWPC. The results of this research can be used to stabilize plant extracts and produce powders with appropriate physicochemical properties and biological activity.

Joseph C, Ismail FN. Influence of Carrier Agents Concentrations and Inlet Temperature on the Physical Quality of Tomato Powder Produced by Spray Drying

The study aims to obtain spray-dried tomato powders with a high and effective product yield and enhanced powder quality. The experiment for this investigation entailed the use of several carrier agents, which were maltodextrin (MD) of 4-7 dextrose equivalents (DE), MD of 10-12 DE, and gum Arabic (GA), each in varied concentrations of 5% and 10% with spray drying inlet temperatures of 140°C, 150°C, and 160°C. Powder yield, bulk density, hygroscopicity, moisture content, water solubility, water absorption, color properties, particle size, and powder morphology were all evaluated in spray-dried tomato powders. The results revealed that the stability of the tomato powder is considerably better at high temperatures and concentrations (at 10%, 160oC), with MD 4-7 DE being the best carrier agent among the three tested carrier agents. According to the powder analysis, the product has a moisture content of 3.17 ± 0.29%, the highest yield percentage of 32.1%, a low bulk density of 0.2943 ± 0.01 g/cm3, the lowest hygroscopicity at 5.67± 0.58 %, a high water solubility index (WSI) at 89.98 ± 1.25%, a low water absorption index (WAI) at 6.22 ± 0.22%, an intermediate particle size of 24.73 µm, and color L*, a*,b* values at 31.59 ± 0.03, 11.62 ± 0.08 and 13.32 ± 0.12. The result showed that at higher temperatures and higher concentrations, the powder characteristics are more likely to have a higher yield, WSI, and larger particle size, as well as lower bulk density, hygroscopicity, moisture content, WAI, and color index.

Comparative Study of Cinnamon and Paprika Oleoresins Encapsulated by Spray Chilling and Particles from Gas Saturated Solutions Techniques: Evaluation of Physical Characteristics and Oleoresins Release in Food Simulated Media

In this study, cinnamon and paprika oleoresins were encapsulated by two technologies, respectively, spray chilling and particles from gas saturated solutions. Both technologies used palm oil as wall materials. The physical characteristics of the microparticles were compared as well as the oleoresins release behavior in high- and low-fat simulated food media. The spray chilling microparticles had an average diameter of 143.7 ± 1.5 µm, spherical shape, smooth surface, and passable flow property. In contrast, microparticles obtained by particles from gas saturated solutions (PGSS) showed an average diameter of 105.7 ± 0.6 µm, irregular shape, porous surface, poor flow property but higher encapsulation efficiency. In evaluating the compounds released in a simulated food medium, the spray chilling particles delivered 30.7%, while PGSS reached 23.1% after 1 h. Both microparticles well fitted the Kosmeyer-Peppas (R2 = 0.98 and 0.96 for spray chilling and PGSS) and Peppas-Sahlin models (R2 = 0.98 and 0.97 for spray chilling and PGSS). However, spray chilling microparticles showed a diffusion mechanism, while for PGSS ones erosion was the main mechanism. Despite the different physical characteristics, both microparticles proved to be possible facilitators in delivering oleoresins in food products.

Preparation of a Low-Calorie, Gluten-Free All-in-One Cake Mix, Containing Bacillus Coagulans Using Quinoa and Inulin Functionality

Celiac patients must follow a strict gluten-free diet along the life that leads to many nutritional deficiencies. This study aimed to produce an “all-in-one gluten-free cakemix based on quinoa flour” for celiac patients and other gluten-sensitive people. Nine treatments were provided with quinoa flour (25, 27.5, and 30% of total formula), inulin as a prebiotic, fat replacer and natural sweetener (2.4, 3.2, and 4% of total formula). The content of oil was reduced using oil powder consisting of sunflower oil and wall materials (resistant starch and maltodextrin 50 : 50). Bacillus coagulans was added as a probiotic bacteria. A commercial cakemix was considered as a control sample. The nutritional and chemical properties of cake mixes (percentage of moisture, protein, mineral, carbohydrate, crude fiber, fat, and calorie) and physical and textural properties of cakes (springiness, specific volume, porosity, chewiness, browning reaction, moisture, and water activity) were tested. Data were analyzed by https://graphpad.ir/prism/software using one way analysis of variance (ANOVA). After sensory evaluation, the treatment number 5 was selected as the most acceptable cake among all treatments. Its amino acid profile, fatty acid profile, and peroxide index were determined. The minerals, protein, and fiber of quinoa cake mixes were significantly higher, and the fat, carbohydrate and calorie were lower than control. Addition of quinoa reduced springiness, specific volume, porosity, chewiness, and increased the browning reaction. But these changes did not have a very negative effect in general. The moisture, water activity, and bacteria count changes were followed during four days of cakes preservation in refrigerator. The reduction trend of quinoa cakes moisture and water activity was slower than control. The number of bacteria was enough to be considered as a probiotic product after 4 days. Quinoa flour could improve the nutritional and functional properties of gluten-free cake mixes.

Ocimum basilicum (kemangi) intervention on powder and microencapsulated Spirulina platensis and its bioactive molecules

Background:  Spirulina platensis contains several bioactive molecules such as phenol, flavonoid and phycocyanin pigments. This study unveils total phenol, flavonoid, antioxidant activity, phycocyanin content and evaluated encapsulation efficiency from  Ocimum basilicum intervention on  S. platensis. O. basilicum intervention aims to reduce unpleasant odors from  S. platensis that will increase consumption and increase bioactive compounds.  

Methods: The intervention was carried out by soaking a  S. platensis control sample (SP) in  O. basilicum with a ratio of 1:4 (w/v) and it was then dried (DSB) and microencapsulated by freeze drying methods (MSB) using a combination of maltodextrin and gelatin. Total flavonoid and phenolic analysis with curve fitting analysis used a linear regression approach. Antioxidant activity of samples was analysed with the 2,2’-azino-bis-3-3thylbenzthiazoline-6-sulphonic acid (ABTS) method. Data were analysed using ANOVA at significance level (p < 0.05) followed by Tukey test models using SPSS v.22. 

Results: The result of this study indicated that  O. basilicum intervention treatment (DSB) has the potential to increase bioactive compounds such as total phenol, antioxidant activity and phycocyanin, and flavonoid content. Intervention of  O. basilicum on  S. platensis (DSB) significantly increases total phenol by 49.5% and phycocyanin by 40.7%. This is due to the phenol and azulene compounds in  O. basilicum which have a synergistic effect on phenol and phycocyanin in  S. platensis. Microencapsulation using a maltodexrin and gelatin coating is effective in phycocyanin protection and antioxidant activity with an encapsulation efficiency value of 71.58% and 80.5%.  

Conclusion: The intervention of  O. basilicum on  S. platensis improved the total phenol and phycocyanin content and there is potential for a pharmaceutical product for a functional food and pharmaceutical product.

Polysaccharides as wall materials in spray-dried microencapsulation of bioactive compounds: Physicochemical properties and characterization

Natural bioactive compounds (BCs) are types of chemicals found in plants and certain foods that promote good health, however they are sensitive to processing and environmental conditions. Microencapsulation by spray drying is a widely used and cost-effective approach to create a coating layer to surround and protect BCs and control their release, enabling the production of high functional products/ingredients with extended shelf life. In this process, wall materials determine protection efficiency, and physical properties, bioavailability, and storage stability of microencapsulated products. Therefore, an understanding of physicochemical properties of wall materials is essential for the successful and effective spray-dried microencapsulation process. Typically, polysaccharide-based wall materials are generated from more sustainable sources and have a wider range of physicochemical properties and applications compared to their protein-based counterparts. In this review, we highlight the essential physicochemical properties of polysaccharide-based wall materials for spray-dried microencapsulation of BCs including solubility, thermal stability, and emulsifying properties, rheological and film forming properties. We provide further insight into possibilities for the chemical structure modification of native wall materials and their controlled release behaviors. Finally, we summarize the most recent studies involving polysaccharide biopolymers as wall materials and/or emulsifiers in spray-dried microencapsulation of BCs.

Fabrication and characterization of gum arabic- and maltodextrin-based microcapsules containing polyunsaturated oils

BACKGROUND

Polyunsaturated oils have various health-promoting effects, however, they are highly prone to oxidation. Encapsulation using biopolymers is one of the most effective strategies to enhance oil stability. This research examined the potential of gum arabic and maltodextrin for microencapsulation of omega-3 rich oils, aiming to enhance encapsulation efficiency and stability of encapsulated oil.

RESULTS

We encapsulated fish and flaxseed oils by emulsification-spray drying. Spray-dried microcapsules were prepared by oil-in-water emulsions consisting of 10 wt% oil and 30 wt% biopolymer (gum arabic, maltodextrin, or their mixture). Results showed that both microcapsules were spherical in shape with surface shrinkage, and exhibited amorphous structures. Gum arabic-based microcapsules had higher encapsulation efficiency as well as better storage stability for both types of oil. Flaxseed oil microcapsules generally had higher oxidative stability regardless of the type of wall material.

CONCLUSIONS

Through a comprehensive characterization of the physical and chemical properties of the emulsions and resulting microcapsules, we proved gum arabic to be a more effective wall material for polyunsaturated oil microencapsulation, especially flaxseed oil. This study provides a promising approach to stabilize oils which are susceptible to deterioration, and facilitates their wider uses as food and nutraceutical products. © 2021 Society of Chemical Industry.

Development of chitosan based microencapsulated spray dried powder of tuna fish oil: oil load impact and oxidative stability

The impact of fish oil concentration on the oxidative stability of microcapsules through the spray drying process using chitosan and maltodextrin as wall material was studied. Emulsions were prepared with different Tuna fish oil (TFO) content (TFO-10%, TFO20%, TF030% TF0-40%) while wall material concentration was kept constant. Microencapsulated powder resulting from emulsion prepared with high fish oil load have high moisture content, wettability, total oil and low encapsulation efficiency, hygroscopicity and bulk tapped density. Oxidative stability was evaluated periodically by placing microcapsules at room temperature. Microcapsules prepared with TFO-10% presented high oxidative stability in terms of peroxide value (2.94±0.04) and anisidine value (1.54±0.02) after 30 days of storage. It was concluded that optimal amounts of fish oil for microencapsulation are 10% and 20% using chitosan and maltodextrin that extended its shelf life during study period.

Application of wool keratin: an anti-ultraviolet wall material in spray drying

Low-molecular-weight keratin (LMWK) obtained from wool was employed as a wall material for the spray drying encapsulation of fish oil. Microcapsules with different LMWK contents were prepared, and their anti-ultraviolet performance and other features were studied. The results showed that LMWK was able to improve the encapsulation efficiency of fish oil because of its good emulsifying properties. When the LMWK content was increased from 0 to 10, 30 and 50%, the shelf life of the microcapsules under ultraviolet irradiation increased from 48 to 96 h, 144 h and 168 h, respectively. The strongest absorption efficiency of LMWK is shown in the UVc band. The chemical structure of LMWK did not change during an ultraviolet accelerating ageing test.

Advancements in liposome technology: Preparation techniques and applications in food, functional foods, and bioactive delivery: A review

Liposomes play a significant role in encapsulation of various bioactive compounds (BACs), including functional food ingredients to improve the stability of core. This technology can be used for promoting an effective application in functional food and nutraceuticals. Incorporation of traditional and emerging methods for the developments of liposome for loading BACs resulted in viable and stable liposome formulations for industrial applications. Thus, the advance technologies such as supercritical fluidic methods, microfluidization, ultrasonication with traditional methods are revisited. Liposomes loaded with plant and animal BACs have been introduced for functional food and nutraceutical applications. In general, application of liposome systems improves stability, delivery, and bioavailability of BACs in functional food systems and nutraceuticals. This review covers the current techniques and methodologies developed and practiced in liposomal preparation and application in functional foods.

Introducing nano/microencapsulated bioactive ingredients for extending the shelf-life of food products

The shelf-life of foods is affected by several aspects, mainly chemical and microbial events, resulting in a considerable decline in consumer's acceptance. There is an increasing interest to substitute synthetic preservatives with the plant-based bioactive ingredients which are safe and natural. However, full implementation of this replacement is postponed by some challenges associated with bioactive ingredients, including their low chemical stability, off-flavor, low solubility, and short-term effectiveness. Encapsulation could overcome these limitations. The present review explains current trends in applying natural encapsulated ingredients for food preservation based on a classified description including essential oils, plant extracts, phenolics, carotenoids, etc. and their application for extending food shelf-life mostly dealing with antimicrobial, ant-browning and antioxidant properties. Encapsulation techniques, especially nanoencapsulation, is a promising strategy to overcome their limitations. Moreover, better results are obtained using a combination of proteins and polysaccharides as wall materials than single polymers. The encapsulation method and type of encapsulants highly influences the releasing mechanism and physicochemical properties of bioactive ingredients. These factors together with optimizing the conditions of encapsulation process leads to a cost-effective and well encapsulated ingredient which is more efficient than its free form in shelf-life improvement. It has been shown that the well-designed encapsulation systems, finally, boost the shelf-life-promoting functions of the bioactive ingredients, mostly due to enhancing their solubility, homogeneity in food matrices and contact surface with deteriorative agents, and providing their prolonged presence over food storage and processing via increasing the thermal and processing stability of bioactive compounds, as well as controlling their release on food surfaces, or/and within food packages. To this end and given the numerous wall and bioactive core substances available, further studies are needed to evaluate the efficiency of many encapsulated forms of both conventional and novel bioactive ingredients in food shelf-life extending since the interactions and anti-spoiling behaviors of the ingredients in various encapsulation systems and foodstuffs are highly variable that should be optimized and characterized before any industrial application.

Encapsulation of isoflavone with milk, maltodextrin and gum acacia improves its stability

This study was carried out for extraction of soy isoflavones and entrapment of the isoflavones so obtained into whole milk via encapsulation techniques. Three different solvent (ethanol, methanol and acetonitrile) were used for the extraction of isoflavone using three stage of extraction. The extracted isoflavone was encapsulated into 200 ml of whole milk by spray drying using different concentrations of gum acacia (4, 6 and 8% w/v) and 10% w/v maltodextrin DE 18. The ratio between cores to coating materials was 1:10. Though acetonitrile extracted higher amount of isoflavone, ethanol was selected for subsequent studies of extraction of isoflavone, as per the legislations regarding use of Food-grade solvents. There was no significant difference (p > 0.5) among all three samples 4% gum acacia+10% maltodextrin (A), 6% gum acacia+10% maltodextrin (B) and 8% gum acacia+10% maltodextrin (C) in terms of moisture content and hygroscopicity. However, insolubility index showed that sample A possessed a higher solubility index. Encapsulation techniques suggested that sample A showed higher encapsulation efficiency than others. Statistical analysis suggested that there was no significant difference among samples A, B and C during storage at 4°C for the time period (30 days) studied, in terms of isoflavone retention rate. However, samples stored at 25 and 37°C showed significant difference in the retention rate. Among all the three samples, sample B showed significantly lower isoflavone degradation rate of 3.80, 4.07 and 4.70 × 10-3/day at 4, 25 and 37°C, respectively. The highest amount of isoflavone degradation was observed at 37°C. Results indicate that isoflavone can be encapsulated using a combination of gum acacia either 4 or 6% w/v and 10% maltodextrin along with milk proteins at 4°C for longer shelf life.

Fish oil/lycopene microcapsules as a source of eicosapentaenoic and docosahexaenoic acids: a case study on spreads

BACKGROUND

The consumption of omega-3 fatty acids has many beneficial effects for human health, but the intake of foods rich in these fatty acids is not enough to achieve the recommended quantity per person and per day, and their direct addition in foods cause oxidation and unacceptable rancidity and off-flavor. Taking account of all these aspects, this study was aimed to develop stable microcapsules of fish oil (omega-3 polyunsaturated fatty acids) and lycopene (antioxidant) and to investigate their effect on different spreads.

RESULTS

The inclusion of different proportions of lycopene in fish oil did not show great benefits in the quality characteristics of emulsions and microcapsules. After the addition of fish oil and fish oil + lycopene microcapsules to dry-cured ham and cheese spreads, no significant differences were found in the proximal composition and oxidative stability, whereas fatty acids composition and sensory analysis were influenced. The eicosapentaenoic and docosahexaenoic acids content increased with the fish oil content in both products, but it decreased significantly after storage in the cheese spreads. Addition of microcapsules did not significantly influence on quantitative-descriptive and acceptability sensory analyses in dry-cured spreads, but it negatively affected the flavor of cheese spreading creams.

CONCLUSION

There is no need to add antioxidants to improve the stability of the fish oil microcapsules in the present study, which are appropriate as eicosapentaenoic acid and docosahexaenoic acid vehicles to enrich meat-derived spreading creams. © 2019 Society of Chemical Industry.

Evaluating the use of fish oil microcapsules as omega-3 vehicle in cooked and dry-cured sausages as affected by their processing, storage and cooking

This work evaluated the use of monolayered (Mo) and multilayered (Mu) fish oil microcapsules as vehicles of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in cooked and dry-cured meat products as affected by the storage and culinary heating or dry-cured processing. Proximate composition, oxidation, EPA and DHA quantity, acceptability and morphology were evaluated. Mo and Mu microcapsules increased the quantity of EPA and DHA, leading to cooked and dry-cured products susceptible to be labeled as "source of omega-3 fatty acids", without influencing physico-chemical characteristics, oxidative stability, acceptability or usual changes that take place during the culinary heating or dry-cured processing. The storage at refrigeration influenced on usual modifications on lipid oxidation and hedonic scores, but overall quality of the meat products enriched seems not to be impaired after storing. Thus, it could be indicated the viability of Mo and Mu as vehicles to enrich meat products subjected to low and high temperature for manufacturing, storage at refrigeration and culinary heating.

Advances in Spray-Drying Encapsulation of Food Bioactive Ingredients: From Microcapsules to Nanocapsules

Many natural food bioactive ingredients are sensitive to processing and environmental conditions and thus it is necessary to improve their stability to create products with long shelf lives. Encapsulation by spray drying is a widely used economical strategy to tackle this issue, and many scientists and manufacturers are using it in their research, development, and production activities. In this review, the spray-drying process is described, as are recent trends in the encapsulation of fish oils, essential fatty acids, probiotics, phenolic compounds, and natural food colorants. The formulation and process conditions used in previous research and the results obtained are tabulated. Also, new innovations in bioactive encapsulation using nano-spray drying are described.

Co-microencapsulation of Lactobacillus plantarum and DHA fatty acid in alginate-pectin-gelatin biocomposites

The aim of this study was to investigate the co-microencapsulation of Lactobacillus plantarum and DHA-rich oil in a novel gastrointestinal-resistant biocomposite composed of alginate, pectin and gelatin. The optimal biocomposite consisted of 1.06% alginate, 0.55% pectin and 0.39% gelatin showed 88.66% survivability of the microencapsulated cells compared to the free cells (50.36%). In addition, co-microencapsule containing probiotic and DHA fatty acid was synthesized and physicochemically analyzed using SEM, FTIR, TGA, XRD. The results from SEM clearly confirmed that cells were completely entrapped in the matrix and DHA increased smoothness and compactness of the surface of the particles. FTIR spectra revealed the formation of hydrogen and Van der Waals bonds between macromolecules and the core materials. X-ray pattern of co-microencapsules identified amorphous structure compared to capsules containing only DHA or probiotic. TGA analysis revealed the thermal stability of DHA-loaded capsules compared to un-loaded ones.

Barley β-d-glucan - modified starch complex as potential encapsulation agent for fish oil

The aim of the study was to examine physicochemical characteristics of fish oil microcapsules produced at different temperatures and estimate the optimal ratio of BG, CS and spray drying temperature. Only the interaction between spray drying and β-d-glucan content played a significant role in influencing the encapsulation efficiency and spray drying itself (p ≤ 0.001 and p ≤ 0.05). Temperature played a significant role in increasing particle size as well, but the coefficient for this parameter was lower (0.179). The observed differences in particle size of microcapsules could be caused by the differences in glass transition temperature of the polymers (β-d-glucan and modified starch) used as wall material. It could be seen that the lowest TBARS content was observed when the β-d-glucan in the wall material was at relatively high level (85%) with moderate temperature applied (154 °C) - 0.56 mg of malonaldehyde/kg of powder. The highest amount of EPA was present in the sample with 50% share of β-d-glucan and spray dried in 150 °C (10.22 ± 0.24). After examination of all runs of the experiment, we have made optimization study to obtain the wall material composition and spray drying temperature values which will be most appropriate for fish oil encapsulation.

Encapsulation of omega 3-6-9 fatty acids-rich oils using protein-based emulsions with spray drying

With an increased awareness of the link between the consumption of omega 3-6-9 fatty acid-rich oils and health, the food industry has been developing innovative strategies for raising their levels within the diet. Microencapsulation is one approach used to protect those oils from oxidative deterioration and to improve their ingredient properties (e.g., handling and sensory). Spray drying is the most commonly used technique to develop microcapsules. The preparation of protein-stabilized emulsions is a fundamental step in the process in order to produce microcapsules with good physical properties, effective protection and controlled release behaviors. This review describes types of emulsions prepared by animal and plant proteins, discusses the relationship between emulsion properties and microcapsule properties, and identifies key parameters to evaluate physical properties (e.g., moisture content, water activity, particle size, surface oil and entrapment efficiency), oxidative stability and release behavior of spray-dried microcapsules for industrial application.

Stability and in vitro release behaviour of encapsulated omega fatty acid-rich oils in lentil protein isolate-based microcapsules

The objective of this study was to investigate the use of a lentil protein isolate-based microcapsule design as a platform for entrapping different types of omega fatty acid-rich oil (e.g. canola, fish and flaxseed oils) and to characterise differences in the physical properties (e.g. moisture content, water activity, colour, wettability, particle size, surface oil and entrapment efficiency), storage stability and in vitro release behaviour of the entrapped oils. All microcapsules displayed similar physical properties regardless of the core material. Free fatty acid content, peroxide value, 2-thiobarbituric acid reactive substances and accelerated oxidation test were investigated between the free and encapsulated oils to determine protective effects from microencapsulation and found the wall material provided the greatest protective effect to the fish oils relative to the others. Based on an in vitro release assay, it was proposed that different intrinsic properties of fatty acids (e.g. polarity, conformation, chain length and number of double bonds) led to different release properties under simulated conditions. For instance, more encapsulated canola oil (∼8.9%) was released within simulated gastric fluid, whereas more encapsulated fish oil (∼73.4%) was released within simulated gastrointestinal fluids. Overall, the capsule design used in this study could be potentially used as a universal platform to deliver more healthy oils.

Design of experiments for microencapsulation applications: A review

Microencapsulation techniques have been intensively explored by many research sectors such as pharmaceutical and food industries. Microencapsulation allows to protect the active ingredient from the external environment, mask undesired flavours, a possible controlled release of compounds among others. The purpose of this review is to provide a background of design of experiments in microencapsulation research context. Optimization processes are required for an accurate research in these fields and therefore, the right implementation of micro-sized techniques at industrial scale. This article critically reviews the use of the response surface methodologies in pharmaceutical and food microencapsulation research areas. A survey of optimization procedures in the literature, in the last few years is also presented.

Improving functional properties of pea protein isolate for microencapsulation of flaxseed oil

Unhydrolysed pea protein (UN) forms very viscous emulsions when used at higher concentrations. To overcome this, UN was hydrolysed using enzymes alcalase, flavourzyme, neutrase, alcalase-flavourzyme, and neutrase-flavourzyme at 50 °C for 0 min, 30 min, 60 min, and 120 min to form hydrolysed proteins A, F, N, AF, and NF, respectively. All hydrolysed proteins had lower apparent viscosity and higher solubility than UN. Foaming capacity of A was the highest, followed by NF, N, and AF. Hydrolysed proteins N60, A60, NF60, and AF60 were prepared by hydrolysing UN for 60 min and used further for microencapsulation. At 20% oil loading (on a total solid basis), the encapsulated powder N60 had the highest microencapsulation efficiency (ME = 56.2). A decrease in ME occurred as oil loading increased to 40%. To improve the ME of N60, >90%, UN and maltodextrin were added. Flowability and particle size distribution of microencapsulated powders with >90% microencapsulation efficiency and morphology of all powders were investigated. This study identified a new way to improve pea protein functionality in emulsions, as well as a new application of hydrolysed pea protein as wall material for microencapsulation.

Microencapsulation of fish oil using supercritical antisolvent process

In order to improve the encapsulation process, a newly supercritical antisolvent process was developed to encapsulate fish oil using hydroxypropyl methyl cellulose as a polymer. Three factors, namely, temperature, pressure, and feed emulsion rate were optimized using response surface methodology. The suitability of the model for predicting the optimum response value was evaluated at the conditions of temperature at 60°C, pressure at 150 bar, and feed rate at 1.36 mL/min. At the optimum conditions, particle size of 58.35 μm was obtained. The surface morphology of the micronized fish oil was also evaluated using field emission scanning electron microscopy where it showed that particles formed spherical structures with no internal voids. Moreover, in vitro release of oil showed that there are significant differences of release percentage of oil between the formulations and the results proved that there was a significant decrease in the in vitro release of oil from the powder when the polymer concentration was high.

Comparative Study on Different Drying Methods of Fish Oil Microcapsules

Microencapsulation is widely used to minimize the oxidation of fish oil products. This study compared the effects of different drying methods, for example, spray drying (SD), freeze drying (FD), and spray freeze drying (SFD) on the microencapsulation of fish oil. Spray drying (SD) is the most common method for producing fish oil microcapsules, and it has low operation cost and short processing time, while the product yield and quality are poor. Freeze drying (FD) can be used to produce oil microcapsules with high quality, but it takes long time and high overall cost for drying. Spray freeze drying (SFD) is a new method for the preparation of microcapsules, which combines the SD and FD processes to obtain high quality powder. The yield of powder reached 95.07% along with porous structure by SFD. The stability and slow-release property of SFD products were better than those of SD and FD, which showed that SFD improved product storage stability and potential digestibility.