Astaxanthin from Haematococcus pluvialis Microencapsulated by Spray Drying: Characterization and Antioxidant Activity

Astaxanthin (AX) is an unstable functional food ingredient. A stable AX powder was developed and its characteristics (such as moisture content, bulk density, solubility, repose angle, and morphology) and antioxidant activity were evaluated. The microencapsulated AX powder was produced by spray drying using maltodextrin (MD)–gelatin and the parameters were optimized by response surface methodology. The results revealed that an optimal microencapsulation process has a ratio of MD to gelatin of 2.1:1, a ratio of wall to core materials of 5.9:1, and a ratio of glycerol monostearate to sucrose fatty-acid ester of 1.1:1. The AX encapsulation yield and encapsulation efficiency were 38.02% and 71.76%, respectively. AX microcapsules had a lower moisture content and bulk density, greater solubility, and good flowability. AX microcapsules showed antioxidant activities greater than Vitamin C, which indicated that the antioxidant activity of AX was not lost. AX microcapsule micrographs showed almost no cracks or fissures on the surface of microcapsules produced by spray drying under the optimal conditions.     

Properties and Stability of Spray-Dried and Freeze-Dried Microcapsules Co-Encapsulated with Fish Oil,Phytosterol Esters,and Limonene

The objectives of this study were to investigate the properties and stability of microcapsules containing fish oil co-encapsulated with phytosterol ester and limonene, prepared by spray-drying and freeze-drying methods. Whey protein isolate and soluble corn fiber were used as wall materials in the encapsulation process. The properties of microcapsules, including structure, glass transition, volatile/non-volatiles retention, microencapsulation efficiency, oxidation stability, color measurement, and sensory profiles, were evaluated after drying and during a seven-day accelerated storage trial. The finding reveals that drying methods have an effect on the retention of volatile fraction and the physical structure of the wall matrix consisted of WPI and SCF, consequently influencing the storage stability of the powders. Significantly higher retention of volatile fraction (p < 0.05) and lower surface oil were found in the spray-dried samples, resulting in the higher microencapsulation efficiency. However, samples dehydrated by both methods have good redispersion properties, showing no statistical significance (p > 0.05). The oxidation of the encapsulated oils was comparable for both spray- and freeze-dried samples during the seven-day accelerated storage trial but the loss of limonene flavor was significantly higher in the freeze-dried samples (p < 0.05). Sensory evaluation indicated that the addition of limonene could mask the unpleasant fishy odor in the co-encapsulated microcapsules. Overall, freeze drying did not produce powders with superior properties and did not show better protection towards the core materials than spray drying.     

Mechanisms of Drylng of Skin-Forming Materials; the Significance of Skin Formation and a Comparison Between Three Types of Material

Comparisons are drawn between the drying characteristics, and the mechanisms of skin formation on, three characteristic types of material. The significance of skin formation, which may be a major factor in valatiles retention in the drying of spray dried products, is discussed. The optimum drying conditions to achieve the highest volatiles retention for each type of skin-forming material are predicted. General comparisons are also drawn between the drvine of skin-formine i.e., materials which form a smooth flexible low- parosity skin at same slage, and normal crust-forming materials. The latter form only a rigid crust with a porosity which is system and drying-condition dependent.     

Encapsulation of bioactive compounds through electrospinning/electrospraying and spray drying: A comparative assessment of food-related applications

Spray drying and electrohydrodynamic processes, namely, electrospinning and electrospraying, are the most promising encapsulation technologies for entrapping and effectively delivering bioactive compounds. Encapsulation is used by the food industry to incorporate such compounds into different food matrices, protect them from adverse environmental conditions, and thereby increase the product shelf life and maintain the health-promoting properties of the composite formulation. This review provides a succinct discussion on the potential of food ingredient-based applications of spray drying and electrohydrodynamic processes on encapsulation as well as the principles and the parameters that affect the structure–morphology of the carrier matrix and the encapsulation efficiency of the process.     

Mechanisms of Drylng of Skin-Forming Materials; the Significance of Skin Formation and a Comparison Between Three Types of Material

ABSTRACT

Comparisons are drawn between the drying characteristics, and the mechanisms of skin formation on, three characteristic types of material. The significance of skin formation, which may be a major factor in valatiles retention in the drying of spray dried products, is discussed. The optimum drying conditions to achieve the highest volatiles retention for each type of skin-forming material are predicted. General comparisons are also drawn between the drvine of skin-formine i.e., materials which form a smooth flexible low- parosity skin at same slage, and normal crust-forming materials. The latter form only a rigid crust with a porosity which is system and drying-condition dependent.     

A New Technique for Spray-Dried Encapsulation of Lycopene

A new technique for lycopene microencapsulation by spray drying using dehumidified air as the drying medium was developed and the optimum operating conditions for encapsulation efficiency were determined. A pilot-scale spray dryer was employed for the spray-drying process. The modification made to the original design consisted of connecting the dryer inlet air intake to an absorption air dryer. The dextrose equivalent (DE) of maltodextrin, ratio of core to wall material, feed temperature, inlet air temperature, drying air flow rate, and compressed air flow rate were the factors investigated with respect to encapsulation efficiency. The resulting microcapsules were evaluated in terms of moisture content, bulk density, rehydration ability, lycopene isomerization, and storage stability. The optimum operating conditions were found to be as follows: ratio of core to wall material, 1:3.3; feed temperature, 52°C; inlet air temperature, 147°C. Under these conditions, the maximum encapsulation efficiency was about 93%. The use of dehumidified air was proven to be an effective way of increasing lycopene encapsulation efficiency.     

A method for pomegranate seed application in food industries: Seed oil encapsulation

During the industrial processing of pomegranate, large volumes of industrial wastes (seeds, peels, leaves) are produced, which have a wide range of nutritional values. In this work, a new method for pomegranate seed application in food industries was developed based on the extraction of seed oil and its subsequent encapsulation by spray drying. Skimmed milk powder was used as encapsulating agent. Ratio of core to wall material, feed solids concentration, inlet air temperature, and drying air flow rate were the factors investigated with respect to encapsulation efficiency using a central composite design. The resulting microcapsules were evaluated in terms of moisture content, particle size, bulk density, and hygroscopicity. The optimum operating conditions were found to be: ratio of core to wall material, 1/9; feed solids concentration, 30% (w/w); inlet air temperature, 187 °C; drying air flow rate, 22.80 m³/h. Under these conditions, the maximum encapsulation efficiency was about 95.6%.     

益生菌在喷雾干燥过程中的活性变化与保护策略

肠道菌群对于人体健康具有重要影响。口服足量的活性益生菌,有助于缓解急慢性肠炎、治疗腹泄、改善消化,已在临床治疗中得到一定应用。在食品市场上,益生菌干粉制剂亟需一种生产成本低、制粉简便的生产方法。喷雾干燥的生产能力强、制粉快速,但干燥过程中,雾化液滴经历一个快速升温与脱水过程,对其中的益生菌带来热胁迫、脱水胁迫、氧化胁迫等多种不利因素,造成菌体活性的大量损失。而喷雾干燥塔的结构,使塔内的液滴干燥过程难以追踪,不利于研究益生菌的失活历程以及探索益生菌与载体材料间的相互作用。本文从雾化液滴在干燥塔内的干燥历程着眼,回顾了益生菌活性随液滴干燥动力学变化的趋势,讨论了益生菌在喷雾干燥中经受的亚细胞结构损伤与功能性损伤,并系统总结了目前文献中报道的提升干燥后益生菌活性的主要方法,包括提升菌体耐受性、优化喷雾干燥条件和采用合适的保护性载体,并着重阐述了载体材料与益生菌细胞间的相互作用关系以及干燥历程的重要影响。文章指出为最大程度上保存喷雾干燥粉末中益生菌的活性,应综合微生物、干燥过程与食品化学（材料学）等领域的保护策略,设计一体化统合生产方案。依据微生物-保护载体间的相互作用设计高效保护配方载体,研发统合从微生物细胞培养至粉末储藏的新型生产工艺,是实验室及工业中合理设计工业级喷雾干燥过程、大量生产高活性益生菌制剂的关键。     

Microencapsulation of extra‐virgin olive oil by spray‐drying: Influence of wall material and olive quality

Encapsulation is a process by which small particles of core products are packaged within a wall material to form microcapsules. One common technique to produce encapsulated products is spray‐drying which involves the conversion of liquid oils in the form of an emulsion into dry powders. Emulsification conditions, wall components, and spray‐drying parameters have been optimized for the microencapsulation of different extra‐virgin olive oils. To achieve this goal, the influences of emulsion conditions have been evaluated for different wall components such as proteins (sodium caseinate and gelatin), hydrocolloids (Arabic gum), and hydrolyzed starches (starch, lactose, and maltodextrin). In addition, for each of the tested conditions the ratio of wall solid‐to‐oil and spray‐drying parameters were as well optimized. The microencapsulation effectiveness was determined based on process yield and the ratio between free and encapsulated oil (microencapsulation efficiency). Highest encapsulation yields were achieved when gelatin, Arabic gum and maltodextrin and sodium caseinate and maltodextrin were used as encapsulation agents and the ratio of wall solid‐to‐oil was 1:4 and 1:2, respectively. Under these conditions, 53% of oil was encapsulated. The influence of olive oil quality in the microencapsulation process was evaluated in terms of fatty acids profile alteration after the microencapsulation process.     

Effect of process conditions on the microencapsulation of coffee oil by spray drying

Microencapsulation is a good alternative to transform liquid food flavourings, such as coffee oil, into stable and free-flowing powders. Thus the aim of this study was to evaluate the influence of process conditions on the microencapsulation of coffee oil by spray drying, using gum Arabic as encapsulating agent. The effect of total solid content (10–30%), oil concentration with respect to total solids (10–30%) and inlet air temperature (150–190 °C) on the encapsulation efficiency, oil retention, moisture content and powder hygroscopicity were evaluated by a complete 2³ central composite rotatable design. Both encapsulation efficiency and oil retention were negatively influenced by oil concentration and inlet air temperature, and positively affected by total solid content, which could be related to the emulsion viscosity and droplet size. Particles produced at the optimized process conditions (30% of total solids, 15% of oil with respect to total solids and inlet air temperature of 170 °C) were evaluated for oxidative stability and showed to be stable during storage at 25 °C, but not at 60 °C. At this temperature, pure oil presented higher lipid oxidation than encapsulated, confirming the protective effect of microencapsulation on the oxidative stability of this product.     

Encapsulation of Orange Essential Oil in a Spout-Fluid Bed Dryer with a Draft Tube on a Bed of Inert Solids

Encapsulation of orange essential oil in modified starch (N-Lok) was performed in a spout-fluid bed dryer with a draft tube (SFB) on a bed of inert solids under different operating conditions. The essential oil retention and encapsulation efficiencies were determined and compared with those obtained in a spray-drying encapsulation process. The results showed that, in general, both SFB efficiencies were lower than those obtained in the spray dryer; however, it was observed that most of the essential oil remaining in the SFB was encapsulated (94% compared with 70% for the spray dryer). The formation of particles with thicker encapsulation walls in the SFB provided better protection of the orange essential oil than that achieved in spray drying.     

Encapsulation and delivery of bioactive compounds using spray and freeze-drying techniques: A review

Abstract

There are various bioactive components exist in plants, fruits, and vegetable origins that have many beneficial health effects (mainly antioxidant). However, they suffer from low-stability against the environmental condition. Thus, the encapsulation approach emerged to decrease their sensitivity and present a target delivery system. Generally, native carrier agents (polysaccharides and proteins) are being applied to embed the core materials. Accordingly, many encapsulation methods have been developed to protect vulnerable components by these carriers. Spray and freeze-drying are common encapsulation methods with the ability of powder production. Both feed emulsion production and drying process factors substantially influence the core embedded within the carrier agents. Spray-drying is well-known to higher applicable and scalable encapsulation procedure in the food and pharmaceutical industries. It is predominantly related to its lower process costs. Nevertheless, its application is limited for more sensitive bioactive compounds due to hot-air drying exertion. In contrast, freeze-drying has been mostly used for thermo-sensitive ingredients. Its application is restricted by economic drawbacks for which long process time (24–48?h) is required. However, freeze-drying is adequately taken into an advantage in the encapsulation of therapeutic compounds since high-added value products will be produced so that bioactive compounds with higher biological activity are needed.     

MICROENCAPSULATION BY SPRAY DRYING

Spray drying technique has been widely used for drying heat-sensitive foods, pharmaceuticals, and other substances, because of the solvent rapid evaporation from the droplets, Although most often considered a dehydration process, spray drying can also be used as an encapsulation method when it entraps 'active' material within a protective matrix, which is essentially inert to the material being encapsulated. Compared to the other conventional microencapsulation techniques, it offers the attractive advantage of producing microcapsules in a relatively simple continuous processing operation. This chapter will present a brief overview of the main considerations involved in the application of spray drying for microencapsulation, with a special emphasis given to microencapsulation of volatile materials. The potential use of spray drying microencapsulation for pharmaceutical applications, particularly the preparation of microparticulate drug delivery systems, will also be discussed     

MICROENCAPSULATION BY SPRAY DRYING

Abstract

Spray drying technique has been widely used for drying heat-sensitive foods, pharmaceuticals, and other substances, because of the solvent rapid evaporation from the droplets, Although most often considered a dehydration process, spray drying can also be used as an encapsulation method when it entraps ‘active’ material within a protective matrix, which is essentially inert to the material being encapsulated. Compared to the other conventional microencapsulation techniques, it offers the attractive advantage of producing microcapsules in a relatively simple continuous processing operation. This chapter will present a brief overview of the main considerations involved in the application of spray drying for microencapsulation, with a special emphasis given to microencapsulation of volatile materials. The potential use of spray drying microencapsulation for pharmaceutical applications, particularly the preparation of microparticulate drug delivery systems, will also be discussed     

A comparative study on conventional and microwave-assisted extraction for microencapsulation of Garcinia fruit extract

(?)-Hydroxycitric acid (HCA) is the principal acid present in the fruit rinds of certain species of Garcinia and is reported to have various health benefits. However, HCA is highly hygroscopic in nature and becomes lactonised during evaporation and drying. To reduce the lactonisation of HCA, Garcinia cowa fruit extract was obtained through two different extraction techniques, autoclave and microwave-assisted extractions, and was then microencapsulated using whey protein isolate (WPI) and denatured whey protein isolate (DWPI) with a 1:1 wall-to-core ratio using a spray drying technique. The microwave-assisted extracts encapsulated with WPI and DWPI had higher free HCA and net HCA recovery than the autoclaved extract encapsulated with similar wall materials. Furthermore, the microwave-assisted extracts and the associated encapsulated samples had higher antioxidant activity than their counterparts. The encapsulation of the microwave-assisted extracts with both wall materials had little variations in their free (55.04 and 54.58% for WPI and DWPI, respectively) and net HCA recovery (84 and 82%) and antioxidant activity (13.3 and 13.6%), which signified a smaller influence of the wall materials. These results indicated that microwave-assisted extraction had a higher extraction efficiency, encapsulation efficiency and antioxidant activity with both wall materials.     

Microencapsulation of Flaxseed Oil by Spray Drying: Effect of Oil Load and Type of Wall Material

The objective of this work was to evaluate the effect of the type of wall material and the oil load on the microencapsulation of flaxseed oil by spray drying. Gum arabic, whey protein concentrate, and a modified starch were used to produce the microcapsules, each with four oil concentrations (10, 20, 30, and 40% oil, w/w, with respect to total solids), for a total of 12 tests. Initially, the feed emulsions were characterized for stability, viscosity, and droplet size. Then they were dried in a laboratory-scale spray dryer and the resulting particles were analyzed for encapsulation efficiency, lipid oxidation, moisture content, and bulk density. The increase in oil concentration led to the production of emulsions with larger droplets and lower viscosity, which directly affected powder properties, resulting in lower encapsulation efficiency and higher lipid oxidation. Among the three wall materials evaluated, the modified starch showed the best performance, with the highest encapsulation efficiency and lowest peroxide values.     

Effect of drying method and wall material composition on the characteristics of camellia seed oil microcapsule powder

Camellia seed oil (CSO) is one of the richest sources of oleic acid (75–80%) and it is considered to provide beneficial health effects to humans. However, its susceptibility to oxidative degradation prevents its widespread use in the food industry. This study was aimed to improve the stability of camellia seed oil by microencapsulation. CSO was microencapsulated using whey protein concentrate (WPC) and maltodextrin (MD) or starch sodium octenylsuccinate (SSOS) as wall materials. The produced oil-in-water emulsion was subsequently dehydrated to produce microcapsule powder using spray and freeze drying techniques, respectively. Various characteristics of oil-in-water emulsion and final microcapsule powder including particle size distribution, encapsulation efficiency, morphology, rheological properties of reconstituted emulsions, in vitro digestion behavior and oxidative stability were determined to investigate the effect of wall material composition and drying method on these microcapsule powder characteristics. The spray-dried powder had significantly higher bulk density and smoother surface compared to freeze-dried powder while the freeze-dried CSO microcapsule powder with WPC/SSOS as wall material had the highest encapsulation efficiency and the lowest surface oil. The subsequent in vitro digestion test suggested the microencapsulated CSO could be successfully controlled-released in the simulated gastric (10.28–13.03%) and the subsequent intestinal fluid (72.89–89.61%). Oxidative stability of camellia seed oil was significantly improved by microencapsulation. The freeze dried CSO microcapsule powder in WPC/SSOS wall material exhibited highest encapsulation efficiency (95.17%) and best oxidative stability (peroxide value and p-anisidine values of 3.57 meq/kg oil and 3.01, respectively, during the 45 days storage at 25°C.     

Microencapsulation of α-Amylase by Carrying Out Complex Coacervation and Drying in a Single Step Using a Novel Three-Fluid Nozzle Spray Drying

The aim of this research was to develop an enzyme encapsulation process in which both the complex coacervation and drying processes are combined into a single step. For this purpose, we used a novel three-fluid nozzle at the atomization step of spray drying. α-Amylase as a model enzyme was encapsulated by coacervation in calcium (Ca) alginate and Ca-alginate + chitosan shell matrices and the powder was obtained in a single step through spray drying. The single-step process was compared to carrying out the complex coacervation and drying processes in two steps using freeze drying, in which α-amylase was encapsulated by carrying out the complexation process in the above-mentioned shell matrices using the same three-fluid atomizer and collecting the coacervates, which were subsequently freeze dried. The results showed that the microcapsules obtained from the single-step encapsulation process (three-fluid nozzle spray drying) had smaller particle sizes, were less porous, and provided better enzyme stability compared to the microcapsules obtained by carrying out the complexation and drying in two steps and the single-step process was faster. It was observed that the egg-box structure was formed in both types of powder particles; however, the complexation with chitosan partially disrupted the formation of this structure. The three-fluid nozzle–based spray drying is a promising technology in which both the complex coacervation and drying processes can be carried out in a single step.     

Microencapsulated ginger oil properties: Influence of operating parameters

The objective of this study was to evaluate the influence of process conditions on the properties of ginger essential oil microencapsulated by spray drying, using whey protein isolate and inulin as encapsulating agents. The treatment with 30% addition in wall material resulted in the largest droplet size in the emulsion. The wettability, encapsulation efficiency, particle size, and polydispersity index were significantly affected by the two analyzed factors. Through the optimization process, the results indicate that moderate wall material concentrations (22.34%) and high inlet air temperature (170°C) were the best conditions for the ginger essential oil spray drying process.     

Agglomeration in Spray Drying Installations (The EDECAD Project): Stickiness Measurements and Simulation Results

Spray drying is used for the manufacture of many consumer and industrial products such as instant dairy and food products, laundry detergents, pharmaceuticals, ceramics, and agrochemicals. During spray drying, agglomerates of powder particles are formed that determine the instant properties of the powder. Agglomeration during spray drying is considered to be a difficult process to control. The main cause of this is the complex interaction of the process variables: the atomization process, the mixing of spray and hot air, the drying of suspension droplets, and the collision of particles, which might lead to coalescence or agglomeration. As a consequence, agglomeration during spray drying is operated by trial and error. In an EC-sponsored project, named the EDECAD project and coordinated by NIZO food research, an industrially validated computer model, using CFD technology, to predict agglomeration processes in spray drying machines is developed. A Euler-Lagrange approach with appropriate elementary models for drying, collision, coalescence, and agglomeration of the dispersed phase is used. The main result of the EDECAD project is a so-called design tool, which establishes relations between the configuration of the drying installation (geometry, nozzle selection), process conditions, product composition, and final powder properties. The design tool has been validated on pilot plant scale and industrial scale. This article presents the setup and results of dynamic stickiness tests and some CFD simulation and validation results.