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Condensed skim milk (CSM) was high pressure jet (HPJ) processed at 100–500 MPa and then spray dried to obtain skim milk powders (SMP-100 to SMP-500). Physical and instant properties of SMP-100 to SMP-400 were similar to those of the control. However, SMP-500 showed a higher apparent particle density (1.25 g cm−3) and a lower solubility (93.2%) compared to the control. A marked increase in foam expansion index (FEI) and foam volume stability index (FVSI) was observed for the reconstituted SMP-400 and SMP-500, with the latter showing a FEI > 110% and a FVSI > 85%, 8 h after foaming. Moreover, emulsions prepared with reconstituted SMP-500 showed a higher emulsion stability index (ESI) compared to other SMPs. The observed differences in interfacial properties of reconstituted SMP-400 and SMP-500 are consistent with HPJ-processed skim milk, which showed extensive pressure- and shear-induced casein micelle modifications.

State-space thermodynamic modeling of vanilla ethanolic extracts spray drying with heat pump and N 2 was developed. Thermodynamic modeling considers activity coefficients for Raoult law deviations of ethanol vapor pressure, water vapor pressure, ethanol evaporation latent heat and water evaporation latent heat in a N 2 -ethanol-water-vanilla solids system. State space considers 12 ordinary differential equations (ODEs) for ethanol and water concentrations in solid, N 2 and condensed liquid; temperatures and condensed liquid rate. The model was validated with 32 treatments of vanilla ethanolic extract experimentally spray dried with heat pump and N 2 . The mathematical model reproduced the experimental gas outlet temperature with 4% of averaged error. An additional two parameters fit reached 11.4% of averaged error with respect to product outlet moisture and gas outlet temperature simultaneously. Proposed model demonstrated that heat pump spray drying can reach a 58% of thermal efficiency and a conventional spray drying can reach only 30%.

Atomisation is an integral element of the spray-drying process, whereby a bulk liquid feed is converted to discrete droplets, greatly increasing the surface area of the feed liquid and thereby increasing considerably the achievable rates of evaporation of water. These droplets, through evaporation of water in the main dryer chamber, become individual powder particles during the spray-drying process. This review provides a comprehensive examination of the most recent developments in atomisation technology for spray-drying, with a particular focus upon dairy applications (e.g., skim and whole milk powders, casein- and whey-based powders, and fat-filled milk powders). As well as a review of principles of different technologies for atomisation, such as rotary atomisers, pressure nozzle atomisers, pneumatic atomisers, ultrasonic atomisers and electrospray atomisers, the industrial applicability and challenges in use of each approach to atomisation are presented. Approaches for monitoring the atomisation process and other factors that influence atomisation, such as feed composition and key process parameters, are considered to provide a holistic analysis of the atomisation process.

In the present work, five polysaccharides were selected as co-encapsulant of skim milk based matrix and used for the microencapsulation of Lactobacillus paracasei Lpc-37 by spray drying. The morphological characterization, physical properties, encapsulation efficiency, gastrointestinal simulation, and storage stability of microencapsules were examined to evaluate the protective capacity against the adverse conditions of the different wall matrices. Addition of polysaccharides was associated with the enhancement of physical performance of microencapsulated powders, such as the flowability and water activity. Encapsulation matrices containing gum Arabic showed the greatest encapsulation efficiency of 97.1% (maximum survival 7.78 log CFU/g). L. paracasei Lpc-37 encapsulated with the matrices incorporating sodium alginate or sodium carboxymethylcellulose exhibited higher survival (>6.5 log CFU/g) after exposed to simulated gastrointestinal condition and lower viability loss (

Date powder is a promising choice for replacement of white sugar in food formulation, especially due to its natural nutritious substances. In this research, for the first time, the impact of biopolymer complexes on microstructural properties of date powder was studied. So, effects of different concentrations of whey protein concentrate (WPC), pectin, and Tween 80 as well as pH values and temperatures on properties of date powder obtained by spray drying were surveyed through Taguchi approach. Drying yield and color of date powders were measured and microstructural characteristics of date powder were assessed by Fourier transform infrared, differential scanning calorimetry, and scanning electronic microscopy to detect critical changes, e.g. new emerging bonds, ascribed to different drying variables. High drying yield of 70% was achieved when WPC maximized and pH value kept at 5.0. Fourier transform infrared analysis revealed that the temperature of 170 °C and WPC level of 10% played crucial role in obtaining distinctive structure and hydrogen bonds between pectin and WPC of date powder. While glass transition temperatures of date powders were varied between 32.5 and 55.8 °C, higher glass transition temperatures seemed to be due to thermal shields caused by either film formation of WPC (in some treatments) or more protein-polysaccharide complex formation (in other treatments). Considering all parameters, 1% surfactant, 5% pectin, 10% WPC at drying temperature of 170 °C and pH value of 8.5 were determined as optimum values.

The effects of cheese age and addition of dairy ingredients on cheese powder properties have not been previously investigated. Hence, the effect of addition 2% sodium caseinate plus 2% buttermilk powder (B2S2) or 4% buttermilk powder (BMP) were evaluated. The addition of these ingredients led to a decrease of the Power Law consistency index in cheese feeds made from 16 to 30 weeks old Danbo cheeses. Powders containing B2S2 presented homogeneous particle size distributions, lower amount of free fat and better flowability, due to improved fat emulsification, confirmed by confocal laser microscopy. Powders with BMP presented higher browning index, cohesiveness and spontaneous primary agglomeration. These powders were also more sensitive to an increased temperature difference (ΔT) between inlet and outlet spray drying temperatures, causing more browning. Cheese powder properties could thus be significantly improved by addition of 2% SC plus 2% BMP, whereas no improvements were observed using only BMP.

This study aimed to evaluate the potential of β-cyclodextrin combination with different wall materials (gum arabic and sodium caseinate) in the microencapsulation of refined kenaf seed oil by spray drying. Three models of microcapsules were developed, including protein-based (β-cyclodextrin/sodium caseinate), carbohydrate-based (β-cyclodextrin/gum arabic) and mixed-based (β-cyclodextrin/gum arabic/sodium caseinate). The characteristics of the obtained microcapsules including moisture content, water activity, wettability, solubility, density, flowability, cohesiveness, bulk porosity, microencapsulation efficiency, particle size, surface morphology, and possible interactions between the oil and wall materials were evaluated. The moisture content and water activity were in the range of 2.7–3.9% and 0.2 to 0.3, respectively, which is suitable for long-term storage. The obtained microcapsules showed a particle size distribution (D[4,3]) of 25.4–37.3 μm. Scanning electron micrographs of microcapsules showed spherical shapes without any apparent cracking on the surfaces. Fourier transform infrared spectroscopy revealed that the oil was well encapsulated in the microcapsules. The highest microencapsulation efficiency was achieved for the carbohydrate-based microcapsule (95.3%), followed by the protein-based microcapsule (93.1%) and mixed-based microcapsule (90.0%). Three formulations offered high microencapsulation efficiency to encapsulate the refined kenaf seed oil in this study.

As popular coating material for encapsulation like milk proteins and maltodextrin do not fully mask unpleasant fish flavors, rice and whey protein blend was tested to aid the use of Baltic herring (BH) oil in functional foods. Particle size and morphology of emulsions (7.5% whey protein, 7.5% rice protein, 15% BH oil and water) produced at pH 3, 6 or 8 with one or two step homogenization and resulting powders were characterized together with fatty acid composition, volatile compounds and oxidative stability. The use of rice and whey proteins lead to stable emulsions with bimodal size distribution and large dispersion (0.05–100 μm). Emulsion's pH affected powder particle sizes, with pH 3 resulting in powders with biggest particle sizes. Morphology of powders showed spherical shape with porous structure. Emulsions with pH 6.5 produced powders with the highest induction periods (1.59–1.73 h) and low content of volatile compounds.

In the present study, peony seed oil was encapsulated using a combination of whey protein isolate, corn syrup and soy lecithin (0.75%) as wall materials by spray drying. This formulation exhibited highest encapsulation efficiency and oxidative stability and least loss of bioactive compounds. The microstructure showed the peony seed oil microcapsules formed a complete core-shell structure with smooth surface and no apparent cracks or fissures. In-vitro digestion behavior showed more than 80% of the encapsulated oil was released from microcapsules after simulated gastrointestinal digestion.

Refined kenaf seed oil was microencapsulated by spray drying using the wall materials of β-cyclodextrin (β-CD), gum arabic (GA), and sodium caseinate (SC) to produce three different models (SC:β-CD, GA:β-CD, GA:SC:β-CD) of microencapsulated refined kenaf seed oil (MRKSO). An in-vitro digestion was used to simulate the human gastrointestinal digestion to examine the oil release behavior of MRKSO, changes in antioxidant activity and bioactive compounds of undigested oil, digested oil, and digested MRKSO samples. The results showed that three models of the MRKSO offered good protection by a lower percentage of oil released (1.43–6.44%) in the simulated gastric fluid and a high percentage of oil released (81.10–91.19%) after simulated gastric and intestinal phases digestion. The degree of lipolysis was in the order of SC:β-CD > GA:SC:β-CD > GA:β-CD > un-encapsulated oil. Among three models of MRKSO, GA:SC:β-CD offered better bioaccessibility by showing an increase in DPPH (20.0% increase) and ABTS (5.0% increase) values, phenolic content (130.4% increase), tocopherol and tocotrienol contents (147.7% increase), as well as slower degradation of phytosterol contents (59.4% decrease) after in-vitro digestion, compared to the undigested kenaf seed oil.

International audience; A well-known probiotic strain, L. rhamnosus GG, was encapsulated by spray-drying in milk water insoluble matrices upon reconstitution in hot water by exploiting and controlling the clotting reaction of milk proteins during the process. The feed solution, composed of probiotic bacteria and milk proteins, was or not subjected to the action of chymosin, a proteolytic enzyme. To optimize microencapsulation efficiency, different outlet air temperatures were tested (55, 70 and 85 degrees C). After spray-drying, small microparticles were recovered for further characterization. All drying conditions led to excellent bacterial survival rates (

Changes of secondary structure and protein interactions of whey protein (WPs) present in native, sweet, acid and salty-WPCs were analyzed following storage at 4, 25 or 45 degrees C and 22 or 33% relative humidity for a period of 90-days. WPs aggregated predominantly through covalent crosslinking, achieving maximum at 45 degrees C and 33% RH. Greater participation of beta-lactoglobulin in covalent crosslinking was evident in all WPCs, while that of alpha-lactalbumin was significantly (p < 0.05) high in acid-WPC only. Reaction order of beta-LG denaturation in acid and salty-WPCs was approximately 2 while approximately 1 in native and sweet WPCs. Activation energy was significantly (p < 0.05) higher in native and sweet-WPCs, with averages recorded as 97 and 49.8 kJ mol(-1), respectively, than that in acid and salty-WPCs with averages of 27.5 and 33.8 kJ mol(-1), respectively, mainly attributed to inherently high concentrations of lactic acid and salts in these WPCs.

Flavor encapsulation was investigated by spray drying with dried Saccharomyces cerevisiae cells. The yeast cells, Saccharomyces cerevisiae, which were by-products in the production of β-glucan, were used in the encapsulation of d-limonene and ethyl hexanoate. Effects of incubation time, temperature, and spray drying conditions on the encapsulated flavor content after spray drying were investigated. The encapsulation rate constant was 0.69 h−1 for d-limonene and ethyl hexanoate. High contents of both flavors were obtained at an incubation temperature of 40 °C for 4 h and an inlet air temperature of 200 °C for spray drying. Inlet air temperature did not significantly affect encapsulation of flavor content for ethyl hexanoate. Flavor content obtained was 37 wt% for d-limonene and 49 wt% for ethyl hexanoate at an inlet air temperature 200 °C. Thus, yeast could be used as a successful flavor-encapsulant by spray drying.

Spray-drying and freeze-drying strategies were used to obtain novel protein powders from an aqueous combination of sodium caseinate and blackcurrant concentrate. The powders differed in physical and functional properties. The effects of incorporating these different novel protein powders into a cookie recipe at a replacement level of 0%, 5%, 10%, and 15% were evaluated in relation to the physicochemical and nutritional properties of cookies. Colour, and texture properties of the cookies, important factors for customer acceptance, changed (p

This study investigated the influence of injecting nitrogen (N2) gas under high pressure into milk protein concentrate (80%, w/w, protein; MPC) prior to spray drying and examining the physical and bulk handling properties of regular (non-agglomerated) and agglomerated powders. MPC powders produced using the N2 injection (NI) process had significantly lower bulk density and flowability, higher wall friction angles and increased levels of interstitial and occluded air. Agglomerated MPC powders had higher flow index values, lower wall friction angles, but were more friable, compared to regular powders. Surface composition analysis of MPC powders showed that NI caused fat to preferentially migrate to the surface in comparison to powders spray dried without NI. The results obtained in this study demonstrate that the injection of N2 into liquid MPC directly prior to spray drying, as well as agglomeration by fines return, can produce ingredients with unique particle and bulk powder properties.

Investigation was carried out to develop spray dried immunoglobulin-rich colostrum powder by employing suitable technological interventions based on rheological analysis. The microfiltration (MF) permeate of skim colostrum and colostrum whey were fractionated and concentrated by ultrafiltration to 2.03 and 2.38 fold to obtain skim colostrum retentate (SCR) and colostrum whey retentate (CWR), respectively. Their thermal gelation behaviour as affected by variations in pH, total solids and added thermal protectants were evaluated, using temperature sweep test and the data were utilized for the optimization of spray drying conditions. TGT for SCR and CWR was 72.2 °C and 74.5 °C. Based on TGT, the outlet air temperature was maintained in the range of 68–72 °C. Under optimized conditions of spray drying 88.5% of total Igs of feed were retained with excellent and acceptable insolubility indexes in powders. Other powder properties were comparable to freeze dried powder. Rheological analysis of protein-rich preparations could be adopted for optimizing the spray drying conditions without adversely affecting protein bioactivity and reconstitution properties.

In this study, various ohmic heating conditions and conventional heating were applied in the inulin extraction process from Jerusalem artichoke tuber (JAT) powder. The inulin extracts were evaporated to be around 30 °Brix and then spray-dried to be inulin powder. The main objectives were (1) to compare the quality of inulin extracts obtained from different extraction conditions and (2) to evaluate the yield of inulin powder production from JAT powder and the inulin powder quality. The results showed that the electrical conductivities of JAT powder solutions ranged between 0.0677 and 0.2057 S/m. The application of ohmic heating method at electrical frequency of 20 kHz and electrical field strengths of 15 and 20 V/cm could not raise the inulin extraction yield when comparing with the conventional heating. The addition of ultrasonic treatment step into the ohmic heating process could not escalate the extraction yield. The sugar and inulin contents in the extracts obtained from various ohmic heating treatments and conventional heating were not much different. The inulin contents of all extract samples were roughly in range between 75 and 80 g/100 g dry mass . The production yields of inulin powder from JAT powder were 14.53–17.29% which was rather low due to the loss of solids occurring in the extraction and spray drying processes. The scanning electron micrographs illustrated that the particle sizes of inulin powders produced in this study were much smaller than those of commercial inulin powders.

Spray-dried resistant starch powder (SD) containing 35% amylose-lipid complex and retrograded starch and having in vitro glycemic index (GI) of 63 was incorporated into white bread at either 20, 30 or 50% (w/w). Increased hardness and less porous structure of bread were noted as SD content increased. GI values of all bread samples containing SD were unexpectedly higher than that of the control white bread, either right after baking or after 1–4 days of storage; GI increased with increased SD content. X-ray diffraction patterns and Fourier transform infrared spectra revealed that double-helix amylopectin in SD experienced complete gelatinization at the baking temperature and hence the higher GI values of bread samples containing SD. Higher content of digestible starch in SD (~65%) also contributed to the higher GI values. Native A-type starch from wheat flour, on the other hand, partially remained in the control white bread, resulting in the lower GI value.

Spray-drying is an effective method in increasing the physicochemical stability and preserving the biological activities of bioactive compounds. However, shear tension and dehydration during spray-drying, and localization of peptides at the water/air interface, leads to their structural instability, thermal damage and loss of their biological activity. In the current research, fractionation of hydrolyzed flaxseed proteins to different molecular weights (10, 30 and 100 kDa) was performed. Then, the peptide fraction with highest antioxidant activity was selected and influence of surfactant (Tween-80) combined with maltodextrin (MD) on production yield, physical stability, antioxidant activity and morphological properties of microencapsulated particles was analysed. Antioxidant features of peptides were affected by their molecular weight and amino acid composition. Using surfactant + MD, significantly led to a lower hygroscopicity (from 42 to 23%), higher production yield (from 37 to 54%), and better retention of radicals-scavenging activity of DPPH (80.3%), ABTS (92.3%), hydroxyl (97.9%), nitric oxide (82.3%), reducing power (98.7%), total antioxidant activity (98.3%), chelating activity of iron (97.6%) and copper (97.5%) proxidants by spray-dried peptides. Also, the use of Tween-80 in feed formulation through competitive surface migration with peptides resulted in the production of spherical particles with relatively smooth surfaces, as revealed by SEM images. Therefore, surfactants can be used as a strategy to increase the biological stability of various food and pharmaceutical peptides during spray-drying encapsulation.

Glycerol monooleate (GMO) improves creaming stability in protein-stabilised emulsions but is unsuitable for direct aqueous applications due to its low solubility in water. Encapsulation could transform waxy solid GMO into a water-dispersible powder. This study assessed spray-drying to produce instantised GMO powders, and investigated emulsion formulation (GMO concentration (33.6%, 47.0%); dextrose equivalent (DE) values of maltodextrin (DE 10, 18)) on emulsion and powder properties. Results showed that all homogenised emulsions were suitable for spray-drying due to their high emulsion stability, monomodal droplet size distributions (150–180 nm) and low viscosity (20–65 mPa s). All instantised powders exhibited good dispersibility (65–90%) in water. The instantised powder with low GMO levels showed high encapsulation efficiencies (93–94%) with low surface oils (3%) and uniform droplet size distributions when reconstituted. Results demonstrated that spray-drying can successfully produce instantised powders for food applications to improve product quality.

Condensed skim milk was processed through a continuous, custom-made high pressure jet spray dryer system (HPJ-SD) at 100–500 MPa. The resulting skim milk powders (SMPs) were evaluated for physiochemical and structural properties. The 500 MPa SMP exhibited increased particle density (1.48 g/cm3) compared to the ≤300 MPa SMP (1.33 g/cm3), but particle size analysis reflected no significant differences between these samples with D[4,3] values of 10.8 μ (100 SMP) and 12.2 μ (500 SMP). The 500 MPa SMP also had a reduced solubility and increased protein surface coverage compared to the 100 MPa SMP. The viscosity of the reconstituted HPJ-SD SMPs (9% w/w) increased from 2.3 mPa s (100 MPa) to 6.0 mPa s (500 MPa). The foam stability of the 500 MPa reconstituted SMP was exceptional with a foam head that remained stationary for 8 h (FVSI of 100%), while the foam in the 100 MPa reconstituted SMP diminished almost entirely in 2 h (FVSI of 21.3%). Evaluation of emulsification ability for reconstituted SMPs (1:9 oil in 2% diluted reconstitute w/w) revealed a 1.6-fold reduction in destabilization rate for the 500 MPa SMP compared to the 100 MPa SMP. HPJ-SD powders have physiochemical properties that can be utilized in a variety of clean label applications including ice cream or specialty beverages (e.g., cappuccino coffee).

Tributyrin (TB) is a source of butyrate with the record of improving gastrointestinal tract (GI) health. The incorporation of TB in food is challenging because of its bitter taste and the need for a controlled release in the GI tract. Encapsulation of tributyrin with whey protein isolate using spray-drying will expand its application in food matrix. In this study, a novel three-fluid nozzle (3FN) for spray-drying was introduced to produce the microcapsules. The effect of two feed streams into 3FN, the emulsion composition in the inner channel and the concentration of the wall material in the outer channel was investigated. Surface oil, encapsulation efficiency, physical properties of the powders, and the stability of reconstituted emulsion were evaluated. All the properties were also compared with the corresponding samples produced with a two-fluid nozzle (2FN). The results showed that 3FN reduced the surface oil of microcapsules compared to 2FN. No significant difference was observed in surface morphology and internal structure of the powders according to SEM images. However, 3FN sample has a lower level of flocculation and coalescence of droplets when reconstituted and stored indicating the higher stability during the 24 h of refrigerated storage than 2FN samples. The results indicated that 3FN is a novel method to produce microcapsules. The results indicated that 3FN provides a new approach to modify the properties of spray-dried powders with two feeding channels.

This paper describes an approach to developing a predictive model for the spray drying of powder nutritional products, both infant and adult formulas, in order to optimize drying efficiency and avoiding the sticking of the powder on the dryer walls. The model is based on the glass transition temperature measurement by rheology method, and subsequent sticky point characterization of the products to set constrains for process variables which affect the drying efficiency and powder stickiness. Three different approaches are presented to characterize the products: 1) using theoretical data, 2) using experimental results based on laboratory tests, and 3) data from direct measurement of the dryer temperature and moisture sensors. Equations for variable manipulations to reach the target powder moisture content have also been developed. The developed models have been successfully applied in a real manufacturing environment, demonstrating how the sticky point model fits an industrial spray drying process and are a useful tool to improving efficiency and reduce quality issues related to powder properties.

This study investigated the stability of cranberry phenolics after spray drying (185 °C) and during storage, and their changes correlated with different wall materials (gum Arabic (GA), maltodextrins (M1, 10–13 DE; M3, 17–20 DE), and blend of GA and M1 (GAM1)). The storage trial was conducted at 4, 25 and 45 °C for 12 weeks. The total phenolic content (TPC), proanthocyanins and antioxidant capacity (AOC) increased after spray drying. The GMA1 powder achieved the highest recovery of TPC, anthocyanin (ANC) and AOC. During storage, the phenolics fluctuated and peaked at 8–10 weeks. Phenolic profiles of powders at week 0, 8 and 12 were studied to provide insight into the changes. Nineteen compounds were quantified using HPLC-DAD-MS/MS, with most of them showed great increases at week 8, in particular quercetin (increased up to 16.3 times). The results verified that the increase in TPC was due to decomposition of phenolic polymers. After storage of 12 weeks at 25 °C, the phenolic composition remained similar to the initial amount in all powders.

Vacuum spray drying is a new technique used to produce concentrated orange juice powder using maltodextrin as a drying agent. The dryer was developed for the low-temperature (40–50 °C) drying powderization of liquefied food using superheated steam (200 °C) as a heating medium. The physicochemical properties of orange juice powder with four different combinations of juice solids: maltodextrin solids at 60:40, 50:50, 40:60, and 30:70 were determined. The moisture content, hygroscopicity, water activity, particle size, particle morphology, color characteristics, rehydration and ascorbic acid retention were significantly affected by the maltodextrin concentration and drying conditions. Water sorption and the glass transition temperature of orange juice powder conditioned at various water activities were also evaluated. The obtained data were well fitted to both BET and GAB models. A strong plasticizing effect of water on Tg was able to predicted by the Gordon–Taylor model, where Tg was greatly reduced by the increasing moisture content of the powder.

The encapsulation of curcumin in whey protein microparticles by spray drying was done to improve solubility and thus, the bioavailability of curcumin. In solution, curcumin formed soluble complexes with whey protein isolate (WPI) via hydrophobic interactions and its solubility increased linearly with WPI concentrations. Solutions of WPI-curcumin complexes were spray-dried as uniform microparticles via a microfluidic jet spray dryer. Nearly 100% curcumin was retained in amorphous state and the microparticles could be easily rehydrated as transparent dispersions irrespective of the drying temperature. Antioxidant properties of these microparticles were studied by DPPH test, showing a higher DPPH radical scavenging activity for curcumin-loaded microparticles compared to that of WPI particles as benchmark. The ability to generate easily dissolved powders containing water-insoluble ingredients such as curcumin is a beneficial approach for pharmaceutical and functional foods applications.

Whey protein isolate-chlorophyll (WPI-CH) microcapsules at different WPI ratios via spray drying were created to improve water solubility and biological stability of chlorophyll. Samples at a higher ratio of WPI resulted in a lower moisture content (1.14 ± 0.12% to 2.47 ± 0.09%), higher chlorophyll encapsulation efficiency (98.34 ± 0.03% to 99.76 ± 0.02%) and greater chlorophyll solubility (79.29 ± 0.07% to 82.24 ± 0.03%). The results of fluorescence and FT-IR spectra showed that the pyrrole ring of chlorophyll became bound to the hydrophobic residues of WPI leading to a change in the crystalline structure of chlorophyll, probably due to the formation of soluble complexes of WPI-CH. In addition, the antioxidant activity of fresh WPI-CH samples, and those stored for 6 months, increased by 19.75% and 18.51% respectively compared to WPI (p

Concentrated extract of mate leaves obtained from the third stage of the freeze concentration process was microencapsulated with maltodextrin by spray drying. The effect of maltodextrin concentration (20%, 30%, and 40%) on the phenolic compounds, antioxidant activity, microencapsulation yield, morphology, particle size, moisture content, water activity, dissolution, hygroscopicity, color and thermal properties were investigated. The retention of phenolic compounds after microencapsulation by spray drying and the stability of the microcapsules at 4 °C for 45 days were also determined. It was possible to note an enhancement of the total phenolic content and antioxidant activity of mate leaves aqueous extract obtained through freeze concentration. The high concentrations of maltodextrin in the microcapsules promoted higher phenolic compounds microencapsulation yield, higher particle size and longer time required for the powders to dissolve in water, while moisture content, water activity and hygroscopicity decreased. The color parameters indicated that maltodextrin protected the microcapsules against heat during spray drying. The results of the thermoanalyses suggested an increase in the stability of the microcapsules. Besides, the microcapsules produced with maltodextrin showed better retention and enhanced stability at 4 °C for 45 days.

The spray drying process is considered a conventional method to convert liquids to powders with some but at an acceptable level of degradation and oxidation of volatile compounds. Spray drying is based on the preparation, homogenization, atomization, dispersion and subsequently dehydration of the solution. Wall deposition is a key processing problem in the spray dryer particles that indirectly affects the quality and quantity of the product. The degree of wall deposition is affected by several factors including operating parameters, type and size of spray dryer and the spray dryer wall properties. The development of wall depositions in the spray dryer deteriorates the yield of the products and hence increases the costs of manufacturing and maintenance. And constructive models are very resourceful in understanding the mechanism of wall deposition which will result in direct economic benefits to the food industry. The aim of this review is to give a physical and chemical description of the wall deposition mechanism and introduce the classified models to simulate and visualize this behavior in spray dryers.

Objectives of the present study were to spray dry high total solids content single layer (SL) and layer-by-layer (LBL) emulsions, and to compare the ability of the SL and LBL powders in preventing the loss of carotenoids upon storage in the vicinity of the glass transition temperature (T g ). Carotenoids stability in humidified spray dried (HSD), non-humidified freeze-dried (NHFD), and humidified freeze-dried (HFD) systems were determined as well. The loss of carotenoids followed first order loss kinetics. An initial rapid followed by a second slower first order loss kinetics was observed in the non-humidified spray dried (NHSD) systems. Storage of systems above the T g delayed carotenoids losses based on the rate constants. The loss of carotenoids in LBL systems was more heat sensitive as the activation energies were generally higher. Activation energy decreased above T g indicating that the loss of carotenoids became less temperature dependent. The application of LBL interface structure reduced the rate of carotenoids losses and can be applied to prevent loss of oil soluble bioactives in formulated materials.

Orange peel extract powders were produced using two steps: microwave-assisted extraction and spray drying. The extraction solvent-to-solid ratio has been found to significantly affect the level of total phenolic compounds in the extract and powder. Under the outlet air temperatures between 43 and 79 °C, spray drying of orange peel extracts resulted in a peak yield trend (between 75% and 92%) and high TPC (total phenolic content) recoveries. An evaluation of economics has also been conducted, suggesting that this process is economically feasible, with profits of 6.1 USD/kg and 8.8 USD/kg for solvent to solid ratios of 2 and 14, respectively. The uncertainty analysis of the economics showed that the selling price, the labor cost and the orange peel cost are the three most important parameters compared with the costs of electricity, natural gas, and water.

The aim of this work was to analyse the relationship between microstructural development, distribution of elemental components and characteristics related to functional properties of powders obtained by spray drying process. Blends of soy protein isolate (SPI), gum Arabic (AG) and maltodextrin 20 DE (MD) at 20% TS were prepared and spray-dried at 250 °C, 200 °C, 175 °C and 150 °C as inlet temperatures of drying air, and the outlet temperature at 70 °C was kept constant. Bulk density, hygroscopicity and wetting time were affected by concentration of wall material, drying air temperature did not suggest effect on these characteristics. Using combined microscopy techniques, the internal microstructure of particles obtained at 150 °C/70° as inlet/outlet drying air temperatures were analysed, results revealed that 26% was the highest percentage of hollow microparticles and the shell thickness from 264 nm to 290 nm. In these microparticles, the elemental analysis revealed that nitrogen was present from 2.93% to 15.37% in particles surface. Additional, a descriptive model to explain the possible assemble of wall material of a microparticle was proposed.

Solutions of 10 wt% solids, reconstituted from three types of dairy powders (milk protein concentrate, calcium caseinate and whey protein concentrate) were sonicated prior to lab scale spray drying at inlet and outlet temperatures of 180 °C and 80 °C respectively. The aim was to investigate the effects of sonication on the surface composition and morphology of the resulting powders. The effects of storage on the functional behaviour of these powders were also observed over 60 days at 25 °C, under two different humidity conditions (23.1% and 75.3%). No significant changes to the surface composition (fat, protein and lactose) of the sonicated and non-sonicated powder samples occurred during storage. The microstructure of non-sonicated powder samples showed the appearance of particle agglomerates upon storage, whereas this was not observed with sonicated samples. Importantly, it is shown that sonication prior to drying can increase powder stability during storage and delay the loss of powder solubility. When powders are reconstituted, the increase in solution viscosity that is normally associated with long term storage is also slowed. This is beneficial to industry where powder stability is important for reconstitution and use in the manufacture of secondary dairy products.

This study investigated the encapsulation of astaxanthin using spray drying method to enhance its stability and application in food systems. Blends of milk protein (either whey protein isolate, WPI or sodium caseinate, SC) and carbohydrate (soluble corn fiber, SCF 70) were applied as the wall materials. The results demonstrated that spray drying could be applied to transform the stable astaxanthin emulsions into powders with reasonably good properties, including water activity, surface morphology and oxidative stability. The reconstituted emulsions also showed good stability similar to the parent emulsions. The microencapsulation efficiency was high (∼95%) for both wall systems under investigation, indicating the suitability of these wall matrices for encapsulating the hydrophobic astaxanthin.