Platinum (Pt)‐based electrocatalysts are the benchmark catalysts for hydrogen evolution reaction (HER); however, they are limited by the scarcity and high price. Introducing an adequate substrate to ...disperse and anchor Pt‐based species is a feasible pathway to improve the utilization efficiency. Herein, a quick and continuous spray drying route is proposed to fabricate 3D crumpled Ti3C2Tx MXene loaded with sub‐nanometer platinum clusters (Pt/MXene). The 3D crumpled structure inhibits the restacking of layered MXene nanosheets and guarantees the fully exposure of Pt clusters. The as‐prepared catalyst exhibits excellent HER performances comparable to commercial Pt/C, including a low overpotential of 34 mV to reach a current density of 10 mA cm−2, a superior mass activity (1847 mA mgPt−1), a small Tafel slope (29.7 mV dec−1), and a high turnover frequency (10.66 H2 s−1). The improved activity of Pt/MXene can be attributed to the charge transfer from Pt clusters to MXene, which weakens the hydrogen adsorption, as evidenced by the density functional theory calculations. The present contribution proposes a novel strategy to anchor low‐mass‐loading sub‐nanometer precious metal clusters on crumpled MXene with fully exposed active sites for catalysis.
A crumpled MXene‐supported platinum (Pt) cluster catalyst is rationally designed. The anchoring of Pt clusters on crumpled MXene weakens the hydrogen adsorption and endows the catalyst an optimized electronic state. The obtained Pt/MXene demonstrates a superior hydrogen evolution reaction mass activity seven times to that of commercial Pt/C.
This work aimed the induction of crystallization on powder mango juice during the process of spray drying and the correlation of the microstructure of the powder obtained with the functional ...properties of stickiness and solubility. To perform this work, we used mango juice with 12 °Brix. Before being dehydrated, the juice undertook addition from the following carriers: maltodextrin, gum arabic and starch waxy in the concentration of 12%. The solution also received addition of crystalline cellulose in the concentrations of 0, 3, 6 and 9%. The powder was obtained through the use of a mini-spray dryer of laboratorial scale. Analyses of microstructure, stickiness, hygroscopicity and solubility were performed on the obtained powder. The microstructure analyses showed that the powders of the mango juices obtained through spray drying using the carriers maltodextrin, gum arabic, starch waxy without the addition of cellulose presented surfaces of amorphous particles. The analysis XRD showed that when 3, 6 and 9% of cellulose were added, the particles showed half-crystalline surfaces. The value of stickiness decreased in terms of the concentration of cellulose reaching values of 0.15, 0.22 and 0.11 Kg-f for maltodextrin, gum arabic and starch waxy, respectively. The functional property of solubility is affected when 9% of cellulose is added reaching the values of 72, 71 and 31% for the carriers maltodextrin, gum arabic and starch wax, respectively.
Polyunsaturated fatty acids, especially long-chain polyunsaturated omega-3 fatty acids (LCω3-PUFA), are essential in human nutrition because they play an important role in humans and prevent several ...diseases. Fish oil is a natural source of LCω3-PUFA that can be incorporated into food products. One of the major drawbacks of oils containing a high amount of LCω3-PUFA, such as fish oils, is their high susceptibility to oxidation and unpleasant flavours. Microencapsulation of fish oil by spray-drying has been proposed as a strategy to retard lipid auto-oxidation, improving oil stability, prolonging its shelf life, limiting the development of off-flavours and controlling the release into food. The encapsulation of fish oil by conventional spray-drying has been performed by preparing fish oil-in-water emulsions (micro- or nano-sized) by applying high shearing forces.
The objective of this review is to compile the scientific research on the encapsulation of fish oil to discuss the main formulation and process variables that affect the physicochemical properties of the fish oil microparticles obtained by conventional spray-drying, the stability of fish oil during storage and the application of fish oil microparticles in food systems. An alternative strategy to conventional spray-drying (water-free spray-drying) is also proposed.
•Encapsulation of fish oil by spray-drying is the most common method.•Formulation and process variables influence the performance of microparticles.•Infeed emulsion is a key step for fish oil microencapsulation.•Water-free spray-drying is an alternative for production of fish oil microparticles.
Since its invention in 1872 by Samuel Percy, the spray drying of food products has been widely used, whether in products consumed by babies in milk formulations, powdered sweets and cocoa soluble in ...milk for children, or food supplements rich in proteins, vitamins, and minerals for adults. All of these products were first formulated in solution and then converted into powders to facilitate the transport and preservation of the properties during storage. In recent years, novel technologies such as nano spray drying have emerged for the development of food formulations with high-cost active ingredients. The aim of the present work is to present a review of the literature reported in the last 10 years related to these technologies. The basis of the spray-drying technologies i.e., conventional and nano, are described and compared, emphasizing the instrumental processing conditions for achieving a desired product. Examples of some unwanted reactions presented during the encapsulation of active ingredients are provided.
Given the diverse health benefits of apigenin (AP), functional foods containing AP might interest the health-conscious market. However, the poor aqueous solubility of AP hinders its direct ...incorporation into food products. To overcome these limitations, AP was encapsulated in spray-dried unilamellar liposomes coated with chitosan. This study investigated the potential of spray-dried chitosan-coated AP liposomes (SCAL) for delivering AP in mango juice. The incorporation of SCAL did not alter the juice's proximate compositions or substantially affect its physicochemical properties. Mango juice with SCAL attained a comparable sensory acceptance to the control juice, with the added benefit of higher antioxidant capacity. Compared to the unencapsulated AP, SCAL exhibited a higher bioaccessibility of AP in mango juice, with a rapid release of AP during intestinal digestion. The pH values, total soluble solids, and colour properties of juice with SCAL did not change remarkably during juice storage at 4 °C for 28 days. On day 28, the retention of AP content and antioxidant capacity were higher in mango juice added with SCAL than the unencapsulated AP. Therefore, SCAL can be promising in delivering AP in aqueous food systems, making it possible to develop functional foods.
•Adding SCAL to mango juice did not remarkably alter the juice's properties.•SCAL improved the bioaccessibility of apigenin in mango juice.•Mango juice with SCAL had above-average sensory acceptance.•Mango juice with SCAL showed retention of apigenin content and antioxidant capacity.•SCAL is potential in delivering apigenin in mango juice.
Colored corn pericarp contains unusually high amounts of industrially valuable phytochemicals, such as anthocyanins, flavanols, flavonoids, and phenolic acids. Polyphenols were extracted in an ...aqueous solution and spray-dried to produce microencapsulates using four carrier materials, namely, maltodextrin (MD), gum arabic (GA), methylcellulose (MC), and skim milk powder (SMP) at three concentrations (1, 2, and 3 %, respectively). The encapsulates were evaluated for their polyphenolic contents using spectrophotometric techniques and HPLC analyses, and their antioxidant properties were evaluated using four different assays. The physicochemical properties of encapsulates were analyzed by measuring the zeta potential (ZP), particle size distribution, water solubility index (WSI), water absorption index (WAI), and color parameters. Structural and thermal properties were evaluated using Fourier transform infrared spectroscopy (FTIR), optical profilometry, and differential scanning calorimetry (DSC) analyses. Comparative analysis of structural characteristics, particle size distribution, zeta potential, WSI, WAI, and aw of the samples confirmed the successful formulation of encapsulates. The microencapsulates embedded with 1 % concentrations of MD, MC, GA, or SMP retained polyphenolic compounds and exhibited noteworthy antioxidant properties. The samples encapsulated with GA or MD (1 %) demonstrated superior physicochemical, color, and thermal properties. Comprehensive metabolomic analysis confirmed the presence of 38 phytochemicals in extracts validating the spray-drying process.
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Zirconia-toughened alumina (ZTA) ceramics have attracted much attention in the medical field as joint replacement materials due to their good mechanical properties and biocompatibility. However, the ...flexural strength of conventional ZTA is still slightly insufficient in traditional preparation techniques. In this study, by improving the slurry system, the effects of the solid content of the slurry, additives, and the pH of the slurry on the slurry system were investigated. ZTA powders with a uniform particle size distribution, high degree of sphericity and high flowability were prepared by spray granulation. The mechanical properties, microstructure and biocompatibility of the ZTA pressing were investigated after degreasing and sintering processes. The results showed that the hardness of the prepared ZTA ceramics was 1658.24 ± 28.04 H V, the fracture toughness was 4.016 ± 0.027 MPa m1/2, and the biaxial bending strength was 501.43 ± 21.44 MPa, and the three-point bending strength reached 635 MPa. The ZTA ceramics also possessed good biocompatibility and a low haemolysis rate, which aligns with the requirements of clinical biomedical implant materials.
This review is primarily focused on the comparison of three emerging techniques: electrospraying, nano spray drying, and electrostatic spray drying techniques. There are persistent advances to ...develop efficient drying technique for sensitive bioactives and to overcome their hurdles. These processes involve electrostatic forces as a promising factor for better encapsulation and stability of dried particles. Their potential differences in experimental setup, influencing factors and recent applications are listed. Introduction of electrostatic interaction between the components during atomization allows electrospraying and electrostatic spray drying as an advanced drying technique for heat-sensitive and labile products. Electrospraying and nano-spray drying demonstrated an effective drying with different solvent systems (organic or non-organic solvents) and also, achieved to encapsulate complex food ingredients (vitamins, minerals, phenolic compounds, probiotics etc.). These electric-assisted technologies showed higher encapsulation efficiency, uniform particle morphology and longer stability of dried powders than classical technologies. Nano-spray dryer with spray mesh technology and electrostatic collector brings out difference in dried powders in terms of particle size and product yield when compared to conventional spray drying. Electrospraying and nano-spray drying have been beneficial for highly valued research products (such as cells, enzymes, genes, etc.) but the scaling up of these processes is still currently in process.
•Three emerging spray drying technologies using electric fields have been reviewed.•Electrospraying, nano-spray & electrostatic spray drying works at lower temperature.•These processes involve electrostatic forces allowing droplets & particle repulsion.•Overall technical considerations, advantages and limitations are discussed.•Industrial set up of electrostatic spray drying is commercially available.
Lemon juice was mixed with different carrier materials (maltodextrin, gum Arabic, carboxymethylcellulose) and dehydrated by nano spray drying, conventional spray drying and freeze-drying technique. ...The obtained powders were compared in terms of their morphology, moisture content, density, porosity, flow and reconstitution properties, and water sorption kinetics. Freeze-dried powders showed an irregular, compact morphology, while spray drying led to more uniformly sized fine spherical particles. Spray-dried powders with gum Arabic had low moisture, high density, but long wetting times and fair dispersibility linked to their smaller particle size and even surface. Fine particle characteristics of nano spray dried powders did not seem to favor their flow and dissolution properties while enhanced their moisture uptake. Conversely, carboxymethylcellulose-containing powders exhibited inferior characteristics likely due to their highly hygroscopic and aggregated structure.
•Wall deposition indirectly affects the quality of the product and direct economic benefits to the food industry.•Wall deposition is affected by operating parameters, type and size of the chamber and ...wall properties.•Wall deposition modeling is proved to be an effective tool to evaluate the results and reliable conclusions.
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.
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