Poor solubility of high protein milk powders can be an issue during the production of nutritional formulations, as well as for end-users. One possible way to improve powder solubility is through the creation of vacuoles and pores in the particle structure using high pressure gas injection during spray drying. The aim of this study was to determine whether changes in particle morphology effect physical properties, such as hydration, water sorption, structural strength, glass transition temperature, and α-relaxation temperatures. Four milk protein concentrate powders (MPC, 80%, w/w, protein) were produced, i.e., regular (R) and agglomerated (A) without nitrogen injection and regular (RN) and agglomerated (AN) with nitrogen injection. Electron microscopy confirmed that nitrogen injection increased powder particles’ sphericity and created fractured structures with pores in both regular and agglomerated systems. Environmental scanning electron microscopy (ESEM) showed that nitrogen injection enhanced the moisture uptake and solubility properties of RN and AN as compared with non-nitrogen-injected powders (R and A). In particular, at the final swelling at over 100% relative humidity (RH), R, A, AN, and RN powders showed an increase in particle size of 25, 20, 40, and 97% respectively. The injection of nitrogen gas (NI) did not influence calorimetric glass transition temperature (T_g), which could be expected as there was no change to the powder composition, however, the agglomeration of powders did effect T_g. Interestingly, the creation of porous powder particles by NI did alter the α-relaxation temperatures (up to ~16 °C difference between R and AN powders at 44% RH) and the structural strength (up to ~11 °C difference between R and AN powders at 44% RH). The results of this study provide an in-depth understanding of the changes in the morphology and physical-mechanical properties of nitrogen gas-injected MPC powders.

The assembly properties of three known spin crossover iron(III) complexes 1–3, at the air–water interface, are reported. All three complexes are amphiphiles, each bearing a pair of C_n alkyl chains on the polyamino Schiff base sal₂trien ligand (n = 6, 12, or 18). Complex 1 is water-soluble but complexes 2 and 3 form Langmuir films, and attempts were made to transfer the film of the C₁₈ complex 3 to a glass surface. The nature of the assembly of more concentrated solutions of 3 in water was investigated by light scattering, cryo-SEM (scanning electron microscopy), and TEM (transmission electron microscopy), all of which indicated nanoparticle formation. Lyophilization of the assembly of complex 3 in water yielded a powder with a markedly different magnetic profile from the powder recovered from the initial synthesis, notably, the spin crossover was almost completely quenched, and the thermal behavior was predominantly low spin, suggesting that nanoparticle formation traps the system in one spin state.

The rehydration properties of original whey protein isolate (WPI_C) powder and spray-dried WPI prepared from either unheated (WPI_UH) or nanoparticulated WPI solutions were investigated. Nanoparticulation of whey proteins was achieved by subjecting reconstituted WPI_C solutions (10% protein, w/w, pH 7.0) to heat treatment at 90 °C for 30 s with no added calcium (WPI_H) or with 2.5 mM added calcium (WPI_HCa). Powder surface nanostructure and elemental composition were investigated using atomic force microscopy and X-ray photoelectron spectroscopy, followed by dynamic visualisation of wetting and dissolution characteristics using environmental scanning electron microscopy. The surface of powder particles for both WPI_UH and WPI_C samples generally appeared smooth, while WPI_H and WPI_HCa displayed micro-wrinkles with more significant deposition of nitrogen and calcium elements. WPI_H and WPI_HCa exhibited lower wettability and solubility performance than WPI_UH and WPI_C during microscopic observation. This study demonstrated that heat-induced aggregation of whey proteins, in the presence or absence of added calcium, before drying increases aggregate size, alters the powder surface properties, consequently impairing their wetting characteristics. This study also developed a fundamental understanding of WPI powder obtained from nanoparticulated whey proteins, which could be applied for the development of functional whey-based ingredients in food formulations, such as nanospacers to modulate protein–protein interactions in dairy concentrates.

Introduction: Emollient therapy is the mainstay for treating skin conditions such as atopic dermatitis and psoriasis. New emollients have been introduced recently and are assumed to be therapeutically interchangeable with the innovator products because, superficially, they appear to have similar compositions. This study compares a) the ex vivo human skin occlusion performance and b) the visual and microscopic properties of Isomol gel (IMG) and Doublebase gel (DBG). Materials and Methods: Occlusion was measured gravimetrically by reduction in cumulative 48-hour evaporative weight loss from ex vivo human skin samples following single applications of the two test emollients and Vaseline^®. Skin samples from a single donor were mounted in Franz diffusion cells and then the emollients were spread over the skin surface with an applied dose of approximately 2 mg/cm². The assemblies (four replicates per treatment) were then accurately weighed at baseline (T₀) and again after 5-, 24-, and 48-hour postapplication. The quality of the two emollient gel formulations was compared by visual examination of their film-forming characteristics and by microstructural examination using environmental scanning electron microscopy (ESEM). Results: Occlusivity of the DBG emollient gel formulation was comparable with Vaseline and substantially better than IMG, with the DBG-treated skin samples losing less than half as much weight as the IMG-treated skin samples over 48 hours and at a much slower rate during the first 5 hours. The film-forming characteristics and microstructure of the gels were also very different. Whereas DBG maintained a smooth, uniform film over 24 hours, the IMG formulation phase-separated. ESEM results showed that the DBG emulsion has a stable structural matrix with uniform oil droplets, whereas for IMG the emulsion system is inhomogeneous with the oil phase coalescing into larger irregular shaped rafts. Conclusions: We have demonstrated substantial performance differences between two prescribed emollient gels.

Introduction: The presence of antibiotic residues in the aquatic environment is a likely contributor to the current increase in antibiotic resistance, posing a significant threat to global health. This study investigated the use of a low-cost and sustainable material based on sawdust with the purpose of removing rifampicin residues from water. Methods: The sawdust was pretreated with 2M sulfuric acid and was characterized using Fourier Transform Infrared spectroscopy (FT-IR), a Mastersizer, scanning electron microscopy (SEM), an elemental analyser, and the pH point of zero charge (pH_pzc). The batch adsorption process was conducted using both raw and treated sawdust to determine the effect of contact time, temperature, pH, adsorbent dosage, and the initial concentration of antibiotic dissolved in water. Results and Discussion: The results revealed that the chemical pretreatment of raw sawdust significantly improved its adsorption capacity. The highest removal efficiency of 65% was achieved using an adsorbent dosage of 31.3 g/L. The thermodynamic studies demonstrated that the process was spontaneous and governed by physisorption within the studied temperature range (293.15 K–318.15 K), being more favourable at higher temperatures. The interactions between the functional groups of sawdust and the rifampicin molecules included electrostatic attraction, hydrogen bonding, and π-π interactions. Conclusions: This research highlights the potential of utilizing waste as a valuable and effective adsorbent of residual antibiotics from water, thus contributing to the sustainable practices of solid waste management and water treatment.