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In this study, caseinate-pectin polyelectrolyte complexes and co-solutions were successfully fabricated at pH 3.0 and 7.0, respectively, to encapsulate bioactive molecules. During the fabrication process, the effect of the sequence in which each component was added on lutein/zeaxanthin (Lut/Zx) complexation with sodium caseinate (NaCas) was investigated. The protective effect of the polyelectrolyte complex and co-solution for Lut/Zx in liquid formulations was compared with that of a binary system containing only caseinate and Lut/Zx. Compared with the binary system, the polyelectrolyte complex at pH 3.0 further enhanced the chemical stability of Lut/Zx during storage, whereas the co-solution at pH 7.0 did not exhibit this ability. Unexpectedly, NaCas-Lut/Zx - pectin (NC-L/Z-P) with a theoretically sandwich structure did not exhibit better protection than NaCas-pectin-Lut/Zx (NC-P-L/Z). Fluorescence quenching spectra revealed that the addition of NaCas to Lut/Zx and ultimately to pectin resulted in the formation of a sandwich structure, which was soon followed by structural rebalancing. Finally, freshly prepared NC-L/Z-P complexes were lyophilized to stabilize their sandwich structure, resulting in improved encapsulation and sustained-release properties compared with those of the dried NC-P-L/Z. These results suggest that protein-polysaccharide complexes, combined with timely dehydration, enhance the combination of Lut/Zx with caseinate, leading to heightened protective effects., Competing Interests: Declaration of competing interest The authors declare that they have no competing financial interests or personal relationships that may have influenced the work reported in this study., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Particle concentrations (w) and oil content (Φ) are crucial factors influencing the gel stability of Pickering emulsions. To understand the stabilization mechanism comprehensively, we prepared emulsion gels stabilized by CNF/DMY composite particles at various w (0.5-1.5 wt%) and Φ (0.2-0.6, v/v). The microstructure revealed the adsorption of these particles at the oil-water interface, with excess particles forming a three-dimensional network structure in the continuous phase. Rheological studies showed that the network structure of Pickering emulsions was significantly influenced by w and Φ, resulting in improved emulsion gel strength that hindered the movement of oil droplets and oxygen in the continuous phase, thereby enhancing emulsion stability. Three scenarios for the critical strain (γ co ) were observed: at Φ = 0.2, γ co decreased with increasing w, while at Φ = 0.4, γ co increased with increasing w. At Φ = 0.6, γ co remained relatively constant regardless of w. In conclusion, adjusting particle concentration and oil content enabled the control of microstructure, rheological properties, and antioxidant capacity of emulsion gels. These findings could be a valuable resource for formulating and ensuring the quality of emulsion gel-based products in the food industry., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The formation, characterization, and functionality of hybrid nanoparticles based on linseed bio-macromolecules extracted as linseed protein (LP) and linseed gum (LG) from the remaining meal after oil extraction were investigated. The assembly of bioparticles at different protein to polysaccharide ratios as a function of pH was characterized in terms of absorbance measurements, dynamic light scattering and surface charge. The wettability of the assembled particles as well as the plain LP and LG was also determined. By increasing the LG proportion in the bioparticles, both the size of the particles and their contact angle tended to decrease, whereas their zeta potential became more negative over the whole studied pH range. The formed negatively charged particles at pH 3 with a 50:50 LP to LG ratio and a size of approximately 300 nm were selected and their functional properties (solubility, emulsifying and foaming properties) were compared to the individual biopolymers. The interaction between LG and LP was found to modify the functional properties of native LP especially at and around its isoelectric point. The LP-LG particles could be useful for stabilizing plant-based emulsions and foams., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Flaxseed protein (FP) and mucilage (FM) complex bioparticles as sustainable ingredients were assembled by electrostatic interaction for plant-based Pickering stabilization of flaxseed oil (FO)-in-water emulsions. The effect of FO content (1-5 wt%) on droplet size and accelerated creaming stability of the emulsions was evaluated, from which it was found that 2.5 wt% FO emulsion had the smallest initial droplet size (i.e. D[4,3] = 8 μm) and creaming velocity (2.9 μm/s). The microstructure of the emulsions was observed using Cryo-SEM, confocal and optical microscopy, showing a thick layer of the particles on the oil surface responsible for the stabilization. The physical stability of FO emulsions stabilized by complex bioparticles against various environmental stress conditions (pH, salt and temperature) was higher compared to plain FP- and polysorbate 80-stabilized emulsions. Thus, the droplet size of FP-stabilized emulsions (pH 3) increased from 21 to 38 μm after thermal treatment (80 °C), whereas the size distribution of particle-stabilized emulsions hardly changed. The latter emulsions also remained stable during 28 days of storage and displayed good stability against a wide range of pH conditions (2-9) and salt concentrations (0-500 mM) with no sign of oiling-off. The complex particles as Pickering emulsifiers were successful to depress the FO oxidation at 4 °C and 50 °C. This study could open a promising pathway for producing natural and surfactant-free emulsions through Pickering stabilization using plant-based biopolymer particles for protecting lipophilic bioactive components., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Quercetin-fortified nanoparticles were prepared from almond gum (AG), a novel biological macromolecule, and Tween 80 (T80) as stabilizers and shellac (SH) as core material using an antisolvent precipitation method. The final nanoparticles were prepared by 0.67% SH, 0.02% Q, 0.5% AG and 0.1% w/v T80 using the stirring speed of 750 rpm at a dosing rate of 0.5 ml/min. The morphology of the particles was characterized using Cryo-SEM and TEM microscopy. The average particle size was 135 ± 8 nm with a polydispersity index of 0.252 ± 0.01 and an encapsulation efficiency of 97.7 ± 1.2%. At pH 7.4 (intestinal pH), quercetin-loaded nanoparticles showed significantly (p < 0.05) higher antioxidant activity compared to free quercetin while the degradation of quercetin was lower in the nanoparticles compared to free quercetin at the similar pH. Quercetin loaded in nanoparticles was successfully found to be 2 times more available for uptake than free quercetin at pH 7.4. MTT and SRB assays revealed that no significant (p > 0.05) toxicity was observed for Caco-2 cells treated with quercetin-loaded nanoparticles with a dilution factor of 100. This study provides information about the formulation of promising nanocarriers using biological macromolecules for oral delivery of bioactive compounds., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Previously, polyunsaturated fatty acids (PUFA) from linseed oil were effectively protected (>80%) against biohydrogenation through polyphenol-oxidase-mediated protein crosslinking of an emulsion, prepared with polyphenol oxidase (PPO) extract from potato tuber peelings. However, until now, emulsions of only 2 wt% oil have been successfully protected, which implies serious limitations both from a research perspective (e.g. in vivo trials) as well as for further upscaling toward practical applications. Therefore, the aim of this study was to increase the oil/PPO ratio. In the original protocol, the PPO extract served both an emulsifying function as well as a crosslinking function. Here, it was first evaluated whether alternative protein sources could replace the emulsifying function of the PPO extract, with addition of PPO extract and 4-methylcatechol (4MC) to induce crosslinking after emulsion preparation. This approach was then further used to evaluate protection of emulsions with higher oil content. Five candidate emulsifiers (soy glycinin, gelatin, whey protein isolate (WPI), bovine serum albumin and sodium caseinate) were used to prepare 10 wt% oil emulsions, which were diluted five times (w/w) with PPO extract (experiment 1). As a positive control, 2 wt% oil emulsions were prepared directly with PPO extract according to the original protocol. Further, emulsions of 2, 4, 6, 8 and 10 wt% oil were prepared, with 80 wt% PPO extract (experiment 2), or with 90, 80, 70, 60 and 50 wt% PPO extract, respectively (experiment 3) starting from WPI-stabilized emulsions. Enzymatic crosslinking was induced by 24-h incubation with 4MC. Ruminal protection efficiency was evaluated by 24-h in vitro batch simulation of the rumen metabolism. In experiment 1, protection efficiencies were equal or higher than the control (85.5% to 92.5% v. 81.3%). In both experiments 2 and 3, high protection efficiencies (>80%) were achieved, except for emulsions containing 10 wt% oil emulsions (<50% protection), which showed oiling-off after enzymatic crosslinking. This study demonstrated that alternative emulsifier proteins can be used in combination with PPO extract to protect emulsified PUFA-rich oils against ruminal biohydrogenation. By applying the new protocol, 6.5 times less PPO extract was required.

We examined the filtration of aqueous suspensions of negatively charged (citrate-stabilized) Ag (14.5±1.1nm) and positively charged CeO 2 (7.3±1.4nm) engineered nanoparticles (ENPs) via different filtration techniques such as paper filtration, micro- and ultrafiltration, and evaluated the impact of initial concentration, matrix composition, and filter type and (pre-)treatment, on nanoparticle retention. Solutions of Ag + and Ce 3+ ions were tested in the same way. Significant retention of nanoparticles was observed even for filters having considerably larger pore sizes than the ENPs size. Retention also seemingly increased with decreasing initial concentration, but generally decreased upon preconditioning of the paper or membrane filters with diluted nitric acid or 0.1M Cu(NO 3 ) 2 , respectively. In ultrapure water, retention appeared to depend more on particle characteristics than on a membrane type. However, in 2mM KNO 3 , NaCl, or CaCl 2 , more significant differences in recovery were observed between different membrane materials. Additionally, background electrolytes might reduce nanoparticle or ionic retention, but could also affect their (colloidal) stability, e.g., resulting in enhanced retention of Ag ENPs and Ag + ions in chloride-containing matrices. Results from centrifugal ultrafiltration recommend using 10kDa filters for nanoparticle removal from the solution, and suggest these filters might potentially be suitable to differentiate between (nano)particulate and dissolved species., (Copyright © 2016 Elsevier B.V. All rights reserved.)

The main objective of this work was to investigate the effects of polysaccharide type (gum Arabic, GA and/or carboxymethyl cellulose, CMC) and concentration (0-0.2% (w/w)) on the electrostatic interactions with β-lactoglobulin (BLG). Biopolymer interaction was studied using turbidimetric analysis, dynamic light scattering (DLS), electrophoretic mobility and relative viscosity measurements. Complexes were developed at pH values below the isoelectric point (pI) of BLG. Increasing polysaccharide concentration increased the stability of nanocomplexes through increasing the negative charges carried by complexes. The differences between GA and CMC were attributed to the polysaccharide structure (linear or branched chains), charge density and flexibility. Phase contrast optical microscopy showed that complexation was of nucleation and growth type mechanism. Relative viscosity measurements confirmed that wrapping phenomenon occurred in both associative mixtures., (Copyright © 2016 Elsevier B.V. All rights reserved.)

The stability of engineered nanoparticles (ENPs) in complex aqueous matrices is a key determinant of their fate and potential toxicity towards the aquatic environment and human health. Metal oxide nanoparticles, such as CeO2 ENPs, are increasingly being incorporated into a wide range of industrial and commercial applications, which will undoubtedly result in their (unintentional) release into the environment. Hereby, the behaviour and fate of CeO2 ENPs could potentially serve as model for other nanoparticles that possess similar characteristics. The present study examined the stability and settling of CeO2 ENPs (7.3±1.4 nm) as well as Ce(3+) ions in 10 distinct natural surface waters during 7d, under stagnant and isothermal experimental conditions. Natural water samples were collected throughout Flanders (Belgium) and were thoroughly characterized. For the majority of the surface waters, a substantial depletion (>95%) of the initially added CeO2 ENPs was observed just below the liquid surface of the water samples after 7d. In all cases, the reduction was considerably higher for CeO2 ENPs than for Ce(3+) ions (<68%). A first-order kinetics model was able to describe the observed time-dependant removal of both CeO2 ENPs (R(2)≥0.998) and Ce(3+) ions (R(2)≥0.812) from the water column, at least in case notable sedimentation occurred over time. Solution-pH appeared to be a prime parameter governing nanoparticle colloidal stability. Moreover, the suspended solids (TSS) content also seemed to be an important factor affecting the settling rate and residual fraction of CeO2 ENPs as well as Ce(3+) ions in natural surface waters. Correlation results also suggest potential association and co-precipitation of CeO2 ENPs with aluminium- and iron-containing natural colloidal material. The CeO2 ENPs remained stable in dispersion in surface water characterized by a low pH, ionic strength (IS), and TSS content, indicating the eventual stability and settling behaviour of the nanoparticles was likely determined by a combination of physicochemical parameters. Finally, ionic release from the nanoparticle surface was also examined and appeared to be negligible in all of the tested natural waters., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Protein binding to nanoparticles is a crucial issue in biomedicine, as it triggers their clearance from the bloodstream after intravenous injection. Many techniques are available for measuring strong protein binding interactions, but weak dynamic interactions are more difficult to assess. To tackle the latter problem, in the present work, cytochrome c was chosen as a representative model of a water-soluble protein and the adsorbing particulates were either small unilamellar phospholipid vesicles or 14 nm diameter solid superparamagnetic iron oxide cores onto which a phospholipid bilayer was strongly chemisorbed (so-called magnetoliposomes). Incorporation of cytochrome c oxidase into the phospholipid bilayer allowed the association of cytochrome c with the surface of the particles to be measured with high sensitivity by VIS-spectrophotometry. The impact of enzyme density as well as some of the physical features of the PEG corona (degree of PEGylation and PEG chain length) adjacent to the surface of the lipid structures on the overall kinetics was also investigated., (Copyright (c) 2010 Elsevier B.V. All rights reserved.)

In the present study, the heat-induced interaction between whey proteins and casein micelles was studied. To that end, the particle size distribution of 5.5% (w/w) casein micellar dispersions was determined by photon correlation spectroscopy as a function of both the whey protein concentration and heating time at 80 degrees C. The results clearly indicated that heat-induced aggregation of the casein micelles only occurred in the presence of whey proteins. In an effort to overcome the heat-induced interactions between whey proteins and casein micelles, the influence of different soybean lecithins was investigated. Comparing native to hydrolysed, as well as hydroxylated soybean lecithin, it was observed that the heat-stabilising effect of the lecithins was directly related to their hydrophilicity: whereas native soybean lecithin had hardly any beneficial effect, highly hydrolysed as well as hydroxylated soybean lecithin largely prevented heat-induced casein micelle aggregation in the presence of whey proteins. From experimental observations on the heat-induced decrease of whey protein solubility both in the absence and presence of hydrolysed lecithin, it was deduced that the latter may stabilise the exposed hydrophobic surface sites of heat-denatured whey proteins. Dynamic surface tension measurements indicated that the heat-stabilising properties of lecithins were mainly determined by their critical aggregation concentration.

Cooked ham-based model systems were prepared using salt-soluble meat protein isolate, κ-carrageenan and sodium and potassium chloride. The pH was set to 6.2 using a 50mM PIPES-buffer. An experimental mixture design was used to study the effect of carrageenan on the structure build-up of the gelled meat products. In situ gelation experiments were carried out on a controlled-stress rheometer, while a texture analyzer was used to determine the large deformation behaviour. The water holding capacity was measured by a centrifugal technique and confocal scanning laser microscopy was used to visualize the microstructure of the gelled meat products. κ-Carrageenan was found to increase the complex modulus, the gel strength and the water holding capacity, although these properties were mainly governed by the concentration of meat protein isolate.