Proteins offer specific functional properties for the development of biodegradable, biopolymer-based materials. Gelatin and sodium caseinate can electrostatically interact in solution and form a complex coacervate, which was used to produce films with enhanced properties intended for dermal application in the cosmetic industry. Complex coacervate based films showed improved physical, mechanical, and barrier properties owing to their intermolecular interactions. Their thermal properties and chemical composition remained unchanged due to the intermolecular interactions being predominantly electrostatic. As sufficient elasticity of films is necessary for their production and use in the cosmetic industry, the optimal type and concentration of plasticizers were determined. Films containing 30% glycerol exhibited the highest improvement in mechanical properties, with balanced barrier and physical properties. The presence of glycerol and its interaction with protein side groups was detected in the FTIR spectra of films. SEM micrographs revealed morphological improvements on the surface and in the cross-sections of films plasticized with glycerol. Overall, the produced films demonstrated satisfactory properties for cosmetic applications and represent a potential replacement for nonsustainable synthetic materials currently in use.

Cutin, a natural polyester, has attracted attention as a precursor for bio-based materials mimicking plant cuticles, particularly in food packaging. Most studies focus on polycondensation of hydrolyzed cutin fractions or combining cutin hydrolysates with other components; however, cutin precipitation, conditions affecting it, and cutin isolate film properties, without addition of other filmogenic material, remain insufficiently understood. Owing to the pH-dependent solubility of cutin, which progressively decreases as pH is lowered from strongly alkaline to acidic conditions, this study investigates the influence of pH on cutin dispersion formation and characteristics, and evaluates the impact of these dispersion properties on the formation and performance of self-assembled cutin isolate films, with a view to developing films with improved water-barrier and moisture-resistance properties. The influence of three plasticizers, glycerol, propylene glycol, and polyethylene glycol 400, at two concentrations was also evaluated. Results demonstrated that pH is the primary factor influencing cutin isolate dispersion characteristics and film performance, with decreasing pH promoting cutin precipitation and particle aggregation, thereby inducing changes in film structure. The strongest effects were observed for swelling, solubility, and tensile strength, followed by water vapor permeability, elongation at break, and thickness. Plasticizer type mainly affected moisture content and significantly influenced permeability and thickness, while concentration of plasticizer primarily impacted permeability. Interactions between pH and plasticizer significantly influenced most properties. Films prepared from cutin dispersions at pH 6.5 and pH 5 with polyethylene glycol (10%) showed the best balance of mechanical and barrier properties. Additionally, films prepared from the cutin solutions at pH 12 with glycerol (20%) exhibited good mechanical performance and high solubility, suitable for specific applications.

(Received January, March, accepted 2025) Abstract: This study aims to compare and analyse the synthesis of microcapsules stabilized with chitosan/sodium dodecyl sulphate complex according to emulsion preparation methods. For this purpose, 20 % oil-in-water emulsions were obtained in two ways: by emulsifying the oil phase in aqueous solution of chitosan and its mixtures with anionic surfactant ("method I") and by subsequently dropping chitosan into an already prepared emulsion stabilized by anionic surfactant ("method II"). Good stability, positive zeta potential of the emulsions and uniform droplet size distribution obtained with both methods, enabled the preparation of chitosan-based microcapsules which were separated by spray drying and investigated in terms of yield, moisture content, particle mean diameter and size distribution. The results showed a uniform particle size distribution and approximately equal mean diameters of emulsion droplets (= 8 mu m), i.e., suspension particles (= 5 mu m), while the microcapsule yields and moisture content for method I were 15 and 1.14 %, and for method II were 1.2 and 2.85 %, respectively. These results indicate that method I may be more suitable for use in the pharmaceutical and food industries for the production of chitosan microcapsules with oil content. The study confirmed that small variations in preparation can lead to large changes in the microencapsulation process and microcapsule structure.

Cutin is a natural plant polyester, a constituent of the cuticle that covers aerial plant surfaces. Following the trends of agricultural and food waste reduction and the growing demand for plant-derived nanomaterials, cutin was extracted from tomato peels, a by-product of tomato processing. Subsequently, dispersions of cutin particles in the nano- and colloidal size range were prepared by pH-dependent precipitation. Four types of the dispersions were obtained, i.e., dispersion from cutin extract—NP E dispersion, dispersions from a solution of different cutin isolates, dialyzed cutin isolate–NP D dispersion, washed cutin isolate–NP W dispersion, and standard cutin isolate–NP S dispersion. Cutin precipitation occurred at pH lower than 7 and cutin dispersions with final pH 3–7 were formed. Zeta potential, particle size, and recovery of four cutin dispersions were investigated. All types of cutin particles bear a negative charge which increases on pH increase from 3 to 7, resulting in decrease in cutin nanoparticle size upon pH increase. In addition to that, the influence of cutin solution concentration and storage time on cutin dispersion particle size was found to be mitigated at pH ≥ 6. Among four dispersions, NP S had the highest cutin nanoparticle recovery at all pHs investigated.

Silk fibroin (SF) is a protein with many outstanding properties (superior biocompatibility, mechanical strength, etc.) and is often used in many advanced applications (epidermal sensors, tissue engineering, etc.). The properties of SF-based biomaterials may additionally be tuned by SF interactions with other (bio)polymers. Being a weak amphoteric polyelectrolyte, SF may form polyelectrolyte complexes (PECs) with other polyelectrolytes of opposite charge, such as poly(acrylic acid) (PAA). PAA is a widely used, biocompatible, synthetic polyanion. Here, we investigate PEC formation between SF and PAA of two different molecular weights (MWs), low and high, using various techniques (turbidimetry, zeta potential measurements, capillary viscometry, and tensiometry). The colloidal properties of SF isolated from Bombyx mori and of PAAs (MW, overlap concentration, the influence of pH on zeta potential, adsorption at air/water interface) were determined to identify conditions for the SF-PAA electrostatic interaction. It was shown that SF-PAA PEC formation takes place at different SF:PAA ratios, at pH 3, for both high and low MW PAA. SF-PAA PEC’s properties (phase separation, charge, and surface activity) are influenced by the SF:PAA mass ratio and/or the MW of PAA. The findings on the interactions contribute to the future development of SP-PAA PEC-based films and bioadhesives with tailored properties.

Evolution of edible electronics has paved the way for groundbreaking advancements in the realm of electronics, fostering innovations that merge sustainability with functionality. As the field of edible electronics continues to flourish, the integration of biocompatible materials and ingestible designs opens doors to applications in healthcare and beyond. Development of edible LRC (inductance, resistance, capacitance) components further extends this vision, and brings us closer to a more sustainable world with green and renewable electronics that are not harmful to the human body. The research focuses on the fabrication of films incorporating activated carbon aimed to innovate edible electronics. The films were prepared using a blend composed of activated carbon, propylene glycol, and zein. These films, created by combining these materials, are the basis for the production of edible electronic components. The fabrication involved the design of the resistor, its fabrication and comprehensive characterization. Through precise fabrication techniques, these films were tailored to meet the unique requirements of ingestible electronics, showcasing the potential for customizable and biodegradable electronic elements. The findings reveal the viability of edible resistors, offering a promising pathway for sustainable and biodegradable electronic applications, effectively linking technology with environmental sustainability in the electronics domain.

Environmental problems caused by food packaging impede the sustainability of packed food. Therefore, efficient and environmentally–friendly solutions need to be urgently implemented. Zein is water–insoluble plant protein which can form biodegradable films that have potential to be used as sustainable food packaging. In this work, zein films (zFc) were prepared from dispersions of zein nanocapsules (zNC) containing carvacrol, using pseudolatex technology. zNC were characterized for zeta potential and size. Influence of carvacrol on zFc water resistance, optical and mechanical properties was tested. Encapsulation efficiency and release curves of carvacrol were determined. Antimicrobial activity of zFc with 20% carvacrol was tested under dynamic conditions. It was shown that continuous zein films can be prepared by coalescence of zNC, using pseudolatex technology. Results showed that tested carvacrol concentrations do not affect zNC and zFc properties. Antimicrobial activity of zFc was found to be sufficient to block the growth of Staphylococcus aureus.

This paper evaluated the potential of zein-resins nanoparticles to act as a carrier for water-insoluble oil carvacrol. The rosin and shellac were used as natural resins in different mass ratios to plant protein zein. Rosin is one of the natural gums. Shellac is a resinous secretion of the insect. The influence of nanoparticle composition on colloidal properties, encapsulation efficiency, and release of oil was studied. Zeta potential and size of thus prepared nanoparticles were studied. Carvacrol encapsulation efficiency and release were determined by the HPLC method developed for these compounds. Results showed that the resin type and share affect encapsulation efficiency and release of carvacrol. It was also shown that the addition of resins enhanced release from nanoparticles, compared to plain zein nanoparticles. Findings in the present work will help further understanding the interaction between alcohol-soluble biopolymers and provide new insight into the development of natural carriers for bioactive compounds. Novelty impact statement Natural polymers derived from food are considered desirable materials for constructing delivery systems to encapsulate, protect, and release bioactive components in nutraceuticals, pharmaceuticals, and food. Therefore, this paper is approached to fabricate the carvacrol-loaded zein/rosin (Z/R) and zein/shellac (Z/S) composite nanoparticles (NPs). Findings in the present work will help further understanding of the interaction between alcohol-soluble biopolymers (e.g., zein, rosin, and shellac) and provide new insight into the development of natural carriers for bioactive compounds.

Microencapsulation of bioactive substances is a common strategy for their protection and release rate control. The use of chitosan (Ch) is particularly promising due to its abundance, biocompatibility, and interaction with anionic surfactants to form complexes of different characteristics with relevance for use in microcapsule wall design. In this study, Ch/sodium dodecyl sulfate (SDS) microcapsules, without and with cross-linking agent (formaldehyde (FA) or glutaraldehyde (GA)), were obtained by the spray drying of vitamin E loaded oil-in-water emulsion. All of the microcapsules had good stability during the drying process. Depending on the composition, their product yield, moisture content, and encapsulation efficiency varied between 11–34%, 1.14–1.62%, and 94–126%, respectively. SEM and FTIR analysis results indicate that SDS as well as cross-linkers significantly affected the microcapsule wall properties. The profiles of in vitro vitamin E release from the investigated microcapsules fit with the Korsmeyer-Peppas model (r2 > 0.9). The chemical structure of the anionic surfactant was found to have a significant effect on the vitamin E release mechanism. Ch/SDS coacervates may build a microcapsule wall without toxic crosslinkers. This enabled the combined diffusion/swelling based release mechanism of the encapsulated lipophilic substance, which can be considered favorable for utilization in food and pharmaceutical products.

The objective of this study was to produce and characterize microcapsules for simultaneous encapsulation hydrophilic and lipophilic active substances. For this purpose, double emulsification process was employed, followed by complex coacervation in the system of two oppositely charged biopolymers, gelatin and sodium caseinate (NaCAS). Properties of the micmcapsules wall have been regulated by cross-linking of the gelatin/NaCAS complex at the interface with genipin. Vitamins C and E were selected as model hydrophilic and lipophilic bioactive compounds for this study. Investigations of surface morphology, encapsulation efficiency (EE) and kinetic of vitamin C release have shown that genipin concentration as well as interaction in gelatin/NaCAS system make an influence on microcapsules properties. Genipin concentration of 2 mmol/g, was chosen as the optimal and the highest EE of the vitamins were obtained at proteins mass ratio of 2:1. The results of release kinetic determination of the vitamins showed that release mechanism is simple diffusion.

In mixed solutions of anionic and cationic surfactants, called catanionics, ion pairs are formed which behave like non-ionic surfactants with a much higher surface activity than the single components. In equimolar mixtures of NaCnSO4 and CmTAB, all surface-active ions are paired. For mixtures with n + m = const, the interfacial properties are rather similar. Catanionics containing one long-chain surfactant and one surfactant with medium chain length exhibit a strong increase in surface activity as compared with the single compounds. In contrast, catanionics of one medium- and one short chain surfactant have a surface activity similar to that of the medium-chain surfactant alone. Both the Frumkin model and the reorientation model describe the experimental equilibrium data equally well, while the adsorption kinetics of the mixed medium- and short-chain surfactants can be well described only with the reorientation model.

The aim of this work was to investigate a possibility of preparing composite zein/natural resin (shellac and rosin) nanoparticles by antisolvent co?precipitation from their aqueous ethanol solutions. Influence of zein/resin mass ratio (1/0, 0.8/0.2, 0.5/0.5, 0.4/0.6 and 0/1) and pH (2?12) on particle size, d, and zeta potential, ?, of the prepared particles was studied. The functional properties of zein/rosin composite nanoparticles were evaluated by studying carvacrol encapsulation. It was shown that the antisolvent precipitation can be successfully used to prepare the shellac and rosin nanoparticles, as well as the composite zein/shellac and the zein/rosin nanoparticles. Colloidal properties, d and ?, of the obtained nanoparticles are influenced by the zein/ /resin mass ratio and the pH of nanoparticles? dispersions. The isoelectric point of composite nanoparticles can be modulated by varying the zein/resin mass ratio. It was found that the zein/rosin nanoparticles are suitable for carvacrol encapsulation, where carvacrol release is enhanced by increasing the rosin share in the composite zein/rosin nanoparticles.

Potential benefit of microencapsulation is its ability to deliver and protect incorporated ingredients such as vitamin E. Microcapsule wall properties can be changed by adding of coss-linking agents that are usually considered toxic for application. The microcapsules were prepared by a spray-drying technique using coacervation method, by depositing the coacervate formed in the mixture of chitosan and sodium lauryl ether sulfate to the oil/water interface. All obtained microcapsules suspensions had slightly lower mean diameter compared to the starting emulsion (6.85 +/- 0.213 mu m), which shows their good stability during the drying process. The choice and absence of cross-linking agents had influence on kinetics of vitamin E release. Encapsulation efficiency of microcapsules without cross-linking agent was 73.17 +/- 0.64 %. This study avoided the use of aldehydes as cross-linking agents and found that chitosan/SLES complex can be used as wall material for the microencapsulation of hydrophobic active molecules in cosmetic industry.

The objective of this study was to investigate interactions of zein (Z) and zein/rosin (Z/R) nanoparticles with gum arabic (GA), at different pH. Nanoparticles were firstly prepared by antisolvent precipitation of biopolymers from aqueous ethanol solutions. Nanoparticles suspensions were then dialyzed against water in order to remove ethanol and other impurities, and water suspensions of zein and zein/rosin nanoparticles were obtained. It was shown that composition of nanoparticles affects their surface charge density. Zeta potential of nanoparticles was positive without GA and changed to negative after addition of GA, at all pH tested. SEM analysis proved both Z and Z/R nanoparticles to be spherical and in size around 200 nm. The effect of addition of GA on particle size was determined using dynamic light scattering method. It was found that addition of GA increases size of nanoparticles at pH = 4 and pH = 5.5, from 150 - 220 nm to 250 - 320 nm. However, at pH = 3 it causes aggregation process, and diameter of particles increases up to few micrometres. Isothermal titration calorimetry was used to measure enthalpy changes in reaction between Z or Z/R nanoparticles and GA. Results showed that reaction between GA and Z or Z/R NPs is exothermic at each pH tested, except for Z NPs at pH = 3, where it was endothermic. At presented pHs, Z/R NPs were less charged compared to Z NPs, and their surface get saturated with GA molecules more rapidly. Z NPs showed greater enthalpy change in reaction with GA, compared to Z/R NPs.

Double emulsions are complex liquid dispersion systems in which the droplets of one dispersed liquid are further dispersed in another liquid, producing W/O/W or O/W/O emulsions. W/O/W emulsions are the most studied systems because they have great potential application. However, despite all the advantages, that these systems offer, it is very difficult to obtain stable formulations, and this is the reason for their limited practical application. The use of biopolymers to stabilize double emulsions could give rise to pharmaceutical and food applications. Based on previous studies, appropriate concentrations of gelatin and sodium caseinate (NaCAS) were selected to investigate the possibility of stabilization of double W/O/W emulsions by this system, if they are present in the outer aqueous phase. The investigations showed that interactions between gelatin and NaCAS in the outer water phase, as well as the composition of the mixtures of lipohilic emulsifiers used for the primary W/O emulsions preparation, influences the droplets size and sedimentation stability of double emulsions. The most stable emulsions were obtained at a NaCAS concentration when an insoluble coacervate forms (0.5 mass %) and at concentrations higher then this, when soluble negatively charged complexes adsorb at the oil/water interface.

Zein, a corn protein, is often used for preparing edible films and coatings. Since zein is insoluble in water, zein films and coatings are usually prepared by spraying or casting its aqueous ethanol solutions to a contact surface (Z(sol) films). However, the use of organic solvents in many food applications is unwanted. In this work, aqueous dispersions of zein nanoparticles were prepared by antisolvent precipitation from 90% v/v aqueous ethanol zein solutions. Zein films were then prepared by casting the dispersions in silicone molds and air-drying at 50 degrees C (Z(dis) films), The obtained films were characterized for morphology, FTIR analysis, mechanical, water barrier and optical properties, and were benchmarked against Z(sol) films. It was found that continuous zein films can be prepared out of aqueous dispersions of zein nanoparticles. Z(dis) films proved to have grainy morphology and higher surface roughness when compared to Z(sol). Surface roughness of Z(dis) films was decreased when plasticizer was added. Water barrier properties of Z(dis) films were found to be comparable to Z(sol) films. No differences in mechanical properties were found between Z(sol) and Z(dis) film. Size of zein particles influenced morphology and optical properties of zein dispersion films.

Chitosan is a cationic biopolymer, which attracts more and more attention in recent years, due to its exceptional physical and chemical properties, expressive biocompatibility and possibilities of obtaining from renewable sources. Formed polymer/surfactant complexes affect changes in the rheological properties and the final result is the formation of coacervates. The purpose of this study was to investigate the rheological properties of aqueous solutions of cationic polyelectrolyte, chitosan and sodium lauryl ether sulfate (SLES), an anionic surfactant, widely used in the cosmetics industry. Using the Thermo Haake RS600 rheometer, changes in the rheological and elastic properties of chitosan and SLES mixtures have been identified, gained as a result of the interaction of the components. In all examined samples coefficient of thixotropy was increasing with increase SLES concentration and achieves a maximum value at the mass ratio chitosan:SLES 1:2, after which it reduces. The oscillatory measurements in mixtures, performed by amplitude sweep method at low oscillating frequency 1 Hz, show that the linear viscoelastic region increases with increasing SLES concentration up to the same chitosan:SLES mass ratio. By monitoring the changes in the rheological parameters of the mixtures over five days, it was observed that the viscosity, the coefficient of thixotropy and elasticity were increasing, indicating that changes in the system occur over a longer period of time. In that manner, obtained results indicate the possibility of using rheological methods for a more detailed description of the interaction in the chitosan/SLES mixtures, important for their application in cosmetics and pharmaceutical industries.

Pumpkin (Cucurbita pepo) seed protein hydrolysate (PSPH) was obtained by enzymatic hydrolysis of pumpkin seed protein isolate using pepsin. Influence of pH (3, 5 and 8) and ionic strength, Ic (0?1 mol dm-3), on the adsorption kinetics of PSPH (diffusion rate constant, kdiff, and adsorption rate constant, kads), interfacial pressure (?) and interfacial dilatational properties (dilatational elasticity, E?, and viscosity, E?) of the oil?PSPH solution interfaces was investigated at different PSPH concentrations (c = 0.0014?14 g dm-3). It was found that PSPH adsorbs to the interface at c ? 0.0014 g dm-3, regardless of pH and ionic strength, as evidenced by the increase in interfacial pressure. The kdiff and kads value were found to be the highest at pH 3 and the lowest at pH 5 at the corresponding concentrations. The dilatational properties of the interfaces, which were investigated at different oscillation frequencies, ?, 0.01?0.2 Hz, showed that the E? of the oil?PSPH solution interfaces is much higher than its E?. Moreover, E? increases with increasing PSPH concentration at pH 5 and 8, and with increasing Ic, regardless of the pH, while E? changes only minimally.