Fabrication of high strength cold-set sodium alginate/whey protein nanofiber double network hydrogels and their interaction with curcumin

Sodium alginate hydrogel loaded with Capparis spinosa L. extract for antimicrobial and antioxidant wound dressing applications

Novel composite hydrogels composed of Capparis spinosa L. extract (CSL) and sodium alginate (SA) were developed for biomedical applications using calcium chloride (CaCl₂) as a nontoxic ionic crosslinker. The swelling degree, antioxidant activity, water retention, and biocompatibility of the CSL/SA composite hydrogels were thoroughly analyzed, along with their antibacterial properties. Scanning electron microscopy (SEM) results indicated that the CSL/SA composite hydrogels exhibited a three-dimensional porous structure with uniform pore distribution. Fourier transform infrared spectroscopy (FTIR) results suggested that CSL was successfully incorporated into composite hydrogels. When the CSL concentration reached 9 %, the swelling degree attained 765.89 ± 21.36 %. Furthermore, the addition of CSL enhanced the oxidation resistance of the composite hydrogels. Agar disk diffusion assessments confirmed that the CSL/SA composite hydrogels exhibited significant antibacterial effects against E. coli and S. aureus. Cytotoxicity studies demonstrated that the composite hydrogels effectively accelerated cell proliferation. Therefore, these hydrogels show promising potential for application as wound dressings.

Preparation, characterization, and application of composite oleogels based on whey protein isolate and sodium alginate

Oleogels with solid-like properties can serve as substitutes for fats, thereby avoiding the consumption of high levels of saturated fatty acids. In this study, we developed a protein-polysaccharide composite network oleogel using whey protein isolate (WPI) and sodium alginate (SA) through an emulsion-templated method. Analysis with Fourier Transform Infrared (FTIR) spectroscopy confirmed the presence of hydrogen bonds and van der Waals forces between WPI and SA, which bolstered the oleogel's structure. The enhanced oxidative stability and oil binding capacity of the WPI-SA composite oleogels were attributed to these interactions, as compared to the WPI single-network oleogel. Large-amplitude oscillatory shear testing demonstrated that the WPI-SA composite oleogels exhibited good plastic behavior and irreversible shear thinning, whereas the WPI single-network oleogel displayed more viscous behavior and shear-thinning characteristics. In applications, replacing pork fat entirely with the WPI-SA composite oleogel in Harbin red sausage resulted in a product with similar texture and sensory qualities to the original sausage. These results suggested that the WPI-SA composite oleogel could be a potential suitable fat substitute in the food industry, particularly for meat products.

Effect of inulin on structural, physicochemical, and in vitro gastrointestinal tract release properties of core-shell hydrogel beads as a delivery system for vitamin B12

In this study, core-shell hydrogel beads were developed as a controlled-release delivery system for vitamin B12. Vitamin B12-loaded microgels (MG) were prepared using gellan gum (GG). Core-shell hydrogel beads were produced by incorporating MG into pea protein isolate (PPI) and sodium alginate (AL) matrix filled/coated with different concentrations (0 %, 1 %, 3 %, 5 %, and 10 %) of inulin (IN). Based on XRD analysis, MG was successfully incorporated into core-shell hydrogel beads. In FE-SEM and FT-IR analyses, the smoother surface and denser structure of the beads were observed as IN concentration increased due to hydrogen bonds between IN and the beads. The encapsulation efficiency increased from 68.64 % to 82.36 % as IN concentration increased from 0 % to 10 %, respectively. After exposure to simulated oral and gastric conditions, core-shell hydrogel beads exhibited a lower cumulative release than MG, and a more sustained release was observed as IN concentration increased in simulated intestinal conditions.

Recent advances in nutraceutical delivery systems constructed by protein-polysaccharide complexes: A systematic review

Most nutraceuticals have low stability and solubility, making it difficult to achieve ideal bioavailability by directly incorporating into food. Therefore, constructing delivery systems to protect nutraceuticals is an essential strategy. Proteins and polysaccharides have become ideal materials for encapsulating nutraceuticals due to their superior nutritional value, edible safety, and physicochemical properties. This review first introduces the binding methods of protein-polysaccharide complexes and analyzes their respective merits, defects, and applications. Then, various protein-polysaccharide complex-based nutraceutical delivery systems are systematically summarized, including emulsions, gels, nanoparticles, microcapsules, complexes, and films, which can improve the stability, encapsulation efficiency, and bioaccessibility of nutraceuticals. In addition to traditional globular proteins mentioned in previous reviews, this review also introduces the advantages of another morphology of proteins (protein fibrils with linear structure) in the formation of protein-polysaccharide complexes and the construction of nutraceutical delivery systems. Next, the affecting factors are analyzed to achieve the precise control of protein-polysaccharide complex-based nutraceutical delivery systems. To improve public acceptability of protein-polysaccharide complex-based nutraceutical delivery systems, the safety and regulatory aspects are also discussed in detail. Moreover, the applications of such delivery systems are presented, including dietary supplements, food ingredients, food packaging, and food detection. Finally, several promising research directions that had not been provided before are innovatively proposed, including cell-cultured meat scaffolds, plant-based meat analogs, three-dimensional printing inks, and "three reductions" foods. Overall, this review provides guidance for designing protein-polysaccharide complex-based nutraceutical delivery systems with customized nutrition and superior bioavailability.

Chitosan/squid ring teeth protein hydrogels for the controlled release of curcumin

Biocompatible and degradable hydrogels are extensively utilized for the delivery and controlled release of bioactive agents. Chitosan/squid ring teeth protein (SRT) hydrogels (CH/SRTs) cross-linked by genipin were fabricated, and their gel properties and structural characteristics were analyzed across varying SRT contents. Additionally, the curcumin-release behavior of curcumin-loaded CH/SRTs (Cur-CH/SRTs) was evaluated. Results indicated that increasing SRT content enhanced the elasticity, viscosity, gel strength, hardness, and thermal stability of CH/SRTs. Specifically, the hardness and gel strength of CH/SRT3 (Chitosan: SRT, 1:1) were 207.8 % and 220.9 % higher, respectively, than those of the pure chitosan hydrogel. Higher SRT content significantly increased the curcumin encapsulation efficiency of Cur-CH/SRTs while substantially reducing curcumin release in simulated gastrointestinal fluid. Compared to the curcumin-loaded pure chitosan hydrogel, the curcumin release rate of Cur-CH/SRT3 decreased by 56.12 % after 480 min of simulated gastrointestinal digestion. These findings were attributed to reduced swelling and improved gel strength of Cur-CH/SRTs with SRT addition. Consequently, CH/SRTs demonstrate potential for applications in the controlled release of drugs and bioactive agents.

Ionic Crosslinking of Linear Polyethyleneimine Hydrogels with Tripolyphosphate

In this work, the mechanical properties of hydrogels based on linear polyethyleneimine (PEI) chemically crosslinked with ethyleneglycoldiglycidyl ether (EGDE) were improved by the ionic crosslinking with sodium tripolyphosphate (TPP). To this end, the quaternization of the nitrogen atoms present in the PEI structure was conducted to render a network with a permanent positive charge to interact with the negative charges of TPP. The co-crosslinking process was studied by 1H high-resolution magic angle spinning (1H HRMAS) NMR and X-ray photoelectron spectroscopy (XPS) in combination with organic elemental analysis and inductively coupled plasma mass spectrometry (ICP-MS). In addition, the mobility and confinement of water molecules within the co-crosslinked hydrogels were studied by low-field 1H NMR. The addition of small amounts of TPP, 0.03 to 0.26 mmoles of TPP per gram of material, to the PEI-EGDE hydrogel resulted in an increase in the deformation resistance from 320 to 1080%, respectively. Moreover, the adsorption capacity of the hydrogels towards various emerging contaminants remained high after the TPP crosslinking, with maximum loading capacities (qmax) of 77, 512, and 55 mg g-1 at pH = 4 for penicillin V (antibiotic), methyl orange (azo-dye) and copper(II) ions (metal ion), respectively. A significant decrease in the adsorption capacity was observed at pH = 7 or 10, with qmax of 356 or 64 and 23 or 0.8 mg g-1 for methyl orange and penicillin V, respectively.

Acid-induced hydrogels of edible Chlorella pyrenoidosa protein with composite biopolymers network

This study aimed to prepare Glucono-δ-lactone (GDL)-induced Chlorella pyrenoidosa protein (CPP) hydrogel and further investigate the effect of polysaccharides on the mechanical properties and stability enhancement of the composite hydrogels. Polysaccharides composed of different ratios of low acyl gellan gum (GE) and guar gum (GU) imparted dense honeycomb-like networks and adjustable textural properties to the composite hydrogels induced by CaCl2. In particular, the hardness of hydrogels increased significantly from 14 to 833 g. Scanning electron microscopy results revealed that CPP-GE/GU composite hydrogels had better stable spatial porous structures. Moreover, fourier transform infrared spectroscopy (FTIR) indicated hydrogen bonding interaction between CPP and GE/GU. The composite network showed improved viscoelasticity, increased thermal stability, and self-healing ability of hydrogels. The composite hydrogels also showed high water holding (89-98%) and swelling (747-862%) properties compared to the pure CPP hydrogel. These findings further expand CPP hydrogel products and broaden application in plant protein-based food.

Glucono-δ-lactone induced Auricularia auricula polysaccharide-casein composite gels for curcumin loading and delivery

Polysaccharides could be used to form the network structure of casein (CA) gel, and affect its gelling properties. Auricularia auricula polysaccharide (AAP) has good gel properties and activity, however, how the AAP affects gelling properties of CA gels remains unclear. In this study, AAP and CA were acid-induced by glucono-δ-lactone (GDL) to prepare composite gels for curcumin loading. The effects of different AAP additions on the gel structure were emphasized. Water holding capacity, rheology, texture profile analysis, sulfhydryl content, surface hydrophobicity and gel microstructure showed that the composite gels were most structurally stable upon addition of 0.4 % AAP. The composite gels exhibited a higher strength and a more regular network structure compared to the CA gels. The results of turbidity studies showed that CA and AAP formed gels through electrostatic interactions due to pH < pI. The results of FT-IR, X-ray diffraction, fluorescence spectroscopy, and UV-Vis spectroscopy indicated that curcumin interacted with the CA and was successfully encapsulated within the gel. In addition, in vitro simulated digestion experiments demonstrated that the composite gels exhibited better protection against curcumin than the single CA gel. The results suggested that composite gels can be used as a curcumin carrier, which may enhance its wider application in the food and health industries.

Construction of biopolymer-based hydrogel beads for encapsulation, retention, and colonic delivery of tributyrin: Development of functional beverages (fortified bubble tea)

Tributyrin (TB) can be hydrolyzed into short chain fatty acids (butyric acid) in the gastrointestinal tract, which are claimed to exhibit beneficial health effects in the colon. However, digestion of tributyrin in the stomach and small intestine may promote its absorption in the upper gastrointestinal tract, thereby reducing its potential colonic health benefits. In this study, we therefore developed a novel method of encapsulating emulsified tributyrin within biopolymer-based hydrogel beads (≈ 800 μm) that were then encapsulated inside the boba beads (≈ 8-10 mm) found in bubble tea. The hydrogel beads were designed to retain and protect the tributyrin under upper gastrointestinal tract (GIT) conditions, but then release it within the colon. The concentration of tributyrin within the boba beads was 33.3 mg/g, which is above the value reported to exhibit health benefits. The morphology, encapsulation properties, water holding capacity, stability, and swelling properties of the tributyrin-loaded boba beads were characterized. Tapioca-based beads exhibited a larger degree of swelling when incubated in water for 12h (>95 %), whereas agar-based beads did not (< 20 %). In addition, the potential gastrointestinal fate of both free and encapsulated tributyrin oil droplets was assessed using an in vitro digestion model. The free tributyrin oil droplets were almost completely hydrolyzed (103.2 %) by the end of the small intestine phase, whereas the tributyrin oil droplets encapsulated within the agar-based (29.4 %) or tapioca-based (40.3 %) boba beads were much more resistant to digestion. The tapioca-based beads were partially broken down as they passed through the simulated GIT, while the agar-based beads maintained their structural integrity. The tapioca-based beads were gradually broken down as they passed through the simulated GIT, while the agar-based ones maintained their structural integrity. Agar beads were also harder, more resilient, and chewier than the tapioca ones. Both types of boba beads tended to swell and disintegrate when heated to high temperatures (90 °C), with the effect being more pronounced for the agar beads. Overall, our results suggest that the agar-based boba beads had greater potential for the delivery of tributyrin to the colon than the tapioca-based ones. The recent popularity of bubble tea means that it may be a suitable vehicle for delivering bioactive food components, like functional lipids, vitamins, nutraceuticals, or probiotics.

Preparation, structural characterization, and functional properties of wheat gluten amyloid fibrils-chitosan double network hydrogel as delivery carriers for ferulic acid

It has been demonstrated that ferulic acid (FA) can be effectively encapsulated using wheat gluten amyloid fibrils (AF) and chitosan (CS) in a double network hydrogel (DN) form, with cross-linking mediated by Genipin (GP). Within this system, the DN comprising gluten AF-FA and CS-FA exhibited optimal loading metrics at a formulation designated as DN8, achieving a load efficiency of 88.5 % and a load capacity of 0.78 %. Analysis through fluorescence quenching confirmed that DN8 harbored the highest quantity of FA. Fourier-transform infrared spectroscopy (FTIR) further verified a significant increase in β-sheet content post-hydrogel formation, enhancing the binding capacity for FA. Rheological assessments indicated a transition from solution to gel, delineating the phase state of the DN. Comprehensive in vitro digestion studies revealed that DN8 provided superior sustained release properties, exhibited the highest total antioxidant capacity, and displayed potent inhibitory activities against angiotensin I converting enzyme (ACE) and acetylcholinesterase (Ach-E). Additionally, the DN significantly bolstered the stability of FA against photothermal degradation. Collectively, these findings lay foundational insights for the advancement of the wheat gluten AF-based delivery system for bioactive compounds and provided a theoretical basis for the development of functional foods.

Foods of the Future: Challenges, Opportunities, Trends, and Expectations

Creating propositions for the near and distant future requires a design to catch the tide of the times and move with or against trends. In addition, appropriate, adaptable, flexible, and transformational projects are needed in light of changes in science, technology, social, economic, political, and demographic fields over time. Humanity is facing a period in which science and developing technologies will be even more important in solving food safety, health, and environmental problems. Adapting to and mitigating climate change; reducing pollution, waste, and biodiversity loss; and feeding a growing global population with safe food are key challenges facing the agri-food industry and the food supply chain, requiring systemic transformation in agricultural systems and sustainable future agri-food. The aim of this review is to compile scientific evidence and data, define, and create strategies for the future in terms of food security, safety, and sufficiency; future sustainable foods and alternative protein sources; factors affecting food and nutrition security and agriculture; and promising food systems such as functional foods, novel foods, synthetic biology, and 3D food printing. In this review, the safety, conservation, nutritional, sensory, welfare, and potential challenges and limitations of food systems and the opportunities to overcome them on the basis of new approaches, innovative interpretations, future possibilities, and technologies are discussed. Additionally, this review also offers suggestions for future research and food trends in light of future perspectives. This article focuses on future sustainable foods, alternative protein sources, and novel efficient food systems, highlights scientific and technological advances and new research directions, and provides a significant perspective on sustainability.

Food Protein Nanofibril Gels: From Conditions, Types and Properties to Applications

Many food proteins can be assembled into nanofibrils under pH conditions far from the isoelectric point and with a low ionic strength by heating them for a long period. These food protein nanofibrils (FPN) have outstanding functional and biological properties and are considered sustainable biomaterials in many fields. In this study, we review the recent developments in FPN gels and introduce the key factors in promoting food protein self-assembly in order to create functional gels. The major variables discussed are the morphology of nanofibrils, protein concentration, heating time, and the type and concentration of salts. We also highlight current advances in the formation and properties of different types of FPN gels. In addition, the various applications of FPN gels in bioactive and nutrient delivery, adsorbents for CO2 and toxic pollutants, cell scaffolding biomaterials, biosensors, and others are introduced and discussed.

Recoverable and degradable carboxymethyl chitosan polyelectrolyte hydrogel film for ultra stable encapsulation of curcumin

Hydrogels have shown great potential for application in food science due to their diverse functionalities. However, most hydrogels inevitably contain toxic chemical cross-linking agent residues, posing serious food safety concerns. In this paper, a curcumin/sodium alginate/carboxymethyl chitosan hydrogels (CSCH) were prepared by self-assembly of two oppositely charged polysaccharides, carboxymethyl chitosan and sodium alginate, to form a three-dimensional network encapsulating curcumin for extending food shelf life. The network structure of the CSCH film confirmed by FTIR, XRD, and XPS was mainly formed by electrostatic interactions. The chemical stability of CSCH network encapsulated curcumin was 4.2 times greater than that of free curcumin, with excellent gas barrier, antimicrobial, antioxidant, and biosafety properties. It was found that CSCH films reduced dehydration, prevented nutrient loss, inhibited microbial growth, and lowered the respiration rate, which effectively maintained the quality of mango and prolonged its shelf-life up to 11 days. Notably, CSCH films possessed the properties of rapid recycling (10 mins) and biodegradability (53 days). This polysaccharide-based hydrogel film provides a viable strategy for the development of green and sustainable food packaging.

Formation of pH-responsive hydrogel beads and their gel properties: Soybean protein nanofibers and sodium alginate

Hydrogel beads prepared from protein nanofibers are popular because of their safety, sleek appearance, and protection of biologically active substances. However, extreme external environmental variations, such as pH and temperature, can limit their practical application. To meet the application requirements of hydrogel beads in different environments, non-covalent mixtures of CaCl2 cross-linked soybean protein nanofibers (SNF) and sodium alginate (SA) were used to prepare hydrogel beads. In the present study, the hardness (782.48 g) and elasticity of hydrogel beads formed at SNF/SA = 7:3 and CaCl2 concentration of 0.1 mol/L were the maximum. Furthermore, the water content and pH swelling also reached a peak (98.68 %, 43.85 g/g) due to the best morphology and regular internal network structure. Meanwhile, the pH-responsive hydrogel beads with added anthocyanins were able to respond to the ambient pH under different temperatures and pH conditions and maintained color stability during 96 h of storage (ΔE < 5). In this experiment, a pH-responsive hydrogel bead based on soybean protein nanofiber (SNF) and sodium alginate (SA) was prepared by simple ionic crosslinking. It provides a theoretical and experimental basis for the future application of plant protein nanofibers as pH-responsive hydrogel materials.

Lysozyme amyloid fibril-chitosan double network hydrogel: Preparation, characterization, and application on inhibition of Nε-(carboxyethyl)lysine

Nε-(carboxyethyl)lysine (CML), a typical advanced glycosylation end product produced during the processing of meat under high temperature, poses health risks. Active substances like polyphenols are known to inhibit the formation of harmful products during the processing of food. In this study, our objective was to prepare a double network hydrogel (DN) loaded with gallic acid using amyloid fibers and chitosan as a rigid and flexible network, respectively. The network as well as the interactions between the two networks were observed and analyzed. Chitosan concentration was the key factor regulating the structure and properties of the DN. At a chitosan concentration of 0.7%wt, the structure of DN became dense and its mechanical properties were improved, with the loading capacity and loading efficiency being increased by 143.79 % and 128.21 %, compared with those of amyloid fibril alone. Furthermore, the digestibility of gallic acid in simulated intestinal fluid was increased by 215.10 %. Moreover, adding DN to the beef patties effectively inhibited the formation of CML in a dose-response dependent manner. Addition of 3 wt% DN resulted in the inhibitory rate of CML in roast beef patties reaching a high 73.09 %. The quality and palatability of beef patties were improved. These findings suggest that DN shows great potential as an application that may be utilized to deliver active substances aimed at inhibiting CML in the meat processing industry.

Effect of Molecules' Physicochemical Properties on Whey Protein/Alginate Hydrogel Rheology, Microstructure and Release Profile

The encapsulation of molecules with different physicochemical properties (theophylline, blue dextran, salicylic acid and insulin) in whey protein (WP) and alginate (ALG) microparticles (MP) for oral administration was studied. MP based on WP/ALG were prepared by a cold gelation technique and coated with WP solution after reticulation. Molecules influenced polymer solution viscosity and elasticity, resulting in differences regarding encapsulation efficiency (from 23 to 100%), MP structure and swelling (>10%) and in terms of pH tested. Molecule release was due to diffusion and/or erosion of MP and was very dependent on the substance encapsulated. All the loaded MP were successfully coated, but variation in coating thickness (from 68 to 146 µm) and function of the molecules encapsulated resulted in differences in molecule release (5 to 80% in 1 h). Gel rheology modification, due to interactions between WP, ALG, calcium and other substances, was responsible for the highlighted differences. Measuring rheologic parameters before extrusion and reticulation appeared to be one of the most important aspects to study in order to successfully develop a vector with optimal biopharmaceutical properties. Our vector seems to be more appropriate for anionic high-molecular-weight substances, leading to high viscosity and elasticity and to MP enabling gastroresistance and controlled release of molecules at intestinal pH.

Gallic acid-functionalized soy protein-based multiple cross-linked hydrogel: Mechanism analysis, physicochemical properties, and digestive characteristics

Herein, carbodiimide hydrochloride/N-hydroxysuccinimide was used to mediate the grafting of gallic acid (GA) (0.005, 0.0015, and 0.025 wt%) with soybean protein isolate (SPI) in the preparation of SPI-GA conjugates and hydrogels. The modified materials were primarily joined via the CN bonds and exhibited excellent antioxidant properties. In addition, spectral analysis revealed that the grafting of GA increased the flexibility of the SPI structure. The SPI-GA hydrogel is fabricated through covalent/non-covalent cross-linking mechanisms, including Schiff base, Michael addition, and hydrogen bonding. Furthermore, the microstructure, rheological properties, thermal stability, and textural properties of the hydrogel were affected by the amount of GA grafted. The SPI-GA hydrogel exhibited the best performance when the amount of GA graft was 0.015 wt%. Furthermore, the tightly cross-linked structure of SPI-GA prevented premature degradation of the protein by pepsin. In conclusion, these capabilities provide numerous possibilities for the development of multifunctional and active substance delivery carriers.

3D Printing of smart labels with curcumin-loaded soy protein isolate

A two-step method for preparing smart labels that can monitor food freshness through color change is presented. The conventional casting method for such labels is not cost-effective, as it uses organic solvents and requires additional cutting processes. Our method is more eco-friendly and customizable, as it uses water as the sole solvent and 3D printing as the fabrication technique. First, curcumin was encapsulated with soy protein isolate (SPI) by a pH-driven method involving hydrogen bonding and hydrophobic interactions. Subsequently, the SPI-curcumin complex was blended with gelatin to create a printable ink. The ink has suitable rheological properties for extrusion, with a yield stress of 400-600 Pa and a viscosity of 122.93-142.82 Pa·s at the optimal printing temperature. The complex modulus of the ink increases to above 2 × 103 Pa when cooled to 25 °C, indicating rapid gel formation. The application of these smart labels to minced meat demonstrated their ability to reflect its freshness by transitioning from yellow to red. Furthermore, the printability and mechanical properties of the labels can be adjusted by changing the glycerol/water ratio. This innovative approach is a promising solution for producing environmentally friendly and customizable smart labels for food freshness monitoring.

Protein-Stabilized Emulsion Gels with Improved Emulsifying and Gelling Properties for the Delivery of Bioactive Ingredients: A Review

In today's food industry, the potential of bioactive compounds in preventing many chronic diseases has garnered significant attention. Many delivery systems have been developed to encapsulate these unstable bioactive compounds. Emulsion gels, as colloidal soft-solid materials, with their unique three-dimensional network structure and strong mechanical properties, are believed to provide excellent protection for bioactive substances. In the context of constructing carriers for bioactive materials, proteins are frequently employed as emulsifiers or gelling agents in emulsions or protein gels. However, in emulsion gels, when protein is used as an emulsifier to stabilize the oil/water interface, the gelling properties of proteins can also have a great influence on the functionality of the emulsion gels. Therefore, this paper aims to focus on the role of proteins' emulsifying and gelling properties in emulsion gels, providing a comprehensive review of the formation and modification of protein-based emulsion gels to build high-quality emulsion gel systems, thereby improving the stability and bioavailability of embedded bioactive substances.

Nanofiber Scaffolds as Drug Delivery Systems Promoting Wound Healing

Nanofiber scaffolds have emerged as a revolutionary drug delivery platform for promoting wound healing, due to their unique properties, including high surface area, interconnected porosity, excellent breathability, and moisture absorption, as well as their spatial structure which mimics the extracellular matrix. However, the use of nanofibers to achieve controlled drug loading and release still presents many challenges, with ongoing research still exploring how to load drugs onto nanofiber scaffolds without loss of activity and how to control their release in a specific spatiotemporal manner. This comprehensive study systematically reviews the applications and recent advances related to drug-laden nanofiber scaffolds for skin-wound management. First, we introduce commonly used methods for nanofiber preparation, including electrostatic spinning, sol-gel, molecular self-assembly, thermally induced phase separation, and 3D-printing techniques. Next, we summarize the polymers used in the preparation of nanofibers and drug delivery methods utilizing nanofiber scaffolds. We then review the application of drug-loaded nanofiber scaffolds for wound healing, considering the different stages of wound healing in which the drug acts. Finally, we briefly describe stimulus-responsive drug delivery schemes for nanofiber scaffolds, as well as other exciting drug delivery systems.

Binary Alginate-Whey Protein Hydrogels for Antioxidant Encapsulation

Encapsulation of antioxidants in hydrogels, i.e., three-dimensional networks that retain a significant fraction of water, is a strategy to increase their stability and bioaccessibility. In fact, low oxygen diffusivity in the viscous gelled phase decreases the rate of oxidation. Moreover, some hydrocolloids such as alginate and whey proteins provide a pH-dependent dissolution mechanism, allowing the retention of encapsulated compounds in the gastric environment and their release in the intestine, where they can be absorbed. This paper reviews the information on alginate-whey protein interactions and on the strategies to use binary mixtures of these polymers for antioxidant encapsulation. Results showed that alginate and whey proteins strongly interact, forming hydrogels that can be modulated by alginate molecular mass, mannuronic acid: guluronic acid ratio, pH, Ca2+ or transglutaminase addition. Hydrogels of alginate and whey proteins, in the forms of beads, microparticles, microcapsules, and nanocapsules, generally provide better encapsulation efficiency and release properties for antioxidants with respect to the hydrogel of alginate alone. The main challenges for future studies are to extend knowledge on the interactions among three components, namely alginate, whey proteins, and the encapsulated bioactive compounds, and to investigate the stability of these structures under food processing conditions. This knowledge will represent the rationale basis for the development of structures that can be tailored to specific food applications.

Protein-Based Fat Replacers: A Focus on Fabrication Methods and Fat-Mimic Mechanisms

The increasing occurrence of obesity and other non-communicable diseases has shifted the human diet towards reduced calorie intake. This drives the market to develop low-fat/non-fat food products with limited deterioration of textural properties. Thus, developing high-quality fat replacers which can replicate the role of fat in the food matrix is essential. Among all the established types of fat replacers, protein-based ones have shown a higher compatibility with a wide range of foods with limited contribution to the total calories, including protein isolate/concentrate, microparticles, and microgels. The approach to fabricating fat replacers varies with their types, such as thermal-mechanical treatment, anti-solvent precipitation, enzymatic hydrolysis, complexation, and emulsification. Their detailed process is summarized in the present review with a focus on the latest findings. The fat-mimic mechanisms of fat replacers have received little attention compared to the fabricating methods; attempts are also made to explain the underlying principles of fat replacers from the physicochemical prospect. Finally, a future direction on the development of desirable fat replacers in a more sustainable way was also pointed out.