Protein-neutral polysaccharide nano- and micro-biopolymer complexes fabricated by lactoferrin and oat β-glucan: Structural characteristics and molecular interaction mechanisms

Impact of trypsin on interfacial conformational evolution of soy protein isolate/soy hull polysaccharide emulsion

The impact of trypsin on the demulsification mechanism of soy protein isolate (SPI)/soy hull polysaccharide (SHP) emulsion under trypsin treatment was investigated. We analyzed the conformational evolution of the emulsion interface induced during the bulk demulsification, focusing on the oil-water interface. During the enzymatic treatment for 0-120 min, various spectral analyses including spectrum analyses of Raman, FT-IR, intrinsic fluorescence, and ultraviolet spectral analyses demonstrated gradual hydrolysis and polymerization of protein molecules within SPI/SHP, SPI, and SHP on the oil-water interface by trypsin, particularly noticeable during 30-90 min. Notably, at 90 min, an increase in β-sheet content and a red shift of the IR spectrum from 3400 to 3380 cm-1 indicated the conjugate effect of small molecules due to large interfacial tension, accompanied by hydrophobic interaction and hydrogen bonding. These alterations in SPI/SHP, SPI, and SHP conformations at the oil-water interface led to droplet demulsification and oil phase release.

Enhancing emulsification properties of pea protein isolate: Impact of heat treatment and soy hull polysaccharides on conformational modification and stability

In order to investigate the effect of conformational change in pea protein isolate (PPI) on its emulsification properties, soy hull polysaccharides (SHP) were added to modify the conformation following heat treatment at 70-100 °C to improve emulsification. The results of UV and fluorescence spectroscopy indicated that the heat treatment exposed the amino acid residues to a more hydrophobic environment. The mean volume diameter (d4,3) of PPI was reduced from 67.25 ± 3.31 to 45.50 ± 0.62 μm, and secondary structure of protein became more ordered. The addition of SHP enhanced the adsorption of protein at the oil-water interface and reduced the interfacial tension. Interestingly, SHP decreased the short-term (12h) thermal stability index (TSI) from 3.5 to 2.8 in PPI/SHP emulsion treated at 100 °C. These findings validated that heat treatment combined with SHP modification can improve the emulsification of PPI, which positively impacts the development of pea-based products for high temperatures applications.

Preparation and characterization of quercetin-loaded nanoparticles based on soy protein isolate-oat β-glucan extrudates: Interaction, structure, stability, and in vitro release properties

Soy protein isolate (SPI)-oat β-glucan (OG) conjugates produced by extrusion were used to prepare nanoparticle carriers for improving quercetin stability. The 70-130 °C SPI-OG extrudate nanoparticles exhibited higher encapsulation efficiency (EE, 75.63-80.30 %) and loading capacity (LC, 46.22-50.83 %), especially 90°C (EE and LC were 80.30 % and 50.83 %, respectively) and 110 °C (EE and LC were 79.84 % and 49.26 %, respectively) SPI-OG extrudate nanoparticles. The average particle size of quercetin-loaded SPI-OG extrudate nanoparticles ranged from 185.77 nm to 244.07 nm. SPI-OG extrudates around quercetin were tightly bound to it through hydrogen bonding and hydrophobic interactions, resulting in the structure of quercetin to change from crystalline state to amorphous state. Stability results of quercetin indicated that SPI-OG extrudate nanoparticles could more effectively protect the antioxidant activity of quercetin and improve its storage stability (quercetin retention of 31.89-39.82 % after 21 days). Meanwhile, SPI-OG extrudate nanoparticles mainly continuously released quercetin during the simulated intestinal digestion (cumulative release rate was 18.99-21.10 % in intestinal stage). These results indicated that SPI-OG extrudate nanoparticles could effectively encapsulate quercetin and prolong its biological activity, thus could be applied in nutritional supplements and functional foods.

Mechanism underlying the effect of soluble oat β-glucan and tea polyphenols on wheat gluten aggregation characteristics

The mechanism of how the coexistence of oat β-glucan (OβG) and tea polyphenols (TP) impacts gluten aggregation properties was investigated. The OβG might form interchain hydrogen bondings and compete for water with gluten, which could increase gluten aggregation and the gluten network's expansion, leading to its increasing average particle size (by 17.23 %) with 5%OβG. The physicochemical characteristics of TP and OβG + TP groups showed similar changing trends, indicating the predominant effect of TP; however, the effect was, to some extent, enhanced with the presence of OβG. This might be because OβG induced a more expanded network of gluten, favoring the access and attack of TP to unfold or disrupt the gluten structure by breaking disulfide bonds, as confirmed by the red-shifts in fluorogram, increasing content of free sulfhydryl by 250 % (without OβG) and 312 % (with OβG), and decreasing particle size of gluten by 10.43 % (without OβG) and 21.08 % (with OβG) when the addition of TP was 2 %. Moreover, with the increasing of TP, the tremendous unfolding or disrupting gluten structure exposed more amino acids whereas decreased the intermolecular contacts and extended chains of gluten, consequently leading to the increasing hydrogen bonds and hydrophobic interactions while reducing the content of β-sheets, respectively.

Analysis of sediment re-formation factors after ginseng beverage clarification based on XGBoost machine learning algorithm

The aim of this study was to explore the sediment re-formation factors of ginseng beverages subjected to four clarification ways (11 subgroups) including the ethanol precipitation, enzymatic treatment, clarifier clarification, and Hollow Fiber Column (HFC) methods, based on the Extreme Gradient Boosting (XGBoost) model. The results showed that the clarity of the ginseng beverages was significantly improved by all the clarification treatments, but still formed sediment after storage. HFC method exhibited the highest transmittance, the least sediment, and stronger antioxidant activity in the clarification treatment groups. According to the results of chemical composition analyses and partition coefficients, carbohydrates, saponins, proteins and metal elements were involved in varying degrees in the re-formation of the sediments in ginseng beverage after clarification. Based on the above data, the XGBoost model predicted that protein, Rd, Na, K, and total saponins were the five most important chemical components affecting the sediment re-formation in ginseng beverages.

Effects of interaction between wheat bran dietary fiber and gluten protein on gluten protein aggregation behavior

Effects of wheat bran dietary fiber (WBDF) as a nutritional additive on flour products quality mainly depends on the interaction between WBDF and gluten protein. In this study, the effects and mechanisms of WBDF with different particle sizes and additive amounts on gluten protein aggregation behavior were investigated. The results showed that the addition of WBDF led to a decrease in free sulfhydryl content, particle size, molecular weight and gluten macromer (GMP) content, an increase in zeta potential and SDS-extractable protein content, and a deterioration in the gluten network morphology compared to the control group, suggesting that the aggregation behavior of gluten protein was inhibited. When WBDF was added at 3 % and 6 %, dilution effect, mechanical shear, steric hindrance, and non-covalent binding were the main mechanisms leading to depolymerization. Further addition of WBDF (9 %, 12 %) inhibited the depolymerization of gluten protein due to competitive hydration and non-covalent binding. However, when WBDF was added at 15 %, the dilution effect, mechanical shear and steric hindrance of WBDF (88 μm < particle size<150 μm) dominated, and their inhibitory of aggregation induced the formation of a loose gluten network structure. In contrast, the weaker mechanical shear and steric hindrance effects of WBDF (particle size<88 μm) mitigated the degradation of gluten network structures by WBDF.

Comparative study of Maillard reaction and blending between soybean protein isolate and soluble soybean polysaccharide: Physicochemical, structure and functional properties

Soybean protein isolate-soluble soybean polysaccharide (SPI-SSPS) complexes and mixtures with varying SPI/SSPS concentration ratios (1: 1, 2:1, 4:1, 8:1) were prepared by Maillard reaction and blending, respectively, and their physicochemical, structure, and functional properties were compared studied. The physical stability of SPI-SSPS complex, which consisted of CN and CS bonds, was better than that of the SPI/SSPS mixture with electrostatic interactions and hydrogen bonds, and both were superior SPI alone. The complex with SPI/SSPS concentration ratio of 8:1 had the highest grafting degree (33.25 %) and a more ordered structure, making its solubility and emulsifying property lower than the SPI/SSPS mixture; however, the physical and thermal stability of the SPI-SSPS complex was higher than that of the SPI and SPI/SSPS mixture. In particular, the SPI-SSPS complex with a high grafting degree showed a higher thermal denaturation temperature (194.06 °C). This study aimed to provide effective modification methods to utilize soybean processing by-products by modifying soybean protein isolate with soluble soybean polysaccharide.

Effect of pH, protein/polysaccharide ratio and preparation method on the stability of lactoferrin-polysaccharide complexes

In this study, carrageenan (CG), xanthan gum (XG) and locust bean gum (LBG), which can be used in infant formulas in China national standards, were selected to prepare LF-polysaccharide complexes to improve the stability of lactoferrin. The results showed that LF interacted more strongly with polysaccharides and did not affect the LF structure to a large extent when the pH and protein/polysaccharide mass ratio were 7 and 10:1 for LF-CG, 8 and 5:1 for LF-XG, 7 and 15:1 for LF-LBG. The zeta potential and fluorescence intensity of the LF-polysaccharide complexes displayed a decreasing trend with the increase in pH. When pH < 6, LF-CG and LF-XG exhibited precipitation and increased UV absorbance. Complexation between LF and CG/XG mainly attributed to electrostatic interactions, while LF and LBG form complexes based on hydrogen bonding or hydrophobic interactions. This study could provide a reference for the practical application of LF in infant formula.

An investigation of a strengthening polysaccharide interfacial membrane strategy utilizing an anionic polysaccharide-alkaline ligand interfacial assembly for all-liquid printing

The applications of polysaccharides as emulsifiers are limited due to the lack of hydrophobicity. However, traditional hydrophobic modification methods used for polysaccharides are complicated and involve significant mechanical and thermal losses. In this study, soy hull polysaccharide (SHP) and terminally aminopropylated polydimethylsiloxane (NPN) were selected to investigate the feasibility of a simple and green interfacial membrane strengthening strategy based on the interfacial polymerization of anionic polysaccharides and fat-soluble alkaline ligands. Our results show that deprotonated SHP and protonated NPN can be complexed at the water/oil (W/O) interface, reduce interfacial tension, and form a strong membrane structure. Moreover, they can quickly form a membrane at the W/O interface upon the moment of contact to produce stable all-liquid printing products with complex patterns. However, the molecular weight of NPN affects the complexation reaction. Consequently, this study has long-term implications to expanding the areas of application for anionic polysaccharides.

Characterization and in vitro calcium release of the novel calcium-loaded complexes using Antarctic krill protein and pectin: Effect of different blending sequences

Food-grade biopolymer-based complexes are of particular interest in the field of biologic ingredient delivery owing to unique controlled-release properties. Herein, three calcium-loaded complexes using Antarctic krill protein (P) and pectin (HMP) with different blending sequences were designed, named P + Ca + HMP, P + HMP + Ca and HMP + Ca + P, respectively. The calcium-loaded capacity, structural properties, and in vitro gastrointestinal calcium release of the complexes were investigated. The results demonstrated that the calcium binding rate and content of the P + Ca + HMP complex were the highest, reaching to 90.3 % and 39.0 mg/g, respectively. Particularly, the P + Ca + HMP complex exhibited a more stable fruit tree-like structure. Furthermore, the structural analysis confirmed that the primary interaction forces involved hydrogen bond, electrostatic, hydrophobic and ionic bond interaction. Ultimately, the P + Ca + HMP complex demonstrated superior calcium delivery. In conclusion, a novel calcium delivery system was successfully developed based on optimized the self-assembly sequence, which held significant importance in promoting the high-value utilization of Antarctic krill protein and enhancing the in vitro bioaccessibility of calcium.

Formation and non-covalent interactions of binary and ternary complexes based on β-casein, Lentinus edodes mycelia polysaccharide, and taxifolin

Polyphenols, polysaccharides, and proteins are essential nutrients and functional substances present in food, and when present together these components often interact with each other to influence their structure and function. Proteins and polysaccharides are also excellent carrier materials for polyphenols. In this context, this study investigated the non-covalent interactions between taxifolin (TAX), Lentinus edodes mycelia polysaccharide (LMP), and β-casein (β-CN). β-CN and LMP spontaneously formed nanocomplexes by hydrogen bonds and van der Waals forces. The quenching constant and binding constant were (1.94 ± 0.02) × 1013 L mol-1 s-1 and (3.22 ± 0.17) × 105 L mol-1 at 298 K, respectively. The altered conformation of β-CN, resulting from the binding to LMP, affected the interaction with TAX. LMP significantly enhanced the binding affinity of TAX and β-CN, but did not change the static quenching binding mode. The binding constant for β-CN-TAX was (3.96 ± 0.09) × 1013 L mol-1, and that for the interaction between TAX and β-CN-LMP was (32.06 ± 0.05) × 1013 L mol-1. In summary, β-CN-LMP nanocomplexes have great potential as a nanocarrier for polyphenols, and this study provides a theoretical foundation for the rational design of non-covalent complexes involving LMP and β-CN, both in binary and ternary configurations.

High moisture extrusion of soybean protein isolate: Effect of β-glucan on physicochemical properties of extrudates

This study is focused on exploring the effect of twin-screw high-moisture extrusion technology on the physico-chemical properties of β-glucan-soybean protein isolate (SPI-BG) extrudates. Different proportions (0 %, 1 %, 2 %, 3 %, 4 %, 5 %) of oat β-glucan (BG) were added with soybean protein isolate (SPI) to prepare SPI-BG extrudates. Results showed that the addition of a high quantity of β-glucan (BG) decreased the elastic properties of soy protein isolate (SPI) extrudates and then increased. The strengthening of S1-S2-S3 interactions (hydrogen bonds, hydrophobic interactions, and disulfide bonds) was primarily responsible for this trend. Fourier transform infrared (FTIR) spectral analysis was conducted which revealed that BG did not significant affect random coil content of SPI. However, it was observed that α-helix content was increased significantly and the β-sheet content was decreased. An observation was noted in the value of enthalpy (ΔH) change that increased from 115.80 J/g to 159.68 J/g.

The effects of ultrasonic processing on the antioxidant activity of Geotrichum candidum LG-8 and its cell wall extracts

Introduction

Extraction techniques that influence cell wall polysaccharides (EPS) is crucial for maximizing their bioactivity. This study evaluates ultrasound technology for extracting antioxidant polysaccharides from Geotrichum candidum LG-8, assessing its impacton antioxidant activity.

Methods

Ultrasound extraction of EPS from G. candidum LG-8 was optimized (18 min, pH 7.0, 40 W/cm2, 0.75 M NaCl). ABTS scavenging efficiency and monosaccharide composition of LG-EPS1 and LG-EPS3 were analyzed using Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM).

Results

The Results showed that ultrasonic treatment markedly increased the ABTS radical scavenging efficiency of LG-8 cells by 47%. At a concentration of 1 mg/mL, the ultrasonically extracted LG-EPS1 and LG-EPS3 polysaccharides exhibited significant ABTS radical scavenging efficiencies of 26% and 51%, respectively. Monosaccharide composition analysis identified mannose and glucose in LG-EPS1, while LG-EPS3 was primarily composed of mannose. FTIR spectra verified the polysaccharides' presence, and SEM provided visual confirmation of the nanoparticle structures characteristic of LG-EPS1 and LG-EPS3.

Discussion

This research not only underscores the technological merits of ultrasound in polysaccharide extraction but also highlights the potential of G. candidum LG-8 derived polysaccharides as valuable bioactive compounds for antioxidant utilization.

Recent progress and treatment strategy of pectin polysaccharide based tissue engineering scaffolds in cancer therapy, wound healing and cartilage regeneration

Natural polymers and its mixtures in the form of films, sponges and hydrogels are playing a major role in tissue engineering and regenerative medicine. Hydrogels have been extensively investigated as standalone materials for drug delivery purposes as they enable effective encapsulation and sustained release of drugs. Biopolymers are widely utilised in the fabrication of hydrogels due to their safety, biocompatibility, low toxicity, and regulated breakdown by human enzymes. Among all the biopolymers, polysaccharide-based polymer is well suited to overcome the limitations of traditional wound dressing materials. Pectin is a polysaccharide which can be extracted from different plant sources and is used in various pharmaceutical and biomedical applications including cartilage regeneration. Pectin itself cannot be employed as scaffolds for tissue engineering since it decomposes quickly. This article discusses recent research and developments on pectin polysaccharide, including its types, origins, applications, and potential demands for use in AI-mediated scaffolds. It also covers the materials-design process, strategy for implementation to material selection and fabrication methods for evaluation. Finally, we discuss unmet requirements and current obstacles in the development of optimal materials for wound healing and bone-tissue regeneration, as well as emerging strategies in the field.

Impact of soybean protein isolate concentration on chitosan-cellulose nanofiber edible films: Focus on structure and properties

Chitosan and cellulose nanofiber films are frequently employed as biodegradable materials for food packaging. However, many exhibit suboptimal hydrophobicity and antioxidant properties. To address these shortcomings, we enhanced the performance by adding different concentrations of soybean protein isolate (SPI) to chitosan-cellulose nanofiber (CS-CNF) films. As SPI concentration varied, the turbidity, particle size, and ζ-potential of the film-forming solutions initially decreased and subsequently increased. This suggests that 1 % SPI augments the electrostatic attraction and compatibility. Rheological analysis confirmed a pronounced apparent viscosity at this concentration. Analyses using Fourier transform infrared spectra, Raman spectra, X-ray diffraction, and Scanning electron microscope revealed the presence of hydrogen bonds and electrostatic interactions between SPI and CS-CNF, indicative of superior compatibility. When SPI concentration was set at 1 %, notable enhancements in film attributes were observed: improvements in tensile strength and elongation at break, a reduction in water vapor permeability by 8.23 %, and an elevation in the contact angle by 18.85 %. Furthermore, at this concentration, the ABTS+ and DPPH scavenging capacities of the film surged by 61.53 % and 46.18 %, respectively. Meanwhile, the films we prepare are not toxic. This research offers valuable insights for the advancement and application of protein-polysaccharide-based films.

Promising effects of β-glucans on gelation in protein-based products: A review

Gel property is one of the most important abilities to endow protein-based food products with a unique texture and higher overall acceptability. Cereal β-glucan (BG) is widely applied in protein-based products to improve the stability of the protein gel by increasing water holding capacity, storage modulus (G'), loss modulus (G") and linking with protein through more exposed sites, making it easier to form a stronger three-dimensional gel network. In addition, BG may be cross-linked with proteins, or physically embedded and covered in protein network structures, interacting with proteins mainly through non-covalent bonds including hydrogen bonding and electrostatic interaction. Furthermore, the transition of the α-helix to the β-form in the protein secondary structure also contributes to the stability of the protein gel. The practical applications of BG from different cereals in protein-based products are summarized, and the rheological properties, microstructure of protein as well as the underlying interaction mechanisms between BG and protein are discussed. In conclusion, cereal BG is a promising polysaccharide in developing nutritional protein-based products with better sensory properties.

Preparations, application of polysaccharide-protein nanoparticles and their assembly at the oil-water interface

With the development of nanotechnology, nanoparticles have played an important role in pharmaceuticals, foods and materials, in particular, protein/polysaccharide based composite nanoparticles have received attention from researchers for safety and green production. This paper summarized in detail the preparation methods, applications of protein/polysaccharide nanoparticles (PPNPs) in recent years, especially the mechanism of stabilizing the oil-water interface. Currently, the polysaccharides applied are more traditional, such as chitosan, pectin and carboxymethyl cellulose, so there is still a lot of room for the development of raw materials that can be used to prepare PPNPs. Based on this, we also proposed three promising polysaccharides: seaweed polysaccharide, lycium barbarum polysaccharide and lactobacillus exopolysaccharides, describing their characteristics as well as their application prospects, this article can serve as a reference for interested researchers.

Effect of extrusion temperature on the structure and emulsifying properties of soy protein isolate-oat β-glucan conjugates formed during high moisture extrusion

In this study, extrusion was used to induce Maillard reaction between soy protein isolate (SPI) and oat β-glucan (OG) and effect of extrusion temperature (70, 90, 110 and 130 °C) on the structure and emulsifying properties of extruded SPI-OG was investigated. SDS-PAGE and fluorescence spectroscopy provided evidence for the formation of SPI-OG conjugates during extrusion. The results showed that 90 °C and 110 °C extruded SPI-OG had the highest level of degree of glycosylation (were 14.34% and 13.70%, respectively, p > 0.05). Structural analysis found that α-helix content of extruded SPI-OG decreased by 8.93-13.14% compared to mixture of SPI and OG. Meanwhile, extruded SPI-OG had lower protein solubility (29.83-34.38%) and surface hydrophobicity (1549-2027), larger average particle size (2363-4807 nm) and higher emulsion stability (74.33-90.15%). Therefore, these findings may provide a theoretical basis for the development of novel food emulsion stabilizers.

Polysaccharide‑platinum complexes for cancer theranostics

Platinum anticancer drugs have been explored and developed in recent years to reduce systematic toxicities and resist drug resistance. Polysaccharides derived from nature have abundant structures as well as pharmacological activities. The review provides insights on the design, synthesis, characterization and associating therapeutic application of platinum complexes with polysaccharides that are classified by electronic charge. The complexes give birth to multifunctional properties with enhanced drug accumulation, improved tumor selectivity and achieved synergistic antitumor effect in cancer therapy. Several techniques developing polysaccharides-based carriers newly are also discussed. Moreover, the lasted immunoregulatory activities of innate immune reactions triggered by polysaccharides are summarized. Finally, we discuss the current shortcomings and outline potential strategies for improving platinum-based personalized cancer treatment. Using platinum-polysaccharides complexes for improving the immunotherapy efficiency represents a promising framework in future.

Reverse-QTY code design of active human serum albumin self-assembled amphiphilic nanoparticles for effective anti-tumor drug doxorubicin release in mice

Human serum albumin (HSA) is a highly water-soluble protein with 67% alpha-helix content and three distinct domains (I, II, and III). HSA offers a great promise in drug delivery with enhanced permeability and retention effect. But it is hindered by protein denaturation during drug entrapment or conjugation that result in distinct cellular transport pathways and reduction of biological activities. Here we report using a protein design approach named reverse-QTY (rQTY) code to convert specific hydrophilic alpha-helices to hydrophobic to alpha-helices. The designed HSA undergo self-assembly of well-ordered nanoparticles with highly biological actives. The hydrophilic amino acids, asparagine (N), glutamine (Q), threonine (T), and tyrosine (Y) in the helical B-subdomains of HSA were systematically replaced by hydrophobic leucine (L), valine (V), and phenylalanine (F). HSArQTY nanoparticles exhibited efficient cellular internalization through the cell membrane albumin binding protein GP60, or SPARC (secreted protein, acidic and rich in cysteine)-mediated pathways. The designed HSArQTY variants displayed superior biological activities including: i) encapsulation of drug doxorubicin, ii) receptor-mediated cellular transport, iii) tumor cell targeting, and iv) antitumor efficiency compare to denatured HSA nanoparticles. HSArQTY nanoparticles provided superior tumor targeting and antitumor therapeutic effects compared to the albumin nanoparticles fabricated by antisolvent precipitation method. We believe that the rQTY code is a robust platform for specific hydrophobic modification of functional hydrophilic proteins with clear-defined binding interfaces.

Molecular Interaction Mechanism and Preservative Effect of Lactone Sophorolipid and Lactoferrin/β-Lactoglobulin Systems

Multispectral and molecular docking methods were used to study the interaction mode and mechanism of two important components of whey proteins, lactoferrin (LF) and β-lactoglobulin (β-LG), and of a lactone sophorolipid (LSL) mixed system. The preservation effect of the mixed system on milk was also studied and compared. The results showed that the quenching mechanism of LSL on both β-LG and LF was static, but that the non-covalent complexes formed were the result of the different interacting forces: hydrogen bonds and the van der Waals force for the LSL-β-LG system, and electrostatic force for the LSL-LF system. The binding constants of LSL-β-LG and LSL-LF were all relatively small, and the interaction of LSL with β-LG was stronger than its interaction with LF. After adding β-LG, LF, or the mixed system with LSL to the milk, the stability of milk emulsion was effectively improved in all cases, while the preservative ability was effectively enhanced only by the addition of LF or LSL-LF. These results provide supportive data and a theoretical basis for enhancing the production of dairy products and other byproducts.

Quality characteristics and gastrointestinal fate of low fat emulsified sausage formulated with konjac glucomannan/oat β-glucan composite hydrogel

The objective of present study was to evaluate the utilization of konjac glucomannan/oat β-glucan composite hydrogel as partial or complete fat replacer on the quality characteristics and gastrointestinal fate of emulsified sausages. The obtained results indicated that in comparison to control emulsified sausage sample, the incorporation of composite hydrogel at a 75 % fat replacement level could not only enhance emulsion stability, water holding capacity (WHC), and compact structure of formulated emulsified sausage, but also decrease their total fat content, cooking loss, hardness, and chewiness. The in vitro digestion results suggested the addition of konjac glucomannan/oat β-glucan composite hydrogel reduced the protein digestibility of emulsified sausage, while it did not change the molecular weight of digestive products. The confocal laser scanning microscopy(CLSM) image showed the addition of composite hydrogel changed the size of fat and protein aggregate of emulsified sausage during digestion. Based on these findings, the fabrication of composite hydrogel containing konjac glucomannan and oat β-glucan was a promising strategy as fat replacer. Furthermore, this study provided a theoretic basis for designing composite hydrogel based fat replacers.

Novel Colloidal Food Ingredients: Protein Complexes and Conjugates

Food proteins, polysaccharides, and polyphenols are natural ingredients with different functional attributes. For instance, many proteins are good emulsifiers and gelling agents, many polysaccharides are good thickening and stabilizing agents, and many polyphenols are good antioxidants and antimicrobials. These three kinds of ingredients can be combined into protein, polysaccharide, and/or polyphenol conjugates or complexes using covalent or noncovalent interactions to create novel multifunctional colloidal ingredients with new or improved properties. In this review, the formation, functionality, and potential applications of protein conjugates and complexes are discussed. In particular, the utilization of these colloidal ingredients to stabilize emulsions, control lipid digestion, encapsulate bioactive ingredients, modify textures, and form films is highlighted. Finally, future research needs in this area are briefly proposed. The rational design of protein complexes and conjugates may lead to the development of new functional ingredients that can be used to create more nutritious, sustainable, and healthy foods.

Nanoparticular and other carriers to deliver lactoferrin for antimicrobial, antibiofilm and bone-regenerating effects: a review

Bone and joint infections are a rare but serious problem worldwide. Lactoferrin’s antimicrobial and antibiofilm activity coupled with its bone-regenerating effects may make it suitable for improving bone and joint infection treatment. However, free lactoferrin (LF) has highly variable oral bioavailability in humans due to potential for degradation in the stomach and small intestine. It also has a short half-life in blood plasma. Therefore, encapsulating LF in nanocarriers may slow degradation in the gastrointestinal tract and enhance LF absorption, stability, permeability and oral bioavailability. This review will summarize the literature on the encapsulation of LF into liposomes, solid lipid nanoparticles, nanostructured lipid carriers, polymeric micro and nanoparticles and hydroxyapatite nanocrystals. The fabrication, characterization, advantages, disadvantages and applications of each system will be discussed and compared.

Advancement of Protein- and Polysaccharide-Based Biopolymers for Anthocyanin Encapsulation

Although evidence shows that anthocyanins present promising health benefits, their poor stability still limits their applications in the food industry. Increasing the stability of anthocyanins is necessary to promote their absorption and metabolism and improve their health benefits. Numerous encapsulation approaches have been developed for the targeted release of anthocyanins to retain their bioactivities and ameliorate their unsatisfactory stability. Generally, choosing suitable edible encapsulation materials based on biopolymers is important in achieving the expected goals. This paper presented an ambitious task of summarizing the current understanding and challenges of biopolymer-based anthocyanin encapsulation in detail. The food-grade edible microencapsulation materials, especially for proteins and polysaccharides, should be employed to improve the stability of anthocyanins for effective application in the food industry. The influence factors involved in anthocyanin stability were systematically reviewed and highlighted. Food-grade proteins, especially whey protein, caseinate, gelatin, and soy protein, are attractive in the food industry for encapsulation owing to the improvement of stability and their health benefits. Polysaccharides, such as starch, pectin, chitosan, cellulose, mucilages, and their derivatives, are used as encapsulation materials because of their satisfactory biocompatibility and biodegradability. Moreover, the challenges and perspectives for the application of anthocyanins in food products were presented based on current knowledge. The proposed perspective can provide new insights into the amelioration of anthocyanin bioavailability by edible biopolymer encapsulation.

Low-sodium salt mediated aggregation behavior of gluten in wheat dough

Reducing sodium in foods has attracted the attention of consumers, it is therefore necessary to explore sodium alternatives (i.e., low-sodium salt). However, the mechanism of low-sodium salt on gluten in dough remains unclear. Effect of low-sodium salt on the aggregation behaviors of gluten in dough was investigated and compared with those with NaCl and KCl in this study. The results showed that low-sodium salt enhanced gluten strength and prolonged gluten aggregation time. Low-sodium salt decreased the content of SDS extractable protein under non-reducing conditions. Low-sodium salt changed the spatial conformation of gluten by reducing β-turn structure and increasing β-sheet structure. Confocal laser scanning microscopy images indicated that low-sodium salt promoted the formation of a larger and dense gluten network. In summary, this study showed that low-sodium salt promoted the aggregation of gluten in dough, and the change of gluten structure explained this aggregation mechanism. Its mode of action was similar to NaCl and KCl, which provided a theoretical basis for the study of sodium substitutes in flour products.

Synthesis, characterization and application of antibacterial lactoferrin nanoparticles

Lactoferrin (L) and gellan gum (G) nanoparticles were produced in different biopolymer proportions through electrostatic complexation to enhance the antimicrobial properties of lactoferrin. The nanoparticles were characterized according to size, charge density, morphology and antimicrobial activity against S. aureus and E. coli, in two different broths to show the effect of the broth composition on the nanoparticle activity. The 9L:1G particles showed the highest positive zeta potential (+21.20 mV) and reduced diameter (92.03 nm) which resulted in a minimum inhibitory concentration six times smaller (0.3 mg/ml) than pure lactoferrin (2 mg/ml). However, the bacteriostatic action of nanoparticles was inhibited in the presence of divalent cations. When applied to strawberries as a coating, lactoferrin nanoparticles extended fruit shelf-life up to 6 days in the presence of carboxymethylcellulose (CMC). Therefore, lactoferrin-gellan gum complexation was proved to be a promising tool to enhance lactoferrin antimicrobial action and broaden its application as a food preserver.

Characterization and diabetic wound healing benefits of protein-polysaccharide complexes isolated from an animal ethno-medicine Periplaneta americana L

Periplaneta americana L. (PA), a type of animal medicine, has been widely used for wound healing in clinical settings. In order to further investigate the bioactive wound healing substances in PA, crude PA protein-polysaccharide complexes were further purified by cellulose DE-52 and Sephadex G100 chromatography in succession. Among these isolated fractions, two fractions eluted by 0.3 M and 0.5 M NaCl with the higher yield, respectively named PaPPc2 and PaPPc3 respectively, were chosen for the wound healing experiments. Mediated by HPGPC, amino acid and monosaccharide composition analysis, circular dichroism spectrum, glycosylation type, FT-IR, and ¹H NMR analysis, the characterization of PaPPc2 and PaPPc3 was implemented. And then, the benefits of PaPPcs to promote cell proliferation, migration, and tube formation of HUVECs were determined in vitro, indicated these fractions would facilitate angiogenesis. Finally, as proof of concept, PaPPc2 and PaPPc3 were employed to accelerate the acute wounds of diabetic mice, involving in increase blood vessels and the amounts of angiogenesis-related cytokines (α-SMA, VEGF, and CD31). In short, this study provides an experimental basis to demonstrate the protein-polysaccharide complexes of Periplaneta americana L. as its wound healing bioactive substances.

Bovine lactoferrin and Lentinus edodes mycelia polysaccharide complex: The formation and the activity to protect islet β cells

The formation of complexes may be used for the development of delivery systems in foods field. The aim of this study was to explore the interaction mechanism between Lentinus edodes mycelia polysaccharide (LMP) and bovine lactoferrin (BLF), and the activity of LMP-BLF complex to inhibit oxidative stress in islet β cells. The interaction mechanisms of LMP with BLF were investigated with multi-spectroscopic techniques. The multi-spectroscopic analysis result showed that LMP bound with BLF by van der Waals force and hydrogen bond. The quenching mechanism of BLF with LMP was static quenching. Cell viability, reactive oxygen species (ROS) level, apoptosis and the related signaling pathways were detected with thiazolyl blue tetrazolium bromide (MTT) assay, 2,7-Dichlorofluorescin diacetate (DCFH-DA) staining, Hoechst 33258 staining and Western blot methods respectively. The complex alleviated apoptosis induced by hydrogen peroxide (H₂O₂), and inhibited oxidative stress via MAPK pathways in MIN6 cells. In addition, the complex was able to promote glucose uptake in HepG2 cells. These results will broaden our understanding of LMP-BLF complexes and the applications of polysaccharide-protein complexes in the foods field.

Formation and Characterization of Irreversible Sediment of Ginseng Extract

Sediment is a key issue in the beverage industry. This study confirmed that reversible and irreversible sediments were formed during low-temperature storage of ginseng extract. The first 30 days of storage are the critical period for sediment formation. As the time of storage extends, the chemical composition changes. The composition interaction model verified that the cross-linking of protein-pectin, protein-oxalic acid and Ca2+-pectin was the main cause of the turbidity of ginseng extract. Based on the characterization of irreversible sediment (IRS), there are typical structures of proteins, polysaccharides and calcium oxalate dihydrate (COD) crystals. Glucose, galacturonic acid, aspartate, glutamic acid, leucine, Ca, K, Al, Mg, Na and Fe are the main monomer components. Effective regulation of these ingredients will greatly help the quality of ginseng beverages.

Effect of Oat β-Glucan on the Rheological Characteristics and Microstructure of Set-Type Yogurt

The oat β-glucan (OG) was added into set-type yogurt as a functional ingredient, in order to evaluate effects on the rheological characteristics and microstructure of set-type yogurt. When the OG concentration increased from 0 to 0.3%, the WHC gradually increased. At 0.3% OG, the set-type yogurt had the highest WHC of 94.67%. Additionally, the WHC continuously decreased, reaching the lowest WHC (about 80%) at 0.5% OG. When 0.3% OG was added, the highest score of sensory evaluation was about 85. The rheological result showed that the fermentation process went through the changes as follows: solid → liquid → solid → liquid. The addition of 0.3% OG decreased the fermentation time of set-type yogurt by about 16 min, making yogurt more inclined to be liquid. The acidity of set-type yogurt with OG was slightly higher. The result of microstructure showed that the addition of OG destroyed the three-dimensional network structure of yogurt, and some spherical aggregate particles could be clearly observed at 0.3% OG. Overall, this study provided a theoretical basis for the application of OG in set-type yogurt.

Effects of insoluble dietary fiber and ferulic acid on the quality of steamed bread and gluten aggregation properties

The effects of insoluble dietary fiber (IDF) and ferulic acid (FA) on steamed bread quality and gluten aggregation properties were investigated. IDF and FA increased the hardness and decreased the specific volume of steamed bread, except for 0.3 g of FA. Compared to the control sample, the hardness of steamed bread with 0.3 g of FA decreased by 36%, and the specific volume increased by 10.91%. FA promoted gluten aggregation through a cross-linking reaction because the sodium dodecyl sulfate extractable protein (SDSEP) of gluten with 1.8 g of FA decreased by 61.32% compared to the control sample under non-reducing condition. The ζ-potential of gluten during the proofing and steaming stages decreased by 46.64% and 68.10% with the increase in IDF, which showed that IDF promoted gluten aggregation by reducing the electrostatic repulsion. Gluten aggregation caused by IDF and FA could be the main reason for steamed bread deterioration.

Effect of heat treatment on the structure and stability of Grass pea (Lathyrus sativus) protein isolate/Alyssum homolocarpum seed gum nanoparticles

In the present study, Grass pea protein isolate (GPPI)- Alyssum homolocarpum seed gum (AHSG) complex nanoparticles were formed through two fabrication methods and their physicochemical properties, structure and stability against sodium chloride and different pHs were investigated. Type 1 particles were formed by creating GPPI nanoparticles, and then coating them with AHSG; while Type 2 particles were fabricated through the heat treatment of GPPI-AHSG complexes at 85 °C for 15 min. The preparation methods did not influence the magnitude of electrical charges on biopolymer particles. The particle size analysis revealed that Type 2 particles had lower mean diameter (d = 360.20 nm) compared to Type 1 particles (d = 463.22 nm). Structural properties of Type 1 and Type 2 particles were determined using Fourier transform infrared (FTIR) spectroscopy, X-ray diffractometry (XRD), Differential scanning calorimetry (DSC), Atomic force microscopy (AFM), and transmission electron microscopy (TEM). Hydrogen bonding, electrostatic and hydrophobic interactions were the main driving forces contributed to the formation of both GPPI-AHSG complex particles. Assessments of morphological and structural properties also indicated that both Type 1 and 2 particles had spherical shapes and heat treatment increased the ordered intermolecular structures in biopolymer particles. Type 2 particles had higher denaturation temperature and better pH and salt stability when compared to Type 1 particles. These results indicate that thermal treatment was effective for the fabrication of stable GPPI-AHSG complex nanoparticles.

An overview on interactions between natural product-derived β-glucan and small-molecule compounds

β-Glucans are widely found in plants and microorganisms, which has a variety of functional activities. During production and application, interactions with other components have a great influence on the structure and functional properties of β-glucan. In this paper, interactions (including non-covalent interaction and free-radical reaction) between natural product derived β-glucan and ascorbic acid, polyphenols, bile acids/salts, metal ion or other compounds were summarized. Besides, the mechanism and influence factors of interactions between β-glucan and small-molecule compounds, and their effects on the functional properties of β-glucan were detailed. This review aims to develop an understanding and practical suggestions on interactions between β-glucan and small-molecule compounds, which is expected to provide a useful reference for processing and application.

Field pea protein isolate/chitosan complex coacervates: Formation and characterization

Influence of chitosan (Ch) with low, medium, and high molecular weight (LMW, MMW, and HMW) on the formation of field pea protein isolate (FPPI)/Ch complex coacervates was investigated. An increase in maximum turbidity and a gradual shift of critical pH values towards the isoelectronic point of FPPI were observed as the FPPI/Ch ratio increased. Formation of FPPI/Ch complex coacervates was dominated by the electrostatic and hydrophobic interactions. FPPI/Ch complex coacervates exhibited a porous network microstructure and relatively uniform-sized and even-distributed pores were found in FPPI/Ch-HMW coacervates. Different thermodynamic profiles were observed during complex coacervation between FPPI and Ch with varying MWs and the largest binding stoichiometry was observed in the Ch-MMW at pH 6.6. In summary, the Ch-HMW was demonstrated to be most suitable for the formation of FPPI/Ch complex coacervates with homogenous microstructure but caused less changes in the tertiary conformation of FPPI compared to the Ch-LWM and Ch-MMW.

Effect of sodium chloride on the thermodynamic, rheological, and microstructural properties of field pea protein isolate/chitosan complex coacervates

The effect of increasing sodium chloride concentration (c_NaCl, 0-0.4 M) on the formation and rheological and microstructural properties of field pea protein isolate (FPPI)/chitosan (Ch) complex coacervates was investigated. The maximum turbidity and zeta potential of FPPI/Ch mixtures consistently decreased with the increasing c_NaCl. The tertiary conformation of FPPI was altered to facilitate the aggregation of FPPI/Ch complexes via hydrophobic interactions. Changes in thermodynamic parameters during the titration of FPPI with Ch confirmed the addition of NaCl could cause the inhibition of electrostatic complexation and the induction of non-Coulombic interactions. FPPI/Ch complex coacervates exhibited first enhanced and then weakened viscoelastic properties and an initially tightened and then a loosened microstructure as the c_NaCl increased. In summary, appropriate c_NaCl favors the formation of FPPI/Ch complex coacervates with improved functionalities via the coordination of promoted hydrophobic interactions and inhibited electrostatic attractions, facilitating the application of this protein ingredient in food development.