Stability, microstructure, and digestibility of whey protein isolate – Tremella fuciformis polysaccharide complexes

Distinctive activation of β-galactosidase by carboxymethylated β-glucan in vitro and mechanism study: Critical role of hydrophobic and electrostatic interactions

β-galactosidase (lactase) is commercially important as a dietary supplement to alleviate the symptoms of lactose intolerance. This work investigated a unique activation of CMP (carboxymethylated (1 → 3)-β-d-glucan) on lactase and its mechanism by comparing it with carboxymethyl chitosan (CMCS), an inhibitor of lactase. The results illustrated that the secondary and tertiary structures of lactase were altered and its active sites exposed after complexation with CMP, and dissociation of lactase aggregates was also observed. These changes favored better accessibility of the substrate to the active sites of lactase, resulting in a maximum increase of 60.5 % in lactase activity. Furthermore, the hydrophobic and electrostatic interactions with lactase caused by the carboxymethyl group of CMP were shown to be crucial for its activation ability. Thus, the improvement of lactase activity and stability by CMP shown here is important for the development of new products in the food and pharmaceutical industries.

Development and Characterization of Hybrid Meat Analogs from Whey Protein-Mushroom Composite Hydrogels

There is a need to reduce the proportion of animal-derived food products in the human diet for sustainability and environmental reasons. However, it is also important that a transition away from animal-derived foods does not lead to any adverse nutritional effects. In this study, the potential of blending whey protein isolate (WPI) with either shiitake mushroom (SM) or oyster mushroom (OM) to create hybrid foods with enhanced nutritional and physicochemical properties was investigated. The impact of OM or SM addition on the formation, microstructure, and physicochemical attributes of heat-set whey protein gels was therefore examined. The mushroom powders were used because they have relatively high levels of vitamins, minerals, phytochemicals, and dietary fibers, which may provide nutritional benefits, whereas the WPI was used to provide protein and good thermal gelation properties. A variety of analytical methods were used to characterize the structural and physicochemical properties of the WPI-mushroom hybrids, including confocal microscopy, particle electrophoresis, light scattering, proximate analysis, differential scanning calorimetry, thermogravimetric analysis, dynamic shear rheology, textural profile analysis, and colorimetry. The charge on whey proteins and mushroom particles went from positive to negative when the pH was raised from 3 to 9, but whey protein had a higher isoelectric point and charge magnitude. OM slightly increased the thermal stability of WPI, but SM had little effect. Both mushroom types decreased the lightness and increased the brownness of the whey protein gels. The addition of the mushroom powders also decreased the hardness and Young's modulus of the whey protein gels, which may be because the mushroom particles acted as soft fillers. This study provides valuable insights into the formation of hybrid whey protein-mushroom products that have desirable physiochemical and nutritional attributes.

Preparation and characterization of tilapia protein isolate - Hyaluronic acid complexes using a pH-driven method for improving the stability of tilapia protein isolate emulsion

This study aimed to investigate the non-covalent complexation between hyaluronic acid (HA) and tilapia protein isolate (TPI) on the stability of oil-in-water (O/W) TPI emulsion. The results showed that HA binds to TPI through electrostatic, hydrophobic, and hydrogen bonding interactions, forming homogeneous hydrophilic TPI-HA complexes. The binding of HA promoted the structural folding of TPI and altered its secondary structure during pH neutralization. The TPI-HA complexes presented significantly improved EAI and ESI (P < 0.05) when the HA concentration was 0.8 % (w/v). Emulsion characterization showed that HA promoted the transfer of TPI to the O/W interface, forming an emulsion with excellent stability, which, combined with the high surface charge and strong spatial site resistance effect of HA, improved TPI emulsion stability. Therefore, non-covalent complexation with HA is an effective strategy to improve the stability of TPI emulsion.

The Emulsification and Stabilization Mechanism of an Oil-in-Water Emulsion Constructed from Tremella Polysaccharide and Citrus Pectin

The objective of this study was to investigate the feasibility of the mixture of tremella polysaccharide (TP) and citrus pectin (CP) as an emulsifier by evaluating its emulsifying ability/stability. The results showed that the TP:CP ratio of 5:5 (w/w) could effectively act as an emulsifier. CP, owing its lower molecular weight and highly methyl esterification, facilitated the emulsification of oil droplets, thereby promoting the dispersion of droplets. Meanwhile, the presence of TP enhanced the viscosity of emulsion system and increased the electrostatic interactions and steric hindrance, therefore hindering the migration of emulsion droplets, reducing emulsion droplets coalesce, and enhancing emulsion stability. The emulsification and stabilization performances were influenced by the molecular weight, esterified carboxyl groups content, and electric charge of TP and CP, and the potential mechanism involved their impact on the buoyant force of droplet size, viscosity, and steric hindrance of emulsion system. The emulsions stabilized by TP-CP exhibited robust environmental tolerance, but demonstrated sensitivity to Ca2+. Conclusively, the study demonstrated the potential application of the mixture of TP and CP as a natural polysaccharide emulsifier.

Chitosan and its oligosaccharide accelerate colonic motility and reverse serum metabolites in rats after excessive protein consumption

Excessive protein consumption (EPC) could increase the gastrointestinal burden and impair gut motility. The present study was designed to explore the improvement of chitosan (CTS) and chitosan oligosaccharide (COS) on colonic motility and serum metabolites in rats after EPC. The results of in vivo experiments fully proved that CTS and COS could improve gut motility and reverse the serum metabolites in rats as indicated by LC-MS/MS analysis, and the COS group even showed a better effect than the CTS group. Furthermore, short-chain fatty acids (SCFAs), which could promote gut motility, were also increased to alleviate EPC-induced constipation after supplementation with CTS or COS. In addition, CTS and COS could decrease the concentration of ammonia in serum and down-regulate the levels of H2S and indole. In summary, the present study revealed that CTS and COS could produce SCFAs, improve the colonic motility in rats, reverse the levels of valine, adenosine, cysteine, 1-methyladenosine, indole, and uracil, and enhance aminoacyl-tRNA biosynthesis and valine, leucine and isoleucine degradation. The present study provides novel insights into the potential roles of CTS and COS in alleviating the adverse effects of EPC.

Effects of Tremella fuciformis Mushroom Polysaccharides on Structure, Pasting, and Thermal Properties of Chinese Chestnuts (Castanea henryi) Starch Granules under Different Freeze-Thaw Cycles

The purpose of this study was to investigate the effect of Tremella fuciformis polysaccharides on the physicochemical properties of freeze-thawed cone chestnut starch. Various aspects, including water content, crystallinity, particle size, gelatinization, retrogradation, thermal properties, rheological properties, and texture, were examined. The results revealed that moderate freezing and thawing processes increased the retrogradation of starch; particle size, viscosity, shear type, hinning degree, and hardness decreased. After adding Tremella fuciformis polysaccharide, the particle size, relative crystallinity, and gelatinization temperature decreased, which showed solid characteristics. Consequently, the inclusion of Tremella fuciformis polysaccharide effectively countered dehydration caused by freezing and thawing, reduced viscosity, and prevented the retrogradation of frozen-thawed chestnut starch. Moreover, Tremella fuciformis polysaccharide played a significant role in enhancing the stability of the frozen-thawed chestnut starch. These findings highlight the potential benefits of incorporating Tremella fuciformis polysaccharides in starch-based products subjected to freeze-thaw cycles.

Protein-polysaccharide nanoconjugates: Potential tools for delivery of plant-derived nutraceuticals

Protein-polysaccharide nanoconjugates are covalently interactive networks that are currently the subject of intense research owing to their emerging applications in the food nanotechnology field. Due to their biocompatibility and biodegradability properties, they have played a significant role as wall materials for the formation of various nanostructures to encapsulate nutraceuticals. The food-grade protein-polysaccharide nanoconjugates would be employed to enhance the delivery and stability of nutraceuticals for their real use in the food industry. The most common edible polysaccharides (cellulose, chitosan, pectin, starch, carrageenan, fucoidan, mannan, glucomannan, and arabic gum) and proteins (silk fibroin, collagen, gelatin, soy protein, corn zein, and wheat gluten) have been used as potential building blocks in nano-encapsulation systems because of their excellent physicochemical properties. This article broadens the discussion of food-grade proteins and polysaccharides as nano-encapsulation biomaterials and their fabrication methods, along with a review of the applications of protein-polysaccharide nanoconjugates in the delivery of plant-derived nutraceuticals.

Improvement of functional characteristics of Hypophthalmichthys molitrix protein by modification with chitosan oligosaccharide

In the food processing field, it is very often that fish proteins are denatured affecting the nutritional value of the product which is vital to be solved. By using appropriate sugar donors for glycosylation with protein, improving the stability and emulsification properties of fish proteins can be achieved. This research looks into the impacts of enzymatic chitosan oligosaccharide (CO) at various concentration (0.15%, 0.30%, 0.45%, 0.60%, w/v) upon the molecular makeup and function of silver carp myofibrillar protein (MP) in an attempt to comprehend the impact of electrostatic binding among MP as well as CO on protein conformation. Analysis was done on the impact of various CO concentrations upon MP's secondary structure, conformational changes, and functional characteristics. Twelve sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) assays were implemented to monitor MP; Fourier transform infrared spectroscopy, endogenous fluorescence spectroscopy, and UV absorption spectra were carried out to investigate the influence of CO on MP; Particle size distribution, emulsifying activity index (EAI), solubility, turbidity, sulfhydryl content, carbonyl content, foaming capacity, surface hydrophobicity, emulsifying stability index (ESI), and foam persistence were all investigated. In addition, we used dynamic light scattering, scanning electron microscope, and atomic force microscope to analyze myosin (MO) and 0.60% CO-MO complex. The results demonstrated that CO and MP form complexes through hydrogen bonding and electrostatic interactions. CO modification not only delayed the oxidation of MP but also promoted MP to show better solubility, foaming, and foaming stability. In addition, CO modified myosin particle size decreased, reducing myosin's roughness and making myosin's structure more compact. To sum up, molecular interaction could change functional characteristics, and products with special properties could be developed after modification with chitosan oligosaccharide.

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.

Antioxidant activity and interactions between whey protein and polysaccharides from different parts of Houttuynia cordata

Houttuynia cordata polysaccharides (PSY) are known to exhibit a variety of beneficial activities, but these are currently not specifically utilized in food. Hence, using the two edible parts of Houttuynia cordata, a herbaceous plant native to Southeast Asia, this study developed polysaccharides of a stem (HCPS)-whey protein concentrate (WPC) complex and a leaf (HCPL)-WPC complex, and studied their stability, structure and antioxidant activity. The results showed that stability differed in complexes with different proportions, exhibiting only relative stability in the two complexes in which the ratio of HCPS-WPC and HCPL-WPC was 1:4, but increased stability in the HCPL-WPC complex (ζ-potential of HCPL-WPC: | -21.87 mv| >ζ-potential of HCPS-WPC: | -21.70 mv|). Structural characterization showed that there was electrostatic interaction between HCPS and WPC and between HCPL and WPC. The HCPL-WPC was found to have better antioxidant activity. The findings of this study, thus, provide a reference for the development of Houttuynia cordata polysaccharide applications in food.

Characterization of Physicochemical Properties of Oil-in-Water Emulsions Stabilized by Tremella fuciformis Polysaccharides

In this paper, emulsions stabilized by Tremella fuciformis polysaccharides (TFP) were prepared and the physiochemical properties were assessed. Results showed that the TFP emulsions illustrated the highest emulsifying activity (EAI) and emulsifying stability (ESI) when the concentration of TFP and oil were 0.8% and 10% (wt%). The higher pH value was in favor of the emulsifying properties, while the addition of NaCl impaired the stability, and the greater the concentration, the lower the EAI and ESI. Besides, the emulsifying and rheological properties and stability analysis were evaluated in comparison with gum arabic, pectin, and carboxymethyl cellulose emulsions. It was discovered that TFP illustrated better storage and freeze-thaw stability, which was proved by the result of zeta-potential and particle size. The rheological measurement revealed that all the emulsions behaved as pseudoplastic fluids, while TFP displayed a higher viscosity. Meanwhile, TFP emulsions tended to form a more stable network structure according to the analysis of the parameters obtained from the Herschel–Bulkley model. FTIR spectra suggested that the O-H bond could be destructed without the formation of new covalent bonds during the emulsion preparation. Therefore, this study would be of great importance for the research of emulsions stabilized by TFP as a natural food emulsifier.

Effect of Tremella fuciformis and Different Hydrocolloids on the Quality Characteristics of Wheat Noodles

To improve the quality characteristics of noodles and enrich nutritional value, Tremella fuciformis (TF) powder was incorporated into noodles. Tremella fuciformis (TF) is an edible fungus with rich nutritional value, and TF gel has good viscosity properties. This paper explored the effect of TF on noodle quality, and compared the difference between TF and three hydrocolloids: sodium alginate (SA), guar gum (GG) and xanthan gum (XG). The results showed that TF could significantly (p < 0.05) increase the hardness, adhesiveness and chewiness of noodles, and showed a decreasing trend for additions greater than 3%. The addition of 3% TF enhanced storage modulus (G′), loss modulus (G″) and elasticity of dough. The addition of 3% TF also increased α-helix and β-sheet content, and degradation temperature in noodles. Meanwhile, it elevated the deeply bound water content and retarded water mobility. In addition, the content of slowly digestible starch and resistant starch in the noodles increased with the addition of 3% TF. It was found that the effect of 3% TF on the above data was not different from the effects of the three hydrocolloids (respectively, their optimal additions), and improved the quality characteristics of the noodles. The results provide guidance for the application of TF and the development of a new natural hydrocolloid and nutritionally fortified noodles.

The non-covalent interactions between whey protein and various food functional ingredients

In daily diet, Whey protein (WP) is often coexisted with various Food functional ingredients (FFI) such as proteins, polyphenols, polysaccharides and vitamins, which inevitably affect or interact with each other. Generally speaking, they may be interact by two different mechanisms: non-covalent and covalent interactions, of which the former is more common. We reviewed the non-covalent interactions between WP and various FFI, explained the effect of each WP-FFI interaction, and provided possible applications of WP-FFI complex in the food industry. The biological activity, physical and chemical stability of FFI, and the structure and functionalities of WP were enhanced through the non-covalent interactions. The development of non-covalent interactions between WP and FFI provides opportunities for the design of new ingredients and biopolymer complex, which can be applied in different fields. Future research will further focus on the influence of external or environmental factors in the food system and processing methods on interactions.

Maillard-Type Protein-Polysaccharide Conjugates and Electrostatic Protein-Polysaccharide Complexes as Delivery Vehicles for Food Bioactive Ingredients: Formation, Types, and Applications

Due to their combination of featured properties, protein and polysaccharide-based carriers show promising potential in food bioactive ingredient encapsulation, protection, and delivery. The formation of protein–polysaccharide complexes and conjugates involves non-covalent interactions and covalent interaction, respectively. The common types of protein–polysaccharide complex/conjugate-based bioactive ingredient delivery systems include emulsion (conventional emulsion, nanoemulsion, multiple emulsion, multilayered emulsion, and Pickering emulsion), microcapsule, hydrogel, and nanoparticle-based delivery systems. This review highlights the applications of protein–polysaccharide-based delivery vehicles in common bioactive ingredients including polyphenols, food proteins, bioactive peptides, carotenoids, vitamins, and minerals. The loaded food bioactive ingredients exhibited enhanced physicochemical stability, bioaccessibility, and sustained release in simulated gastrointestinal digestion. However, limited research has been conducted in determining the in vivo oral bioavailability of encapsulated bioactive compounds. An in vitro simulated gastrointestinal digestion model incorporating gut microbiota and a mucus layer is suggested for future studies.

Extraction, isolation, purification, derivatization, bioactivity, structure-activity relationship and application of polysaccharides from white jellyfungus

White jellyfungus is one of the most popular nutritional supplements. The polysaccharide (WJP) is an important active component of white jellyfungus, it not only has a variety of biological activities but also is non-toxic to humans. So, many scholars have carried out different researches on WJP. However, the lack of a detailed summary of WJP limits the scale of industrial development of WJP. Herein, the research progress of WJP in extraction, isolation, structure, derivatization and structure-activity relationship was reviewed. Different extraction methods were compared, the activity and application of WJP were summarized, and the structure-activity relationship of WJP was emphasized in order to provide effective theoretical support for improving the utilization of WJP and promoting the application of related industries. This article is protected by copyright. All rights reserved.

A review on the production, structure, bioactivities and applications of Tremella polysaccharides

Tremella polysaccharide is known to be structurally unique and biologically active natural products, abundant and versatile in activities and applications in food industry, daily chemical industry and medicine industry. In order to improve the industrialisation of Tremella polysaccharide, the limitations of preparation and structure-activity relationship of Tremella polysaccharide were reviewed in this paper. The research progress of Tremella polysaccharide in the past 20 years was summarized from the sources, preparation methods, molecular structure, activity and application, and the research trend in the future was also prospected. The application prospect of Tremella polysaccharide in against multiple sub-health states was worth expecting.

Molecular Properties of Flammulina velutipes Polysaccharide-Whey Protein Isolate (WPI) Complexes via Noncovalent Interactions

Whey protein isolate (WPI) has a variety of nutritional benefits. The stability of WPI beverages has attracted a large amount of attention. In this study, Flammulina velutipes polysaccharides (FVPs) interacted with WPI to improve the stability via noncovalent interactions. Multiple light scattering studies showed that FVPs can improve the stability of WPI solutions, with results of radical scavenging activity assays demonstrating that the solutions of the complex had antioxidant activity. The addition of FVPs significantly altered the secondary structures of WPI, including its α-helix and random coil. The results of bio-layer interferometry (BLI) analysis indicated that FVPs interacted with the WPI, and the equilibrium dissociation constant (K_D) was calculated as 1.736 × 10^-4 M in this study. The in vitro digestibility studies showed that the FVPs protected WPI from pepsin digestion, increasing the satiety. Therefore, FVPs effectively interact with WPI through noncovalent interactions and improve the stability of WPI, with this method expected to be used in protein-enriched and functional beverages.

Evaluation of gels formulated with whey proteins and sodium dodecyl sulfate as a fat replacer in low-fat sausage

Consumers are increasingly interested in low-fat meat products. Therefore, there is demand for new fat replacers that improve the quality of low-fat meat products. Whey protein isolate (WPI; 10% (w/v)) and sodium dodecyl sulfate (SDS; 0-0.09% (w/v)) were used to produce WPI-SDS gel as a fat replacer of low-fat meat products. Characteristics of WPI-SDS gel were evaluated using SDS-PAGE, FT-IR, viscometer, and texture analyzer. Addition of SDS to WPI increased gelation while reducing aggregation. Addition of 0.06% SDS to WPI-SDS gel has the highest viscosity and hardness, while 0.09% SDS decreased the heat stability of WPI. Quality characteristics including cooking loss, emulsion stability, hardness, and chewiness were significantly improved in WPI-SDS gel-supplemented low-fat sausages. Particularly, the highest hardness and chewiness were obtained in the low-fat sausage added with WPI-SDS gel containing 0.06% SDS. Our results suggest that WPI-SDS gel can be used as a fat replacer in low-fat meat products.

Chemical physics of whey protein isolate in the presence of mucin: From macromolecular interactions to functionality

Oral processing, textural perception and functionality of colloidal foods are strongly influenced by the interactions between the salivary mucins and the food proteins. This work studies the physico-chemical aspects of mixtures of a typical food protein, whey protein isolate (WPI) and mucin. Phase separations result from aggregation between the two components at pH 7 and at pH 3. ζ-potential and fluorimetry data show that electrostatics contribute to entropically-driven interactions at pH 3, while at pH 7, two different non-electrostatic interactions, an entropically-driven and an enthalpically-driven one lead to aggregation and phase separation. Substitution of WPI with increasing mucin concentrations at pH 7 results in a marked increase of the shear viscosity in comparison with pH 3. Mucin enhances the extensional viscosity in a similar fashion, e.g. the incorporation of mucin into a WPI system at 6:4 ratio increases the extensional viscosity ≥ 3-fold (0.27-0.85 Pa s) and ≥2-fold (0.38-0.89 Pa s) at pH 3 and pH 7, respectively. These results indicate a notable increase of the extensional over shear viscosity ratio (Trouton's ratio). The above highlight the effect of the molecular-level interactions between food and salivary macromolecules on phase behavior and flow during oral processing.