Purified salep glucomannan synergistically interacted with xanthan gum: Rheological and textural studies on a novel pH-/thermo-sensitive hydrogel

Spectral analysis of the impact of various polysaccharides on the entrapment of curcumin by whey protein isolate

This study employed spectroscopic methods to investigate the interactions between whey protein isolate/polysaccharide (WPI/PS) complexes and curcumin. The UV-visible absorption spectra and fluorescence spectra indicated effective binding of curcumin to WPI and its complexes with chitosan (CS), carrageenan (CAR) and carboxymethylcellulose (CMC). This binding significantly increased the UV-visible absorption intensity of curcumin, with its maximum fluorescence emission peak shifting from 552 nm to 510 nm. Fluorescence kinetics analysis suggested that the binding constant between curcumin and WPI/CS complexes reached a maximum of 4.0794 × 105 L/mol. Circular dichroism and infrared spectroscopy indicated that the higher binding constant was attributed to the binding of CS, which reduced the α-helix structure and exposed hydrophobic groups of WPI. Curcumin entrapped by WPI/CS complexes showed the highest DPPH radical scavenging activities, UV and thermal stability. In summary, the WPI/CS complexes effectively protect curcumin against various environmental stresses and maintain its antioxidant properties.

Synergistic effect of edible salts on the physicochemical properties of whey protein isolate-carrageenan complexes and their application as foam and emulsion stabilizers

NaCl and CaCl2 are commonly used edible salts in food. The synergistic influences of these two salts on the physicochemical properties of whey protein isolate-carrageenan (WPI-Car) complexes were investigated in relation to their foaming and emulsifying properties. The results showed that as the ratio of NaCl: CaCl2 decreased from 6:0 to 3:3, the turbidity of the complexes increased from 0.51 to 0.77 and the absolute zeta potential decreased from 28.86 to 9.05 mV (P < 0.05). NaCl caused the exposure of hydrophobic groups, whereas CaCl2 caused hydrophobic groups to be buried within the molecule. The transformation between the α-helix structure and β-sheet structure of WPI was closely related to the ratios of NaCl to CaCl2. The electrostatic force, hydrophobic interaction, and hydrogen bond were significantly influenced by the synergistic influence of NaCl and CaCl2. The foaming capacity of WPI-Car complexes reached a maximum of 90.0 % at a NaCl: CaCl2 ratio of 3:3. Compared to the individual effects of monovalent NaCl and divalent CaCl2, the mixture of NaCl and CaCl2 (5:1) produced suitable refolding due to their synergistic effect, which improved the emulsifying properties of WPI-Car complexes. The findings of this study provide useful information for designing and preparing WPI-Car complexes for food applications.

Fabrication, Functional Properties, and Potential Applications of Mixed Gellan-Polysaccharide Systems: A Review

Gellan, an anionic heteropolysaccharide synthesized by Sphingomonas elodea, is an excellent gelling agent. However, its poor mechanical strength and high gelling temperature limit its application. Recent studies have reported that combining gellan with other polysaccharides achieves desirable properties for food- and biomaterial-related applications. This review summarizes the fabrication methods, functional properties, and potential applications of gellan-polysaccharide systems. Starch, pectin, xanthan gum, and konjac glucomannan are the most widely used polysaccharides in these composite systems. Heating-cooling and ionic-induced cross-linking approaches have been used in the fabrication of these systems. Composite gels fabricated using gellan and various polysaccharides exhibit different functional properties, possibly because of their distinct molecular interactions. In terms of applications, mixed gellan-polysaccharide systems have been extensively used in texture modification, edible coatings and films, bioactive component delivery, and tissue-engineering applications. Further scientific studies, including structural determinations of mixed systems, optimization of processing methods, and expansion of applications in food-related fields, are needed.

The Preparation and Characterization of Quinoa Protein Gels and Application in Eggless Bread

The properties of xanthan gum protein gels composed of quinoa protein (XG-QPG) and ultrasound-treated quinoa protein (XG-UQPG) were compared for the preparation of high-quality quinoa protein gels. The gel qualities at different pH values were compared. The gels were used to produce eggless bread. Microscopically, the secondary structure of the proteins in XG-QPG (pH 7.0) was mainly α-helix, followed by random coiling. In contrast, the content of β-sheet in XG-UQPG was higher, relative to the viscoelastic properties of the gel. Moreover, the free sulfhydryl groups and disulfide bonds of XG-QPG (pH 7.0) were 48.30 and 38.17 µmol/g, while XG-UQPG (pH 7.0) was 31.95 and 61.58 µmol/g, respectively. A high disulfide bond content was related to the formation of gel networks. From a macroscopic perspective, XG-QPG (pH 7.0) exhibited different pore sizes, XG-UQPG (pH 7.0) displayed a loose structure with uniform pores, and XG-UQPG (pH 4.5) exhibited a dense structure with small pores. These findings suggest that ultrasound can promote the formation of a gel by XG-UQPG (pH 7.0) that has a loose structure and high water-holding capacity and that XG-UQPG (pH 4.5) forms a gel with a dense structure and pronounced hardness. Furthermore, the addition of the disulfide bond-rich XG-UQPG (pH 7.0) to bread promoted the formation of gel networks, resulting in elastic, soft bread. In contrast, XG-UQPG (pH 4.5) resulted in firm bread. These findings broaden the applications of quinoa in food and provide a good egg substitute for quinoa protein gels.

Hydro- and aerogels from quince seed gum and gelatin solutions

The composite hydro/aerogels were designed using gelatin and quince seed gum (QSG) at total polymer concentration (TPC) of 1, 1.5 and 2% and gelatin/QSG ratio of 1:0, 1:0.5 and 1:1. The gel syneresis decreased significantly with increase in TPC and QSG. Although, hydrogels with 2% TPC had remarkably higher gel strength and elasticity than 1% TPC ones, the addition of high levels of QSG to the gelatin (i.e., gelatin/QSG 1:1) led to a decrease in its gel strength (∼0.97-fold) and elasticity (∼3,463-fold). The temperature-sweep test showed higher melting points in gelatin/QSG hydrogels (>60 °C) compared to the gelatin ones (∼58 °C). Additionally, QSG addition to the gelatin led to more porous networks with higher gel strength, thermal stability, and crystallinity, as observed by scanning electron microscopy, differential scanning calorimetry, and X-ray diffractometer. Therefore, QSG could be used as a natural hydrocolloid to modify gelatin functionality.

Monovalent Salt and pH-Stimulated Gelation of Scallop (Patinopecten yessoensis) Male Gonad Hydrolysates/κ-Carrageenan

The gelation of scallop Patinopecten yessoensis male gonad hydrolysates (SMGHs) and κ-carrageenan (KC) subjected to pH (2-8, 3-9) and NaCl/KCl stimuli-response was investigated. SMGHs/KC gels subjected to a NaCl response exhibited an increasing storage modulus G'from 2028.6 to 3418.4 Pa as the pH decreased from pH 8 to 2, with corresponding T23 fluctuating from 966.40 to 365.64 ms. For the KCl-treated group, SMGHs/KC gels showed an even greater G' from 4646.7 to 10996.5 Pa, with T23 fluctuating from 622.2 to 276.98 ms as the pH decreased from 9 to 3. The improved gel strength could be ascribed to the blueshift and redshift of hydroxyl groups and amide I peaks, enhanced enthalpy and peak temperature, and gathered characteristic diffraction peaks from SMGHs, KC, NaCl, and KCl. The CLSM and cryo-SEM images further reflected that SMGHs/KC gels showed more flocculation formation and denser and more homogeneous networks with smaller pore sizes in more acidic domains, especially when subjected to the KCl response. This research gives a theoretical and methodological understanding of the construction of salt- and pH-responsive SMGHs/KC hydrogels as novel functional soft biomaterials applied in food and biological fields.

Understanding Gel-Powers: Exploring Rheological Marvels of Acrylamide/Sodium Alginate Double-Network Hydrogels

This study investigates the rheological properties of dual-network hydrogels based on acrylamide and sodium alginate under large deformations. The concentration of calcium ions affects the nonlinear behavior, and all gel samples exhibit strain hardening, shear thickening, and shear densification. The paper focuses on systematic variation of the alginate concentration-which serves as second network building blocks-and the Ca²⁺-concentration-which shows how strongly they are connected. The precursor solutions show a typical viscoelastic solution behavior depending on alginate content and pH. The gels are highly elastic solids with only relatively small viscoelastic components, i.e., their creep and creep recovery behavior are indicative of the solid state after only a very short time while the linear viscoelastic phase angles are very small. The onset of the nonlinear regime decreases significantly when closing the second network (alginate) upon adding Ca²⁺, while at the same time the nonlinearity parameters (Q₀, I₃/I₁, S, T, e₃/e₁, and v₃/v₁) increase significantly. Further, the tensile properties are significantly improved by closing the alginate network by Ca²⁺ at intermediate concentrations.

Fabrication of grape seed proanthocyanidin-loaded W/O/W emulsion gels stabilized by polyglycerol polyricinoleate and whey protein isolate with konjac glucomannan: Structure, stability, and in vitro digestion

In this work, the effects of konjac glucomannan (KGM) concentrations on microstructure, gel properties, stability and digestibility of water-in-oil-in-water emulsion gels stabilized by polyglycerol polyricinoleate and whey protein isolate were investigated. Visual appearance indicated that a non-layered double emulsion gel was formed when KGM increased to 0.75%. Emulsion gels with 1.5% KGM showed the highest encapsulation, freeze-thaw and photochemical stability due to the formation of the smallest droplets, which were supported by microscopic observations. Moreover, the addition of KGM improved water holding capacity, rheological and texture properties of emulsion gels. Particularly, at 1.5% or 1.75% KGM, color and potential of hydrogen showed the most stable level after 14 days of storage. During in vitro digestion, KGM delayed the hydrolysis of protein and oil droplets, and then improved the bioavailability of grape seed proanthocyanidin. These results promoted the application of KGM in emulsion gels and the encapsulation of nutraceuticals.

Preparation and characterization of mussel-inspired hydrogels based on methacrylated catechol-chitosan and dopamine methacrylamide

A novel mussel-inspired adhesive hydrogel with enhanced adhesion based on methacrylated catechol-chitosan (MCCS) and dopamine methacrylate (DMA) was prepared via photopolymerization. The structure and morphology of the MCCS/DMA adhesive hydrogel were investigated by using FTIR, NMR, XRD, TG, and SEM. The rheological and texture properties, swelling and degradation characteristics, as well as the adhesion mechanism of the hydrogels were also examined. These results revealed that the MCCS/DMA hydrogels have a dense double cross-linking network structure with porous internal microstructures, and exhibited controllable swelling and degradation properties, good thermostability, and stable rheological characteristics. Furthermore, the adhesive mechanism of MCCS/DMA hydrogel has been confirmed by the FTIR and 2D correlation FTIR spectroscopy. Additionally, the results of in vitro cytotoxicity assessment indicated that the resulting hydrogels have good cytocompatibility. Overall, the MCCS/DMA adhesive hydrogel may have potential applications in medical bioadhesives.

Spray drying of non-chemically prepared nanofibrillated cellulose: Improving water redispersibility of the dried product

Despite increasing interest in using nanofibrillated cellulose (NFC) as food thickener and emulsifier, poor water redispersibility of dried NFC, which is form suitable for practical utilization, significantly limits such applications. Studies are lacking on preparation of dried NFC with superior redispersibility. The present study therefore proposed and examined strategies to improve water redispersibility of spray dried NFC via the use of selected co-carriers, i.e., gum Arabic with/without xanthan gum, carboxymethyl cellulose or pectin. Synergistic interactions between NFC and co-carriers, as confirmed by X-ray diffraction (XRD) patterns and Fourier transform infrared (FTIR) spectra, helped prevent NFC agglomeration during spray drying. All reconstituted spray-dried NFC/co-carriers suspensions exhibited shear-thinning and gel-like behaviors, thus supporting the use of such suspensions as thickener and emulsifier. Spray-dried NFC with 80% gum Arabic and 20% xanthan gum (SD-NFC/GA20XG) resulted in suspension with highest viscosity; the suspension also performed best at recovering viscous characteristics of NFC. Water thickened by SD-NFC/GA20XG had strongest shear-thinning behavior, indicating that SD-NFC/GA20XG suspension resulted in smoothest mouth feel and easiest swallowing. Such observations were supported by XRD patterns of SD-NFC/GA20XG, which suggested that its relative crystallinity was the lowest. Its FTIR spectra also showed the highest intensity of -OH bending and carbonyl bands, which are directly related to water adsorption capability of NFC. Use of reconstituted SD-NFC/GA20XG as emulsifier also resulted in highest stability for oil-in-water (O/W) Pickering emulsion during storage for up to 30 days.

Increasing agar content improves the sol-gel and mechanical features of starch/agar binary system

Starch/agar systems are highly potential for versatile applications such as packaging and biomedical materials. Here, how combined factors affect the features of a starch/agar binary system were explored. An increase of starch amylose/amylopectin ratio from 0/100 to 50/50 increased the sol-gel transition temperature and gel hardness of the aqueous starch/agar mixture. An increased agar content (mainly from 30% to 70%) allowed increases in both the tensile strength (reaching 50-60 MPa) and elongation at break of the starch/agar binary films. This phenomenon should be related to the strengthened crystalline structure and the weakened hydrogen bonding between starch chains (reflected by infrared spectroscopy). Furthermore, a higher relative humidity (from 30% to 70%) allowed enhanced chain interactions and probably nanoscale molecular order but weakened the crystalline structure, leading to reduced tensile strength and increased elongation at break. This work could facilitate the design of starch/agar binary systems with improved sol-gel and mechanical performance.

Polyvinyl alcohol inclusion can optimize the sol-gel, mechanical and hydrophobic features of agar/konjac glucomannan system

The practical features (e.g., sol-gel, mechanical and hydrophobic) of biopolymer systems are crucial for their materials applications. This work reveals how polyvinyl alcohol (PVA) inclusion affects the practical features of agar/konjac glucomannan (KGM) system. From rheological analysis, incorporating PVA (especially 6%) enhanced the chain entanglements of resulted ternary solution (A₇₀K₂₄P₆) with stabilized sol-gel transition point. Such effect not only increased the zero-shear viscosity (ca. 1.5 times that of agar/KGM counterpart) and structural recovery degree of A₇₀K₂₄P₆ solution, but also caused reduced crystallites and simultaneously increased tensile strength, elongation at break and hydrophobicity for A₇₀K₂₄P₆ film from solution dehydration. This ternary film exhibited a tensile strength of ca. 105 MPa, an elongation at break of ca. 20%, and a water contact angle of ca. 97.6°. Additionally, incorporating PVA almost unaffected the morphology of film fracture surface. These results are valuable for the design of agar/KGM systems with improved practical features.

Rheological behavior of nanocellulose gels at various calcium chloride concentrations

In this work, the effects of calcium chloride (CaCl₂) concentration on the creep-recovery, linear and nonlinear rheological behavior of nanocellulose gels had been investigated to quantify gel properties. The absolute zeta potential of nanocellulose gels were decreased as the CaCl₂ concentration increased, which was related to the electrostatic repulsion that origin from carboxyl group could be effectively screened with increasing CaCl₂ concentration. Rheological measurements further confirmed this result for nanocellulose gels, which revealed that the increased modulus and viscoelastic properties were obtained in the presence of CaCl₂. The rheological properties of nanocellulose gels were showed to depend on CaCl₂ concentration. The enhanced gel network structure was related to the Ca²⁺ ions that promoted crosslink between nanocellulose by salt bridge. This work highlighted the potential of using electrostatic complexation between nanocellulose and Ca²⁺ ions to form gels, and demonstrated the tunability of the rheological behavior by adjusting the concentration of CaCl₂.

Gummy candies production with natural sugar source: Effect of molasses types and gelatin ratios

Nowadays, attention has been dedicated towards the development of foodstuffs whose constituents are from natural sources. In this study, grape, mulberry, and carob molasses containing natural sugars were evaluated in order to replace the use of sugar syrup and artificial additives in the production of gummy candy which was prepared by varied gelatin ratios. The molasses which have similar °Brix values (78-79) presented different types and amounts of sugar components. High invert sugar with low sucrose was observed in grape and mulberry but high sucrose with low fructose and glucose appeared in carob molasses. Unlike grape and mulberry, carob based jellies had a whitish appearance possibly as a result of the crystallization due to its high sucrose/invert sugar ratio. For all parameters of TPA, carob candy with 5 g/100 g gelatin and grape candy with 10 g/100g gelatin had the lowest and highest values, respectively. Gelatin concentration dependency trend of hardness, gumminess, chewiness and resilience was determined as grape > mulberry > carob. No significant effect (p > 0.05) on gelling temperatures (21-29 °C) but significant effect (p < 0.05) on melting points (33-39 °C) of molasses types were observed for candies. The properties of grape based candy having higher thermal stability and lower temperature sensitivity were attributed to its higher total sugar contents than other samples. The sensorial acceptability score for molasses gummy candies obtained more than 3.0 on a 5-point hedonic scale. These results illustrate the potential for the use of molasses in a healthier confectionery product development instead of commonly used sugars.

Hydrophobized cellulose nanocrystals enhance xanthan and locust bean gum network properties in gels and emulsions

Locust bean/xanthan gum (LBG/XG) synergistic networks have previously been well studied, with evidence that junction zones between the two polymers result in hydrophobic domains. Here we report on the effect of both hydrophilic and hydrophobic cellulose nanocrystals (CNCs) on the rheological properties of the individual gums, the gum networks, and emulsion gels consisting of the gum network and corn oil. We also take advantage of differences in the autofluorescent spectra for each of the components to map their distribution within the gel and emulsion gel systems. Whilst both types of CNC confer thermal stability to the systems, hydrophilic CNCs induce minor changes in rheological properties of synergistic gels and prove to be detrimental to the stability of the emulsion gels. In contrast, hydrophobic CNCs associate with the LBG/XG network, affecting the rheological response. Their inclusion in the emulsion gel system results in smaller, more homogeneously distributed oil droplets with a resultant increase in the storage modulus by an order of magnitude compared to the CNC-free and hydrophilic CNC systems. We conclude that hydrophobic CNCs play a critical role in stabilising LBG/XG network gels and emulsions.