Promoted strain-hardening and crystallinity of a soy protein-konjac glucomannan complex gel by konjac glucomannan

Improvement of 3D printing age-friendly brown rice food on rough texture, swallowability, and in vitro digestibility using fermentation properties of different probiotics

Probiotics can promote the balance of the intestinal microbial community and enhance the biological activity of food. They are beneficial to the health of elderly people. Therefore, five different probiotics (4% of the total weight) were added to pasted brown rice to study the printability, swallowability, and digestibility of fermented inks (at 40 °C for 10 h). The results showed that probiotics reduced the apparent viscosity and resistance to deformation of brown rice inks. The inks with Lactobacillus bulgaricus (LB), Bifidobacterium longum (BL), and Lactiplantibacillus plantarum (LP) had better printing properties and finer appearances. Probiotics significantly reduced the adhesiveness, gumminess, and hardness of inks but had little effect on cohesiveness. LB, Streptococcus thermophilus (ST), and LP were categorized as having class 4 consistency with easy-to-swallow characteristics. The growth and multiplication of probiotics detached the internal structure of brown rice inks and reduced the relative crystallinity. They also modulated the nutrient content and flavor components by producing short-chain fatty acids, and improved the digestion of starch.

Role of pectin in the delivery of β-carotene embedded in interpenetrating emulsion-filled gels made with soy protein isolate

This study investigated the effects of different matrices on gel properties, lipid digestibility, β-carotene bioaccessibility, released free amino acids and gel network degradation. Microstructure studies have proven that sugar beet pectin/soy protein isolate-based emulsion-filled gel (SBP/SPI-E) with interpenetrating networks was formed. SBP/SPI-E exhibited higher hardness (2.67 N, p < 0.05) and released lesser free amino acids (269.48-μmol/g SPI) than soy protein isolate-based emulsion-filled gel (SPI-E) in simulated intestinal fluid (SIF); however, both had similar free amino acids contents in simulated colonic fluid. SBP has the potential to delay gel network degradation in SIF, as evidenced by the sugar stain strips of SDS-PAGE and microstructure observation. Furthermore, SBP/SPI-E and SPI-E exhibited similar β-carotene bioaccessibility in SIF, suggesting that SBP from composite gel could not affect the aforementioned bioaccessibility. The study provides useful information for the design of functional gels in the application of fat-soluble nutrient delivery.

Konjac glucomannan-fibrin composite hydrogel as a model for ideal scaffolds for cell-culture meat

In this study, composite gel was prepared from konjac glucomannan (KGM) and fibrin (FN). Composite gels with different concentration ratios were compared in terms of their mechanical properties, rheological properties, water retention, degradation rate, microstructure and biocompatibility. The results showed that the composite gels had better gel strength and other properties than non-composite gels. In particular, composite hydrogels with low Young's modulus formed when the KGM concentration was 0.8% and the FN concentration was 1.2%. The two components were cross linked through hydrogen-bond interaction, which formed a more stable gel structure with excellent water retention and in-vitro degradation rates, which were conducive to myogenic differentiation of ectomesenchymal stem cells (EMSCs). KGM-FN composite gel was applied to the preparation of cell-culture meat, which had similar texture properties and main nutrients to animal meat as well as higher content of dry base protein and dry base carbohydrate.

Effect and mechanism of freezing on the quality and structure of soymilk gel induced by different salt ions

BACKGROUND

The increasing attention toward frozen soy-based foods has sparked interest. Variations exist in the quality and structure of soymilk gels induced by different salt ions, leading to diverse changes post-freezing. This study compared and analyzed the effects of calcium chloride (CC), magnesium chloride (MC) and calcium sulfate (CS) on the quality characteristics and protein structure changes of soymilk gels (CC-S, MC-S and CS-S) before and after freezing, and clarified the mechanisms of freezing on soymilk gel.

RESULTS

The formation rate of soymilk gel is influenced by the type of salt ions. In comparison to CS and MC, soymilk gel induced by CC exhibited the fastest formation rate, highest gel hardness, lowest moisture content, and smaller gel pores. However, freezing treatment deteriorated the quality of soymilk gel induced by different salt ions, leading to a decline in textural properties (hardness and chewiness). Among these, the textual state of CC-induced soymilk gel remained optimal, exhibiting the least apparent damage and minimal cooking loss. Freezing treatments prompt a transition of soymilk gel secondary structure from β-turns to β-sheets, disrupting the protein's tertiary structure. Furthermore, freezing treatments also fostered the crosslinking between soymilk gel protein, increasing the content of disulfide bonds.

CONCLUSION

The quality of frozen soymilk gel is influenced by the rate of gel formation induced by salt ions. After freezing, soymilk gel with faster gelation rates exhibited a greater tendency for the transformation of protein-water interactions into protein-protein interactions. They showed a higher degree of disulfide bond formation, resulting in a more tightly knit and firm frozen gel network structure with denser and more uniformly distributed pores. © 2024 Society of Chemical Industry.

Investigation into the fabrication of plant-based simulant connective tissue utilizing algae polysaccharide-derived hydrogel

Connective tissue is an important component of meat products that provides support to animal muscles. Hydrogels are considered a promising alternative to connective tissues and simulate actual products by adjusting the gel texture and mouthfeel. This study used soybean protein isolate (SPI), corn starch (CS), konjac glucomannan (KGM), and seaweed powder (SP) as raw materials to examine the effect of different added SP and KGM concentrations on the gel texture. The G' of the gel increased five-fold when the SP and KGM concentration was increased from 1 % to 3 %. The results of mechanical property tests showed that with the addition of SP, the gel hardness increased from 316.00 g to 1827.23 g and the tensile strength increased from 0.027 MPa to 0.089 MPa. Sensory evaluation showed that the samples with 2 % SP and KGM presented the highest overall acceptability score and the most significant similarity to real connective tissue. The connective tissue simulants exhibited excellent water-holding capacity (>90 %), significantly increasing their juiciness. SEM indicated that 2 % KGM addition improved gel network structure stability. The results demonstrate the potential of seaweed polysaccharide-derived hydrogels as connective tissue mimics. This provides a new strategy for the preparation of high mechanical strength hydrogels and lays the foundation for structural diversification of plant-based meat.

Germination-induced modifications of starch structure, flour-processing characteristics, and in vitro digestive properties in maize

Current research on maize germination suffers from long sampling intervals, and the relationship between the starch structure and the processing properties of flour in maize is still unclear. This study observed the effect of germination on the structure and composition of maize starch and the processing properties of maize flour over a 72 h period using a short interval sampling method. At 36 h, the short-range ordered structure, crystallinity, and enthalpy of starch reached the highest values of 1.02, 34.30%, and 9.90 J/g, respectively. At 72 h, the ratios of rapidly-digested starch (RDS) and slowly-digested starch (SDS) enhanced to 29.37% and 28.97%; the RS content reduced to 35.37%; and the flow properties of the starch were improved. This study enhances the understanding of the effects of germination on the processing properties of maize starch and flour, determines the appropriate application, and recommends the use of germination in the food industry.

Development of soy protein isolate gels added with Tremella polysaccharides and psyllium husk powder as 3D printing inks for people with dysphagia

The aim of this study was to investigate the feasibility of soy protein isolate (SPI) gels added with Tremella polysaccharides (TPs) and psyllium husk powder (PHP) as 3D printing inks for developing dysphagia-friendly food and elucidate the potential mechanism of TPs and PHP in enhancing the printing and swallowing performance of SPI gels. The results indicated that the SPI gels with a TP : PHP ratio of 3 : 7 could be effectively used as printing inks to manufacture dysphagia-friendly food. The addition of TPs increased the free water content, resulting in a decrease in the viscosity of the SPI gels, which, in turn, reduced the line width of the 3D-printed product and structural strength of the gel system. The addition of PHP increased disulfide bond interactions and excluded volume interactions, which determined the mechanical strength of SPI gels and increased the line width of the printed product. The synergistic effects between TPs and PHP improved the printing precision and structural stability. This study presents meaningful insights for the utilization of 3D printing in the creation of dysphagia-friendly food using protein-polysaccharide complexes.

Effect of apple high-methoxyl pectin on heat-induced gelation of silver carp myofibrillar protein

The effect of adding apple high-methoxy pectin (HMP) (0-3 mg∙mL-1) on heat-induced gel characteristics of low concentration silver carp myofibrillar protein (MP) (15 mg∙mL-1) was studied. It was found that the hardness of gel increased by 20.6 times with adding 2 mg∙mL-1 HMP. Besides, HMP aided in the development of disulfide bonds and the aggregation of hydrophobic groups. During gel formation, the maximal storage modulus (G') of samples supplemented with 2 mg·mL-1 HMP was raised by a factor of 2.7. Of note, the images of SEM showed that protein and water were tightly combined with a proper amount of HMP and made its pores more uniform and dense. Meantime, the addition of moderate amounts of HMP enabled the formation of gels with favorable texture and performance at low concentration of MP was identified, which could provide a theoretical reference for the design and production of flesh low-calorie food gel.

Regulation of glycose and lipid metabolism and application based on the colloidal nutrition science properties of konjac glucomannan: A comprehensive review

The physicochemical properties of dietary fiber in the gastrointestinal tract, such as hydration properties, adsorption properties, rheological properties, have an important influence on the physiological process of host digestion and absorption, leading to the differences in satiety and glucose and lipid metabolisms. Based on the diversified physicochemical properties of konjac glucomannan (KGM), it is meaningful to review the relationship of structural characteristics, physicochemical properties and glycose and lipid metabolism. Firstly, this paper bypassed the category of intestinal microbes, and explained the potential of dietary fiber in regulating glucose and lipid metabolism during nutrient digestion and absorption from the perspective of colloidal nutrition. Secondly, the modification methods of KGM to regulate its physicochemical properties were discussed and the relationship between KGM's molecular structure types and glycose and lipid metabolism were summarized. Finally, based on the characteristics of KGM, the application of KGM in the main material and ingredients of fat reduction food was reviewed. We hope this work could provide theoretical basis for the study of dietary fiber colloid nutrition science.

Age Gelation in Direct Steam Infusion Ultra-High-Temperature Milk: Different Heat Treatments Produce Different Gels

To investigate the gelation process of direct ultra-high-temperature (UHT) milk, a pilot-scale steam infusion heat treatment was used to process milk samples over a wide temperature of 142-157 °C for 0.116-6 s, followed by storage at 4 °C, 25 °C, and 37 °C. The results of the physicochemical properties of milk showed that the particle sizes and plasmin activities of all milk samples increased during storage at 25 °C, but age gelation only occurred in three treated samples, 147 °C/6 s, 142 °C/6 s, and 142 °C/3 s, which all had lower plasmin activities. Furthermore, the properties of formed gels were further compared and analyzed by the measures of structure and intermolecular interaction. The results showed that the gel formed in the 147 °C/6 s-treated milk with a higher C* value had a denser network structure and higher gel strength, while the 142 °C/6 s-treated milk had the highest porosity. Furthermore, disulfide bonds were the largest contributor to the gel structure, and there were significant differences in disulfide bonds, hydrophobic interaction forces, hydrogen bonds, and electrostatic force among the gels. Our results showed that the occurrence of gel was not related to the thermal load, and the different direct UHT treatments produced different age gels in the milk.

Chitosan entrapping of sodium alginate / Lycium barbarum polysaccharide gels for the encapsulation, protection and delivery of Lactiplantibacillus plantarum with enhanced viability

To preserve the viability of probiotics during digestion and storage, encapsulation techniques are necessary to withstand the challenges posed by adverse environments. A core-shell structure has been developed to provide protection for probiotics. By utilizing sodium alginate (SA) / Lycium barbarum polysaccharide (LBP) as the core material and chitosan (CS) as the shell, the probiotic load reached 9.676 log CFU/mL. This formulation not only facilitated continuous release in the gastrointestinal tract but also enhanced thermal stability and storage stability. The results obtained from Fourier transform infrared spectroscopy and thermogravimetric analysis confirmed that the addition of LBP and CS affected the microstructure of the gel by enhancing the hydrogen bond force, so as to achieve controlled release. Following the digestion of the gel within the gastrointestinal tract, the released amount was determined to be 9.657 log CFU/mL. The moisture content and storage stability tests confirmed that the encapsulated Lactiplantibacillus plantarum maintained good activity for an extended period at 4 °C, with an encapsulated count of 8.469 log CFU/mL on the 28th day. In conclusion, the newly developed core-shell gel in this study exhibits excellent probiotic protection and delivery capabilities.

Pickering emulsion with high freeze-thaw stability stabilized by xanthan gum/lysozyme nanoparticles and konjac glucomannan

In this study, freeze-thaw cycle experiments were conducted on food-grade Pickering emulsions co-stabilized with konjac glucomannan (KGM) and xanthan gum/lysozyme nanoparticles (XG/Ly NPs). The rheological properties, particle size, flocculation degree (FD), coalescence degree (CD), centrifugal stability, Differential scanning calorimetry (DSC), X-ray diffraction (XRD) and microstructure of Pickering emulsion stabilized by KGM before and after freeze-thaw were characterized. It was found that as the concentration of KGM increased, the flocculation degree (FD) and coalescence degree (CD) of the emulsion decreased after the freeze-thaw cycle compared to the control sample, and the microscopic images showed that the droplets became smaller and less affected by the freeze-thaw cycles. The rheological and water-holding properties also confirmed that the KGM-added emulsions still had a strong gel network structure and prevented the separation of the continuous and dispersed phases of the droplets after freezing and thawing. Freeze-thaw treatments had a negative effect on the stable emulsion of XG/Ly NPs, while the addition of KGM improved the freeze-thaw stability of the emulsion, which provided a theoretical basis for the development of emulsion products with high freeze-thaw stability.

Effect of variation in basic emulsion structure and polysaccharide content on the physicochemical properties and structure of composite-based emulsion gels as cube fat mimetics

This study aimed to reveal the effect of different basic emulsion structures (W/O/W and O/W) and polysaccharide additions on protein-polysaccharide composite-based emulsion gels utilizing soybean protein isolate, palm oil and konjac glucomannan. The results of texture profile, rheological tests, microstructure observations, and oral tribology showed that basic emulsion structures and konjac glucomannan addition had significant effect on the emulsion gels' properties, while the impact of konjac glucomannan addition was stronger. W/O/W double emulsion gels (DEG) exhibited lower oral friction coefficients and obtained higher scores for oiliness and juiciness during the sensory evaluation. However, O/W single emulsion gels (SEG) displayed a firmer texture and higher chewiness, a 29.62% and 49.57% increase compared to the DEG at 7% konjac glucomannan addition on the hardness and chewiness respectively. It has demonstrated the emulsion gels' potential as cube fat mimetics and feasibility of adjusting their properties by changing the basic emulsion structure.

Characterization of fruit pulp-soy protein isolate (SPI) complexes: Effect of superfine grinding

Superfine grinding (SG), as an innovative technology, was conducted to improve the physicochemical and structural properties of fruit pulps. Nectarine, apple, and honey peach were selected as the materials. With the increase in SG frequency, the soluble solids content, viscosity, D[4, 3], D[3, 2], G' and G″ of fruit pulps were evidently decreased, whereas the turbidity was increased. The smallest D[4, 3] (294.90 µm) and D[3, 2] (159.67 µm) were observed in nectarine pulp under SG at 50 Hz. The highest turbidity (266.33) was shown in honey peach pulp under SG at 50 Hz. The active groups of the fruit pulps with SG were exposed by Fourier transform infrared spectroscopy (FT-IR). Notably, the excessive destruction in structure was confirmed in SG with 50 Hz. With soy protein isolate (SPI) addition, D[4, 3] and D[3, 2] of complexes decreased, whereas G' and G″ increased. The formation of new fruit pulp-SPI complexes was demonstrated by FT-IR and LF-NMR analysis. The dense and uniform structure was found in complexes prepared by SPI and fruit pulp with 30 Hz SG. Especially, apple-SPI complex with 30 Hz SG showed the highest water-holding capacity (WHC) (0.75) and adhesiveness (7973.00 g s). A significant correlation between fruit pulps and the complexes was revealed. Taken together, the impact of SG modification on fruit pulps would enhance WHC, rheology, and textural properties of the fruit pulp-SPI complexes, especially for SG with 30 Hz. PRACTICAL APPLICATION: This research provided a comprehensive exploration of the potential of SG technology to modify fruit pulps, solving the diversity of textural customization problems and offering valuable insights for the development of semisolid food products.

Quality, Thermo-Rheology, and Microstructure Characteristics of Cubic Fat Substituted Pork Patties with Composite Emulsion Gel Composed of Konjac Glucomannan and Soy Protein Isolate

Composite emulsion gel can effectively mimic animal adipose tissue. In this study, composite emulsion gels composed of soy protein isolates and konjac glucomannan (KGM) were prepared as plant-based cubic fat substitutes (CFS). The effects of CFS on the quality and structure of pork patties were investigated in terms of the proximate composition, lipid oxidation stability, technological characteristics, color, sensory attributes, texture, thermo-rheological behavior, and microstructure. CFS samples composed of various ratios of KGM were added to lean meat patties to ascertain the optimal CFS composition for its potential replacement of pork back fat in patties. The addition of CFS containing 7.0% KGM was found to decrease the hardness of the lean meat patties by 71.98% while simultaneously improving their sensory quality. The replacement of pork back fat with CFS also reduced the fat content of the patties to as little as 3.65%. Furthermore, the addition of CFS enhanced the technological characteristics, lipid oxidation stability, and surface color of the fat-replaced patties, with no significant impact on their overall acceptability. The gel network of the patties was shown to be fine and remained compact as the fat replacement ratio increased to 75%, while the texture parameters, storage modulus, and fractal dimension all increased. Quality and structure improvements may allow the composite emulsion gels to replace fat in pork patties to support a healthy diet. This study may be beneficial for the application and development of plant-based cubic fat substitutes.

Comprehensive investigation into the effects of yeast dietary fiber and temperature on konjac glucomannan/kappa-carrageenan for the development of fat analogs

In this study, yeast dietary fiber (YDF) was incorporated into konjac glucomannan/kappa-carrageenan (KGM/κ-KC) for the development of fat analogs, and the impact of YDF on the gelation properties and behavior of KGM/κ-KC composite gels was assessed. YDF improved the composite gel whiteness value, and affected the mechanical properties of the composite gel, especially enhancing its hardness, and decreasing its chewiness, elasticity, and gel strength, making it more similar to porcine back fat. When the yeast dietary fiber content was 0.033 g/mL and the heating temperature was 80 °C (T80-2), the textural properties of the composite gel were closest to porcine back fat. The frequency sweep results suggested that YDF incorporation led to enhancement of the intermolecular interaction and intermixing and interaction among more easily at higher processing temperatures (80 °C and 90 °C). By scanning electron microscopy, the fatty surface of porcine back fat was flat and covered with a large amount of oil, while KGM/κ-KC/YDF composite gels developed a dense, stacked network structure. YDF caused more fragmented, folded, and uneven structures to emerge. Overall, YDF could influence the gel behavior of KGM/κ-KC composite gels, and change their colors and mechanical properties. This work could serve as a guide for preparing fat analogs with KGM/κ-KC composite gels.

Rapidly degradable konjac glucomannan hydrogels cross-linked with olsalazine for colonic drug release

BACKGROUND

Polysaccharide hydrogel is one of the most important materials for the colon target drug release system. However, the degradation time of polysaccharide hydrogel is much longer than the retention time in the colon. The drugs are expelled from the body before being released.

OBJECTIVE

In order to match the degradation of drug carriers and their retention time in the colon, a rapidly degradable konjac glucomannan (KGM) hydrogel was designed for colon target drug release.

METHODS

A crosslinker containing azo bond, olsalazine, was used to prepare the rapidly degradable KGM hydrogel. The degradation and drug release of the hydrogels with different crosslinking densities in the normal buffer and the human fecal medium were studied to evaluate the efficiency of colon drug release.

RESULTS

More than 50% of the KGM hydrogel by weight was degraded and more than 60% of the 5-fluorouracil (5-Fu) was released within 48 h in 5% w/v human fecal medium.

CONCLUSION

The drug was released more rapidly in a simulated colon environment than in a normal buffer. Furthermore, the drug release was controlled by the degradation of the hydrogel. The KGM hydrogel containing azo crosslinker has great potential for colon drug release.

Investigation of the effect and mechanism of nanocellulose on soy protein isolate- konjac glucomannan composite hydrogel system

To enrich the application of nanocomposite hydrogels, we introduced two types of nanocellulose (CNC, cellulose nanocrystals; CNF, cellulose nanofibers) into the soy protein isolate(SPI)- konjac glucomannan (KGM) composite hydrogel system, respectively. The similarities and differences between the two types of nanocellulose as textural improvers of composite gels were successfully explored, and a model was developed to elaborate their interaction mechanisms. Appropriate levels of CNC (1.0 %) and CNF (0.75 %) prolonged SPI denaturation within the system, exposed more buried functional groups, improved molecular interactions, and strengthened the honeycomb structural skeleton formed by KGM. The addition of CNC resulted in greater gel strength (SKC1 2708.53 g vs. Control 810.35 g), while the addition of CNF improved the elasticity (SKF0.75 1940.24 g vs. Control 405.34 g). This was mainly attributed to the reinforcement of the honeycomb-structured, water binding and trapping, and the synergistic effect of covalent (disulfide bonds) and non-covalent interactions (hydrogen bonds, ionic bonds) within the gel network. However, the balance and interactions between proteins and polysaccharides were disrupted in the composite system with excessive CNF addition (≥0.75 %), which broken the stability of the honeycomb-like structure. We expect this study will draw attention on potential applications of CNC and CNF in protein-polysaccharide binary systems and facilitate the creation of novel, superior, mechanically strength-regulated nanofiber composite gels.

Wheat bran arabinoxylan-soybean protein isolate emulsion-filled gels as a β-carotene delivery carrier: Effect of polysaccharide content on textural and rheological properties

This study aimed to investigate the effects of different wheat bran arabinoxylan (WBAX) concentrations (1, 2, 3, and 4 wt%) on the structural and physicochemical properties of WBAX-soybean protein isolate (SPI) emulsion-filled gels (EFGs) prepared using laccase and heat treatment. The properties of the various gels as well as their microstructure, rheology, and in vitro digestion behaviors were investigated. Results showed that WBAX-SPI EFGs with a 3 wt% WBAX concentration had a smooth and uniform appearance, high water holding capacity (98.5 ± 0.2 %), and enhanced mechanical properties. Rheological experiments suggested that a stronger and closer gel network was formed at 3 wt% WBAX concentration. Fourier transform infrared spectroscopy showed that laccase and heat treatment not only catalyzed the intramolecular crosslinking of WBAX and SPI, respectively, but also promoted the interaction between WBAX and SPI. Confocal laser scanning microscopy revealed that the WBAX gel network was interspersed within the SPI network. The interactions contributing to the gelation analysis revealed that chemical (disulfide bond) and physical (hydrogen bond and hydrophobic) interactions promoted the formation of denser EFGs. Furthermore, the WBAX-SPI EFGs provided a β-carotene bioaccessibility of 21.8 ± 0.6 %. Therefore, our study suggests that WBAX-SPI EFGs hold promising potential for industrial applications in the delivery of β-carotene.

Improvement of kefir fermentation on rheological and microstructural properties of soy protein isolate gels

Soy protein isolate (SPI) has become a promising plant-based material as an animal protein products alternative. However, its application was limited due to the weak gelling properties. To investigate the effect of kefir fermentation on SPI gels properties, SPI-polysaccharide gels was produced by unfermented and kefir-fermented SPI using different concentration of KGM, chitosan, and calcium chloride in this study. Characterization of fermented SPI gels showed that fermentation by kefir grains can be applied to improve the textural strength, mechanical structure, and thermal characteristics of SPI gels. Compared to unfermented SPI gels, the water-holding capacity was remarkably enhanced to 63.11% and 65.71% in fermented SPI-chitosan gels. Moreover, the hardness of fermented SPI-KGM gels were significantly increased to 13.43 g and 27.11 g. And the cohesiveness and resilience of fermented-KGM gels were also improved than unfermented samples. Results of rheological characterization and thermogravimetric analysis revealed the strengthened mechanical features and higher thermal stability of fermented SPI gels. Additionally, the main role of hydrophobic interactions and secondary structure variations of SPI gels were demonstrated by intermolecular force measurements, Fourier-transform infrared spectroscopy, and X-ray diffraction. Moreover, the network structure was observed more compact and homogeneous performed by microstructural images in fermented SPI gels. Therefore, this research provided a novel approach combining multi-species fermentation with protein gelation to prepare SPI gel materials with improved nutrition and structural properties.

Fabrication and Characterization of Complex Coacervation: The Integration of Sesame Protein Isolate-Polysaccharides

The exceptional biocompatibility of emulsion systems that rely on stabilizing protein-polysaccharide particles presents extensive possibilities for the transportation of bioactive carriers, making them highly promising for various biological applications. The current work aimed to explore the phenomenon of complex coacervation between sesame protein isolate (SPI) and four distinct polysaccharides, namely, Arabic gum (GA), carrageenan (CAR), sodium carboxymethyl cellulose (CMC), and sodium alginate (SA). The study objective was achieved by fabricating emulsions through the blending of these polymers with oil at their maximum turbidity level (φ = 0.6), followed by the measurement of their rheological properties. The turbidity, ζ-potential, and particle size were among the techno-parameters analyzed to assess the emulsion stability. The microstructural characterization of the emulsions was conducted using both transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Furthermore, the functional properties were examined using Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The SPI incorporated with SA, CMC, and CAR reached the maximum turbidity (0.2% w/v) at a ratio of 4:1, corresponding to the pH values of 4.5, 3, or 3.5, respectively. The SPI-GA mixture exhibited the maximum turbidity at a ratio of 10:1 and pH 4.5. Results from the FTIR and XRD analyses provided evidence of complex formation between SPI and the four polysaccharides, with the electrostatic and hydrogen bond interactions facilitating the binding of SPI to these polysaccharides. SPI was bound to the four polysaccharides through electrostatic and hydrogen bond interactions. The SPI-CMC and SPI-SA emulsions were more stable after two weeks of storage.

Modification of low-salt myofibrillar protein using combined ultrasound pre-treatment and konjac glucomannan for improving gelling properties: Intermolecular interaction and filling effect

The quality deterioration of low-salt meat products has been gained ongoing focus of researchers. In this study, konjac glucomannan (KGM) was used to alleviate the finiteness of ultrasound treatment on the quality improvement of low-salt myofibrillar protein (MP), and the modification sequence was also investigated. The results revealed that the single and double sequential modification by utilizing KGM and ultrasound significantly influenced the gelation behavior of low-salt MPs. The uniform MP-KGM mixture formed by a single ultrasound treatment had limited protein unfolding, resulting in relatively weak intermolecular forces in the composite gel. Importantly, ultrasound pre-treatment combined with KGM modification promoted the unfolding and moderate thermal aggregation of proteins and remarkably improved the rheological behaviors and gel strength of the composite gel. This result could also be corroborated by the highest percentage of trans-gauche-trans conformation of SS bridges and maximum β-sheet proportion. Furthermore, molecular dynamic simulation and molecular docking elucidated that the hydrogen bond length between protein and KGM was shortened after ultrasound pre-treatment, which was the molecular basis for the enhanced intermolecular interactions. Therefore, ultrasound pre-treatment combined with KGM can effectively improve the gelling properties of low-salt MPs, providing a practical method for the processing of low-salt meat products.

Formation mechanism of salted egg yolk mudding during storage: Protein oxidation, gel structure, and conformation

The aim of this study was to investigate the formation mechanism of salted egg yolk (SEY) mudding during storage. Results showed that the soluble protein, hardness, and intrinsic fluorescence intensity of SEY decreased significantly during storage, while total volatile basic nitrogen, sulfhydryl group, dityrosine, adhesiveness, and surface hydrophobicity increased significantly, and the intrinsic fluorescence peak position red-shifted at first and then blue-shifted. In addition, from the results of infrared and microstructure analyses, there was an obvious oxidation reaction between protein and lipid in the late storage stage; the structure of SEY was destroyed, many random coils were formed, and the degree of protein-lipid binding and the crystallinity of SEY protein decreased during storage. Finally, the heatmap analysis revealed that the protein and lipid oxidation and conformational changes might be the main reasons for SEY mudding. This study can provide theoretical guidance for the control of SEY mudding.

Structural, functional properties of protein and characteristics of tofu from small-seeded soybeans grown in the Loess Plateau of China

The structural, functional properties of protein isolated from small-seeded soybeans were investigated and characteristics of tofu were studied. Small-seeded soybean protein had obvious α', α, β, acidic and basic subunits bands and two endothermic peaks (76.02-76.63℃ and 91.94-94.25℃). Small-seeded black soybean protein isolates (SBSPI) had more β-sheet (31.90-33.54%) structure, while small-seeded yellow soybean protein isolates (SYSPI) had more α-helix (18.89-20.72%) structure. SYSPI had higher fluorescence intensity (839.10-847.80) than SBSPI (482.70-565.10). SBSPI exhibited higher surface hydrophobicity (939.51-1252.75) and water absorption capacity (8.07-8.50 g/g). Tofu made from small-seeded yellow soybeans had higher yield (549.46-560.23 g/100 g soybean) and was brighter (L*, 74.61-77.48) and more yellowish (b*, 14.83-14.95) in color. Tofu made from Fugu small-seeded black soybean (FGSBS) had the highest hardness (178.52 g), adhesiveness (-25.77 g.sec), chewiness (87.45 g) and resilience (0.26), signifying a more compact structure.

Legume protein/polysaccharide food hydrogels: Preparation methods, improvement strategies and applications

For the development of innovative foods and nutritional fortification, research into food gel is essential. As two types of rich natural gel material, both legume proteins and polysaccharides have high nutritional value and excellent application potential, attracting wide attention worldwide. Research has focused on combining legume proteins with polysaccharides to form hybrid hydrogels as their combinations show improved texture and water retention compared to single legume protein or single polysaccharide gels, and these properties can be tailored for specific applications. This article reviews hydrogels of common legume proteins and discusses heat induction, pH induction, salt ion induction, and enzyme-induced assembly of legume protein/polysaccharide mixtures. The applications of these hydrogels in fat replacement, satiety enhancement, and delivery of bioactive ingredients are discussed. Challenges for future work are also highlighted.

Insight into the spatial distribution and interaction model of heat-induced micro- and nano-starch/myofibrillar protein blends

This work investigated the gelatinizing and hydration properties of raw and milled tapioca starches at micron and nano scale as well as their effects on gelation of myofibrillar proteins (MP) from Ctenopharyngodon idellus by analyzing rheology, texture and microstructure of heat-induced MP/starch blends. Milling induced starch granules damage to micron and nano scale, causing a fall in starch swelling power and a jump in water solubility. Among raw and milled starches, nano-starch had the best reinforcement effect on MP gel, i.e., MP/nano-starch showed the lowest critical gel concentration, highest G', strongest resistance to deformation and highest texture performance. Correlation analysis revealed that starch water solubility was responsible for the reinforced MP gel rather than starch swelling power. A schematic model was proposed for illustrating the interaction of starches and MP. All the blends had the ordered filamentous network as the basic skeleton, with some starches (granules and their fragments) in the voids or on the edge or surface of MP filaments as inert fillers, and some (chain segments) embedded in the filaments as active fillers. Almost all nano-starch were actively filled into the MP filaments to enhance the strength of filaments, thus achieving the best reinforcement effect on MP gel.

Properties of whey protein isolation/konjac glucomannan composite gels: Effects of deacetylation degrees

The effects of konjac glucomannan (KGM) with different deacetylation degrees (DDs) on the gel properties of whey protein isolate (WPI) were investigated. The appropriately deacetylated KGM (DDs in the range of 0-53.85 %) incorporated within WPI and formed relatively uniform compound gels, while excessive deacetylated KGM (DDs = 63.46 or 71.63 %) caused macroscopic precipitation and aggregation in WPI-KGM system. The water holding capacity of WPI-KGM gels decreased with the gradual increase of DDs, and the removal of acetyl groups reduced the whiteness of the composite gels. The hardness and chewiness of the composite gel tended to increase and subsequently decrease with the enhancement of DDs, and reached the maximum (244.15 and 148.88 g, respectively) at the DDs of 53.85 %. The rheological analysis indicated that rigid structured WPI-KGM gels could be formed when incorporated with moderately deacetylated KGM. The deacetylated KGM (DDs = 53.85 %) enhanced the hydrogen bond and disulfide bond within the mixed system, resulting in a more compact network structure of the composite gels. Moreover, deacetylated KGM particles might also reinforce the gel strength by the "filling effects". Overall, the gelation characteristics of the WPI-KGM system can be regulated by controlling the DDs of KGM.

Fabrication of biodegradable blend plastic from konjac glucomannan/zein/ PVA and understanding its multi-scale structure and physicochemical properties

Exploration and synthesis of degradable plastics can alleviate and avoid environmental pollution induced by petroleum-based plastics. In this study, a konjac glucomannan (KGM)/zein/PVA ternary blend plastic was successfully prepared by casting. The results showed that, despite the presence of particle aggregation from incompatible components in blend plastic, the addition of KGM and zein improved its compatibility which is consistent with the formation of continuous dark regions and the reduction of roughness average (Ra) results in the AFM characterization. Also, XRD and FT-IR results indicated that the addition of KGM and zein disrupted the molecular and crystalline structure of PVA, induced stretching vibration of alcohol and hydroxyl groups, and crystallinity reduction. In addition, KGM deacetylation (d-KGM) reduced the intramolecular hydroxyl groups, reduced the water absorption and water vapor transmission rate of the blend plastics, and increased the crystallization temperature (Tc) and melting temperature (Tm). Furthermore, the blended plastics exhibited the best tensile strength (TS), elongation at break (E), and elastic modulus (EM) when the proportion of KGM to zein was 9:1. Notably, the blended plastic with KGM and zein added displayed more pores and cracks after soil burial, implying that the lack of degradability of pure PVA plastic was improved.

A green method for decolorization of polysaccharides from alfalfa by S-8 macroporous resin and their characterization and antioxidant activity

In this study, the decolorization conditions of polysaccharides extracted from alfalfa by S-8 macroporous adsorption resin were optimized through the response surface method, and the physicochemical properties and antioxidant activity of decolorized polysaccharides were investigated. The optimal decolorization conditions were determined to be as follows: the amount of S-8 macroporous adsorption resin was 1.4 g, the adsorption time was 2 h, and the adsorption temperature was 58 °C. Under these optimal conditions, a decolorization ratio of 71.43 ± 0.23% was achieved, which was consistent with the model hypothesis. The adsorption curve showed that S-8 macroporous adsorption resin adsorption of pigment molecules in alfalfa polysaccharides (APS) agreed with the Freundlich and pseudo-second-order equations, and the adsorption was a spontaneous endothermic process. High-performance liquid chromatography (HPLC) analysis of monosaccharide composition showed that APS was composed of mannose, glucose, galactose, arabinose and glucuronic acid in a molar ratio of 1.18 : 8.04 : 1.22 : 0.92 : 1. The results of antioxidant activity studies showed that APS had strong scavenging activity against ABTS, DPPH and hydroxyl radicals. This study will help to further understand the adsorption mechanism of macroporous resin on polysaccharide pigment molecules and lay a basis for evaluating their physiological activity.

The decolorization process and adsorption mechanism of pigment molecules in alfalfa polysaccharides by S-8 resin were studied. Meanwhile, the physicochemical properties and antioxidant activity of alfalfa polysaccharides were analyzed.