Comparison of citrus pectin and apple pectin in conjugation with soy protein isolate (SPI) under controlled dry-heating conditions

Enhancing techno-functional attributes of plant protein and curcumin complexation: A comparative examination of Maillard conjugation induced by manothermosonication and ultrasonication

The Maillard conjugation of hemp protein with d-xylose was studied, focusing on the influence of ultrasonic waves, processing time, and pressure. Cavitation-driven processes, including ultrasonication (US) and manothermosonication (MTS), were found to impact the degree of grafting, functional characteristics, and structural alterations, affecting conjugation efficiency. The glycation of hemp protein with xylose assisted with US and MTS was investigated under varying pressures. MTS- and US-assisted glycation processes result in 4.22- and 1.64-fold higher degrees of grafting compared to the classical method within a short time frame. The MTS procedures also improved solubility (+3.6-fold), emulsion (+15-fold), and foaming (+1.7-fold) properties, especially at optimized pressure levels, compared to classical conjugates. Furthermore, the complexation of MTS-assisted conjugates with curcumin (Cur) enhanced Cur stability by more than 1.4-fold compared to the classical procedure during 20-day storage at 4 oC. The findings suggest potential applications in the pharmaceutical industry, active dairy/meat analog development, and gel formulation.

Pectin-associated immune responses in plant-microbe interactions: A review

This review explores the role of pectin, a complex polysaccharide found in the plant cell wall, in mediating immune responses during interactions between plants and microbes. The objectives of this study were to investigate the molecular mechanisms underlying pectin-mediated immune responses and to understand how these interactions shape plant-microbe communication. Pectin acts as a signaling molecule, triggering immune responses such as the production of antimicrobial compounds, reinforcement of the cell wall, and activation of defense-related genes. Pectin functions as a target for pathogen-derived enzymes, enabling successful colonization by certain microbial species. The document discusses the complexity of pectin-based immune signaling networks and their modulation by various factors, including pathogen effectors and host proteins. It also emphasizes the importance of understanding the crosstalk between pectin-mediated immunity and other defense pathways to develop strategies for enhancing plant resistance against diseases. The insights gained from this study have implications for the development of innovative approaches to enhance crop protection and disease management in agriculture. Further investigations into the components and mechanisms involved in pectin-mediated immunity will pave the way for future advancements in plant-microbe interaction research.

Stability of a novel glycosylated peanut protein isolate delivery system loaded with gallic acid

To overcome the shortcomings of gallic acid (GA) application, a novel glycosylated PPI delivery system was prepared for the first time in this study using the interaction between peanut protein isolate (PPI) and GA. The effects of glycosylation on the structural and functional properties of PPI and the functional properties of nanoparticles were investigated. The optimal nanoparticles were prepared at a mass ratio 1:3 of glycosylated PPI to GA with a particle size of 338.351 ± 18.823 nm and a PDI of 0.222 ± 0.039. Hydrophobic interactions were the main force maintaining the nanoparticle structure. The nanoparticles remained stable when exposed to different environmental factors. In addition, the DPPH and ABTS radical scavenging activities of nanoparticle-embedded GA were 35.94 ± 3.24 % and 62.59 ± 5.07 % after 108 h, which were significantly higher than those of the free GA group (P < 0.05). This study is important for developing GA and hydrophilic polyphenol delivery systems.

Exploring the Untapped Potential of Pine Nut Skin By-Products: A Holistic Characterization and Recycling Approach

The increasing population, food demand, waste management concerns, and the search for sustainable alternatives to plastic polymers have led researchers to explore the potential of waste materials. This study focused on a waste of pine nut processing referred to in this paper as pine nut skin. For the first time, its nutritional profile, potential bioactive peptide, contaminants, and morphological structure were assessed. Pine nut skin was composed mainly of carbohydrates (56.2%) and fiber (27.5%). The fat (9.8%) was about 45%, 35%, and 20% saturated, monounsaturated, and polyunsaturated fatty acid, respectively, and Omega-9,-6, and -3 were detected. Notably, oleic acid, known for its health benefits, was found in significant quantities, resembling its presence in pine nut oil. The presence of bioactive compounds such as eicosapentaenoic acid (EPA) and phytosterols further adds to its nutritional value. Some essential elements were reported, whereas most of the contaminants such as heavy metals, polycyclic aromatic hydrocarbons, rare earth elements, and pesticides were below the limit of quantification. Furthermore, the in silico analysis showed the occurrence of potential precursor peptides of bioactive compounds, indicating health-promoting attributes. Lastly, the morphological structural characterization of the pine nut skin was followed by Fourier Transform Infrared and solid-state NMR spectroscopy to identify the major components, such as lignin, cellulose, and hemicellulose. The thermostability of the pine nut skin was monitored via thermogravimetric analysis, and the surface of the integument was analyzed via scanning electron microscopy and volumetric nitrogen adsorption. This information provides a more comprehensive view of the potential uses of pine nut skin as a filler material for biocomposite materials. A full characterization of the by-products of the food chain is essential for their more appropriate reuse.

Preparation and characterization of zein-caseinate-pectin complex nanoparticles for encapsulation of curcumin: pectin extracted by high-speed shearing from passion fruit (Passiflora edulis f. flavicarpa) peel

BACKGROUND

Pectin extracted by high-speed shearing from passion fruit peel (HSSP) is a potentially excellent wall material for encapsulating curcumin, which has multiple advantages over pectin prepared by heated water extraction. HSSP was used to fabricate complex nanoparticles of zein-sodium caseinate-pectin for encapsulation of curcumin in this study. The influence of heating on the physicochemical properties of the composite nanoparticles was also investigated, as well as the effect of composite nanoparticles on the encapsulation efficiency, antioxidant activity and release characteristics of curcumin.

RESULTS

The nanoparticles were formed through electrostatic interactions, hydrogen bonds and hydrophobic interactions between the proteins and HSSP. A temperature of 50 °C was more favorable for generating compact and small-sized nanoparticles, which could effectively improve the encapsulation efficiency and functional properties. Moreover, compared to other pectin used in the study, the nanoparticles prepared with HSSP showed the best functionality with a particle size of 234.28 ± 0.85 nm, encapsulation rate of 90.22 ± 0.54%, free radical scavenging rate of 78.97% and strongest protective capacity in simulated gastric fluid and intestinal release effect.

CONCLUSION

Zein-sodium caseinate-HSSP is effective for encapsulating and delivering hydrophobic bioactive substances such as curcumin, which has potential applications in the functional food and pharmaceutical industries. © 2024 Society of Chemical Industry.

Microbial inactivation of pressure spray combined with high-voltage electrospray and its application in honey raspberry juice

Pressure spray combined with high-voltage electrospray (PS-ES) has garnered considerable interest as a novel, non-thermal approach for microbial inactivation and preservation of liquid food. This study compared PS-ES with heat treatment (HT) to understand its inactivation mechanism against E. coli and S. aureus in a simulated system. Microbial activity, cell permeability, membrane integrity, membrane potential, and cell membrane structure were assessed. Furthermore, the impact of PS-ES treatment on microbial activity and flavor in honey raspberry juice, was examined. The changes in microbial growth and color during storage were also discussed. The experimental findings revealed that PS-ES treatment effectively reduced the number of E. coli and S. aureus by 1.99 and 1.83 log colony-forming units (CFU/mL). Additionally, it disrupted the integrity of bacterial cell membranes increasing their permeability, which led to the release of cellular proteins and nucleic acids. PS-ES treatment lowered the membrane potential and altered the structure of bacterial proteins. Application of PS-ES in honey raspberry juice reduced bacterial counts from 4.48 log CFU/mL to 1.99 log CFU/mL, with less flavor deterioration compared to HT treatment. After 30 days of storage at 4 °C and room temperature, PS-ES effectively controlled the growth of microorganisms in raspberry juice and maintained the color of the juice.

Freeze-thaw stability of transglutaminase-induced soy protein-maltose emulsion gel: Focusing on morphology, texture properties, and rheological characteristics

In this study, soy protein isolate (SPI) and maltose (M) were employed as materials for the synthesis of a covalent compound denoted as SPI-M. The emulsion gel was prepared by transglutaminase (TGase) as catalyst, and its freeze-thaw stability was investigated. The occurrence of Maillard reaction was substantiated through SDS-PAGE. The analysis of spectroscopy showed that the structure of the modified protein was more stretched, changed in the direction of freeze-thaw stability. After three freeze-thaw cycles (FTC), it was observed that the water holding capacity of SPI-M, SPI/M mixture (SPI+M) and SPI emulsion gels exhibited reductions of 8.49 %, 16.85 %, and 20.26 %, respectively. Moreover, the soluble protein content also diminished by 13.92 %, 23.43 %, and 35.31 %, respectively. In comparison to unmodified SPI, SPI-M exhibited increase in gel hardness by 160 %, while elasticity, viscosity, chewability, and cohesion demonstrated reductions of 17.7 %, 23.3 %, 33.3 %, and 6.76 %, respectively. Concurrently, the SPI-M emulsion gel exhibited the most rapid gel formation kinetics. After FTCs, the gel elastic modulus (G') and viscosity modulus (G″) of SPI-M emulsion were the largest. DSC analysis underscored the more compact structure and heightened thermal stability of the SPI-M emulsion gel. SEM demonstrated that the SPI-M emulsion gel suffered the least damage following FTCs.

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.

A double-layer cellulose/pectin-soy protein isolate-pomegranate peel extract micro/nanofiber dressing for acceleration of wound healing

Multi-layered wound dressings can closely mimic the hierarchical structure of the skin. Herein, a double-layer dressing material is fabricated through electrospinning, comprised of a nanofibrous structure as a healing-support layer or the bottom layer (BL) containing pectin (Pec), soy protein isolate (SPI), pomegranate peel extract (P), and a cellulose (Cel) microfiber layer as a protective/monitoring layer or top layer (TL). The formation of a fine bilayer structure was confirmed using scanning electron microscopy. Cel/Pec-SPI-P dressing showed a 60.05 % weight loss during 7 days of immersion in phosphate buffered solution. The ultimate tensile strength, elastic modulus, and elongation at break for different dressings were within the range of 3.14-3.57 MPa, 32.26-36.58 MPa, and 59.04-63.19 %, respectively. The release of SPI and phenolic compounds from dressings were measured and their antibacterial activity was evaluated. The fabricated dressing was non-cytotoxic following exposure to human keratinocyte cells. The Cel/Pec-SPI-P dressing exhibited excellent cell adhesion and migration as well as angiogenesis. More importantly, in vivo experiments on Cel/Pec-SPI-P dressings showed faster epidermal layer formation, blood vessel generation, collagen deposition, and a faster wound healing rate. Overall, it is anticipated that the Cel/Pec-SPI-P bilayer dressing facilitates wound treatment and can be a promising approach for clinical use.

Structural, chemical and technofunctional properties pectin modification by green and novel intermediate frequency ultrasound procedure

The impact of intermediate frequency ultrasound (IFUS, 582, 864 and 1144 kHz), mode of operation (continue and pulsed) and ascorbic acid (Aa) addition on the structural, chemical and technofunctional properties of commercial citrus high methoxyl-grade pectin (HMP) was investigated. The chemical dosimetry of IFUS, monitored by the triiodide formation rate (I3-), demonstrated that the pulsed ratio (1900 ms on/100 ms off) at the three frequencies was similar to that of continue mode but IFUS1144 kHz produced more acoustic streaming demonstrated by the height liquid measured using image analysis. In presence of Aa, HMP presented higher fragmentation than in its absence. IFUS did not give rise any changes in the main functional groups of the HMP. In general, a reduction in molecular weight was observed, being the presence of Aa the most influencing factor. Regarding monosaccharides, IFUS modified the structure of homogalacturonan and rhamnogalacturonan-I and increased of GalA contents of the HMP in presence of Aa at the above three frequencies. A reducing of the consistency index (k) and increasing of the flow index (n) of HMP were showed by IFUS frequency and Aa addition. The emulsifying activity and stability index were increased for HMP treated by IFUS in continue mode at all frequencies and in presence of Aa. The results presented in this research shown the effectiveness of IFUS as tool to modify pectin into different structures with different functionalities.

Characterization of a low-methoxyl pectin extracted from red radish (Raphanus sativus L.) pomace and its gelation induced by NaCl

There is an increasing demand for obtaining pectin from new sources. Red radish (Raphanus sativus L.) pomace pectin extracted by alkali was low-methoxyl pectin with esterification degree of 10.17 %, galacturonic acid content of 69.71 % (wt), and average molar weight of 78.59 kDa. The pectin primarily consisted of rhamnogalacturonan I and homogalacturonan domains. The predominant monosaccharides of the pectin were galacturonic acid (46.32 mol%), arabinose (16.03 mol%), galactose (10.46 mol%), and rhamnose (10.28 mol%), respectively. The red radish pomace pectin solution exhibited a shear-thinning behavior. NaCl could induce gelation of red radish pomace pectin, and the gel properties of red radish pomace pectin were considerably affected by the NaCl concentration. As the NaCl concentration (0.25-0.50 mol/L) increased, the rate of gelation accelerated, and the time to gelation point appeared earlier. There was an optimal NaCl concentration (0.50 mol/L) for the pectin to form a gel with the greatest solid-like properties, gel hardness (33.84 g) and water-holding capacity (62.41 %). Gelation force analysis indicated gel formation mainly caused by electrostatic shielding effect of Na+ and hydrogen bonding. This research could facilitate the applications of the red radish pomace pectin in the realm of edible hydrocolloids.

Ambient plasma treatment of pectin in aqueous solution to produce a polymer used in packaging

Water resistance, mechanical behavior and coloration of pectin needs to be tuned for packing utilization. Plasma was used for the treatment of natural products, but there is no research on its effect on the biomass in the presence of ammonia. Though the reaction of pectin (PE) and ammonia was known to impart the ammonolysis and de-esterification, the plasma treatment on PE solution containing ammonia was explored to exemplify the amination and polymerization of the carbohydrate at the ambient condition. The plasma treatment increased the coloration of the solution due to the deprotonation of PE for the production of more sp2 carbon. The film from the amination of PE showed higher hydrophobicity and water stability than the bare PE. The plasma treatment alone decreased the Young's modulus (4.3 MPa versus 22 MPa), while the nitrogen addition enhanced the Young's modulus to 160 MPa and increased the tensile strength (28.7 MPa versus 25.8 MPa of PE). The hydrogen bonds from the amine group induced a glass-to-rubber transition at 77.9 °C by the increasing the crosslinking. This work provided a facile way of aminating and conjugating the biomass in solution to produce polymer with improved mechanical properties using plasma and ammonia incorporation.

Effect of localized electrochemical pH and temperature synergistic modification on the structural and antibacterial properties of pectin/polyvinyl alcohol/zinc oxide nanorod films

Two low-methoxy pectins (LMPs) were obtained by local electrochemical pH modification using an H-type double-layer water bath sealed electrochemical cell at the voltage of 180 V for 3 h. The weight-average molecular weight (Mw) of citrus peel pectin (CPP) prepared in the anodic part at room temperature (CPP-A5/RT) and in the cathodic part at 5 °C (CPP-C5/RT) were 346 kDa and 328 kDa, respectively, and the degrees of methylation (DM) were 36.8 % and 11.9 %. Moreover, the second-order kinetic model was most appropriate for the degradation processes, as free radicals were generated in the anodic part and β-elimination occurred in the cathodic part. Subsequently, CPP-A5/RT and CPP-C5/RT were utilized to fabricate food packaging film blending with polyvinyl alcohol (PVA), bcZnO (ZnO coupled with bentonite and colophony) nanorods, and Ca2+ ions by casting method. Then the prepared films were studied for their ability to maintain the freshness of strawberries. The addition of Ca2+ ions and bcZnO nanorods increased the thickness, water contact angle (WCA), and mechanical properties of the composite films, while decreased water vapor permeability (WVP). Therefore, the CPP-based films, supplemented with bcZnO nanorods and crosslinked with Ca2+ ions by "egg-box" model, can serve as an antibacterial food packaging material for food preservation.

Construction of protein-, polysaccharide- and polyphenol-based conjugates as delivery systems

Natural polymers, such as polysaccharides and proteins, have been used to prepare several delivery systems owing to their abundance, bioactivity, and biodegradability. They are usually modified or combined with small molecules to form the delivery systems needed to meet different needs in food systems. This paper reviews the interactions of proteins, polysaccharides, and polyphenols in the bulk phase and discusses the design strategies, coupling techniques, and their applications as conjugates in emulsion delivery systems, including traditional, Pickering, multilayer, and high internal-phase emulsions. Furthermore, it explores the prospects of the application of conjugates in food preservation, food development, and nanocarrier development. Currently, there are seven methods for composite delivery systems including the Maillard reaction, carbodiimide cross-linking, alkali treatment, enzymatic cross-linking, free radical induction, genipin cross-linking, and Schiff base chemical cross-linking to prepare binary and ternary conjugates of proteins, polysaccharides, and polyphenols. To design an effective target complex and its delivery system, it is helpful to understand the physicochemical properties of these biomolecules and their interactions in the bulk phase. This review summarizes the knowledge on the interaction of biological complexes in the bulk phase, preparation methods, and the preparation of stable emulsion delivery system.

Pickering Emulsions Stabilized by Conjugated Zein-Soybean Polysaccharides Nanoparticles: Fabrication, Characterization and Functional Performance

This study aims to fabricate zein-based colloidal nanoparticles, which were used to stabilize Pickering emulsions, by conjugation with soybean polysaccharide (SSPS) through the Maillard reaction. The physicochemical properties of the conjugated particles as well as the physical and oxidative stability of the fabricated Pickering emulsion that utilized conjugated colloidal particles with the volumetric ratio of water and oil at 50:50 were investigated. The grafting degree of zein and SSPS was verified through examination of FT-IR and fluorescence. Moreover, the conjugated Zein/SSPS nanoparticles (ZSP) that were prepared after dry heating for 48-72 h exhibit excellent colloidal stability across a range of pH values (4.0-10.0). Further, the wettability of ZSP decreased based on a contact angle analysis of θ~87°. Confocal laser scanning microscopy (CLSM) images indicated that ZSP particles were located around the oil droplets. Additionally, the ZSP effectively improved the oxidative stability of the Pickering emulsions, as demonstrated by a significant decrease in both peroxide value (PV) and thiobarbituric acid reactive substances (TBARS). The results of this study demonstrate that ZSP represents a promising food-grade Pickering emulsifier, capable of not only stabilizing emulsions but also inhibiting their oil oxidation.

Application of soy protein isolate-xylose conjugates for improving the viability and stability of probiotics microencapsulated by spray drying

BACKGROUND

Production and consumption of probiotics need to meet many adverse stresses, which can reduce their health-promoting effects on humans. Microencapsulation is an effective technique to improve the biological activity of probiotics and wall materials are also required during encapsulation. Application of Maillard reaction products (MRPs) in probiotic delivery is increasing.

RESULTS

This work aims to study the effects of soy protein isolate (SPI)-xylose conjugates heated at different times on the viability and stability of probiotics. SPI-xylose MRPs formed after heat treatment based on changes in the browning intensity, sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Fourier transform infrared spectroscopy. After heat treatment, α-helix and β-sheet contents of SPI-xylose mixture shifted from 11.3% and 31.3% to 6.4-11.0% and 31.0-36.9%, respectively, and the thermal stability slightly changed. During spray drying, except for MRP240@LAB, probiotic viability was higher in the MRP-based probiotic microcapsules (21.36-25.31%) than in Mix0@LAB (20.17%). MRP-based probiotic microcapsules had smaller particle sizes (431.1-1243.0 nm vs. 7165.0 nm) and greater intestinal digestion tolerance than Mix0@LAB. Moreover, the MRP-based probiotic microcapsules showed better storability than Mix0@LAB and adequate growth and metabolism capacity.

CONCLUSION

SPI-xylose Maillard reaction products are a promising wall material for probiotics microencapsulation, which can improve bacterial survivability during spray drying and enhance bacterial gastrointestinal digestion resistance. This study sheds light on preparing probiotic microcapsules with superior properties by spray drying. © 2023 Society of Chemical Industry.

Non-Digestible Carbohydrates: Green Extraction from Food By-Products and Assessment of Their Effect on Microbiota Modulation

The nature and composition of the waste produced by food industrial processing make its abundance and accumulation an environmental problem. Since these by-products may present a high potential for revalorization and may be used to obtain added-value compounds, the main goals of the technological advancements have been targeted at reducing the environmental impact and benefiting from the retrieval of active compounds with technological and health properties. Among the added-value substances, nondigestible carbohydrates have demonstrated promise. In addition to their well-known technological properties, they have been discovered to modify the gut microbiota and enhance immune function, including the stimulation of immune cells and the control of inflammatory reactions. Furthermore, the combination of these compounds with other substances such us phenols could improve their biological effect on different noncommunicable diseases through microbiota modulation. In order to gain insight into the implementation of this combined strategy, a broader focus concerning different aspects is needed. This review is focused on the optimized green and advanced extraction system applied to obtain added-value nondigestible carbohydrates, the combined administration with phenols and their beneficial effects on microbiota modulation intended for health and/or illness prevention, with particular emphasis on noncommunicable diseases. The isolation of nondigestible carbohydrates from by-products as well as in combination with other bioactive substances could provide an affordable and sustainable source of immunomodulatory chemicals.

Conjugation of soy protein isolate with carboxymethyl cellulose through dielectric barrier discharge (DBD) plasma

The present study aimed to evaluate the physicochemical properties of dielectric barrier discharge (DBD) plasma grafted carboxymethyl cellulose (CMC) and soy protein isolate (SPI). Therefore, the mixture of SPI and CMC was treated at 16, 18 and 20 kV for 5, 10 and 15 min with DBD plasma. The results of FTIR, XRD, FESEM and SDS-PAGE confirmed the SPI-CMC conjugate formation after plasma treatment, and a glycation degree of about 21 % was obtained after 15 min treatment at 18 kV. Significantly higher levels of emulsifying activity and stability, as well as solubility, were obtained for the conjugates, as compared with the SPI-CMC mixture. Also, the smaller droplet sizes were observed in emulsions obtained from conjugate produced at 18 kV for 5 min, which had the most stability after 14 days of storage at 4 °C. Eventually, it was detected that DBD plasma could graft SPI and CMC in a short time.

Understanding the impact of pectin on browning of polyphenol oxidation system in thermal and storage processing

Browning of some processed fruit products was affected not only by polyphenol oxidation but also by cell wall polysaccharides (pectin). The study was performed to understand the mechanism of browning in the pectin system. The catechin/chlorogenic acid oxidation system in three pectins significantly enhanced their browning during thermal storage with pectin structure- and concentration-dependent. Particularly, the structural and physicochemical properties of pectin were examined to determine its effects on the kinetics of polyphenol oxidation and the stability of free polyphenols. Moreover, pectin impacted the fluorescence characteristics of polyphenols by cross-linking with the aromatic ring of polyphenols. In turn, the interaction between polyphenols and pectin impacted the chemical bond vibration of pectin, thereby affecting its optical features and browning. The correlation analysis revealed that the monosaccharide composition, Ratio 1, Ratio 2, Ratio 3, methyl esterification, ζ-potential, and polydispersity index of pectin were significantly correlated with the browning of the pectin-polyphenol oxidation system.

Preparation of high complex concentration emulsion stabilized by soy protein/dextran sulfate composite particles

BACKGROUND

Soy protein isolate (SPI) could be used as an emulsifier to stabilize emulsions, while SPI is unstable under low acidic conditions. The stable composite particles of SPI and dextran sulfate (DS) could be formed by the electrostatic interaction at the pH was 3.5. And the SPI/DS composite particles were used to prepare the high complex concentration emulsion. The stabilization properties of high complex concentration emulsion were investigated.

RESULTS

Compared to uncompounded SPI, the particle size of SPI/DS composite particles was smaller at 1.52 μm, and the absolute value of the potential increased to 19.9 mV when the mass ratio of SPI to DS was 1:1 and the pH was 3.5. With the DS ratio increased, the solubility of the composite particles increased to 14.44 times of the untreated protein at pH 3.5, while the surface hydrophobicity decreased. Electrostatic interactions and hydrogen bonds were the main forces between SPI and DS, and DS was electrostatically adsorbed on the surface of SPI. The emulsion stability significantly enhanced with the increase of complex concentration (38.88 times higher than at 1% concentration), the emulsion average droplet size was the lowest (9.64 μm), and the absolute value of potential was the highest (46.67 mV) when the mass ratio of SPI to DS was 1:1 and the complex concentration of 8%. The stability of the emulsion against freezing was improved.

CONCLUSION

The SPI/DS complex has high solubility and stability under low acidic conditions, and the SPI/DS complex' emulsion has a well stability. This article is protected by copyright. All rights reserved.

Antimicrobial high molecular weight pectin polysaccharides production from diverse citrus peels using a novel PL10 family pectate lyase

The discovery of environmentally friendly enzymes that can convert inexpensive and abundant citrus peel pectin into high value-added product is a potential avenue for the citrus peel application. In this study, a novel PL10-family pectate lyase (pelA) was characterized from marine bacterium Echinicola pacifica. PelA was a Ca²⁺ dependent pectate lyase whose activity was highest at pH 8 and 40 °C. It was capable of degrading polygalacturonic acid (PGA) and citrus peel pectin (CPP), but not apple peel pectin. Notably, PelA hydrolyzed PGA to high molecular weight polysaccharide (average molecular weight 111.4 kDa). Moreover, PelA was also able to degrade CPP from nine distinct citrus species into polysaccharides (average molecular weight ranging from 84.7 to 539.2 kDa) that showed antimicrobial activity against Staphylococcus epidermidis (88.8 %), Bacillus subtilis (99.8 %), Staphylococcus aureus (92.1 %), Escherichia coli (100.0 %) and Klebsiella pneumoniae (86.4 %). Considering the high market value of pectin in the food industry, PelA's capacity to convert citrus pectin into high molecular weight polysaccharides lays a foundation for its applications.

Controlled release of Lactiplantibacillus plantarum by colon-targeted adhesive pectin microspheres: Effects of pectin methyl esterification degrees

The aim of this study is to report the preparation of pectin microspheres by varying degrees of methyl esterification (DM) cross-linked with divalent cationic calcium to encapsulate Lactiplantibacillus plantarum STB1 and L. plantarum LJ1, respectively. Scanning electron microscopy revealed the compact and smooth surface of pectin of DM 28 %, and the stochastic distribution of L. plantarum throughout the gel reticulation. And the pectin of DM 28 % considerably increased probiotics tolerance after continuous exposure to stimulated gastrointestinal tract conditions, with viable counts exceeding 10⁹ CFU/mL. This data indicated that low methoxy-esterification pectin was more efficient to improve the targeted delivery of probiotics in GIT. Additionally, the controlled release of microspheres was dependent on various pH levels. At pH 7.4, the release rates of L. plantarum STB1 and L. plantarum LJ1 reached up to 97.63 % and 95.33 %, respectively. Finally, the Caco-2 cell adhesion model was used to evaluate the cell adhesion rate after encapsulation, which exhibited better adhesion at DM of 60 %.

Food protein glycation: A review focusing on stability and in vitro digestive characteristics of oil/water emulsions

Recently, increasing studies have shown that the functional properties of proteins, including emulsifying properties, antioxidant properties, solubility, and thermal stability, can be improved through glycation reaction under controlled reaction conditions. The use of glycated proteins to stabilize hydrophobic active substances and to explore the gastrointestinal fate of the stabilized hydrophobic substances has also become the hot spot. Therefore, in this review, the effects of glycation on the structure and function of food proteins and the physical stability and oxidative stability of protein-stabilized oil/water emulsions were comprehensively summarized and discussed. Also, this review sheds lights on the in vitro digestion characteristics and edible safety of emulsion stabilized by glycated protein. It can further serve as a research basis for understanding the role of structural features in the emulsification and stabilization of glycated proteins, as well as their utilization as emulsifiers in the food industry.

Edible pullulan enhanced water-soluble keratin with improved sizing performance for sustainable textile industry

Feather keratin from waste feather has become an attractive target to replace petroleum-based Poly (vinyl alcohol) sizes due to its easy film-forming ability, excellent adhesive property, biodegradability and low cost. However, poor water-solubility and brittleness of pure keratin films have become the bottlenecks and restricted the application of keratin as sizing agents. Therefore, water-soluble keratin was extracted by the reduction-preservation method and enhanced by saccharides in aqueous system to obtain all-green keratin-based slurry. The results showed that the keratin-based slurry exhibited improved sizing performance in the order of sucrose ≤ glucose ≤ pullulan by the moderate Maillard reaction. Among them, the fabricated pullulan-keratin sizes films had 27.86 %, 2684.08 % and 2911.31 % increment in tensile strength, elongation and work of facture compared with pure keratin sizes films. Besides, the addition of pullulan and subsequently moderate Maillard reaction improved the thermo-tenacity of keratin-based sizes, which was expected to tackle with the brittleness of pure keratin size films. In addition, novel pullulan-keratin sizes had good sizing performance and high desizing efficiency to cotton, cotton/polyester and polyester yarns and fabrics. Successful utilization of pullulan-keratin sizes will bring opportunities for high value utilization of waste feather and promote the green and low-carbon development of textile industry.

Sustainable utilization of Citrus limetta peel for obtaining pectin and its application in cookies as a fat replacer

In this study, a five-factorial central composite design was employed to optimize pectin extraction from novel source, through ultrasound-assisted extraction. A 35.58% yield was obtained under optimized conditions of pH 1.0, solid (g): liquid (mL) ratio 1:24, amplitude 84.2 Hz, duty cycle 23 s/30 s, and time 30 min. The equivalent weight, methoxyl content, anhydrouronic acid content, degree of esterification, water-holding capacity, and oil-holding capacity of the extracted pectin were 796.40 ± 2.07, 8.29 ± 0.38%, 71.32 ± 0.54%, 64.66 ± 2.08%, 8.04 ± 0.10 g water/g pectin, and 2.24 ± 030 g oil/g pectin, respectively. The chemical profile of the extracted pectin was assessed with FTIR and NMR analyses. The extracted pectin was utilized as a butter substitute in cookies. Up to 30% butter in cookies could be replaced with the extracted pectin without altering the sensory and physicochemical properties. Overall, results of presented work suggest that using waste-derived pectin as a fat substitute in cookies offers a sustainable and health-promoting approach for converting waste into wealth.

Influence mechanism of polysaccharides induced Maillard reaction on plant proteins structure and functional properties: A review

Plant proteins have high nutritional value, a wide range of sources and low cost. However, it is easily affected by the environmental factors of processing and lead the problem of poor functionality. These problems of plant proteins can be improved by the polysaccharides induced Maillard reaction. The interaction between proteins and polysaccharides through Maillard reaction can change the structure of proteins as well as improve the functional properties and biological activity. The products of Maillard reaction, such as reductone intermediates, heterocyclic compounds and melanoidins have certain antioxidant, antibacterial and other biological activities. However, heterocyclic amines, acrylamide, and products generated in the advanced stage of the Maillard reaction also have a negative impact, which may increase cytotoxicity and be associated with chronic diseases. Therefore, it is necessary to effectively control the process of Maillard reaction. This review focuses on the modification of plant proteins by polysaccharide-induced Maillard reaction and the effects of Maillard reaction on protein structure, functional properties and biological activity. It also points out how to accurately reflect the changes of protein structure in Maillard reaction. In addition, it also points out the application ways of plant protein-polysaccharide complexes in the food industry, for example, emulsifiers, delivery carriers of functional substances, and natural antioxidants due to their improved solubility, emulsifying, gelling and antioxidant properties. This review provides theoretical support for controlling Maillard reaction based on protein structure.

Formation mechanism and functional properties of walnut protein isolate and soy protein isolate nanoparticles using the pH-cycle technology

Walnut protein isolate (WPI) is a nutritious protein with poor solubility, which severely limits its application. In this study, composite nanoparticles were prepared from WPI and soy protein isolate (SPI) using the pH-cycle technology. The WPI solubility increased from 12.64 to 88.53% with a WPI: SPI ratio increased from 1: 0.01 to 1: 1. Morphological and structural analyses illustrated that interaction forces with hydrogen bonding as the main effect jointly drive the binding of WPI to SPI and that protein co-folding occurs during the neutralization process, resulting in a hydrophilic rigid structure. In addition, the interfacial characterization showed that the composite nanoparticle with a large surface charge enhanced the affinity with water molecules, prevented protein aggregation, and protected the new hydrophilic structure from damage. All these parameters helped to maintain the stability of the composite nanoparticles in a neutral environment. Amino acid analysis, emulsification capacity, foaming, and stability analysis showed that the prepared WPI-based nanoparticles exhibited good nutritional and functional properties. Overall, this study could provide a technical reference for the value-added use of WPI and an alternative strategy for delivering natural food ingredients.

Plant Protein versus Dairy Proteins: A pH-Dependency Investigation on Their Structure and Functional Properties

Plant proteins are constantly gaining attention as potential substitutes for dairy proteins, due to their suitable functionality and nutritional value. This study was designed to compare the structural and functional responses of different plant protein isolates (soy, pea, lentil, and chickpea) with two commonly used dairy protein (whey protein isolates and sodium caseinate) under different pH treatments (pH 3.0, 5.0, 7.0, and 9.0). The results showed that pH had a different alteration on the structural, surface properties and functional properties of plant and dairy proteins. Plant protein generally possessed a darker color, lower solubility, emulsifying properties, and foaming capacity, whereas their foaming stability and water holding capacity were higher than those of dairy proteins. Soy protein isolates were characterized by its comparable proportion of β-turn and random coils, zeta-potential, emulsifying (30.37 m²/g), and water-holding capacity (9.03 g/g) at alkaline conditions and chickpea protein isolates showed good oil-holding capacity (3.33 g/g at pH 9) among plant proteins. Further analysis confirmed that pH had a greater influence on the structural and functional properties of proteins as compared to protein sources, particularly at acidic conditions. Overall, this study might help processors select the appropriate plant protein as dairy alternatives for their target application in plant-based food products.

Gellan gum conjugation with soy protein via Maillard-driven molecular interactions and subsequent clustering lead to conjugates with tuned technological functionality

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Soy protein isolate (SPI) was conjugated to low acyl gellan gum (LAGG).

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Conjugate formation was confirmed by glycation degree (DG) and structural changes.

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SPI-LAGG conjugates were classified into low, medium, and high DG clusters.

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A low DG was enough to enhance the techno-functional properties of SPI.

Soy proteins are frequently used in the food industry; however, they have rigid and compact structure with relatively poor interfacial properties and solubility. This study was therefore aimed to modify techno-functional characteristics of soy protein isolate (SPI; 0.1% w/v) by conjugating to low acyl gellan gum (LAGG; 0.1, 0.2, and 0.3% w/v), through the Maillard reaction (at 90 °C for 90 min). The SPI-LAGG conjugates were confirmed by changes in pH, glycation degree (DG; up to 48%), Fourier transform infrared spectroscopy, and sodium dodecyl sulphate polyacrylamide electrophoresis. The conjugates were then classified into three clusters of low, medium, and high DG, via K-means clustering method. The low DG conjugate had lower surface hydrophobicity and foaming capacity, and higher thermal stability, solubility, emulsifying properties, foam stability, and antioxidant activity compared to the other clusters. This indicated that a low DG is required to enhance the functional properties of proteins.

Physicochemical, structural, and functional properties of wampee (Clausena lansium (Lour.) Skeels) fruit peel pectin extracted with different organic acids

Effects of different extraction acids on physicochemical, structural, and functional properties of wampee fruit peel pectin (WFPP) were comparatively investigated. The hydrochloric acid extracted WFPP (HEP) exhibited the highest degrees of methylation (67.79%) and acetylation (86.29%) coupling with abundant monosaccharides and rhamnogalacturonan branches, but lowest molecular weight (5.58 × 10⁵ Da). The results of SEM, X-ray diffraction, and Fourier transform infrared spectroscopy analyses showed that acid types had little effect on the surface morphology of WFPP. However, compared to commercial citrus pectin (CCP), several specific absorbance peaks (1539, 1019, 920 cm^-1) were found in WFPPs, which corresponds to aromatic skeletal stretching, pyranose, and d-glucopyranosyl, respectively. Moreover, the rheological behavior revealed that WFPP solution was pseudoplastic fluid and affected by acid types. And the WFPPs exhibited higher emulsifying activity and emulsion stability than CCP. All these WFPPs presented well antioxidant activity and promoting probiotics ability, especially for HEP.

In Vitro Digestion and Storage Stability of β-Carotene-Loaded Nanoemulsion Stabilized by Soy Protein Isolate (SPI)-Citrus Pectin (CP) Complex/Conjugate Prepared with Ultrasound

In this study, we employed the ultrasound-prepared electrostatic complex and covalent conjugate of soy protein isolate (SPI) and citrus pectin (CP) to prepare β-carotene-loaded nanoemulsions. The in vitro digestion and storage stability of nanoemulsions stabilized by different types of emulsifiers were investigated and compared. Nanoemulsions stabilized by ultrasound-treated complex/conjugate showed the highest encapsulation efficiency; during gastric digestion, these nanoemulsions also demonstrated the smallest droplet sizes and the highest absolute values of zeta potential, indicating that both electrostatic complexation/covalent conjugation and ultrasound treatment could significantly improve the stability of the resulting nanoemulsions. In comparison, complexes were more beneficial for the controlled release of β-carotene; however, the conjugate-stabilized nanoemulsion showed an overall higher bioaccessibility. The results were also confirmed by optical micrographs. Furthermore, nanoemulsions stabilized by ultrasound-prepared complexes/conjugates exhibited the highest stability during 14-day storage at 25 °C. The results suggested that ultrasound-prepared SPI–CP complexes and conjugates had great application potential for the delivery of hydrophobic nutrients.

Effects of Different Amounts of Corn Silk Polysaccharide on the Structure and Function of Peanut Protein Isolate Glycosylation Products

Covalent complexes of peanut protein isolate (PPI) and corn silk polysaccharide (CSP) (PPI-CSP) were prepared using an ultrasonic-assisted moist heat method to improve the functional properties of peanut protein isolate. The properties of the complexes were affected by the level of corn silk polysaccharide. By increasing the polysaccharide addition, the grafting degree first increased, and then tended to be flat (the highest was 38.85%); the foaming, foam stability, and solubility were also significantly improved. In a neutral buffer, the solubility of the sample with a protein/polysaccharide ratio of 2:1 was 73.69%, which was 1.61 times higher than that of PPI. As compared with PPI, the complexes had higher thermal stability and lower surface hydrophobicity. High addition of CSP could made the secondary structure of PPI change from ordered α-helix to disordered β-sheet, β-turn, and random coil structure, and the complex conformation become more flexible and loose. The results of multiple light scattering showed that the composite solution exhibited high stability, which could be beneficial to industrial processing, storage, and transportation. Therefore, the functional properties of peanut protein isolate glycosylation products could be regulated by controlling the amount of polysaccharide added.

Micronization using combined alkaline protease hydrolysis and high-speed shearing homogenization for improving the functional properties of soy protein isolates

The present study aimed to investigate the functional properties of soybean protein isolate (SPI) treated with alkaline protease and high-speed shearing homogenization. Alkaline protease-hydrolyzed SPIs that were characterized by varying degrees of hydrolysis between 0 and 6% were treated with high-speed shearing homogenization to obtain different micro-particulate proteins. The results showed that this combined treatment could significantly reduce the particle size of SPI by markedly degrading the structure of both the 7S and 11S subunits, thereby resulting in a significantly reduced content of β-sheet and β-turn structures. The surface hydrophobicity increased considerably for samples with hydrolysis below the threshold of 2% and then declined gradually above this threshold. Furthermore, the combination of hydrolysis and homogenization significantly improved the emulsion stability of SPI hydrolysates. It also significantly improved the foaming properties of SPI. These results demonstrated that alkaline protease hydrolysis combined with high-speed shearing homogenization represents a promising approach for improving the functional and structural properties of SPI.