A family of chitosan-peptide conjugates provides broad HLB values, enhancing emulsion's stability, antioxidant and drug release capacity

Synthesis and Characterization of Emulsifiers Based on the Maillard Reaction and Its Application in Stabilized DHA Algal Oil Nanoemulsions

The aim of this study was to optimize the formation of sodium caseinate (CS) and gum arabic (GA) complexes through the Maillard reaction and to evaluate their effectiveness in improving the emulsification properties and stability of docosahexaenoic acid (DHA) nanoemulsions. First, the best target polysaccharides were selected, and the best modification conditions were determined using orthogonal experiments. Secondly, the response surface experiments were used to optimize the preparation process of the emulsion. The stability, in vitro digestion characteristics, and rheological characteristics of the emulsion prepared by means of CS-GA were compared with the emulsion prepared using a whey protein isolate (WPI). After the orthogonal test, the optimal modification conditions were determined to be a reaction time of 96 h, a CS-GA mass ratio of 1:2, a reaction temperature of 60 °C, and a degree of grafting of 44.91%. Changes in the infrared (IR), Raman, ultraviolet (UV), and endogenous fluorescence spectra also indicated that the complex structure was modified. The response surface test identified the optimal preparation process as follows: an emulsifier concentration of 5 g/L, an oil-phase concentration of 5 g/L, and a homogenization frequency of five, and the emulsion showed good stability. Therefore, the use of a nanoemulsion as a nanoscale DHA algal oil delivery system is very promising for extending the shelf life and improving the stability of food.

Casein-based conjugates and graft copolymers. Synthesis, properties, and applications

Biobased natural polymers, including polymers of natural origin such as casein, are growing rapidly in the light of the environmental pollution caused by many mass-produced commercial synthetic polymers. Although casein has interesting intrinsic properties, especially for the food industry, numerous chemical reactions have been carried out to broaden the range of its properties, most of them preserving casein's nontoxicity and biodegradability. New conjugates and graft copolymers have been developed especially by Maillard reaction of the amine functions of the casein backbone with the aldehyde functions of sugars, polysaccharides, or other molecules. Carried out with dialdehydes, these reactions lead to the cross-linking of casein giving three-dimensional polymers. Acylation and polymerization of various monomers initiated by amine functions are also described. Other reactions, far less numerous, involve alcohol and carboxylic acid functions in casein. This review provides an overview of casein-based conjugates and graft copolymers, their properties, and potential applications.

Fabrication of high-preformance emulsifier from conjugating maltodextrin onto myofibrillar protein peptide with microwave- ultrasound synergy

In this study, we systematically investigated the emulsifying capabilities of myofibrillar protein (MP)- and MP peptide (MPP)-based conjugates synthesized through intensification techniques: water bath (WB), microwave, ultrasound, and the combined ultrasound-microwave (UM) methods. Compared with WB, microwave, and ultrasound treatments, the combined UM treatment greatly promoted the glycation reaction because ultrasound and microwave mutually reinforced modification effects. The resultant conjugate structure tended to unfold with more flexible conformation and homogeneous morphology. Moreover, the emulsifying properties of conjugates developed with single and combined ultrasound-assisted glycation displayed substantial improvement, and pre-hydrolysis further enhanced these performances, as observed in the Principal Component Analysis as well. Remarkably, MPP grafted by maltodextrin with the assistance of a combined UM field produced the smallest and most uniform emulsion system, positioning it as the most efficient emulsifier among all the fabricated glycoconjugates. Our study highlighted the potential of synergistically applying ultrasound and microwave techniques to develop a well-performance glycation with an ideal conjugate structure, in which they would be associated into a strong film that provided the robust physical barrier, creaming stability, heat retention, and oxidation resistance. These findings offered a basis for better utilizing complex ultrasonic technology to develop novel and improved MP-based food products.

Comprehensive structural and functional characterization of a new protein-polysaccharide conjugate between grass pea protein (Lathyrus sativus) and xanthan gum produced by wet heating

The purpose of this work was to use a controlled wet-heating process to promote Maillard reaction (MR) between grass pea protein (GPPI) and xanthan gum (XG), and then analyse structural, functional and antioxidant properties of the conjugate (GPPI-XGCs). During heating, the degree of glycation of all conjugated samples was raised (up to 37.43 %) and, after heating for 24 h, the lightness of the samples decreased by 24.75 %. Circular dichroism showed changes in secondary structure with lower content of α-helix and random coil in conjugates. XRD patterns showed that MR destroyed the crystalline structure of the protein. In addition, Lys and Arg content of the produced conjugates decreased by 16.94 % and 6.17 %, respectively. Functional properties including foaming capacity and stability were increased by 45.17 % and 37.17 %, and solubility reached 98.88 %, due to the protein unfolding driven by MR. GPPI-XGCs showed significantly higher antioxidant activities with maximum ABTS-RS value of 49.57 %. This study revealed how MR can improve GPPI's properties, which can aid the food industry in producing a wide range of plant-based foods. Especially, among other characteristics, the foaming properties were significantly improved and the final product can be introduced as a promising foaming agent to be used in food formulation.

Research progress on chitin/chitosan-based emulsion delivery systems and their application in lipid digestion regulation

Excessive lipid intake is linked to an elevated risk of health problems. However, reducing lipid contents may influence food structure and flavor. Some alternatives are needed to control the lipid absorption. Emulsions are common carriers for lipids, which can control the hydrolysis and absorption of lipids. Chitin (Ch) and chitosan (CS) are natural polysaccharides with good biodegradability, biocompatibility, and unique cationic properties. They have been reported to be able to delay lipolysis, which can be regarded as one of the most promising agents that regulates lipid digestion (LiD). The application of Ch/CS and their derivatives in emulsions are summarized in this review with a focus on their performances and mechanisms for LiD regulation, aiming to provide theoretical guidance for the development of novel Ch/CS emulsions, and the regulation of LiD. A reasonable design of emulsion interface can provide its resistance to the external environment and then control LiD. The properties of emulsion interface are the key factors affecting LiD. Therefore, systematic study on the relationship between Ch/CS-based emulsion structure and LiD can not only instruct the reasonable design of emulsion interface to accurately regulate LiD, but also provide scientific guidelines for applying Ch/CS in functional food, medicine and other fields.

Protein-polysaccharide-based delivery systems for enhancing the bioavailability of curcumin: A review

In recent years, a wide attention has been paid to curcumin in medicine due to its excellent physiological activities, including anti-inflammatory, antioxidant, antibacterial, and nerve damage repair. However, the low solubility, poor stability, and rapid metabolism of curcumin make its bioavailability low, which affects its development and application. As a unique biopolymer structure, protein-polysaccharide (PRO-POL)-based delivery system has the advantages of low toxicity, biocompatibility, biodegradability, and delayed release. Many scholars have investigated PRO-POL -based delivery systems to improve the bioavailability of curcumin. In this paper, we focus on the interactions between different proteins (e.g. casein, whey protein, soybean protein isolate, pea protein, zein, etc.) and polysaccharides (chitosan, sodium alginate, hyaluronic acid, pectin, etc.) and their effects on complexes diameter, surface charge, encapsulation drive, and release characteristics. The mechanism of the PRO-POL-based delivery system to enhance the bioavailability of curcumin is highlighted. In addition, the application of PRO-POL complexes loaded with curcumin is summarized, aiming to provide a reference for the construction and application of PRO-POL delivery systems.

Gastroprotective effect of the Lachnum polysaccharide and polysaccharide-dipeptide conjugates against gastric ulcer

Polysaccharides from Lachnum have many important biological activities. The LEP2a-dipeptide derivative (LAG) was obtained by carboxymethyl modification and alanyl-glutamine modification of LEP2a, an extracellular polysaccharide component of Lachnum. Mice with acute gastric ulcers were treated with 50 (low doses) and 150 (high doses) mg/kg, and their therapeutic effects were evaluated from the aspects of pathological damage to gastric tissue, oxidative stress response and inflammatory signal cascade reaction. High doses of LAG and LEP2a significantly inhibited pathological damage to the gastric mucosa, increased the activities of SOD and GSH-Px, and decreased the levels of MDA, and MPO. LEP-2A and LAG could also inhibit the production of proinflammatory factors and reduce the inflammatory response. They significantly decreased the levels of IL-6, IL-1β and TNF-α, while upregulated the level of PGE2 at high doses. LAG and LEP2a inhibited the protein expression of p-JNK, p-ERK, p-P38, p-IKK, p-IKB α and p-NF-KBP65. LAG and LEP2a protect the gastric mucosa in mice with ulcers by improving oxidative stress, blocking the MAPK/NF-κB pathway and inhibiting the production of inflammatory factors, and the anti-ulcer activity of LAG is superior to that of LEP2a.

Characteristics and antioxidant properties of Harpadon nehereus protein hydrolysate-xylose conjugates obtained from the Maillard reaction by ultrasound-assisted wet heating in a natural deep eutectic solvents system

BACKGROUND

Harpadon nehereus is a high-protein marine fish. A valuable way to add value to H. nehereus is to convert it into protein hydrolysate. The Maillard reaction is an effective way to improve the functional properties of peptides and proteins, which are affected by many factors such as reactant concentration, water activity, pH, temperature, and heating time. However, the traditional Maillard reaction method is inefficient. The purpose of this study was therefore to explore the effect of the ultrasound-assisted wet heating method on the Maillard reaction of H. nehereus protein hydrolysate (HNPH) in a new-type green solvent - a natural hypereutectic solvent (NADES).

RESULTS

Harpadon nehereus protein hydrolysate-xylose (Xy) conjugates were prepared via a Maillard reaction in a NADES system using an ultrasound-assisted wet heating method. The effects of different treatment conditions on the Maillard reaction were studied. The optimized glycation degree (DG) of HNPH-Xy conjugates was obtained with a water content of 10%, a reaction temperature of 80 °C, a reaction time of 35 min, and an ultrasonic power level of 300 W. Compared with HNPH, the structure of HNPH-Xy conjugates were significantly changed. Moreover, the functional properties and antioxidant activity of HNPH-Xy were all superior to the HNPH.

CONCLUSIONS

An ultrasound-assisted wet-heating Maillard reaction between HNPH and Xy in the NADES system could be a promising way to improve the functional properties of HNPH. © 2023 Society of Chemical Industry.

Recent Trends in Improving the Oxidative Stability of Oil-Based Food Products by Inhibiting Oxidation at the Interfacial Region

In recent years, new approaches have been developed to limit the oxidation of oil-based food products by inhibiting peroxidation at the interfacial region. This review article describes and discusses these particular approaches. In bulk oils, modifying the polarity of antioxidants by chemical methods (e.g., esterifying antioxidants with fatty alcohol or fatty acids) and combining antioxidants with surfactants with low hydrophilic–lipophilic balance value (e.g., lecithin and polyglycerol polyricinoleate) can be effective strategies for inhibiting peroxidation. Compared to monolayer emulsions, a thick interfacial layer in multilayer emulsions and Pickering emulsions can act as a physical barrier. Meanwhile, high viscosity of the water phase in emulsion gels tends to hinder the diffusion of pro-oxidants into the interfacial region. Furthermore, applying surface-active substances with antioxidant properties (such as proteins, peptides, polysaccharides, and complexes of protein-polysaccharide, protein-polyphenol, protein-saponin, and protein-polysaccharide-polyphenol) that adsorb at the interfacial area is another novel method for enhancing oil-in-water emulsion oxidative stability. Furthermore, localizing antioxidants at the interfacial region through lipophilization of hydrophilic antioxidants, conjugating antioxidants with surfactants, or entrapping antioxidants into Pickering particles can be considered new strategies for reducing the emulsion peroxidation.

Biodegradable Nanoparticles Prepared from Chitosan and Casein for Delivery of Bioactive Polysaccharides

Ophiopogon japonicus polysaccharides (OJPs) have great anti-inflammation and immunomodulatory abilities. However, the low bioavailability of OJPs reduces its applicability in the biomedical and pharmaceutical fields. Chitosan (CS) has excellent mucoadhesive properties and absorption-enhancing ability in oral administration. Casein hydrolysate (CL) has good interfacial diffusivity and emulsifying ability, and can interact with polysaccharides to form complexes combining the individual properties of both. Therefore, chitosan and casein hydrolysate are good candidates for developing nanoformulations for oral delivery. In this study, bioactive polysaccharides (OJPs), CS and CL, were combined to prepare CS/OJPs/CL co-assembled biodegradable nanoparticles. The interactions between polysaccharides (CS and OJPs) and peptide (CL) resulted in the formation of nanoparticles with an average particle size of 198 nm and high OJPs loading efficiency. The colloidal properties of the nanoparticles were pH-dependent, which were changed significantly in simulated digestive fluid at different pH values. OJPs released from the CS/OJPs/CL nanoparticles were greatly affected by pH and enzymatic degradation (trypsin and lysozyme). The nanoparticles were easily internalized by macrophages, thereby enhancing the OJPs’ inhibitory ability against Ni²⁺-induced cytotoxicity and LPS-induced nitric oxide production. This study demonstrates that prepared polysaccharide/protein co-assembled nanoparticles can be potential nanocarriers for the oral delivery of bioactive polysaccharides with anti-inflammatory functions.

Recent advances on formation mechanism and functionality of chitosan-based conjugates and their application in o/w emulsion systems: A review

Chitosan is very attractive in the food industry due to its good biocompatibility and high biodegradability. In particular, it can be used as a preferred material for the fabrication of stabilizers in emulsion-based foods. However, poor solubility and antioxidant activity limit its wide application. The functionality of chitosan can be extended by forming chitosan-based conjugates, which can be used to modulate the characteristics of the oil-water interface, thereby improving the stability and performance of the o/w emulsions. This review highlights the recent progress of chitosan-based conjugates, focusing on the classification, formation mechanism and functional properties, and the applications of these conjugates in o/w emulsions are summarized. Lastly, the promising research trends and challenges of chitosan-based conjugates and their emulsion systems in this field are also discussed. This review will provide a theoretical basis for the wide application of chitosan-based conjugates in emulsion systems.

Protein-polysaccharide interactions for the fabrication of bioactive-loaded nanocarriers: Chemical conjugates and physical complexes

As unique biopolymeric architectures, covalently and electrostatically protein-polysaccharide (PRO-POL) systems can be utilized for bioactive delivery by virtue of their featured structures and unique physicochemical attributes. PRO-POL systems (i. e, microscopic /nano-dimensional multipolymer particles, molecularly conjugated vehicles, hydrogels/nanogels/oleogels/emulgels, biofunctional films, multilayer emulsion-based delivery systems, particles for Pickering emulsions, and multilayer coated liposomal nanocarriers) possess a number of outstanding attributes, like biocompatibility, biodegradability, and bioavailability with low toxicity that qualify them as powerful agents for the delivery of different bioactive ingredients. To take benefits from these systems, an in-depth understanding of the chemical conjugates and physical complexes of the PRO-POL systems is crucial. In this review, we offer a comprehensive study concerning the unique properties of covalently/electrostatically PRO-POL systems and introduce emerging platforms to fabricate relevant nanocarriers for encapsulation of bioactive components along with a subsequent sustained/controlled release.

A soft Pickering emulsifier made from chitosan and peptides endows stimuli-responsiveness, bioactivity and biocompatibility to emulsion

Polymeric Pickering emulsifiers may bring new insights to emulsion theory and practice due to their soft characters. Herein, a group of soft Pickering emulsifiers, chitosan-casein hydrophobic peptides nanoparticles (CS-CHP NPs) were prepared with a non-covalent anti-solvent procedure. The CS-CHP NPs provided the contact angles of 37.2°-87.4°, stabilizing O/W or W/O emulsions with enhanced thermal stability, endowing the emulsion with pH and CO₂/N₂ responsiveness. The emulsifying behavior and mechanism presented by CS-CHP NPs were different from that of ordinary hard Pickering emulsifiers, where the appropriate contact angle was 37.2° instead of 87.4° for stabilizing O/W emulsions. Moreover, the nanoparticles possess antioxidant, antibacterial activities and excellent biocompatibility. DPPH and ABTS scavenging activity of the CS-CHP NPs were >220% of that of CS NPs. The last, the emulsion provided high-efficient encapsulation of curcumin, making the soft Pickering emulsifiers a group candidate for drug delivery in food, cosmetics and pharmaceutical industry.

Improving method, properties and application of polysaccharide as emulsifier

At present, there are still some problems for the emulsification of polysaccharides such as lack of green, efficient and industrialized methods, lack of systematic and in-depth structure-activity relationship, and need of expanding its application scope. The physical, chemical and biological methods for improving the emulsifying of polysaccharides, the emulsifying properties and influencing factors of polysaccharides and application in food were reviewed herein. It was pointed out that the future research should focus on the effect of physical-biological synergistic function on the emulsification of polysaccharides, the effect of processing process on the structure and emulsification mechanism of polysaccharides, and further expanding the application field of polysaccharides with emulsification activity to improve the quality of products.