Fabrication and Characterization of Quercetagetin-Loaded Nanoparticles Based on Shellac and Quaternized Chitosan: Improvement of Encapsulation Efficiency and Acid and Storage Stabilities

Gastrointestinal digestion behavior and bioavailability of greenly prepared highly loaded myofibrillar-luteolin vehicle

In this study, the highly loaded myofibrillar protein (MP)-luteolin (Lut) complexes were noncovalently constructed by using green high-pressure homogenization technology (HPH) and high-pressure micro-fluidization technology (HPM), aiming to optimize the encapsulation efficiency of flavonoids in the protein-based vehicle without relying on the organic solvent (i.e. DMSO, ethanol, etc.). The loading efficiency of Lut into MPs could reach 100 % with a concentration of 120 μmol/g protein by using HPH (103 MPa, 2 passes) without ethanol adoption. The in vitro gastrointestinal digestion behavior and antioxidant activity of the complexes were then compared with those of ethanol-assisted groups. During gastrointestinal digestion, the MP digestibility of complexes, reaching more than 70.56 % after thermal treatment, was higher than that of sole protein. The release profile of Lut encapsulated in ethanol-containing and ethanol-free samples both well fitted with the Hixson-Crowell release kinetic model (R2 = 0.92 and 0.94, respectively), and the total phenol content decreased by ≥ 40.02 % and ≥ 62.62 %, respectively. The in vitro antioxidant activity (DPPH, ABTS, and Fe2+) of the digestive products was significantly improved by 23.89 %, 159.69 %, 351.12 % (ethanol groups) and 13.43 %, 125.48 %, 213.95 % (non-ethanol groups). The 3 mg/mL freeze-dried digesta significantly alleviated lipid accumulation and oxidative stress in HepG2 cells. The triglycerides and malondialdehyde contents decreased by at least 57.62 % and 67.74 % after digesta treatment. This study provides an easily approached and environment-friendly strategy to construct a highly loaded protein-flavonoid conjugate, which showed great potential in the formulation of healthier meat products.

Insect chitosan/pullulan/gallium photo-crosslinking hydrogels with multiple bioactivities promote MRSA-infected wound healing

Methicillin-resistant Staphylococcus aureus (MRSA) and other drug-resistant bacteria have become more common in recent years, which has made it extremely difficult to treat and heal many different kinds of wounds and caused enormous financial losses. Because of its unique "Trojan horse" function, Ga3+ has been recognized as a new possible candidate for inhibiting and eradicating drug-resistant bacteria. Furthermore, natural polysaccharide materials with outstanding biological characteristics, such as insect chitosan (CS) and pullulan (PUL), have attracted significant interest. In this study, we used quaternized-catechol chitosan (QDCS-PA), methacrylate-dialdehyde pullulan (DPUL-GMA), and gallium ion (Ga) to create a multi-crosslinked photo-enhanced hydrogel (Q-D/Ga/UV) with antimicrobial, hemostatic, self-healing, and injectable properties for promoting MRSA-infected wound healing. In vitro, the Q-D/Ga/UV hydrogels demonstrated good mechanical properties, antioxidant capabilities, biocompatibility, hemostatic properties, and antibacterial activity. The addition of gallium ions enhanced the hydrogels' mechanical properties, hemostatic capabilities, antibacterial activity, and ability to induce wound healing. Q-D/Ga/UV hydrogel significantly promoted wound contraction, collagen deposition, and angiogenesis while also suppressing inflammation in a whole-skin wound model of MRSA-infected rats. In conclusion, Q-D/Ga/UV hydrogels demonstrate significant promise for healing wounds infected with drug-resistant bacteria.

Shellac-based delivery systems for food bioactive compounds

Shellac is a natural resin featuring some attractive properties such as amphiphilicity, pH responsiveness, biocompatibility, and biodegradability. There has been increasing interest in employing shellac for controlled delivery of food bioactive compounds. This review outlines the recent advances in different types of shellac-based delivery systems, including nanoparticles, zein-shellac particles, hydrogels, nanofibers, and nanomicelles. The preparation method, formation mechanism, structure, and delivery performance are investigated. These systems could improve the stability and shelf-life of bioactive compounds, allow for targeted release at the small intestine or colon site, and increase bioavailability. The deficiencies and challenges of each of the systems are also discussed. The promising results in this review could guide future trends in more efficient shellac-based delivery platforms for functional food applications.

Enhanced environmental stress resistance and functional properties of the curcumin-shellac nano-delivery system: Anti-flocculation of poly-γ-glutamic acid

Curcumin was widely designed as nanoparticles to remove application restrictions. The occurrence of flocculation is a primary factor limiting the application of the curcumin nano-delivery system. To enhance the environmental stress resistance and functional properties of shellac-curcumin nanoparticles (S-Cur-NPs), γ-polyglutamic acid (γ-PGA) was utilized as an anti-flocculant. The encapsulation efficiency and loading capacity of S-Cur-NPs were also improved with γ-PGA incorporation. FTIR and XRD analysis confirmed the presence of amorphous characteristics in S-Cur-NPs and the combination of γ-PGA and shellac was driven by hydrogen bonding. The hydrophilic, thermodynamic, and surface potential of S-Cur-NPs was improved by the incorporation of γ-PGA. This contribution of γ-PGA on S-Cur-NPs effectively mitigated the flocculation occurrence during heating, storage, and in-vitro digestive treatment. Furthermore, it was revealed that γ-PGA enhanced the antibacterial and antioxidant properties of S-Cur-NPs and effectively protected the functional activity against heating, storage, and in-vitro digestion. Release studies conducted in simulated gastrointestinal fluids revealed that S-Cur-NPs have targeted intestinal release properties. Overall, the design of shellac with γ-PGA was a promising strategy to relieve the application stress of shellac and curcumin in the food industry.

Quaternary-ammonium chitosan, a promising packaging material in the food industry

Quaternary-ammonium chitosan (QAC) is a polysaccharide with good water solubility, bacteriostasis, and biocompatibility. QAC is obtained by methylating or grafting the quaternary-ammonium group of chitosan and is an important compound in the food industry. Various QAC-based complexes have been prepared using reversible intermolecular interactions, such as electrostatic interactions, hydrogen bonding, metal coordination, host-guest interactions, and covalent bonding interactions consisting of Schiff base bonding and dynamic chemical bond cross-linking. In the food industry, QAC is often used as a substrate in film or coating for food preservation and as a carrier for active substances to improve the encapsulation efficiency and storage stability of functional food ingredients. In this review, we have assimilated the latest information on QAC to facilitate further discussions and future research. Advancement in research on QAC would contribute toward technology acceleration and its increased contribution to the field of food technology.

Photodynamic-responsive gelatin-based coating with high utilization curcumin loaded bilayer nanoencapsulation: A promising environmental food packaging

The development and application of curcumin-mediated antimicrobial photodynamic techniques (PDT) in food preservation are highly anticipated to resist microbial contamination and prevent food spoilage. In this study, high-utilization curcumin-loaded bilayer nanoencapsulation was prepared to incorporated into a gelatin-based edible coating for beef preservation. Bilayer nanoencapsulation composed of shellac and poly-γ-glutamic acid (CS-NPs) improved the encapsulation efficiency of shellac to curcumin by >1.5 times. The incorporation of CS-NPs improved the compact of coating structure with hydrogen bonds. In food simulants, coatings possessed control release properties and the release mechanism was Fick diffusion (without the addition of γ-PGA) and non-Fick diffusion (with the addition of γ-PGA). These prepared coatings exhibited excellent barrier, antibacterial (antibacterial ratio > 95 %), and antioxidant properties (scavenging ratio > 90 %). Curcumin mediated antimicrobial photodynamic techniques (PDT) of the coatings were verified with the activity of blue light-induced reactive oxygen species (ROS). The shelf-life of beef was extended by the coating with blue light. In summary, the design of bilayer CS-NPs significantly improved the utilization of curcumin which provided a high-efficiency strategy for PDT-responsive food packaging with environmental practical.

Tailorable antibacterial and cytotoxic chitosan derivatives by introducing quaternary ammonium salt and sulfobetaine

Chitosan (CS) derivatives with improved water solubility, antibacterial activity and adequate biocompatibility are attracting increasingly interest in medical application. Herein, we have successfully synthesized isocyanate terminated quaternary ammonium salt (IQAS) and sulfopropylbetaine (ISB) to be readily covalently bounded to CS skeleton by selective reaction with amino and hydroxyl groups. And their molecular structures and crystallinity were confirmed by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, and X-ray diffraction. The effect of the substitution degree, carbon chain length, content ratio of IQAS/ISB on their water solubility, antibacterial activity and cytotoxicity were systematically investigated, which shows that those properties of the CS derivatives can be tailored by adjusting the grafted antibacterial agents and their additive amount. The structure-property relationship of these CS derivatives may provide a solid guidance on the development of CS derivatives for more efficient practical applications.

Co-assembly of egg white-derived peptides and protein-polysaccharide complexes for curcumin encapsulation: The enhancement of stability, redispersibility, and bioactivity

In this study, a nanocomposite was developed by introducing egg white-derived peptides (EWDP) into protein-polysaccharide complexes to trigger the self-assembly of EWDP for encapsulating curcumin (Cur) via the pH-driven method. In this system, EWDP could cooperate with protein-polysaccharide complexes to exert superior colloidal properties with excellent Cur aqueous solubility, redispersibility, and physical stability and act as a bioactivity amplifier to endow the delivery system with the synergistic antioxidant activity. This phenomenon was ascribed to the additional hydrophobic cavities, hydrogen bonding, and electrostatic interactions organized by EWDP. Additionally, the presence of EWDP could considerably boost the cellular antioxidant activity of Cur by decreasing reactive oxygen species (ROS) levels, improving free radical scavenging capacity, and recovering the activity of endogenous antioxidant enzymes. These findings might open up an avenue to reinforce lipophilic nutraceuticals' physicochemical properties and functionalities based on the co-assembly of food-derived peptides and protein-polysaccharide complexes.