Konjac glucomannan/carboxymethyl chitosan film embedding gliadin/casein nanoparticles for grape preservation

Polyvinyl alcohol/soybean isolate protein composite pad with enhanced antioxidant and antimicrobial properties induced by novel ternary nanoparticles for fresh pork preservation

In this study, oregano essential oil (OEO)-loaded soluble soybean polysaccharide (SSPS) -nisin nanoparticles (ONSNPs) were formulated through electrostatic attraction-driven and hydrophobic interactions utilizing SSPS, nisin, and OEO as raw materials. ONSNPs were integrated into polyvinyl alcohol (PVA) and soybean protein isolate (SPI) matrices to create composite pads (PS-ONSNPs) by physically cross-linked using a simple freeze-thaw cycling process. The effects of ONSNPs content on the structure and physicochemical properties were evaluated. The results revealed that strong intermolecular interactions between ONSNPs and the PS matrices affected the crystallinity, microstructure, and thermal stability of the pads. Upon incorporating 5 % to 15 % ONSNPs, the structure of composite pads became denser, and the mechanical properties and water resistance were enhanced. Concurrently, the PS-ONSNPs pads facilitated the protection and controlled release of OEO. Furthermore, ONSNPs significantly improved the antioxidant activity of the pads and effectively inhibited the growth of Staphylococcus aureus and Escherichia coli. The prepared PS-ONSNPs 15 % pad was applied to storage experiments of fresh pork, which could extend the shelf life of meat to 10-12 days under 4 °C storage conditions. Therefore, the composite pad devised in this research holds promise as a viable option for intelligent active packaging of fresh meat.

Preparation, characterization, antimicrobial evaluation, and grape preservation applications of polyvinyl alcohol/gelatin composite films containing zinc oxide@quaternized chitosan nanoparticles

This study employed a precipitation method to synthesize zinc oxide@quaternised chitosan nanoparticles (ZnO@QAC NPs) containing different concentrations of zinc oxide, namely ZnO@QAC-2, ZnO@QAC-4, and ZnO@QAC-6. Subsequently, these nanoparticles were incorporated into matrices consisting of gelatine (Gn) and polyvinyl alcohol (PVA) separately, which were prepared by casting to form a biodegradable film. We assessed the physicochemical properties of ZnO@QAC NPs and physicochemical characteristics, antioxidant properties, antimicrobial activity and grape preservation efficacy of the film. Compared to the control group, the films showed a reduction in water vapor permeability by >9.38 %, an increase in tensile strength by over 51.95 %, over 70 % scavenging of ABTS free radicals, and good biocompatibility. Additionally, the antimicrobial activity of the films containing ZnO@QAC-6 increased by 37.6 %. In the grape preservation experiment, the weight loss of grapes wrapped in ZnO@QAC-2 film was reduced by 40.13 % on day 15 compared to unwrapped grapes. These results demonstrate that ZnO@QAC/PVA/Gn films have considerable potential for food packaging applications.

Recent functionality developments of carboxymethyl chitosan as an active food packaging film material

In recent years, environmental concerns regarding the persistence of petroleum-based plastic food packaging have increased, prompting the exploration of biopolymer alternatives. Carboxymethyl chitosan (CMCS), a derivative of chitosan, exhibits superior water-soluble film properties, making it an ideal material for degradable food packaging applications. This study comprehensively examines the synthesis methods and properties of CMCS, with a particular emphasis on recent advancements in CMCS-based food packaging films. Various functionalized CMCS-based food packaging films, including coblended, nanoparticle composite, plant extract composite, and cross-linked films, were reviewed. The practical applications of CMCS-based food packaging films and edible coatings in food preservation are also showcased. This study emphasizes that the notable compatibility of CMCC with a range of polymers and additives has facilitated the development of multifunctional packaging films. These innovations, including antibacterial, antioxidant, and smart-indicating variants, have demonstrated remarkable efficacy in preserving fruits, aquatic products, poultry, and other perishable goods.

Improvement of mechanical, barrier properties, and water resistance of konjac glucomannan/curdlan film by zein addition and the coating for cherry tomato preservation

The mechanical, barrier properties, and water resistance of packaging materials are crucial for the preservation of fruits and vegetables. In this study, zein was incorporated as a hydrophobic substance into the konjac glucomannan (KGM)/curdlan (KC) system. The KC/zein (KCZ) showed good compatibility with the zein aggregates uniformly distributed in the network formed by an entanglement of KGM and curdlan micelles based on hydrogen bonds. The presence of zein inhibited the extension of the KC entangled structure and enhanced the solid-like behavior. The high content of zein (>6 %) increased zein aggregation and negatively affected the structure and properties of KCZ. The zein addition significantly improved the water vapor permeability, tensile strength, and elongation at break. The hydrophobicity of the KCZ films was significantly enhanced, accompanied by the water contact angle increasing from 81° to 112°, and the moisture content, swelling, and soluble solid loss ratio decreasing apparently. The K56C40Z4 coating exhibited an excellent preservation effect to inhibit the respiration of cherry tomatoes, significantly reducing the water loss and firmness decline and maintaining the appearance, total solid, total acid, and ascorbic acid content. This work provided a strategy to fabricate hydrophobic packaging for the preservation of fruits and vegetables.

Quercetin-loaded melanin nanoparticle mediated konjac glucomannan/polycaprolactone bilayer film with dual-mode synergistic bactericidal activity for food packaging

It is still difficult for a single antibacterial modality to realize satisfactory management of bacterial breeding in food preservation. To solve this problem, we developed a photothermal-derived dual-mode synergistic bactericidal konjac glucomannan (KGM)/polycaprolactone (PCL) bilayer film incorporated with quercetin-loaded melanin-like nanoparticles (Q@MNPs). The results showed that the mechanical properties (TS: 29.8 MPa, EAB: 43.1 %), UV shielding properties, and water resistance (WCA: 124.1°, WVP: 3.92 g mm/m2 day kPa) of KGM-Q@MNPs/PCL bilayer films were significantly improved. More importantly, KGM-Q@MNPs/PCL bilayer film presented outstanding photothermal inversion and controlled release behavior of Q triggered by near infrared (NIR) radiation, thus contributing to excellent dual-mode synergistic antibacterial properties against E. coli and S. aureus. Meanwhile, the KGM-Q@MNPs/PCL bilayer film possessed good biocompatibility and low toxicity. As a proof-of-concept application, we further verified the significant value of film for the preservation of cherry tomatoes. Since KGM-Q@MNPs/PCL bilayer film showed excellent biodegradability, this work will aid the development of sustainable antibacterial food packaging materials.

Konjac glucomannan: A comprehensive review of its extraction, health benefits, and pharmaceutical applications

Konjac glucomannan (KG) is a dietary fiber hydrocolloid derived from Amorphophallus konjac tubers and is widely utilized as a food additive and dietary supplement. As a health-conscious choice, purified KG, along with konjac flour and KG-infused diets, have gained widespread acceptance in Asian and European markets. An overview of the chemical composition and structure of KG is given in this review, along with thorough explanations of the processes used in its extraction, production, and purification. KG has been shown to promote health by reducing glucose, cholesterol, triglyceride levels, and blood pressure, thereby offering significant weight loss advantages. Furthermore, this review delves into the extensive health benefits and pharmaceutical applications of KG and its derivatives, emphasizing its prebiotic, anti-inflammatory, and antitumor activities. This study highlights how these natural polysaccharides can positively influence health, underscoring their potential in various biomedical applications.

Preparation and characterization of zein-tannic acid nanoparticles/chitosan composite films and application in the preservation of sugar oranges

Chitosan-based food packaging film was prepared by incorporating zein-tannic acid nanoparticles (ZTNPs) into chitosan and was evaluated in terms of structure, physical, mechanical and functional properties. Results showed that there were hydrogen bonding interactions between ZTNPs and chitosan matrix, which is conductive to mechanical enhancements of chitosan films. Compared with the pure chitosan film, the composite films with 10% ZTNPs at pH 4 showed the increased tensile strength by 196.58%, increased elongation at break by 161.37%, decreased water vapor permeability by 70.76% and decreased oxygen permeability by 40.68%. The highest inhibition rates of this composite film-forming fluid against Escherichia coli and Staphylococcus aureus reached 83.32% and 72.35%, respectively. The composite film forming solution formed by adding 10% ZTNPs was used for sugar orange preservation. The weight loss rate of oranges was reduced and the nutrient retention rate was improved. This study expanded the application of chitosan-based packaging materials in fruit preservation.

Advances in the construction and application of konjac glucomannan-based delivery systems

Konjac glucomannan (KGM) has been widely used to deliver bioactive components due to its naturalness, non-toxicity, excellent biodegradability, biocompatibility, and other characteristics. This review presents an overview of konjac glucomannan as a matrix, and the types of konjac glucomannan-based delivery systems (such as hydrogels, food packaging films, microencapsulation, emulsions, nanomicelles) and their construction methods are introduced in detail. Furthermore, taking polyphenol compounds, probiotics, flavor substances, fatty acids, and other components as representatives, the applied research progress of konjac glucomannan-based delivery systems in food are summarized. Finally, the prospects for research directions in konjac glucomannan-based delivery systems are examined, thereby providing a theoretical basis for expanding the application of konjac glucomannan in other industries, such as food and medicine.

Preparation and characterization of active films based on oregano essential oil microcapsules/soybean protein isolate/sodium carboxymethyl cellulose

This study aimed to prepare oregano essential oil microcapsules (EOMs) by the active coalescence method using gelatin and sodium alginate as wall materials and oregano essential oil (OEO) as the core material. EOMs were added to the soybean protein isolate (SPI)/sodium carboxymethyl cellulose (CMC) matrix to prepare SPI-CMC-EOM active films, and the physical and chemical features of the active films and EOMs were characterized. The results showed that the microencapsulated OEO could protect its active ingredients. Scanning electron microscopy results showed that EOMs were highly compatible with the film matrix. The solubility of active films decreased upon adding EOMs, and their ultraviolet resistance and thermal stability also improved. When the added amount of EOMs was 5 %, the active films had the best mechanical properties and the lowest water vapor permeability. The active films prepared under this condition had excellent comprehensive performance. Also, adding EOMs considerably enhanced the antioxidant of the active films and endowed them with antibacterial properties. The application of the SPI-CMC-EOM films to A. bisporus effectively delayed senescence and maintained the freshness of the postharvest A. bisporus. This study provided a theoretical foundation for the incorporation of EOMs into active films based on biological materials.

Biosynthesis of Quercetin-Loaded Melanin Nanoparticles for Improved Antioxidant Activity, Photothermal Antimicrobial, and NIR/pH Dual-Responsive Drug Release

Quercetin (QCT) is a promising dose-dependent nutraceutical that usually suffers from poor water solubility and low bioavailability issues. In this work, a novel QCT-loaded nanoscale delivery system was constructed based on the oxidative self-polymerization of melanin (Q@MNPs). The FT-IR, XRD, and Zeta potential analyses confirmed that QCT was successfully absorbed on the melanin nanoparticles (MNPs) via Π-Π and hydrogen bonding interactions. The encapsulation efficiency and particle size of Q@MNPs were 43.78% and 26.68 nm, respectively. Q@MNPs improved the thermal stability of QCT and the antioxidant properties in comparison to MNPs. Meanwhile, Q@MNPs presented fantastic photothermal conversion capacity and stability triggered by the NIR laser, which significantly enhanced the antibacterial capability with a sterilization rate of more than 98% against E. coli and S. aureus. More importantly, Q@MNPs exhibited NIR/pH dual-responsive drug release behavior and good biocompatibility (at concentrations of < 100 μg/mL). Thus, Q@MNPs show promising prospects for flavonoid delivery.