Preparation of sodium alginate/konjac glucomannan active films containing lycopene microcapsules and the effects of these films on sweet cherry preservation

Application of chitosan in fruit preservation: A review

Fruit preservation after harvest is one of the key issues in current agriculture, rural areas, and for farmers. Using chitosan to keep fruits fresh, which can reduce the harm caused by chemical preservative residue to human health. It also helps avoid the disadvantages of the high cost of physical preservation and the challenges associated with difficult operation. This review focuses on the application progress of chitosan in fruit preservation. Studies have shown that chitosan inhibits the growth of bacteria and fungi, and delays fruit aging and decay. Furthermore, it can regulate the respiration and physiological metabolism of fruit, helping to maintain its quality and nutritional value. The preservation mechanism of chitosan includes its antibacterial properties, film-forming properties, and its effects on the physiological processes of fruit. However, in practical applications, issues such as determining the optimal concentration and treatment of chitosan still require further research and optimization.

Improving physicomechanical properties of arrowroot starch films incorporated with kappa-carrageenan: Sweet cherry coating application

Arrowroot starch (AS)-based films potential is influenced by its low-cost processing and high transparency packaging material but low tensile strength; hence, AS was blended with kappa-carrageenan (KC) to improve mechanical properties of AS-based films and enhance its potential use in food packaging or coating applications. AS-KC-based films were characterized based on structural, physicomechanical, thermal, pasting properties, and coating application in sweet cherry. The films demonstrated high tensile strength from 3.2 to 29.4 MPa and low elongation properties from 160.3 % to 1.9 %. Moreover, AS/KC films exhibited peak viscosities of 18.7 to 34.8 RVU, and thermal analysis depicted lower weight losses (59-45 %) compared to AS-based films (62 %). In addition, sweet cherry samples coated with AS/KC films and stored at 20 °C for 15 days depicted lower weight losses (26.6 %) compared to non-coated samples (>41 %), which indicated the potential use of the film's coating application in extending the shelf life and quality of fresh fruits.

Mechanism of the G/M ratio and zein in enhancing the mechanical and hydrophobic properties of sodium alginate films

This study developed an edible film based on calcium-crosslinked sodium alginate (SA) using the casting method. The investigation assessed how the α-L-guluronic acid/β-D-mannuronic acid (G/M ratio) and zein addition influence the film's physicochemical properties. Fourier transform infrared spectroscopy and scanning electron microscopy findings suggest that the G/M ratio modulates the film's physicochemical characteristics by altering SA molecular cross-linking strength and the film's network structure density. At a G/M ratio of 0.85, the film exhibits a more uniform network structure, enhanced moisture resistance, hydrophobicity, and mechanical properties. Zein, evenly dispersed within the film matrix, establishes strong hydrogen bonds and electrostatic interactions with SA, enhancing the film's network structure and boosting its thermophysical, mechanical, and moisture resistance characteristics. The study demonstrates that modifying the G/M ratio and incorporating zein enhances the film's mechanical and hydrophobic properties, broadening its potential applications in food packaging.

Alginate-based active and intelligent packaging: Preparation, properties, and applications

Alginate-based packaging materials have emerged as promising alternatives to conventional petroleum-based plastics due to their biodegradability, renewability, and versatile functionalities. This review provides a comprehensive analysis of the recent advances in the development and application of alginate-based films and coatings for food packaging. The composition and fabrication methods of alginate-based packaging materials are discussed, highlighting the incorporation of various functional compounds to enhance their physicochemical properties. The mechanisms of action and the factors influencing the release and migration of active compounds from the alginate matrix are explored. The application of alginate-based packaging materials for the preservation of various food products, including meat, fish, dairy, fruits, and vegetables, is reviewed, demonstrating their effectiveness in extending shelf-life and maintaining quality. The development of alginate-based pH-sensitive indicators for intelligent food packaging is also discussed, focusing on the colorimetric response of natural pigments to spoilage-related pH changes. Furthermore, the review highlights the challenges and future perspectives of alginate-based packaging materials, emphasizing the need for novel strategies to improve their performance, sustainability, and industrial adoption.

Preparation and Keep-Refreshing Effect of Chitosan/Sea Buckthorn Polysaccharide Composite Film on the Preservation of Yellow Cherry Tomatoes

In this study, sea buckthorn polysaccharides (SBP) were added as functional substances to chitosan (CS), and chitosan/sea buckthorn polysaccharide (SCS) composite films were prepared using the casting method. The effects of SBP addition on the optical properties, physical properties, mechanical properties, structure, antioxidant activity, and antibacterial activity of the SCS composite films were studied, and the prepared SCS composite films were used to preserve yellow cherry tomatoes. The results showed that SCS composite films exhibited good UV resistance, water solubility, and antioxidant activity, but its apparent structure, hydrophobicity, and mechanical properties needed further improvement. Meanwhile, SBP has inhibitory effects on all 8 experimental strains. In addition, the SCS composite film with the addition of 200 mg/L SBP could reduce the weight loss rate of yellow cherry tomatoes, maintain hardness, delay the decrease of total soluble solids, titratable acid, and Vitamin C content, and inhibit the accumulation of malondialdehyde. SCS composite films are beneficial for enhancing the quality of yellow cherry tomatoes during storage, and their application in fruit and vegetable preservation has development prospects.

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.

Incorporation of Polygonatum cyrtonema extracts of NADES into chitosan/soybean isolate protein films: Impact on sweet cherry storage quality

This study developed a biodegradable food film, incorporating bioactive components of Polygonatum cyrtonema extracted using natural deep eutectic solvents (NADES) into a matrix of chitosan and soy protein isolate. The films containing varying concentrations (0 %-5 %) of P. cyrtonema extract (PCE) were characterized. The addition of PCE improved the mechanical (+25.9 MPa for tensile strength), optical (+11.29 mm-1 for opacity), and thermal stability (-14.39 % for weight loss) of the films. The DPPH and ABTS radical scavenging rates increased by approximately 1.1 times and 0.5 times, respectively, and malondialdehyde formation reduced by 8 %. The films also effectively inhibited the growth of Staphylococcus aureus or Escherichia coli. The films showed complete biodegradability after 7 days. Using the NADES-PCE coated film reduced the weight loss of sweet cherries by 41.04 % while significantly decreasing the loss of hardness, total phenols, vitamin C, total soluble solids, and titratable acidity, thereby considerably extending the storage life of the sweet cherries. Overall, this study developed a new environmentally friendly packaging material and improved the functionality of the packaging film by leveraging natural plant extracts, demonstrating tremendous potential in the field of food preservation and packaging.

Novel Carboxymethyl Cellulose/Gelatin-Based Film Incorporated with Zein-Stabilized Lemon Essential Oil Pickering Emulsion for the Preservation of Cherries

In this study, a zein-stabilized lemon essential oil Pickering emulsion (ZLPE) was incorporated into a carboxymethyl cellulose/gelatin (CMC/GL) composite film to develop a bio-based packaging material with bioactive properties. The average droplet size of the ZLPE was measured at 3.62 ± 0.08 μm, with a zeta potential of -31.33 ± 0.32 mV, highlighting its excellent stability. The image results of confocal laser microscopy and scanning electron microscopy validated the uniform distribution of ZLPE in the film. The incorporation of ZLPE reduced the water solubility of films by 45.90% and decreased its water vapor permeability by 22.61%, thereby enhancing its hydrophobicity. Additionally, the ZLPE-loaded film improved mechanical properties, enhanced UV-blocking capabilities, and increased thermal stability. The introduction of ZLPE led to the antioxidant activity of the CMC/GL film increasing by six times the original level and endowed it with outstanding antibacterial properties. As a result, cherries packaged with the ZLPE film demonstrated superior preservation performance and extended shelf life in the preservation experiment, exhibiting the film's potential as a food packaging material.

A new active packaging system based on chickpea-based edible coatings added with microcapsules of Cosmos sulphureus Cav. flower extract

BACKGROUND

The Cosmos sulphureus Cav. plant is studied for its high polyphenolic content with antioxidant properties. Its flowers, rich in phenolic acids, flavonoids, and tannins, hold promise as antioxidants in food preservation. The inclusion of these compounds in chickpea-based coatings with a previously studied preservative effect would be an excellent option as a food preservation method and microencapsulation addresses challenges like dispersion and degradation of polyphenols in the coating. The objective of this research was to evaluate the in vitro antioxidant activity of Cosmos sulphureus leaves, seed, and flower extracts and explore the protective effects of chickpea-based coatings containing microcapsules of flower polyphenolic extract on the chemical quality of stored roasted sunflower seeds during storage.

RESULTS

The ethanolic leaf extract exhibited the highest antiradical activity, followed by the aqueous flower extract. After a storage period of 15 days, at 40 °C, the chickpea-based coatings effectively delayed lipid oxidation in the roasted sunflowers seeds, and the inclusion of polyphenolic microcapsules with 0.01% extract (SMC 0.01%) in the coating significantly improved the protective effect. By day 15 of storage, SMC 0.01% showed comparable peroxide value, conjugated dienes, and linoleic acid content to samples containing the synthetic antioxidant BHT (butylated hydroxytoluene). Samples that only contained chickpea-based coating and coating with polyphenolic microcapsules with 0.005% extract exhibited significantly greater reduction in fatty acid content compared to the 0.01% SMC treatment.

CONCLUSION

The chickpea-based coating with polyphenolic microcapsules demonstrated antioxidant activity akin to synthetic BHT, offering a promising biopackaging solution for lipid-rich foods like roasted sunflower seeds. © 2024 Society of Chemical Industry.

Rapid in situ formation of κ-carrageenan-carboxymethyl chitosan-kaolin clay hydrogel films enriched with arbutin for enhanced preservation of cherry tomatoes

Food waste resulting from perishable fruits and vegetables, coupled with the utilization of non-renewable petroleum-based packaging materials, presents pressing challenges demanding resolution. This study addresses these critical issues through the innovative development of a biodegradable functional plastic wrap. Specifically, the proposed solution involves the creation of a κ-carrageenan/carboxymethyl chitosan/arbutin/kaolin clay composite film. This film, capable of rapid in-situ formation on the surfaces of perishable fruits, adeptly conforms to their distinct shapes. The incorporation of kaolin clay in the composite film plays a pivotal role in mitigating water vapor and oxygen permeability, concurrently bolstering water resistance. Accordingly, tensile strength of the composite film experiences a remarkable enhancement, escalating from 20.60 MPa to 34.71 MPa with the incorporation of kaolin clay. The composite film proves its efficacy by preserving cherry tomatoes for an extended period of 9 days at 28 °C through the deliberate delay of fruit ripening, respiration, dehydration and microbial invasion. Crucially, the economic viability of the raw materials utilized in the film, coupled with the expeditious and straightforward preparation method, underscores the practicality of this innovative approach. This study thus introduces an easy and sustainable method for preserving perishable fruits, offering a cost-effective and efficient alternative to petroleum-based packaging materials.

Robust construction of konjac glucomannan/polylactic acid nanofibrous films incorporated with carvacrol via microfluidic blow spinning for food packaging

In recent years, the application of biopolymer-based nanofibers prepared via microfluidic blow spinning (MBS) for food packaging has continuously increased due to their advantages of biocompatibility, biodegradability, and safety. However, the poor spinnability, undesirable water barrier capacity, and loss of antibacterial and antioxidant properties of biopolymer-based nanofibers strictly restrict their real-world applications. In this work, carvacrol (CV) incorporated konjac glucomannan (KGM)/polylactic acid (PLA) nanofibrous films (KP-CV) were produced by MBS. The FTIR spectra and XRD analysis revealed the hydrogen bonding interactions among CV, PLA, and KGM, thus significantly improving the TS of KP-CV nanofibrous films from 0.23 to 1.27 MPa with increased content of CV from 0 % to 5 %. Besides, KP-CV nanofibrous films showed improved thermal stability, excellent hydrophobicity (WCA: 128.19°, WVP: 1.02 g mm/m2 h kPa), and sustained release of CV combined with good antioxidant activities (DPPH radical scavenging activity: 77.51 ± 1.57 %), and antibacterial properties against S. aureus (inhibition zone: 26.33 mm) and E. coli (inhibition zone: 22.67 mm). Therefore, as prepared KP-CV nanofibrous films can be potentially applied as packaging materials for the extended shelf life of cherry tomatoes.

Moisture loss inhibition with biopolymer films for preservation of fruits and vegetables: A review

In cold storage, fruits and vegetables still keep a low respiratory rate. Although cold storage is beneficial to maintain the quality of some fruits and vegetables, several factors (temperature and humidity fluctuations, heat inflow, air velocity, light, etc.) will accelerate moisture loss. Biopolymer films have attracted great attention for fruits and vegetables preservation because of their biodegradable and barrier properties. However, there is still a certain amount of water transfer occurring between storage environment/biopolymer films/fruits and vegetables (EFF). The effect of biopolymer films to inhibit moisture loss of fruits and vegetables and the water transfer mechanism in EFF system need to be studied systematically. Therefore, the moisture loss of fruits and vegetables, crucial properties, major components, fabrication methods, and formation mechanisms of biopolymer films were reviewed. Further, this study highlights the EFF system, responses of fruits and vegetables, and water transfer in EFF. This work aims to clarify the characteristics of EFF members, their influence on each other, and water transfer, which is conducive to improving the preservation efficiency of fruits and vegetables purposefully in future studies. In addition, the prospects of studies in EFF systems are shown.

Modified cellulose nanocrystals enhanced polycaprolactone multifunctional films with barrier, UV-blocking and antimicrobial properties for food packaging

The packaging industry demands improved eco-friendly materials with new and enhanced properties. In this context, bio-nanocomposite films with antimicrobial and UV-shielding properties based on modified cellulose nanocrystals/polycaprolactone (MCNC/PCL) were fabricated via solution casting method, and then food packaging simulation was carried out. CNCs were obtained by acid hydrolysis followed by successful functionalization with Quaternary ammonium surfactant, confirmed by FTIR, XPS, XRD, TEM, and DLS analyses. Furthermore, the morphological, physical, antibacterial, and food packaging properties of all prepared films were investigated. Results showed that the mechanical, UV blocking, barrier properties, and antibacterial activity of all composite films were remarkably improved. Particularly, the addition of 3 wt% MCNC increased the tensile strength and elongation at break by 27.5 % and 20.0 %, respectively. Moreover, the permeability of O2, CO2, and water vapor dramatically reduced by 97.6 %, 96.7 %, and 49.8% compared to the Neat PCL. Further, the UV-blocking properties of the composite films were significantly improved. The antimicrobial properties of MCNC/PCL films showed good antimicrobial properties against S. aureus. Finally, cherry packaged with 1 and 3 wt% MCNC films exhibited satisfactory freshness after 22 days of preservation. Overall, the fabricated PCL nanocomposite films can be utilized in the food packaging industry.

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.

Antibacterial Activity of Modified Sesbania Gum Composite Film and Its Preservation Effect on Wampee Fruit (Clausena lansium (Lour.) Skeels)

The primary challenges in fruit and vegetable preservation include extending storage duration while preserving sensory quality and nutritional value. In this study, sesbania gum (SG) was oxidized to prepare oxidized sesbania gum (OSG). An OSG/ZnO composite film was subsequently prepared, combining OSG, sodium carboxymethyl cellulose (CMC), and nano-zinc oxide (nano-ZnO). The preparation technology was determined via a response surface optimization experiment. When the addition amount of nano-ZnO exceeded 0.3 mg/mL, the composite films exhibited an antibacterial rate of over 90% against E. coli and S. aureus. For wampee (Clausena lansium (Lour.) Skeels) preservation, a OSG/ZnO-0.3 film was directly applied as a coating. The findings demonstrated favorable results in terms of the rate of rotting, soluble solids, and titrable acidity, effectively prolonging wampee fruit storage. This suggests the potential of an OSG composite film with nano-ZnO as a promising fruit packaging material, thereby expanding the application of SG and wampee fruit preservation.

Chitosan coatings with different degrees of deacetylation regulate the postharvest quality of sweet cherry through internal metabolism

In this study, chitosan coatings with different degrees of deacetylation (DD, 88.1 % and 95.2 %) were electrostatically sprayed on sweet cherries to evaluate their impacts on postharvest characteristics and internal metabolism. The results showed that chitosan coating could effectively delay the change of weight, color, firmness, and maintain the content of total phenols, flavonoids and titratable acids, and inhibit the activities of β-galactosidase and polyphenol oxidase during cold storage. The storage qualities and physiological activities of sweet cherry were significantly correlated with the contents of sorbitol, 4-hydroxycinnamic acid, hydrogenated hydroxycinnamic acid, tyrosine, proline, glutamine, phenylalanine, and other metabolites. Chitosan coating may modulate fruit quality by inhibiting the energy metabolism, accelerating the accumulation of carbohydrates, and promoting the metabolism of phenylalanine and flavonoid. Especially, chitosan coating with 88.1 % DD had better wettability on sweet cherry's peel and displayed more obvious preservation effect through stronger metabolic regulation ability.

Intelligent active films of sodium alginate and konjac glucomannan mixed by Lycium ruthenicum anthocyanins and tea polyphenols for milk preservation and freshness monitoring

To achieve real-time monitoring of food freshness, a pH-responsive film based on sodium alginate-konjac glucomannan loaded with Lycium ruthenicum anthocyanins (LRA) was prepared, with the addition of tea polyphenols (TP) to enhance the stability of LRA. The surface structure of the films was observed by AFM. The results of FTIR and molecular docking simulation showed that LRA and TP were bound to polysaccharide by hydrogen bonds. The mechanical properties, barrier properties, and antioxidant/antibacterial properties of the films were significantly improved and the films showed obvious color response to pH. Notably, the AFM images showed TP and LRA could lead to more severe damage to the bacterial structure. The results of molecular docking simulation suggested that TP and LRA could act on different components of the bacterial cell wall, indicating their synergistic mechanism in antimicrobial activity. Moreover, the stability of LRA was improved due to the interactions of TP and polysaccharides with LRA. The aggregates formed by TP and LRA were clearly observed by AFM. Finally, the film showed excellent preservation and freshness monitoring effect in milk. In conclusion, TP-LRA-SA-KGM intelligent film exhibited excellent performance and represented a promising novel food packaging material with potential applications.

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

Constructing biopolymer-based packaging films with fantastic water resistance and mechanical properties for food preservation is highly desirable and challenging. In this work, Gliadin/Casein nanoparticles (GCNPs) were prepared by pH-driven method and embedded into konjac glucomannan/carboxymethyl chitosan (KC) film matrix to improve the water resistance and mechanical properties of KC film. Gliadin and Casein showed good compatibility and co-assembled to form compact GCNPs clusters through hydrogen bonding and hydrophobic interaction verified by FT-IR spectroscopy, and fluorescence spectroscopy. The particle size and zeta potential of GCNPs was 269.7 nm and -7.6 mV, respectively. The effect of GCNPs on the mechanics, water barrier, thermal stability, and UV-shielding of KC-GCNPs film was investigated. SEM images revealed that GCNPs uniformly distributed into KC film matrix and significantly improved the mechanics (tensile strength: 75.6 MPa, elongation at breaking: 36.7 %), water barrier ability (water contact angle: 91.3°, water vapor permeability: 0.994 g mm/m2 day kPa, water solubility: 52.0 %), thermal stability and UV blocking property of KC-GCNPs film. Furthermore, KC-GCNPs film could also be applied to extend the shelf life of grapes. This paper demonstrated the great potential of GCNPs as functional nanofillers in enhancing the physicochemical properties of KC film.

Recent Advances in Lycopene for Food Preservation and Shelf-Life Extension

In recent years, there has been increasing concern about the safety of additives used to extend the shelf-life of food products. As a result, lycopene, a natural phytochemical compound, has attracted attention, as it has been demonstrated to be a potential alternative to traditional artificial antioxidants, with significant health benefits when applied to food preservation. Based on this, this review introduces the specific forms of lycopene currently used as an antioxidant in foods, both in its naturally occurring forms in fruits and vegetables and in artificially added forms involving technologies such as composite coating, active film packaging, emulsion, and microcapsules. In addition, it also provides a comprehensive summary of the effects and progress of lycopene in the preservation of different types of food products, such as meat, seafood, oil, dairy products, fruits, and vegetables, in the last decade. At last, it also points out the limitations of lycopene, including its insolubility in water, dark color, and high sensitivity to heat or light, as well as the potential solutions to load lycopene on suitable carriers, such as combining lycopene with antimicrobial substances or other actives, in order to broaden its applications as an antioxidant in future foods.

Composite films of sodium alginate and konjac glucomannan incorporated with tea polyphenols for food preservation

At present, food waste has become a serious issue and the use of petroleum-based food packaging films has resulted in a series of potential hazards. Therefore, more attention has been focused on the development of new food packaging materials. The polysaccharide-based composite film loaded with active substances considered to be an excellent preservative material. A novel packaging film based on sodium alginate and konjac glucomannan (SA-KGM) blended with tea polyphenols (TP) was prepared in the present study. The excellent microstructure of films was shown by atomic force microscopy (AFM). It was indicated by FTIR spectra that the components could interact with each other through hydrogen bonds, which was also confirmed by molecular docking simulation. Meanwhile, the mechanical properties, barrier property, oxidation property, antibacterial activity, and stability of the structure of the TP-SA-KGM film were significantly improved. The AFM images and results of molecular docking simulation indicated that TP could affect the cell wall of bacteria by acting with peptidoglycan. Finally, the film showed excellent preservation effects in both beef and apples, which suggested that TP-SA-KGM film could be a novel bioactive packaging material with wide application potential in food preservation.

Acylated pectin/gelatin-based films incorporated with alkylated starch crystals: Characterization, antioxidant and antibacterial activities, and coating preservation effects on golden pomfret

Pectin and starch crystals were modified by ethyl gallate and octadecyl-trimethoxysilane, respectively, followed by using acylated pectin (AP) and alkylated starch crystals (ASCs) as bioactive reagents and hydrophobic enhancers to improve the physiochemical properties of gelatin-based films and evaluate their coating preservation effects on golden pomfret. The properties of AP and ASC were investigated by Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-vis), proton-nuclear magnetic resonance (¹H NMR) and X-ray diffraction (XRD). The ethyl-gallate-modified pectin/gelatin (AP/G) containing 3 % ASC (AP/G/ASC-3 %) was shown to have the maximum tensile strength and Young's modulus of all the tested composite films. The AP/G containing 10 % ASC exhibited a water contact angle higher than 94°, coupled with a significant improvement in UV-shielding efficiency. FTIR and SEM analysis of the AP/G/ASC-3 % film indicated that the molecular interactions in the composite film components were noncovalent linkages, including hydrogen bonds, hydrophobic interactions, and electrostatic interactions, contributing to homogeneous and smooth microstructures. Additionally, the solutions of AP/G and AP/G/ASC composite films presented obvious antioxidant and antibacterial activities against Escherichia coli and Staphylococcus aureus. Furthermore, the AP/G and AP/G/ASC active coatings could effectively inhibit lipid oxidation and improve the textural acceptability of golden pomfret (Trachinotus blochii) fillets during 4 °C storage.

Effect of hydroxypropyl-β-cyclodextrin and lecithin co-stabilized nanoemulsions on the konjac glucomannan/pullulan film

In this study, the various ratio of hydroxypropyl-β-cyclodextrin (HPCD) to lecithin (LEC) was 0:1, 0.5:1, 1:1, 1.5:1 and 2:1 (w/w) co-stabilized cinnamon essential oil (CEO) nanoemulsions were prepared. These nanoemulsions were successfully incorporated in the konjac glucomannan/pullulan polysaccharides-based film matrix. The composition of nanoemulsions and the effect of various nanoemulsions on rheological, mechanical, Water vapor permeability, optical, color, morphology properties, and CEO retention rate of the composite films were characterized. The results demonstrated that HPCD and LEC nanoemulsions had small particle size under 120 nm and high stability during 21 days storage, the incorporation of nanoemulsions reduced the viscosity of film-solution, transmittance, Water vapor permeability and mechanical properties of films, but an appropriate HPCD content 1:1 w/w of nanoemulsions could restored the mechanical properties of the films. Otherwise, 1:1 w/w of nanoemulsion film also exhibited a more compact and uniform structure, Furthermore, 2:1 w/w of nanoemulsion films with high retention rate of CEO, and the antioxidant and better antibacterial activities against E. coli and S. aureus. The nanoemulsion films utilized in this study also prolonged the shelf life of Agaricus bisporus mushrooms and cherries while maintaining their commercial value.