Formation mechanism of nano-scale antibiotic and its preservation performance for silvery pomfret

Effects of cinnamon essential oil Pickering emulsion on the quality of refrigerated Hairtail (Trichiurus haumela)

The preservation of hairtail (Trichiurus haumela) under refrigerated conditions is notably difficult, as it is highly prone to spoilage caused by microbial activity and protein oxidation. This study investigated the effectiveness of a novel Zein-AG-CBO Pickering emulsion, enriched with cinnamon bark oil, in enhancing the shelf life and quality of hairtail. The emulsions, with different concentrations from 0MIC to 2MIC, were applied to evaluate its preservative effect on the hairtail in terms of physicochemical, microbiological and myofibrillar proteins over a 10-day storage period at 4 °C. The preservation effect on the hairtail was reflected through evaluations of total volatile basic nitrogen (TVB-N), water holding capacity (WHC), total bacterial count (TVC) and other parameters. Additionally, the impact of the Zein-AG-CBO Pickering emulsion on hairtail myofibrillar proteins was assessed primarily through measurements of total protein content, protein particle size, Ca2+-ATPase activity, sulfhydryl content, carbonyl content, and surface hydrophobicity. Results indicated that the emulsion could prolong the shelf life of hairtail from 6 days to 10 days at 4 °C by retarding the microbial growth and protein degradation. The highest concentration (2MIC) was particularly effective, showing superior retention of sensory attributes, markedly lower levels of TVB-N and microbial counts, more protective effect on hairtail myofibrillar proteins during storage, compared to lower concentrations and the control counterpart. The findings suggested that the Zein-AG-CBO Pickering emulsion is a promising natural preservative that effectively maintained the quality and extended the shelf life of hairtail, offering excellent alternative for the seafood.

Characterization and application of Cinnamaldehyde-loaded zein nanoparticles in a polyvinyl alcohol/chitosan film for silver pomfret (Pampus argenteus) packaging

This study aims to prepare and characterize cinnamaldehyde-loaded zein/sodium alginate nanoparticles (ZCNPs) and incorporate them into polyvinyl alcohol/chitosan (PVA/CS) bioactive films (PSCN) to investigate their compatibility, physicochemical properties, and their application as a preservation material for pomfret fish. The results indicate that the anionic sodium alginate coating improved the particle size, zeta potential, and PDI of zein nanoparticles. The ZCNPs were uniformly dispersed within the films, enhancing the mechanical properties and water vapor barrier performance. The X-ray diffraction (XRD) and Fourier transform infrared (FTIR) analyses confirmed the amorphous structure of the films and the formation of hydrogen bonds. In the PVA/CS film, with the increase of ZCNPs, the thermal decomposition temperature of the film increased from 298 °C to 308 °C, while the film thickness and water contact angle were not significantly affected, remaining around 0.31 cm and 23°, respectively. Additionally, after the incorporation of ZCNPs, the DPPH radical scavenging rate of the film increased from 14.58 % to 95.38 %, significantly delaying the quality deterioration of pomfret during storage.

Chitosan/polyvinyl alcohol food packaging incorporated with purple potato anthocyanins and nano-ZnO: Application on the preservation of hairtail (Trichiurus haumela) during chilled storage

The objective of this work was to evaluate the potential application of chitosan/PVA food packaging films incorporating nano-ZnO and purple potato anthocyanins for preserving chilled hairtail pieces. The hairtail pieces were packaged with chitosan/PVA (CP) and chitosan/PVA/nano-ZnO/purple potato anthocyanins (CPZP), respectively, and Control named without any packaging. The changes in pH, total volatile basic nitrogen (TVB-N), total bacterial colony (TVC), thiobarbituric acid (TBA), color value, and sensory evaluation scores of hairtail pieces were periodically determined. Notably, pH, TVC, TVB-N and TBA values of CPZP group on day 15 were 11.67 %, 23.71 %, 80.73 %, and 35.07 %, respectively, lower than Control group. In addition, CPZP group also performed the best in color and sensory evaluation. These results indicated that CPZP, an active food packaging, could extend the shelf-life of hairtail at least 6 days. Overall, chitosan/PVA food films incorporated with nano-ZnO and purple potato anthocyanins (180 mg/100 mL) provides a potential application in food preservation.

Effect of konjac glucomannan-based preservation pads on quality changes in refrigerated large yellow croaker (Pseudosciaena crocea)

The purpose of this study was to evaluate the preservation effects of konjac glucomannan (KGM)/oregano essential oil (OEO) Pickering emulsion-based pads (K/OPE pads) on large yellow croaker (Pseudosciaena crocea) fillets stored at 4 °C. The K/OPE pads were fabricated using a freeze-drying technique. The homogeneous distribution of the OEO Pickering emulsions in the KGM matrix was observed using scanning electron microscopy. Fourier transform infrared spectroscopy confirmed that the OEO emulsions were encapsulated in the KGM and there was hydrogen bonding interaction between them. Compared with the KGM pads, the K/OPE pad groups demonstrated enhanced antioxidant and antimicrobial properties. When the content of OPE was increased from 20 % to 40 %, the antioxidant performance of the K/OPE pads increased from 48.09 % ± 0.03 % to 86.65 % ± 0.02 % and the inhibition range of Escherichia coli and Staphylococcus aureus increased to 13.84 ± 0.81 and 16.87 ± 1.53 mm, respectively. At the same time, K/OPE pads were more effective in inhibiting the formation of total volatile alkaline nitrogen and the production of thiobarbituric acid-reactive substances, thereby helping in reducing water loss and maintaining the muscle tissue structure of fish fillets for a longer storage time. Consequently, these K/OPE40 pads extended the shelf life of the fish fillets by an additional 4 days and delayed spoilage during refrigerated storage. The findings suggest that the K/OPE pads can effectively safeguard the quality of refrigerated large yellow croaker fillets, presenting their potential as an active packaging material in the fish preservation industry.

Gelatin Improves the Performance of Oregano Essential Oil Nanoparticle Composite Films-Application to the Preservation of Mullet

In this study, the addition of oregano oil chitosan nanoparticles (OEO-CSNPs) was conducted to enhance the comprehensive properties of gelatin films (GA), and the optimal addition ratio of nanoparticles was determined for its application in the preservation of mullet. Oregano oil chitosan nanoparticles were organically combined with gelatin at different concentrations (0%, 2%, 4%, 6% and 8%) to obtain oregano oil-chitosan nanoparticle-GA-based composite films (G/OEO-CSNPs), and thereafter G/OEO-CSNPs were characterized and investigated for their preservative effects on mullet. Subsequent analysis revealed that OEO-CSNPs were uniformly dispersed in the GA matrix, and that G/OEO-CSNPs had significantly improved mechanical ability, UV-visible light blocking performance and thermal stability. Furthermore, the nanoparticles exhibited excellent antioxidant and antibacterial properties, and they improved the films' suitability as edible packaging. The attributes of the G/OEO-CSNPs were optimized, the films had the strongest radical scavenging and lowest water solubility, and electron microscopy also showed nanoparticle penetration into the polymer when the concentration of OEO-CSNPs was 6% (thickness = 0.092 ± 0.001, TS = 47.62 ± 0.37, E = 4.06 ± 0.17, water solubility = 48.00 ± 1.11). Furthermore, the GA-based composite film containing 6% OEO-CSNPs was able to inhibit microbial growth, slow fat decomposition and protein oxidation, reduce endogenous enzyme activity, and delay the spoilage of mullet during the refrigeration process, all of which indicate its excellent potential for meat preservation application.

The properties of pH-responsive gelatin-based intelligent film as affected by ultrasound power and purple cabbage anthocyanin dose

A pH-sensitive intelligent film was prepared using gelatin as base substrate and purple cabbage anthocyanins (PCA) as indicator with the aid of ultrasound. Fourier transforms infrared and X-ray diffraction analysis showed that 600 W ultrasound brought changes to characteristic bands of gelatin and PCA, and flattened diffraction peak around 2θ = 20°. Film prepared with 600 W ultrasound exhibited high tensile strength and elongation at break and showed high transition temperature and surface hydrophobicity by differential scanning calorimetry and contact angle analysis. The incorporation of <0.35 % PCA had no effect on mechanical properties of films, but it improved the antioxidative activity. Films with 0.14 %, 0.21 % and 0.28 % PCA suggested pronounced color difference at pH 5-8, in accordance with the sharp ΔE difference. Films with 0.28 % PCA was applied for monitoring chilled-stored fish quality. It showed visible color change from pink to atrovirens during storage. The difference of ΔE at various days was ≥5 and ΔE highly correlated with total volatile basic nitrogen. Therefore, gelatin along with PCA under appropriate ultrasound treatment could prepare intelligent film to preserve and monitor the quality of chilled-stored fish.

Eugenol-chitosan nanoemulsion as an edible coating: Its impact on physicochemical, microbiological and sensorial properties of hairtail (Trichiurus haumela) during storage at 4 °C

Effects of the eugenol-chitosan nanoemulsion as an edible coating on the quality of hairtail (Trichiurus haumela) during storage at 4 °C were evaluated. For all samples, such parameters as pH, thiobarbituric acid (TBA), total volatile basic nitrogen (TVB-N), water holding capacity (WHC), electrical conductivity (EC), total bacteria count (TVC) and sensory were examined periodically. The results demonstrated that eugenol-chitosan nanoemulsion coating showed better preservative effects than chitosan nanoemulsion alone. Therefore, a coating based on eugenol-chitosan nanoemulsion could be regarded as an effective food-grade biopreservative to maintain the quality of hairtail fish and prolong its shelf life during chilled storage.

Shelf life extension of aquatic products by applying nanotechnology: a review

Aquatic products are extremely perishable due to their biological composition. Conventional preservation methods such as freezing, chemical treatments, packaging, and so forth are unable to inhibit enzymatic and microbiological spoilage efficiently and/or energy intensive and/or potentially toxic. However, the demand of consumers for aquatic products with long shelf life and high quality has urged the food industries to pursuit highly effective preservation methods for shelf life extension of aquatic products. Nanotechnology-related shelf life prolongation process possess the ability to overcome the drawbacks of conventional preservation technologies due to its unique properties. In this article, the aquatic products spoilage mechanisms, recent application of nanotechnology-related preservation techniques for aquatic products as well as the risk and regulation of nanomaterials have been reviewed. It has been shown that nanotechnology-related preservation techniques can effectively extend the shelf life without impairing the quality of aquatic products. However, the safety of nanotechnology is still remained controversial, therefore, the application of nanotechnology should be considered cautiously.

Species identification and quantification of silver pomfret using the droplet digital PCR assay

Adulteration of the high-value silver pomfret (Pampus argenteus) is a serious problem worldwide, necessitating accurate identification and quantification of the species. In this study, optimisation of the digital droplet PCR (ddPCR) assay for the identification and quantification of the silver pomfret was carried out. The primer and probe concentrations, melting temperature, and PCR cycle number were optimised by combining single-factor experiments with an orthogonal experimental design. The absolute limits of detection and quantification of the ddPCR were 2copies/μl and 21 copies/μl, respectively. Its sensitivity was 0.1% for meat mixtures and 0.5% for DNA mixtures. The ddPCR was 156 times more sensitive than the real-time PCR, although both methods had similar specificities. However, the overall time needed to complete the ddPCR method was twice that of the real-time PCR. Notwithstanding, the ddPCR methodology established in this study can be a valuable tool for addressing species adulteration issues.

Enhanced functional properties of biopolymer film incorporated with curcurmin-loaded mesoporous silica nanoparticles for food packaging

Curcumin loaded mesoporous silica nanoparticle (SBA-15) was incorporated into chitosan (CS) film to improve the functional properties of pure CS film. Curcumin was loaded into SBA-15 (SBA-15-Cur) through a rotavapor method. The structural properties of SBA-15-Cur were characterised in detail by small-angle X-ray scattering, fourier transform-infrared (FT-IR) spectroscopy, transmission electron microscopy and N₂ adsorption-desorption analyses. The CS/SBA-15-Cur bionanocomposite film was prepared by solvent casting. The mechanical properties of the bionanocomposite film were improved by the addition of the SBA-15-Cur nanofiller, as revealed by the FT-IR analysis of the biocomposite film. However, the water vapour permeability of the films was not significantly influenced by the filler. Release studies suggested that the CS/SBA-15-Cur bionanocomposite film exhibited pH-responsive and sustained release behaviour of curcumin. The CS/SBA-15-Cur film demonstrated efficient antimicrobial activity against Staphylococcus aureus and Escherichia coli. These data indicated that the CS/SBA-15-Cur bionanocomposite film could be a promising active food packaging material.