Food Packaging and Shelf Life最新文献

Pathogenic microorganisms pose a significant threat to postharvest fruits and vegetables, resulting in extensive food waste, economic losses, and potential risks to human health. Developing new and efficient antibacterial preservation materials is of utmost importance. In this study, we used zeolitic imidazolate framework-67 (ZIF-67) as a template to synthesize silver nanoparticles (Ag NPs) in situ, preparing Ag@ZIF-67 composite nanoparticles with broad-spectrum antibacterial properties. Then, carboxymethylcellulose (CMC) incorporated with Ag@ZIF-67 was developed for antibacterial food packaging, resulting in the creation of the Ag@ZIF-67&CMC film. This film exhibited improved physicochemical properties, including enhanced mechanical strength, thermal stability, and gas barrier capabilities. Furthermore, the Ag@ZIF-67&CMC film effectively inhibited the growth of bacteria in a preservation experiment involving peaches. This study confirmed that Ag@ZIF-67 as a highly promising antibacterial nanomaterial, while highlighting the Ag@ZIF-67&CMC film as a potent and promising solution for effective food preservation.

Water-borne coating paper, with its food contact potential, raises concerns due to unknown contaminants. Herein, the presence and migration of volatile and semi-volatile compounds, along with chemical elements from two water-borne coating paperboards were investigated using 4 % acetic acid, 50 % ethanol, and 95 % ethanol, while also evaluating associated health risks. The results showed that the overall migration to 95 % ethanol from both papers indicated the non-compliance with the reference limit of 10 mg/dm². Utilizing an optimized direct immersion-solid-phase microextraction coupled to gas chromatography-mass spectrometry method, a total of 66 migrants were identified, among which 16 and 7 were classified as Cramer Ⅲ and Cramer Ⅱ, respectively, linked to coating and paper raw materials. Additionally, 28 chemical elements released from papers were analysed using inductively coupled plasma mass spectrometry, where higher levels of elements (i.e., Na, K) were observed in the migration of 4 % acetic acid, potentially from additives or raw materials used in papermaking processes. More importantly, health risk assessment based on the Threshold of Toxicological Concern approach or worst-case dietary intake assumption indicated that, the estimated daily intake of most migrants and chemical elements through human exposure fell below toxicological reference values. However, certain migrants (e.g., 2-ethylhexyl acrylate, methyl benzoate, phenanthrene, and longifolene) exhibited concerning migration levels in 50 % ethanol and 95 % ethanol that exceed their safety thresholds and may pose health risks. Overall, understanding the migration and potential risk of migrants are imperative for ensuring the safety of using commercially available water-borne coating paper in food contact applications.

Nowadays, it is of high desirable to develop active smart films for food freshness monitoring in real time and protection. Herein, cellulose acetate (CA) matrix was incorporated with cobalt-based metal-organic framework (Co-MOF) to develop an active multi-colorimetric CA/Co-MOF film. The Co-MOF was of cubic structure, which was hydrogen-bonded with CA matrix with good dispersion. In addition to the outstanding UV-blocking capacity, the presence of Co-MOF enhanced the film′s strength, thermal stability, and barrier. Interestingly, the films of CA/Co-MOF were sensitive to ethanol (EtOH), NH₃ and NH₃-H₂S with visual color changes. Among them, the color changes towards EtOH and NH₃ were reversible, while towards NH₃-H₂S was irreversible. Furthermore, the films had good antibacterial activity. In practical application scenarios, the target film of CA/Co-MOF20 can monitor the pork freshness and extend its shelf-life by ∼100 % at 25 ℃, suggesting its good perspective in freshness monitoring and protection. This study will provide a new strategy for development of active multi-colorimetric film for food packaging.

To extend the shelf-life of chilled flesh foods, an antimicrobial packaging incorporated with cinnamon essential oil (CEO) was developed by emulsion electrospinning using polyvinyl alcohol (PVA) and zein. The CEO demonstrated an encapsulation efficiency and loading capacity of 87.42 % and 13.83 %, respectively. Electron microscopy and Fourier transform infrared spectra confirmed the successful encapsulation of CEO in the core part of nanofiber with a diameter on average of 976.12 nm. Furthermore, the results of antimicrobial studies showed that the inhibition zones of nano film against E. coli, S. aureus, P. fluorescens, and L. monocytogenes were 8.41, 26.77, 18.93, and 36.24 mm, respectively, and the non-contact inhibition rates were 100 %. Preservation studies revealed that the nano film could effectively extend shelf life of the pork loin and shrimp to 10 and 6 days, along with the released contents of CEO being 90.9 % and 80.4 %, respectively. Therefore, the nano film exhibits a potential application for the preservation of chilled flesh foods.

We developed edible films composed of sodium alginate (SA) and varying concentrations of kiwifruit seed essential oil (KSO) (10 %, 30 %, and 50 % v/w SA) and extensively characterized. Gas chromatography-mass spectrometry/mass spectrometry revealed that cyclotene, valencene, and camphene are the major components of KSO. Film’s physiochemical parameters revealed that KSO increased the solution’s viscosity from 4.8 to 6.0 cp, and the film’s opacity from 4.2 to 10.6 mm^-1, while also enhancing thermal stability and elongation at break. Fourier-transform infrared spectroscopy and scanning electron microscopy confirmed the induction of KSO into SA. Water contact angle, moisture content, and water vapor permeability results indicated that KSO30 was more hydrophobic than control, KSO10 and KSO50, identifying KSO30 the optimal composition. The final treatments to evaluate partial (P) and full (F) coating on persimmon fruits were uncoated (control), SA, and KSO30. Results indicated that KSO30 was effective in reducing the weight loss and maintaining the firmness and respiration rate compared to the control and SA. Although no significant differences in the respiration rate, firmness, color, or TSS were observed between partially and fully coated persimmons, full coating was more effective in retaining weight loss and pH. At the final day of storage, KSO30 had 5.1 % weight loss and a pH of 6.3, while control fruits had 6.8 % weight loss and a pH of 6.1. Therefore, incorporating SA with KSO is a promising coating material for prolonging the shelf-life of persimmon fruit, and partial coating could be a more economical and viable alternative to full coating.

A pH-sensitive colorimetric bilayer film was constructed on the basis of layer-by-layer self-assembly, with chitosan (CS)-loaded purple carrot anthocyanin (PCA) as the inner indicator layer and gellan gum (GG)-loaded Mg-doped carbon dots (Mg-CDs) as the protective outer layer. X-ray diffraction and scanning electron microscopy analyses confirmed the successful preparation of the bilayer film and the incorporation of Mg-CDs. Fourier transform infrared spectroscopy indicated that the Mg-CDs formed hydrogen bonds with the film matrix. Thermogravimetric analysis revealed that the Mg-CDs improved the thermal stability of the double-layer films. Moreover, the addition of 7 wt% Mg-CDs increased the water vapor permeability, oxygen permeability, and tensile strength of the films by 0.94-, 0.79-, and 3.18-fold, respectively. The antioxidant and antimicrobial activities of the films were significantly enhanced by including Mg-CDs as the active agents. Illumination experiments revealed that the relative color change (S values) increased by only 2.76 % and 4.69 % after the addition of 7 wt% Mg-CDs to the GG -Mg-CDs layer after 21 days of visible light and 72 h of UV light exposure, respectively. These bilayer films containing PCA and Mg-CDs exhibit good pH color responsiveness and biosafety. The C-P/G-7 %CD film had the best overall performance and can effectively reflect pork freshness during storage. Therefore, this research has great potential for developing a double-layer film for monitoring meat quality changes in intelligent food packaging.

In this paper, we designed a food packaging which could not only accelerate the postharvest ripening of banana, but also prolong the shelf life of banana. First, we prepared polycaprolactone (PCL) nanofibers deposited with nanosized γ-cyclodextrin metal-organic frameworks (CD-MOFs) and TiO₂ nanoparticles (TiO₂ @CD-MOF@PCL), CD-MOFs were used to encapsulate ethylene, and TiO₂ nanoparticles were used to degrade ethylene. The ethylene adsorption capacity of nanosized CD-MOF was evaluated, and results showed that the isosteric enthalpy of adsorption (ΔH_ads) was −41.58 kJ/mol. The ethylene pressure, as the critical factor, led to ethylene loading content reaching 1.46 % by 1.6 MPa pressure, 25 °C temperature, 24 h encapsulation time, and 10 min electrospraying time. The releasing behavior of ethylene was affected by humidity and temperature, and under 90 % RH and 20 °C, 92.12 % ethylene was released on the 3th day. The photooxidation degradation experiment proved that as the TiO₂ nanoparticle loading content increased from 1 % to 3 %, the photooxidation degradation activity increased. The degradation rate of ethylene was improved as ethylene concentration increased. In addition, E @ TiO₂ @CD-MOF@PCL (E represents ethylene) nanofiber film was proved that it could shorten ripening period of banana by releasing ethylene. After being irradiated by ultraviolet, shelf life of banana was prolonged by degrading ethylene.

CO₂ atmospheres have the potential to influence raspberry (Rubus idaeus L.) sensory quality after harvest. Our study determined the optimal postharvest atmosphere to extend shelf life without negatively impacting sensory quality. Raspberry fruit were stored at 5 ℃ in 15, 8, 5 or 0.03 kPa CO₂ in combination with 6, 13, 16 or 21 kPa O₂, respectively. A trained sensory panel conducted a descriptive sensory evaluation of the raspberry fruit after 5, 10, and 13 d of storage. Raspberries stored in 15 kPa CO₂ with 6 kPa O₂ (15 kPa) atmosphere followed by that in 8 kPa CO₂ with 13 kPa O₂ (8 kPa) atmosphere had higher firmness than that in 5 kPa CO₂ with 16 kPa O₂ (5 kPa) and 0.03 kPa CO₂ with 21 kPa O₂ (0.03 kPa) atmosphere. Panelists found that raspberries stored in 8 kPa and 15 kPa CO₂ atmosphere had the least off-flavor and highest tartness. Raspberries stored in 8 kPa scored highest in raspberry flavor with substantial juiciness and sweetness scores. The fermentative volatiles acetaldehyde and ethanol were higher in raspberries stored in 15 kPa despite the low off-flavor scores, while most other raspberry volatiles decreased with increasing CO₂ concentration, including flavor-related volatiles α-ionone, α-terpineol, limonene and linalool. After 10 d, the quality of raspberries stored in 0.03 kPa or 5 kPa atmosphere had degraded considerably. While 15 kPa atmosphere prolonged shelf life the longest, 8 kPa atmosphere prolonged shelf life to 10 d while maintaining sensory quality and was the best overall atmosphere.

Silicones can contain oligomers known as siloxanes, which are either by-products of the polymerization process or arise from chemical reactions during processing. They may also have both intentionally and non-intentionally added substances, making it crucial to verify that silicone molds are safe and appropriate for food use. In this study 44 silicone molds available in the market from different European countries were studied. Triple sequential migration assays at 100 ºC for 8 h each using food simulants (3 % acetic acid, 20 % ethanol, and 50 % ethanol) were conducted. Some samples were also tested 4 h at 100 ºC. Global migration assessments were only conducted on turbid samples, while qualitative and quantitative analyses of volatile compounds were performed using solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) in total immersion mode. During the screening analysis of samples of 50 % ethanol at 100 ºC for 8 h a total of 112 different volatile compounds were tentatively identified by MS spectra and quantitatively estimated (LODs = 0.00005–0.014 mg/kg). However, there was no observable migration in the case of 3 % acetic acid and 20 % ethanol. All samples comply with the legislation (Royal Decree 847/2011) in the case of siloxanes. Some samples exceeded specific migration limits for volatile compounds other than siloxanes after third migration in 50 % EtOH at 100 ºC for 8 h.

A novel hybrid nanostructure was synthesized by functionalizing an iron-based metal-organic framework (MOF) with carbon quantum dots (CD@MOF). The developed CD@MOF had an octahedral crystal structure and exhibited favorable antioxidant, antifungal, and antibacterial activities. MOF and CD@MOF particles are incorporated into agar/gelatin (Agar/Gel) blend polymers. The compatibility and dispersion of CD@MOF in the polymer were confirmed through FTIR, XPS, and SEM analysis. The conjugation of MOF with CDs enriched in active edges resulted in superb antioxidant (71.9 % DPPH and 100 % ABTS) and antibacterial activities. The addition of CD@MOF increased the tensile strength and gas (water vapor and oxygen) barrier and UV barrier (100 % UV blocking) properties of the film. In addition, tomato fruits were packaged with fabricated films and stored at 4 ℃ for 24 days, and quality changes were investigated. The experimental outcomes indicated the effective preservation performance of the Agar/Gel/CD@MOF films on packaged tomatoes.