Search

An intelligent indicator film was prepared with chitosan (CS) and sodium alginate (SA) as film-forming material with added black apple peel anthocyanin (BAA). The effects of different concentrations of BAA on the microstructure, thickness, color, mechanical properties, moisture content, and ultraviolet (UV) transmittance of the composite film were analyzed and compared. In addition, the feasibility of applying the composite film for monitoring shrimp freshness was studied. The results showed that addition of BAA made the components of the composite film interact with each other. BAA was well dispersed in the composite film, which significantly improved the mechanical properties of the composite film, and reduced its water content and UV transmittance. Furthermore, the color of BAA changed from red to yellow in the pH range of 1–14, which showed an obvious respond to pH. The composite film containing 15% BAA was sensitive to pH and thus could be used for monitoring shrimp freshness. On the 5th day of storage at 4 ℃, the total volatile basic nitrogen (TVB-N) content and pH of shrimp exceeded the spoilage threshold, indicating shrimp spoilage, and the color of the film changed from red to dark gray. Therefore, CS-SA composite films can be used as a good carrier for BAA to prepare an intelligent indicator film for shrimp freshness monitoring.

Summary: A high‐glycaemic index diet can lead to elevated blood glucose levels and chronic diseases. In this study, Dictyophora indusiata powder, oats powder and Polygonatum kingianum powder were substituted for some wheat flour to make pizza crust. The aim was to investigate the effects of the three powders on the chemical composition, physical quality, antioxidant properties, in vitro digestibility of starch and sensory characteristics of pizza crust. The addition of the three powders enhanced the nutritional value of the pizza crust, especially the dried Dictyophora indusiata flour and oats powder were rich in dietary fibre and protein, the three powders also increased the total phenolic content (214%) and antioxidant activity (ABTS+185%, DPPH30.5%) of the pizza crust and improved the shelf‐life of the pizza crust. In addition, the three powders increased the slowly digestible starch (25.9%) and decreased the reducing sugar levels and hydrogenation index, and expected glycaemic index of the pizza crust compared to the control group. The results suggest that the three powders could be used as functional ingredients to enhance the nutritional value and lower the glycaemic index of pizza crusts. This study provides new ideas for the development of nutritious and hypoglycaemic functional bakery products. [ABSTRACT FROM AUTHOR]

The aim of this study was to prepare a novel pH-sensitive smart film based on the addition of purple garlic peel extract (PGE) and TiO2 nanoparticles in a sodium alginate (SA)/polyvinyl alcohol (PVA) matrix to monitor the freshness of beef. FT-IR spectroscopy revealed the formation of stronger interaction forces between PVA/SA, PGE, and TiO2 nanoparticles, which showed good compatibility. In addition, the addition of PGE improved the tensile strength and elongation at break of the composite film, especially in different pH environments, and the color response was obvious. The addition of 1% TiO2 nanoparticles significantly improved the mechanical properties of the film, as well as the light barrier properties of the film. PGE could effectively be uniformly dispersed into the composite film, but it also had a certain slow-release effect on the release of PGE. PGE had high sensitivity under different pH conditions with rich color changes, and the color showed a clear color change from red to yellow-green when the pH increased from 1 to 14. The same change was observed when it was added to the film. In particular, by applying this film to the process of beef preservation, we judged the freshness of beef by monitoring the changes in the TVB-N value and pH value during the storage process of beef and found that the film showed obvious color changes during the storage process of beef, from blue (indicating freshness) to red (indicating non-freshness), and finally to yellow-green (indicating deterioration), which indicated that the color change of the film and the freshness of the beef maintained a highly consistent. [ABSTRACT FROM AUTHOR]

Smart film is widely used in the field of food packaging. The smart film was prepared by adding anthocyanin-rich Robusta coffee peel (RCP) extract into a chitosan (CS)–glycerol (GL) matrix by a solution-casting method. By changing the content of RCP (0, 10%, 15% and 20%) in the CS–GL film, the related performance indicators of CS–GL–RCP films were studied. The results showed that the CS–GL–RCP films had excellent mechanical properties, and CS–GL–RCP15 film maintained the tensile strength (TS) of 16.69 MPa and an elongation-at-break (EAB) of 18.68% with RCP extract. CS–GL–RCP films had the best UV-vis light barrier property at 200–350 nm and the UV transmittance was close to 0. The microstructure observation results showed that CS–GL–RCP films had a dense and uniform cross section, which proved that the RCP extract had good compatibility with the polymer. In addition, the CS–GL–RCP15 film was pH-sensitive and could exhibit different color changes with different pH solutions. So, the CS–GL–RCP15 film was used to detect the fermentation process of pickles at 20 ± 1 °C for 15 days. The pickles were stored in a round pickle container after the boiling water had cooled. The color of the CS–GL–RCP15 film changed significantly, which was consistent with the change of pickles from fresh to mature. The color of the smart film changed significantly with the maturity of pickles, and the difference of ΔE of film increased to 8.89 (15 Days), which can be seen by the naked eye. Therefore, CS–GL–RCP films prepared in this study provided a new strategy for the development of smart packaging materials. [ABSTRACT FROM AUTHOR]

Polylactic acid (PLA) is one of the most promising biodegradable materials, which can reduce the environmental pollution caused by food and material industry. The effect of the addition proportion of nano‐silver and different food simulant on the migration and the performance changes of film during migration were evaluated, revealing the association between the performance changes and nano‐silver migration. The results showed that nano‐silver had the largest migration amount and the fastest migration rate in 4% (v/v) acetic acid solution, followed by 50% (v/v) ethanol solution, and the lowest in isooctane solution. Performance changes were affected by the compatibility of silver nanoparticles and PLA, and the strength of the interaction between the film and acetic acid. Performances of composite film deteriorated during high proportions of nano‐silver addition and long soaking. Adding a small amount of nano‐silver to the composite was the effective method considering the balance between good performances and migration. [ABSTRACT FROM AUTHOR]

Summary: This work prepared a controlled release food packaging film by solvent volatilization using polylactic acid (PLA) and mesoporous silica nanoparticles (MSNs) loaded with clove essential oil (CEO). White button mushrooms were packaged with PLA and CEO‐loaded MSN PLA composite films to investigate postharvest qualities. The result indicated that PMC‐3 film improves the postharvest qualities of Agaricus bisporus, as reflected by lower weight loss (7.03%), higher total phenolics (2.29 g/kg), and ascorbic acid (27.1 mg/kg) compared with A. bisporus packaged with PLA film. In addition, PMC‐1, PMC‐2, and PMC‐3 treatment significantly improved the antioxidant system of A. bisporus, which inhibited the activity of polyphenol oxidase and peroxidase, as well as control the release of clove essential oil during the storage period. These findings suggest that PMC film is a promising method in postharvest preservation of A. bisporus. [ABSTRACT FROM AUTHOR]

The plant Sophora tonkinensis, possessed a range of active compounds, was traditionally used in the medicine of Chinese minorities. Endophytic fungi were isolated from this plant, of which the fungus Diaporthe sp. GDG-118 was fermented and extracted with methanol. The extract was screened by antifungal and antibacterial assays leading to the discovery of two new 21-acetoxycytochalasins (1–2) and five known cytochalasins (3–7). These two new compounds were elucidated by spectroscopic analyses, and further their absolute configurations were determined by the X-ray of compound 3 and comparing their experimental CD spectra. The antibacterial and antifungal effects of these compounds were evaluated. Compound 2 showed significant inhibitory activity against Bacillus anthraci and Escherichia coli with MIC value of 12.5 μg/mL, and 7 showed strong antifungal activity against Alternaria oleracea, Pestalotiopsis theae and Colletotrichum capsici with MIC values of 3.125, 1.56 and 1.56 μg/mL, respectively. [ABSTRACT FROM AUTHOR]

BACKGROUND: Our living environment is being increasingly polluted by petroleum‐based plastics and there is an increasing demand for biodegradable food packaging. In this study, the effect of various ultrahigh‐pressure (UHP) treatments (0, 200 and 400 MPa) on the microstructure and thermal, barrier and mechanical properties of poly(lactic acid) (PLA)/ZnO nanocomposite films was studied. RESULTS: The film‐forming solution was processed using UHP technology. The crystallinity, strength and stiffness of the composite film after UHP treatment increased. In addition, barrier property analysis showed that the UHP treatment significantly (P < 0.05) reduced the oxygen permeability and water vapor permeability (WVP) coefficient of the PLA/ZnO nanocomposite film. Furthermore, the WVP value of the film treated at 400 MPa (50 g kg−1 nano‐ZnO content) was the lowest and reduced by 47.3% compared with that of pure PLA film. The improvement in these properties might be due to the interaction between nano‐ZnO and PLA matrix promoted by UHP treatment. CONCLUSIONS: Therefore, the application of UHP technology on the film‐forming solution could improve the crystallinity and functional properties of the nanocomposite film, and has great potential in the production of food packaging films with ideal functions. © 2021 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Summary: This work aimed to prepare a controlled‐release antibacterial food packaging film by solvent volatilisation using chitosan (CS) and acidified modified montmorillonite (MMt) loaded with CIN (acid‐MMt‐CIN). MMt was successfully acidified and CIN was successfully loaded into acid‐MMt, which had been confirmed by X‐ray diffraction. The coordination of acid‐MMt‐CIN significantly increased the barrier properties of CS film to water vapour, as well as the rigidity and ductility of the film. Furthermore, the CS/acid‐MMt‐CIN film could significantly improve their UV resistance. It was found that the CIN release time of CS/acid‐MMt‐CIN film in isooctane (simulated fatty food) could reach 168 h, which was 72 h longer than that of CS/CIN film. The addition of acid‐MMt‐CIN had a significant inhibitory effect on Staphylococcus aureus and Escherichia coli. In short, CS/acid‐MMt‐CIN film could potentially be used as an antibacterial active food packaging film. [ABSTRACT FROM AUTHOR]

The use of biodegradable packaging films for post-harvest preservation of wild edible mushrooms is an eco-friendly method. In this study, the nanocomposite films were prepared based on poly (lactic acid) and mesoporous silica (2, 4 and 6 wt% based on polylactide) loaded with citral. The effects of nanocomposite film on the postharvest quality and specific spoilage bacteria of Russula virescens wild mushroom were evaluated. The results showed that firmness, weight loss, color, electrolyte leakage for Russula virescens treated with mesoporous silica loaded with citral based on poly (lactic acid) films were maintained compared to the control group. In particular, the 4% mesoporous silica loaded with citral group prolonged the freshness of mushroom by 6 days. Acinetobacter , Lactococcus, Weissella, Serratia, unclassified Enterobacteriaceae , and unclassified Gammaproteobacteria were identified as the main dominant bacteria. After 12 d of storage, the relative abundance of these bacterial for mushrooms packed by 4 wt% mesoporous silica loaded with citral based on poly (lactic acid) film was reduced, except Lactococcus. This revealed that the poly (lactic acid) film prepared by 4 wt% mesoporous silica loaded with citral could be used to extend the shelf life of Russula virescens. • The MSN/CIT/PLA film inhibited POD and PPO enzyme activities. • The MSN/CIT/PLA film retarded the browning of R. virescens wild mushroom. • The relative abundance of bacteria for MSN/CIT/PLA group was reduced. • The MSN/CIT/PLA film could extend the shelf life of R. virescens. • 4MSN/CIT/PLA film was the most effective in preserving freshness of R. virescens. [ABSTRACT FROM AUTHOR]

As a new type of packaging method, the anthocyanin-based pH-sensitive indicator film has gained much attention owing to low cost, small size, and visually informative property. In this study, an intelligent film based on chitosan/gelatin (CG) matrix with Zingiber striolatum Diels (ZSD) anthocyanin for fish freshness monitoring was developed. The film properties, including thickness, moisture content, color, mechanical properties, UV-vis light barrier property, as well as pH and ammonia sensitivity, were evaluated. The CG-ZSD films exhibited a more compact structure when compared with the CG film. The CG-ZSD20 film showed the highest elongation at break (6.33 ± 0.62%) and lowest tensile strength (20.0 ± 0.58 MPa). FTIR spectra revealed the strong hydrogen bond interactions between ZSD and polymer matrix. Film incorporated with 15% anthocyanin extract has increased melting temperature at 118.9 °C, and a lower weight loss (13.8%) at melting temperature. In pH 1-14 buffer, the color of CG-ZSD films underwent a significant change from red to yellow-green. The CG-ZSD15 film was utilized for monitoring fish freshness and showed visible color changes from deep purple to brown. The total volatile basic nitrogen content and pH value changes of fish were closely related to the visual color changes in film. This demonstrated that the film was a highly pH-sensitive film for quantifying fish freshness in real-time., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors. Published by Elsevier Ltd.)

Nine new highly oxygenated meroterpenoids, peniciacetals A-I (1-9), along with five known analogues (10-14) were isolated from the mangrove-derived fungus Penicillium sp. HLLG-122 based on the guidance of molecular networking and OSMAC approach. Peniciacetals A-B (1-2) were characterized with a unique 6/6/6/6/5 pentacyclic system possessing an unusual 4,6-dimethyl-2,5-dioxohexahydro-6-carboxy-4H-furo[2,3-b]pyran moiety. Peniciacetals C-D (3-4) possessed an uncommon 3,6-dimethyldihydro-4H-furo[2,3-b]pyran-2,5-dione unit with 6/6/6/5/6 fused pentacyclic skeleton. The structures and absolute configurations of new compounds were elucidated by HR-ESI-MS, 1D and 2D NMR spectroscopic data, X-ray diffraction analysis, and quantum chemical electronic circular dichroism (ECD) calculation. The plausible biosynthetic pathway of 1-9 were also proposed. Compound 14 showed good cytotoxicity against HepG2, MCF-7, HL-60, A549, HCT116 and H929 cell with IC 50 values of 6.6, 14.8, 3.2, 5.7, 6.9 and 3.0 μM, respectively. Further research showed that the compound 14 induced necrosis or late apoptosis contributes to the HL-60 cells toxicity., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)