Comprehensive properties of photodynamic antibacterial film based on κ-Carrageenan and curcumin-β-cyclodextrin complex

Reduction of biofilm and pathogenic microorganisms using curcumin-mediated photodynamic inactivation to prolong food shelf-life

Pathogenic microbial contamination (bacteria and fungi) in food products during production poses a significant global health risk, leading to food waste, greenhouse gas emissions, and aesthetic and financial losses. Bacteria and fungi, by forming solid biofilms, enhance their resistance to antimicrobial agents, thereby increasing the potential for cross-contamination of food products. Curcumin molecule-mediated photodynamic inactivation (Cur-m-PDI) technology has shown promising results in sterilizing microbial contaminants and their biofilms, significantly contributing to food preservation without compromising quality. Photosensitizers (curcumin) absorb light, leading to a chemical reaction with oxygen and producing reactive oxygen species (ROS) that effectively reduce bacteria, fungi, and biofilms. The mechanism of microorganism inhibition is caused by exposure to ROS generated via the type 1 pathway involving electron transfer (such as O2•-, H2O2, -OH•, and other radicals), the type 2 pathway involving energy transfer (such as 1O2), secondary ROS, and weakening of antioxidant enzymes. The effectiveness of the inactivation of microorganisms is influenced by the concentration of curcumin, light (source type and energy density), oxygen availability, and duration of exposure. This article reviews the mechanism of reducing microbial food contamination and inhibiting their biofilms through Cur-m-PDI. It also highlights future directions, challenges, and considerations related to the effects of ROS in oxidizing food, the toxicity of PDI to living cells and tissues, conditions/types of food products, and the stability and degradation of curcumin.

Advances in the preparation and application of cyclodextrin derivatives in food and the related fields

Cyclodextrin (CD) derivatives have recently gained worldwide attention, which have versatile advantages and restrained the defects of parent CDs. The superior properties of CD derivatives in encapsulation, stabilization, and solubilization facilitate their application in food, biomedicine, daily chemicals, and textiles. In this review, the preparation, classification, and main benefits of CD derivatives are systematically introduced. By introducing targeted groups into the parent CD molecule, they exhibit significant improvement in their required characteristic. Besides, the important point closely related to application, the safety assessment, has also been highlighted. Most tested CD derivatives have been verified to be relatively safe in a limited dosage. Then, the applications of CD derivatives have been described in detail from the food to its related field. In food field, CD derivatives play an important role in the stability and bioavailability of bioactive compounds, control flavor release, and improve the antimicrobial and antioxidant properties of packaging materials. These advantages can also be expanded to the related field, offering innovative solutions that enhance product quality, human health, and environmental sustainability. This review highlights the broad applications and potential of CD derivatives, underscoring their role in driving advancements across multiple industries.

Photodynamic inactivation of edible photosensitizers for fresh food preservation: Comprehensive mechanism of action and enhancement strategies

Foodborne harmful bacteria not only cause waste of fresh food, but also pose a major threat to human health. Among many new sterilization and preservation technologies, photodynamic inactivation (PDI) has the advantages of low-cost, broad-spectrum, energy-saving, nontoxic, and high efficiency. In particular, PDI based on edible photosensitizers (PSs) has a broader application prospect due to edible, accessible, and renewable features, it also can maximize the retention of the nutritional characteristics and sensory quality of the food. Therefore, it is meaningful and necessary to review edible PSs and edible PSs-mediated PDI, which can help to arouse interest and concern and promote the further development of edible PSs-mediated PDI in the future field of nonthermally sterilized food preservation. Herein, the classification and modification of edible PSs, PS-mediated in vivo and PS-mediated in vitro mechanism of PDI, strengthening strategy to improve PDI efficiency by the structure change synergistic and multitechnical means, as well as the application in fresh food preservation were reviewed systematically. Finally, the deficiency and possible future perspectives of edible PSs-mediated PDI were articulated. This review aimed to provide new perspective for the future food preservation and microbial control.

An antibacterial film using κ-carrageenan loaded with benzyl isothiocyanate nanoemulsion: Characterization and application in beef preservation

Benzyl isothiocyanate (BITC) is a naturally active bacteriostatic substance and κ-carrageenan (KC) is a good film-forming substrate. In the present study, a nanoemulsion incorporating BITC was fabricated with a particle size of 224.1 nm and an encapsulation efficiency of 69.2 %. Subsequently, the acquired BITC nanoemulsion (BITC-NE) was incorporated into the KC-based film, and the light transmittance of the prepared composite films was lower than that of the pure KC film. Fourier transform infrared spectroscopy and scanning electron microscopy revealed that BITC-NE was compatible with the KC matrix. BITC-NE incorporation enhanced the tensile strength of the KC-based films by 33.7 %, decreased the elongation at break by 33.8 %, decreased the water vapor permeability by 60.1 %, increased the maximum thermal degradation temperature by 48.8 %, and decreased the oxygen permeability by 42 % (p < 0.05). Furthermore, the composite films showed enhanced antimicrobial activity against Staphylococcus aureus, Salmonella typhimurium, and Pseudomonas fluorescens. The developed KC-based composite films were applied to wrap raw beef, which significantly delayed the increase in total viable count, total volatile base nitrogen content, and thiobarbituric acid reactive substances, and prolonged the shelf-life of the raw beef by up to 10 days. These results indicated that the composite films prepared by incorporating BITC nanoemulsions into KC matrices have great antimicrobial application potential.

Synthesis and application of gelatin-based controlled-release antibacterial films containing oregano essential oil/β-cyclodextrin microcapsules for chilling preservation of grass carp fillets

This work aimed to synthesize oregano essential oil/β-cyclodextrin microcapsules (OEO/β-CDs) and then prepare gelatin-based controlled-release antibacterial films with different OEO/β-CDs contents (0%-2%) for chilling preservation of grass carp fillets. The results of FTIR, XRD, DSC and accelerated release ratio showed that OEO was successfully encapsulated in OEO/β-CDs and its thermal stability was effectively improved. Moreover, at 2% of addition amount of OEO/β-CDs, the tensile strength of the films increased from 14.43 MPa to 18.72 MPa. In addition, the films showed significant antibacterial activity against Pseudomonas (61.52%), Aeromonas (62.87%), and Shewanella putrefaciens (66.67%). Preservation experiments showed that the films effectively prevented the increase of TVB-N, and TBA value of the refrigerated fillets and significantly suppressed the growth of spoilage organisms, thus extending the shelf life by 2-3 days. Therefore, the synthesized film has promising potential as an active packaging material for the preservation of grass carp.

Preparation of chitosan photodynamic antibacterial film loaded with VK3 complex in the preservation of chilled mutton

To effectively utilize the photodynamic antibacterial ability of vitamin K3 (VK3), by solving the photothermal instability of VK3, it was combined with natural polymers to apply the preservation of chilled mutton. We encapsulated VK3 in the (2-Hydroxypropyl)-β-cyclodextrin (HP-β-CD) to construct VK3-HP-β-CD complex and then introduced the complex to chitosan (CS) and polyvinyl alcohol (PVA) to fabricate an antibacterial film (CS/PVA-VK3-HP-β-CD film). Through the packaging performance test of the film, the content of VK3-HP-β-CD was an important factor determining the properties of film including tensile strength, elongation at break, water vapor permeability, water content and water contact angle. Meanwhile, CS/PVA-VK3-HP-β-CD films could continuously release ROS under light and suspended in dark, thus realizing >99 % antibacterial rate for Escherichia coli and Staphylococcus aureus. In the application experiment of chilled mutton, CS/PVA-VK3-1-HP-β-CD film could significantly inhibit the increase of total viable count (TVC), pH value (pH) and total volatile base nitrogen (TVB-N) of chilled mutton, and extended its shelf life for at least 12 days. These results indicated that the CS/PVA film with the VK3-HP-β-CD complex might have promising potential as an antibacterial material for packaging and preserving food.

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.

Herbal Products-Powered Thermosensitive Hydrogel with Phototherapy and Microenvironment Reconstruction for Accelerating Multidrug-Resistant Bacteria-Infected Wound Healing

Wound healing and infection remain significant challenges due to the ineffectiveness against multidrug-resistant (MDR) bacteria and the complex oxidative wound microenvironments. To address these issues, thymoquinone-reinforced injectable and thermosensitive TQ@PEG-PAF-Cur hydrogels with dual functions of microenvironment reshaping and photodynamic therapy are developed. The hydrogel comprises natural compound thymoquinone (TQ) and poly (ethylene glycol)-block-poly (alanine-co-phenyl alanine) copolymers (PEG-PAF) conjugated with natural photosensitizer curcumin (Cur). The incorporation of TQ and Cur reduces the sol-to-gel transition temperature of TQ@PEG-PAF-Cur to 30°C, compared to PEG-PAF hydrogel (37°C), due to the formation of strong hydrogen bonding, matching the wound microenvironment temperature. Under blue light excitation, TQ@PEG-PAF-Cur generates significant amounts of reactive oxygen species such as H2O2, 1O2, and ·OH, exhibiting rapid and efficient bactericidal capacities against methicillin-resistant Staphylococcus aureus and broad spectrum β-lactamases Escherichia coli via photodynamic therapy (PDT). Additionally, Cur effectively inhibits the expressions of proinflammatory cytokines in skin tissue-forming cells. As a result, the composite hydrogel can rapidly transform into a gel to cover the wound, reshape the wound microenvironment, and accelerate wound healing in vivo. This collaborative antibacterial strategy provides valuable insights to guide the development of multifunctional materials for efficient wound healing.

Carrageenan/polyvinyl alcohol composite film reinforced with spermidine carbon dots: An active packaging material with dual-mode antibacterial activity

Exploring biopolymer-based antibacterial packaging materials is promising to tackle the issues caused by petroleum plastic pollution and microbial contamination. Herein, a novel packaging material with two antibacterial modes, continuous and efficient, is constructed by dispersing positively charged spermidine carbon dots (Spd-CDs) in a carrageenan/polyvinyl alcohol (CP) composite biopolymer. The obtained nanocomposite film (CP/CDs film) not only gradually releases the ultra-small Spd-CDs but also rapidly generates reactive oxygen species to inhibit the reproduction of E. coli and S. aureus. Benefiting from the complementary advantages of carrageenan and polyvinyl alcohol, as well as the addition of Spd-CDs, the CP/CDs films exhibit high transparency, good mechanical performance, water vapor barrier ability, low migration, etc. The CP/CDs film as a packaging material is validated to be effective in preventing microbial contamination of pork samples. Our prepared nanocomposite film with sustainability and efficient antibacterial properties is expected as food active packaging.

Fabrication of zein-tamarind seed polysaccharide-curcumin nanocomplexes: their characterization and impact on alleviating colitis and gut microbiota dysbiosis in mice

In this work, a zein-tamarind seed polysaccharide (TSP) co-delivery system was fabricated using an anti-solvent precipitation method. The formation mechanism, characterization, and effect on alleviating colitis and gut microbiota dysbiosis in mice of zein-TSP-curcumin (Z/T-Cur) nanocomplexes were investigated. Hydrogen bonding and the hydrophobic effect played a key role in the formation of Z/T-Cur nanocomplexes, and the interactions were spontaneous and driven by enthalpy. The encapsulation efficiency, loading capacity, and bioavailability increased from 60.8% (Zein-Cur) to 91.7% (Z/T-Cur1:1), from 6.1% (Zein-Cur) to 18.3% (Z/T-Cur1:1), and from 4.7% (Zein-Cur) to 20.0% (Z/T-Cur1:1), respectively. The Z/T-Cur significantly alleviated colitis symptoms in DSS-treated mice. Additionally, the prepared nanocomplexes rebalanced the gut microbiota composition of colitis mice by increasing the abundance of Akkermansia. Odoribacter and Monoglobus were rich in the Z-T-Cur treatment group, and Turicibacter and Bifidobacterium were rich in the zein-TSP treatment group. This study demonstrated that the TSP could be helpful in the targeted drug delivery system.

Gelatin/carboxymethylcellulose composite film combined with photodynamic antibacterial: New prospect for fruit preservation

Plastic packaging causes environmental pollution, and the development of simple and effective biodegradable active packaging remains a challenge. In this study, gelatin (G) and sodium carboxymethylcellulose (CMC) were used as film materials, with the addition of curcumin (Cur), a photosensitive substance, to investigate the changes in the physical and chemical properties of the film and its application in fruit preservation. The results demonstrated that Cur was compatible with the film. With the addition of Cur, the thickness of the film increased up to 1.3 times, while the moisture content was reduced to 12.10 %. The tensile strength (TS) and elongation at break (EAB) of the film can reach 8.84 MPa and 19.33 %, respectively. The photodynamic antibacterial experiment revealed that the film containing 0.5 % Cur exhibited the highest antibacterial rate, reaching 99.99 % against Staphylococcus aureus (S. aureus) and 95 % against Escherichia coli (E. coli). During storage, the grapes remained unspoiled for up to 9 days after being phototreated with the film and the microbial content of the skin was much lower than that of the control group. In addition, Cur provided antioxidant activity for the film, with a scavenging activity of 39.54 % against the 2,2-diphenyl-1-picrind radical (DPPH). Bananas exposed to the film-forming solution for a short period of time remained fresh for up to 6 days. During preservation, the weight of the treated bananas decreased more slowly than that of the control group. In addition, the activity of SOD on the 7th day was approximately 20 U/g higher than that of the control group, which helped to reduce oxidative stress during banana preservation. In summary, G-CMC/Cur film is an optional fruit-cling film that can be used in food packaging.

Fluorescence and pectinase double-triggered chitosan/pectin/calcium propionate/curcumin-β-cyclodextrin complex film for pork freshness monitoring and maintenance

An intelligent and active food packaging film based on chitosan (CS), pectin (P), calcium propionate (CP), and curcumin-β-cyclodextrin complex (Cur-β-CD) was prepared. The CS/P/CP/Cur-β-CD film exhibited improved hydrophobicity (74.78 ± 0.53°), water vapor (4.55 ± 0.16 × 10-11 g·(m·s·Pa)-1), and oxygen (1.50 ± 0.06 × 10-12 g·(m·s·Pa)-1) barrier properties, as well as antioxidant (72.34 ± 3.79 % for DPPH and 86.05 ± 0.14 % for ABTS) and antibacterial (79.41 ± 2.89 % for E. coli and 83.82 ± 3.96 % for S. aureus) activities. The release of CP and Cur could be triggered by pectinase, with their cumulative release reaching 92.62 ± 1.20 % and 42.24 ± 1.15 %, respectively. The CS/P/CP/Cur-β-CD film showed delayed alterations in surface color, pH value, total volatile bases nitrogen, total viable counts, thiobarbituric acid reactive substance, hardness, and springiness of pork. Additionally, the fluorescence intensity of the film gradually decreased. In conclusion, we have developed a pH-responsive film with pectinase-triggered release function, providing a new concept for the design of multi-signal responsive intelligent food packaging.

Antibacterial photodynamic properties of silver nanoparticles-loaded curcumin composite material in chitosan-based films

In order to cope with the increasingly severe food contamination and safety problems, a powerful sterilization of food packaging material is urgently needed. Chitosan (CS) has potential applications in food packaging due to its good film-forming properties, but its antibacterial activity is not sufficient to meet the needs in practical applications. Silver nanoparticles (AgNPs) have the problem of weak immediate antibacterial activity as a broad-spectrum antibacterial agent. Therefore, in this study, AgNPs@GA@Cur-POTS (AGCP) composite antibacterial system was prepared by combining AgNPs with antibacterial photodynamic therapy using gallic acid (GA) as a reducing agent, curcumin (Cur) as a photosensitizer and perfluorosilane (POTS) for surface modification. The results showed that AGCP could produce a large number of reactive oxygen species under blue light irradiation, killing >90 % of E. coli and S. aureus within 2 h. Subsequently, the composite film of CS loaded with AGCP (CS/AGCP) was prepared by the flow-delay method. The CS/AGCP composite film exhibited excellent barrier properties and antioxidant activity, while its antibacterial rates against E. coli and S. aureus reached 98.44 ± 1.27 % and 99.11 ± 0.24 %, respectively, while the OD630 values of the two groups of bacteria treated with it showed no significant increase in incubation for up to 132 h, exhibiting remarkable and sustained antibacterial effects. Taken together, this work will provide a new strategy for antibacterial food packaging.

Highly ammonia-responsive starch/PVA film with gas absorption system as the 'bridge' for visually spoilage monitoring of animal-derived food

In the context of food waste and human diseases caused by food pollution, color renderement intelligent packaging came into being. Improving its indicator stability and sensitivity is essential for application. On the basis of our previous work, corn starch/polyvinyl alcohol was used as the matrix, the synthesized zirconium-based UiO-66 and anthocyanin-loaded ovalbumin-carboxymethylcellulose nanocomposites were embedded in to stabilize anthocyanins and improve gas adsorption performance of film. The study found that incorporating appropriate amount of UiO-66 (3%) in films resulted in uniform distribution and formation of holes. Mechanical properties, water stability and barrier properties were significantly improved, and gas adsorption capacity increased by approximately 10 times. More crucially, films that incorporate UiO-66 can react more quickly and visibly to lower concentrations of ammonia gas. The color change of SP/OVA-CMC-ACNs/3% UiO-66 film was noticeable (from purple to gray and then to green) when applied to monitor freshness of shrimp and pork.

Design of cationic surfactant reinforced carrageenan waterproof composite films and applied as water induced electricity generator

Carrageenan (CR) is a renewable polysaccharide material for packaging application due to its good film-forming property, but its use can be limited by the water solubility. In this research, CR hydrogels were modified by quaternary ammonium surfactants with different length of hydrocarbon tails (n, 8≦n≦16) by adsorption method and waterproof films were obtained after drying. The composition and charge interaction of composite films was confirmed by FTIR. Both thermogravimetric analysis and energy dispersive spectrometer indicated that the surfactant ions replaced K+ to form complexes with CR. The X-ray diffraction revealed the decreased amorphous nature of composite films compared to neat CR film. Water-related physical properties, such as water content, weight percentage change after contact with water, water vapor transmission, and water contact angle were intimately related to n. When 8≦n≦14, the waterproof properties were enhanced with the increase of n. Meanwhile, the waterproof property of composite film was ascertained by the no leakage result in the boiling water packaging experiment. When n = 16, sandwich structure was found in the sectional micromorphology images, and water bag structure formed after immersed into water. By comparing the mechanical properties of the composite films in different condition, we found that quaternary ammonium surfactants improved significantly the tensile strength in water and increased elongation at break in dry state. The composite films can be used as water induced voltage generator for their polyelectrolyte nature. Benefiting from the high stability of the composite films in water, their water-induced voltage generation process had good recyclability. Due to the antimicrobial activity of the quaternary ammonium salts and the waterproof property, composite films were more stable and degraded more slowly than neat CR film in nature environment.

Development of curcumin-containing polyvinyl alcohol/chitosan active/intelligent films for preservation and monitoring of Schizothorax prenanti fillets freshness

Active/intelligent films for the preservation and monitoring of Schizothorax prenanti fillets freshness were prepared by combining curcumin (CUR) with polyvinyl alcohol/chitosan (PVA/CS) matrix. SEM images showed that the CUR with a maximum content of 1.5 % (w/w) was evenly distributed in the composite matrix. The addition of CUR did not affect the chemical structure of PVA/CS matrix, as confirmed by FTIR investigation. When 1.5 % (w/w) CUR was added, the water vapor barrier property, tensile strength and antioxidant activity of the composite film were the best, which were 5.38 ± 0.25 × 10-11 g/m·s·Pa, 62.05 ± 1.68 MPa and 85.50 ± 3.63 %, respectively. Water solubility of PVA/CS/CUR-1.5 % film was reduced by approximately 27 % compared to PVA/CS film. After adding CUR, the antibacterial properties of the composite film increased significantly. Although the addition of CUR reduced the biodegradability of PVA/CS film, the PVA/CS/CUR-1.5 % film degraded >60 % within 5 weeks. By measuring pH, weight loss, total volatile base‑nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARS), and total viable counts (TVC), the preservation effect of the composite films on the fish freshness was evaluated. The fish shelf life treated by PVA/CS/CUR-1.5 % film expanded from 3-6 days to 12-15 days at 4 °C. In addition, when PVA/CS/CUR-1.5 % film was used to monitor the fish freshness, it exhibited clear color fluctuations, from yellow to orange and to red, corresponding to first-grade freshness, second-grade freshness, and rottenness of the fish, respectively. As a result, the films can be successfully used for Schizothorax prenanti fillets preservation and deterioration monitoring.

Synergistic Antimicrobial Hybrid Bio-Surface Formed by Self-Assembled BSA Nanoarchitectures with Chitosan Oligosaccharide

Innovation in green, convenient, and sustainable antimicrobial packaging materials for food is an inevitable trend to address global food waste challenges caused by microbial contamination. In this study, we developed a biogenic, hydrophobic, and antimicrobial protein network coating for food packaging. Experimental results show that disulfide bond breakage can induce the self-assembly of bovine albumin (BSA) into protein networks driven by hydrophobic interactions, and chitosan oligosaccharide (COS) with antimicrobial activity can be stably bound in this network by electrostatic interactions. The inherent antimicrobial activity of COS and the numerous hydrophobic regions on the surface of the BSA-network give the BSA@COS-network significant in vitro antimicrobial ability. More importantly, the BSA@COS-network coating can prolong the onset of spoilage of strawberries in various packaging materials by nearly 3-fold in storage. This study shows how surface functionalization via protein self-assembly is integrated with the biological functioning of natural antibacterial activity for advanced food packaging applications.

Fabrication of BODIPY/polyvinyl alcohol/alkaline lignin antibacterial composite films for food packing

Foodborne pathogens seriously endanger people's health and cause significant economic losses. Therefore, it is of great significance to design potent packaging materials with the function of alleviating food spoiling and extending shelf life. Here, three BODIPY derivatives (named as N-BDPI, B-BDPI and P-BDPI) were synthesized by substituting the 8-position of BODIPY with naphthalene, biphenyl and pyridine groups, respectively, and their photophysical properties as well as antibacterial capacities were characterized. The results demonstrated that N-BDPI had the best singlet oxygen generation ability and could completely kill S. aureus under light irradiation with the minimum inhibitory concentration of only 50 nmol/L. In addition, 1.0% BDPI@PVA/AL composite film was fabricated by doping N-BDPI into polyvinyl alcohol (PVA) and alkaline lignin (AL) exhibited high antibacterial activity on Gram-positive bacteria. The coating of strawberries with 1.0% BDPI@PVA/AL film not only effectively inhibited the mildew of strawberries, but also extended their shelf life.

Effective Preservation of Chilled Pork Using Photodynamic Antibacterial Film Based on Curcumin-β-Cyclodextrin Complex

A biodegradable photodynamic antibacterial film (PS-CF) was prepared using the casting method, with κ-Carrageenan (κ-Car) as the film-forming substrate and curcumin-β-cyclodextrin (Cur-β-CD) complex as photosensitizer. Chilled pork samples were coated with PS-CF and stored at 4 °C to investigate the effects of PS-CF combined with LED light irradiation (425 nm, 45 min) (PS+L+) on pork preservation during 10 days of storage. The total viable count (TVC) of bacteria, total volatile basic nitrogen value (TVB-N) and the pH of pork treated with PS+L+ were all lower than the control, and the water-holding capacity (WHC) was higher. Ten days later, the TVB-N value was 12.35 ± 0.57 mg/100 g and the TVC value was 5.78 ± 0.17 log CFU/g, which was within the acceptable range. Sensory evaluation determined that the color, odor, and overall acceptability of pork treated with PS+L+ were significantly better than the control. These findings suggest that PS+L+ treatment effectively extended the shelf life of chilled pork from ~4-5 to 10 days. Correlation analysis showed that the sensory quality of the chilled pork significantly correlated with total bacterial counts, TVB-N and thiobarbituric acid reactive substances (TBARS) (p < 0.05), suggesting that these biomarkers could be used as standard indicators for evaluating the freshness of chilled pork. These findings demonstrate the effectiveness of Cur-β-CD photodynamic antibacterial film for the preservation of chilled pork and provide a theoretical basis for the application of the film for the preservation of fresh food in general.

Preparation and Characterization of Biodegradable κ-Carrageenan Based Anti-Bacterial Film Functionalized with Wells-Dawson Polyoxometalate

In the present study, an anti-bacterial film (Carr/POM film) was prepared through the incorporation of Wells-Dawson polyoxometalate K₆[Mo₁₈O₆₂P₂] into κ-carrageenan-based polymers using the tape-casting method. The mechanical properties, thermal stability, and morphology of the prepared film were characterized. The obtained results showed that incorporation of K₆[Mo₁₈O₆₂P₂] significantly affected the morphology and structure of the films. Moreover, the polyoxometalate-based film demonstrated desirable bactericidal activity against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive). Carr/POM (@8 mg/mL) film resulted in an obvious inhibition zone around the film in Kirby-Bauer disk diffusion test, which could also remove 99% of S. aureus and E. coli on plastic, glass, and stainless steel. In addition, this anti-bacterial film also demonstrated good biodegradability, which could be decomposed in soil in around 1 week. In conclusion, the polyoxometalate-based film showed good anti-bacterial property against food-borne pathogenic microbes, suggesting the prepared film has great potential to be developed as promising food packaging.

Complexation of curcumin with cyclodextrins adjusts its binding to plasma proteins

Curcumin shows poor bioaccessibility due to its poor water solubility that limiting its application in aqueous formulations, and the weak binding to plasma proteins that hindering its transportation to targeted...