The thermal stress of the quartz oscillator module packaging isinvestigated using digital-im- age correlation method (DICM), and theexperimental results are given. Under the quartz oscillator modulepackaging, the quar...The thermal stress of the quartz oscillator module packaging isinvestigated using digital-im- age correlation method (DICM), and theexperimental results are given. Under the quartz oscillator modulepackaging, the quartz oscillator and the Fe-Sn-Cu alloy frame arejoined together with the electroconductive adhesive (PI), and theelectroconductive adhesive needs to be cured twice at 150 deg. C and275 deg. C respective- ly.展开更多
A procedure for preparing a nanofluid that a solid-liquid composite material consists of solid nanoparticles with sizes typically of 1-100 nm suspended in liquid was proposed. By means of the procedure, Cu-H2O nanoflu...A procedure for preparing a nanofluid that a solid-liquid composite material consists of solid nanoparticles with sizes typically of 1-100 nm suspended in liquid was proposed. By means of the procedure, Cu-H2O nanofluids with and without dispersant were prepared, whose sediment pho-tographs and particle size distribution were given to illustrate the stability and evenness of suspension with dispersant. The viscosity of Cu-H2O nanofluid was measured using capillary viscometers. The mass fractions（w） of copper nanoparticles in the experiment varied between 0.04% and 0.16% with the temperature range of 30-70 ℃. The experimental results show that the temperature and SDBS concentration are the major factors affecting the viscosity of the nano-copper suspensions, while the effect of the mass fraction of Cu on the viscosity is not as obvious as that of the temperature and SDBS dispersant for the mass fraction chosen in the experiment. The apparent viscosity of the copper nano-suspensions decreases with the temperature increase, and increases slightly with the increase of the mass fraction of SDBS dispersant, and almost keeps invariability with increasing the mass fraction of Cu. The influence of SDBS concentration on the viscosity of nano-suspension was relatively large comparing with that of the nanoparticle concentration.展开更多
Three kinds of novel aromatic diamine-based benzoxazines containing naphthalene, propane-2,2-diyldibenzene and neopentyl groups in the backbone, respectively （designated as BAPNCP, BAPBACP and BAPNPGCP, respectively...Three kinds of novel aromatic diamine-based benzoxazines containing naphthalene, propane-2,2-diyldibenzene and neopentyl groups in the backbone, respectively （designated as BAPNCP, BAPBACP and BAPNPGCP, respectively）, were synthesized and characterized. In addition, the effects of backbone structures on curing behaviors of the monomers and thermal and flammability properties of the resulting polymers were systematically studied. The results indicated that BAPNPGCP displayed the highest enthalpy of the curing reaction associated with the ring-opening of benzoxazine, which was due to the effect of benzoxazine ring content per unit mass. Interestingly, the 5 wt% weight loss temperature and char residue after thermogravimetric test for poly（BAPNPGCP） were 8 ℃ and 7% higher than those of poly（BAPBACP）. Meanwhile, the total heat release of poly（BAPNPGCP） was less than half of that for poly（BAPBACP）, indicating the substantial effect of benzoxazine ring content on flammability and char formation. Furthermore, it was found that poly（BAPNCP） gave the best thermal stability and flame retardancy, which was due to the synergistic effect between naphthalene group and benzoxazine ring content. This study provides new insight into the curing behavior of benzoxazine and further understanding on the high performance of polybenzoxazine.展开更多
Titanium dioxide (TiO2) nano-particle is widely used in composite materials to its improved mechanical properties.TiO2 nano-particle was used in the composite material that consists of palm oil sludge from the palm oi...Titanium dioxide (TiO2) nano-particle is widely used in composite materials to its improved mechanical properties.TiO2 nano-particle was used in the composite material that consists of palm oil sludge from the palm oil production and activated sludge cake from a papermaking process.TiO2 was synthesized by a hydrolysis of titanium isopropoxide.The parameter was investigated by the mole ratio of reactant to different solvents (isopropanol and isobutanol).The solution was prepared by adjusting pH to acid solution,resulting in different sizes and distributions of precipitate which was heated at different temperatures.The obtained samples were then morphologically and structurally characterized using X-ray diffraction (XRD) and particle size distribution (PSD).The experimental results show that the TiO2 sample from isopropanol solvent with heated temperature of 600 °C exhibits the best results.Consequently,different mass fractions of TiO2 (0,0.5%,1.0%,2.0%,4.0% and 8.0%) were used for specimens that were made from palm oil sludge mixed with activated sludge cake.All samples were later characterized by 3-point bending test and compression test.The results indicate that the adding 0.5% and 1.0% TiO2 particles to the composite material outperforms the other fractions in terms of enhancing mechanical properties.Nonetheless,mechanical properties tends to decrease when adding 2.0% TiO2.展开更多
Partially exfoliated nanocomposite （2） has been synthesized by intercalation of poly（propylene carbonate） （PPC） into commercial clay, Cloisite 20B （PPC/C-20B）. Nanocomposite 2 was characterized phiso-chemicall...Partially exfoliated nanocomposite （2） has been synthesized by intercalation of poly（propylene carbonate） （PPC） into commercial clay, Cloisite 20B （PPC/C-20B）. Nanocomposite 2 was characterized phiso-chemically and exhibited high thermal, mechanical and anti-water sorption properties as compared to PPC and intercalated nanocomposite （1） of PPC/C- 20B having same amount of clay. TGA results revealed that the thermal decomposition temperature （Td, 50%） of 2 increased significantly, being 40 K and 17 K higher than that of pure PPC and 1, respectively, while DSC measurements indicated that the nano-filler dispersion of 2 increased the glass transition temperature from 21℃ to 31℃. Accordingly, 2 showed high elastic modulus, hardness and anti-water absorption capacity. These thermal, mechanical alad anti-water absorption improvements are of great importance for the application of PPC as packaging and biomaterials.展开更多
Aiming at the dispersion stability of nanopartieles regarded as the guide of heat transfer enhancement, we investigate the viscosity and the thermal conductivity of Cu and Al2O3 nanoparticles in water under different ...Aiming at the dispersion stability of nanopartieles regarded as the guide of heat transfer enhancement, we investigate the viscosity and the thermal conductivity of Cu and Al2O3 nanoparticles in water under different pH values. The results show that there exists an optimal pH value for the lowest viscosity and the highest thermal conductivity, and that at the optimal pH value the nanofluids containing a small amount of nanoparticles have noticeably higher thermal conductivity than that of the base fluid without nanoparticles. For the two nanofluids the enhancements of thermal conductivity are observed up to 13% （Al2O3-water） or 15% （Cu-water） at 0.4 wt%, respectively. Therefore, adjusting the pH values is suggested to improve the stability and the thermal conductivity for practical applications of nanofluid.展开更多
Aiming at the dispersion stability of nanofluids,we investigate the absorbency and the zeta potential of TiO_(2) and Al2O3 nanofluids under different pH values and different dispersant concentrations.The results show ...Aiming at the dispersion stability of nanofluids,we investigate the absorbency and the zeta potential of TiO_(2) and Al2O3 nanofluids under different pH values and different dispersant concentrations.The results show that in the mass fraction 0.05%alumina and 0.01%titanium dioxide nanosuspensions,the absolute value of the zeta potential and the absorbency of the two nanofluids with sodium dodecyl sulfate(SDS)dispersant are the highest at an optimal pH(pHAl_(2)O_(3)≈6.0,pHTiO2≈9.5)and that there is a good correlation between absorbency and zeta potential:the higher the absolute value of the zeta potential is,the greater the absorbency is,and the better the stability of the system is.The optimizing concentrations for SDS are 0.10%and 0.14%,respectively,at which the two nanofluids have the best dispersion results.The calculated DLVO interparticle interaction potentials verify the experimental results of the pH effect on the stability behavior.展开更多
With the rapid increase in power density of electronic devices,thermal management has become urgent for the electronics industry.Controlling temperature in the back-end-of-line is crucial for maintaining the reliabili...With the rapid increase in power density of electronic devices,thermal management has become urgent for the electronics industry.Controlling temperature in the back-end-of-line is crucial for maintaining the reliability of integrated circuits,where many atomic-scale interfaces exist.The theoretical models of interface thermal conductance not only accurately predict the values but also help to analyze the underlying mechanism.This review picks up and introduces some representative theoretical models considering interfacial roughness,elastic and inelastic processes,and electron–phonon couplings,etc.Moreover,the limitations and problems of these models are also discussed.展开更多
Postharvest seafood mushroom(Hypsizygus marmoreus)is highly susceptible to rapid dehydration,decay,and softening,rendering single preservation technologies insufficient to effectively address these issues.This study i...Postharvest seafood mushroom(Hypsizygus marmoreus)is highly susceptible to rapid dehydration,decay,and softening,rendering single preservation technologies insufficient to effectively address these issues.This study investigated a complementary strategy by integrating a low-voltage electrostatic field(LVEF)with biodegradable poly(butylene adipate-co-terephthalate)/polylactic acid(PBAT/PLA)packaging to extend the mushroom's shelf life.Results showed that compared with conventional low-density polyethylene(LDPE),PBAT/PLA film effec-tively prevented moisture condensation and maintained lower CO_(2)concentrations.In contrast,LVEF treatment could suppress respiratory intensity,modulate relevant enzyme activity,and significantly mitigate excessive moisture loss caused by PBAT/PLA films.The findings indicated that the combined treatment effectively increased the mushrooms'antioxidant capacity,maintained cell membrane stability,sustained cell wall poly-saccharide levels,and preserved optimal appearance and texture during storage.The combined application of LVEF and PBAT/PLA packaging effectively preserved quality and extended the shelf life at 4℃from 6 to 15 days,offering a promising,eco-friendly strategy for preserving high-respiration edible fungi.展开更多
Maltol(MAL)and ethyl maltol(EMAL)are volatile flavor enhancers with antimicrobial properties,making them demonstrated candidates for bakery products.This study developed biodegradable films incorporating MAL and EMAL ...Maltol(MAL)and ethyl maltol(EMAL)are volatile flavor enhancers with antimicrobial properties,making them demonstrated candidates for bakery products.This study developed biodegradable films incorporating MAL and EMAL to enhance their antimicrobial function.Biodegradable films were produced via cast-extrusion by blending polybutylene adipate terephthalate(PBAT)with polybutylene succinate(PBS),incorporating MAL or EMAL at concentrations of 0,1.5,3,6,and 12%.Microstructures demonstrated good polymer compatibility and adhesion between the polymer and the MAL or EMAL,resulting in smooth,compact structures.Infrared absorption spectra indicated peak shifting in the C-H stretching region of the polyesters with added MAL and EMAL.This shift varied depending on the loading content and the recrystallization of MAL and EMAL,which caused phase separation from the polyester phase.The interactions between the polymer and volatile flavoring agents decreased oxygen permeability.Gas chromatography equipped with mass-spectrophotometry indicated a larger release of MAL than EMAL from PBAT/PBS matrix.Both MAL and EMAL exhibited antibacterial efficacy against Bacillus cereus,Staphylococcus aureus,and Escherichia coli,and delayed fungal growth(Aspergillus niger).However,EMAL had more antibacterial efficacy than MAL,while the MAL exhibited greater antifungal efficacy than EMAL.Moreover,the films containing MAL or EMAL effectively extended the shelf-life of packaged butter cake by more than 2-fold,with the effect increasing with loading content.The food industry will be significantly impacted by these results when it comes to improving packaging techniques to extend the shelf life of products and maintain quality.展开更多
Poly(lactic acid)(PLA)has limited promise as a bio-based antimicrobial packaging material due to its lack of plasticization,which limits antimicrobial agent release and antimicrobial efficiency.PLA were plasticized wi...Poly(lactic acid)(PLA)has limited promise as a bio-based antimicrobial packaging material due to its lack of plasticization,which limits antimicrobial agent release and antimicrobial efficiency.PLA were plasticized with polyethylene glycol(PEG)and blended with ethyl maltol or ethylenediaminetetraacetic acid(EDTA)as antibacterial agents by melt extrusion.The effects of combining PEG,EDTA,and ethyl maltol on sheet properties and antibacterial activity were investigated.Incorporation of ethyl maltol created a dense and smooth homogeneous surface,while EDTA addition caused large pores in the PLA sheet microstructure impacting swelling degree,water solubility and surface hydrophilicity.Fourier transform infrared(FTIR)spectroscopy and differential scanning calorimetry(DSC)showed that both ethyl maltol and EDTA addition modified the amorphous and crystalline phases of plasticized PLA.FTIR results suggested interaction between the functional groups of PLA chains,PEG,ethyl maltol or EDTA which affected the glass transition temperature(T_(g)),degree of crystallinity,and thermal stability of PLA.Adding PEG into PLA-EDTA enhanced antibacterial activity against Gram-positive Staphylococcus aureus(reduction of 1.35 log CFU/mL from the initial inoculum).The higher water solubility of sheets corresponded to a suitable release rate and sufficient amounts of antimicrobial compounds against Staphylococcus aureus.In vitro antifungal testing,PLA-PEG-EDTA sheets did not exhibit a clear zone of inhibition but delayed Penicillium sp.spore formation until day 5 of incubation.PEG plasticized PLA sheets functionalized with ethyl maltol and EDTA showed potential as active biomaterials against food-borne pathogen bacteria Staphylococcus aureus.展开更多
The market and the future trends of smart packaging show a tendency towards a continuous increase. Several reports have revealed about the increase of consumer concern for food quality and safety, which gives rise to ...The market and the future trends of smart packaging show a tendency towards a continuous increase. Several reports have revealed about the increase of consumer concern for food quality and safety, which gives rise to the demand of intelligent packaging. Nano-enabled food packaging has attracted considerable interest and driven a variety of potential applications in the intelligent packaging. The presence of nanomaterials as nanodevices or nanosensors has been recognized as a part of the modern intelligent packaging for monitoring the condition of packaged food or the environment surrounding the product. Among of nanosensors, optical indicator has been widely applied in the market due to the convenient and easy to use. The utilization of nanomaterial such as metal nanoparticles or photonic nanocrystals shows superior performance in novel communicative functions than the traditional colorimetric indicator because of their unique optical properties and high surface reactivity. This review focuses exclusively on ongoing scientific research and recent technological breakthroughs related to nanotechnology-derived colorimetric indicators. The challenges of their application are highlighted and discussed to provide adequate information for future development.展开更多
The average transient lifetime of a chaotic transient versus the Lyapunov dimension of a chaotic saddle is studied for high-dimensional nonlinear dynamical systems. Typically the average lifetime depends upon not only...The average transient lifetime of a chaotic transient versus the Lyapunov dimension of a chaotic saddle is studied for high-dimensional nonlinear dynamical systems. Typically the average lifetime depends upon not only the system parameter but also the Lyapunov dimension of the chaotic saddle. The numerical example uses the delayed feedback differential equation.展开更多
Enhancing the antimicrobial functions of biodegradable polyesters facilitates the utilization of sustainable food packaging.Poly(butylene succinate)(PBS)and polybutylene adipate terephthalate(PBAT)blends were compound...Enhancing the antimicrobial functions of biodegradable polyesters facilitates the utilization of sustainable food packaging.Poly(butylene succinate)(PBS)and polybutylene adipate terephthalate(PBAT)blends were compounded with zinc oxide(ZnO)nanoparticles(up to 4.5%)into a master batch via twin-screw extrusion.Biodegradable films were produced via cast extrusion,and the morphologies and packaging properties were determined.Adding ZnO nanoparticles up to 2.7% modified the film’s surface topography,causing non-homogeneity and voids.ZnO tended to form aggregates at higher loading,while phase separation of metal oxide from PBAT/PBS matrices occurred.Dispersion of ZnO nanoparticles reduced water vapor permeability,with the lowest effects on oxygen permeability.Adding ZnO in combination with the molecular orientation of the polymer effectively reinforced the matrices and improved the mechanical properties of PBAT/PBS blends.PBAT/PBS/ZnO films exhibited antimicrobial capacity against Escherichia coli and Bacillus cereus.PBAT/PBS with ZnO>2.7% delayed discoloration of red pigments in packaged minced pork due to efficient inhibition of microbial growth and UV blocking.ZnO-loaded polyester enhanced antimicrobial functions,producing sustainable active nanocomposite packaging.展开更多
Biodegradable polyester polymers including poly(butylene adipate-co-terephthalate)(PBAT)and poly(butylene succinate)(PBS)are used as sustainable and eco-friendly food packaging but poor water vapor barrier properties ...Biodegradable polyester polymers including poly(butylene adipate-co-terephthalate)(PBAT)and poly(butylene succinate)(PBS)are used as sustainable and eco-friendly food packaging but poor water vapor barrier properties limit their applications with moisture-sensitive products.This research blended PBAT/PBS materials at 60/40 and 50/50 with silicon dioxide(SiO2)nanoparticles as master batch pellets via twin-screw extrusion before sheet-casting to improve food packaging barrier properties.PBAT/PBS/SiO2 nanocomposite films were investigated by X-ray diffraction(XRD)and Fourier transform infrared(FTIR)spectroscopy and also for mechanical relaxation,microstructure,surface topography,and barrier properties.Scanning electron microscopy-energy dispersive X-ray analysis(SEM-EDX)indicated dispersed SiO2 nanoparticle aggregation in polymer matrices at higher loading.FTIR spectroscopy results suggested modified C--O stretching vibrations in polyesters,concurrent with shifting X-ray diffraction angles depending on nanoparticle content and polymer blend ratios.Adding SiO2 nanoparticles at up to 1% exponentially reduced water vapor permeability by up to 26%,while decreasing oxygen permeability(up to 8%).Mechanical properties reduced when adding SiO2 nanoparticles but film stretching improved polymer orientation at higher loading,thereby increasing tensile strength and elongation.Compounding SiO2 nanoparticles with PBAT/PBS polyester polymer blends enhanced barrier properties for biodegradable food packaging.展开更多
Packaging material has an important role in extending the shelf-life of fruits.This study investigated the effectiveness of cellulose nanocrystals(CNCs)derived from Kudzu(Pueraria montana)vine to reinforce to starch-b...Packaging material has an important role in extending the shelf-life of fruits.This study investigated the effectiveness of cellulose nanocrystals(CNCs)derived from Kudzu(Pueraria montana)vine to reinforce to starch-based films.In addition,the essential oil was incorporated into these nanocomposite films to evaluate further improvement in film properties and applications.Different packaging materials,including the pearl millet starch(PMS),PMS reinforced with Kudzu CNCs,and PMS reinforced with Kudzu CNCs stabilized pickering emulsion containing clove bud oil(CBO),was used to develop biodegradable nanocomposite films.The films were investigated for their thermal,morphological,mechanical,and barrier properties.In addition,the films were used as packaging material to improve the shelf life of the grapes for 15 days at 5℃.PMS films reinforced with Kudzu CNCs stabilized pickering emulsion of CBO were most effective in extending the shelf life of red grapes up to 15 days at 5℃ by maintaining the weight,firmness,and soluble solids in grapes for a longer duration during storage.The study suggests that PMS+Kudzu CNCs+EO films have the potential for commercial packaging of fruits during short storage periods without adversely affecting their quality and sensory attributes.展开更多
Leather is a collagen-based biomass prepared from raw skins or hides by a series of unit operations, in which the unhairing and fiber opening are extremely important operations. However, the conventional Na2S/Ca(OH)2 ...Leather is a collagen-based biomass prepared from raw skins or hides by a series of unit operations, in which the unhairing and fiber opening are extremely important operations. However, the conventional Na2S/Ca(OH)2 system used in unhairing and fiber opening has given rise to the pollution to the environment. It is necessary to develop substitute technology for the Na2S/Ca(OH)2. In the present study, 1-allyl-3-methylimidazolium chloride ([AMIm]Cl) was used to cooperate with dispase for cycle unhairing and one-pot beamhouse to recycle waste bovine hides and com-pared with conventional processing. During those processes, the mechanism of [AMIm]Cl-dispase synergistic unhair-ing and collagen fibers opening were studied. Besides, plant hazard, organic matter and [AMIm]Cl of wastewater from [AMIm]Cl-dispase process were respectively investigated and separated to evaluate the environmental and economic benefits of the [AMIm]Cl-dispase process. As a result, enzyme activity after unhairing by [AMIm]Cl-diapase system for using 5 times is higher than that by KCl-dispase system, and needs lower unhairing time, which is because of rapid penetration of [AMIm]Cl-dispase solution in bovine hides. For this reason, the tensile strength and elastic modulus of tanned leather from [AMIm]Cl-dispase process are higher than those from the KCl-diapase and conventional pro-cesses, and its hydrothermal shrinkage temperature is comparable to that of the conventional one. Because of the 58.13% lower wastewater discharge (WD), 66.60% lower total solids (TS), 97.23% lower ammonia nitrogen (NH3-N), non-toxic wastewater and organic matter recovery in wastewater are reached from [AMIm]Cl-dispase process, which is expected to be an alternative to the conventional process to reduce environmental pollution and realize the sustainable development of technology for leather manufacturing.展开更多
Ylang-ylang(Cananga odorata)essential oils(EO)has several active components with flora odorants which are compatible with several foods and desserts.Incorporation of Ylang-ylang EO into biodegradable polymers potentia...Ylang-ylang(Cananga odorata)essential oils(EO)has several active components with flora odorants which are compatible with several foods and desserts.Incorporation of Ylang-ylang EO into biodegradable polymers potentially produce functional packaging,releasing desirable aroma which is attractive to consumers.This research aimed to enhance active function of biodegradable polyester blend films namely polybutylene adipateco-terephthalate(PBAT)and polybutylene succinate(PBS)using cast extrusion with Ylang-ylang EO.Characterizations of the film include morphology,relaxation,infrared absorption and packaging properties.Adding EO gave a smoother microstructure and surface topography and modified the crystal lattice of the PBS phase.Infrared absorption indicated EO-polymer interaction involving C-H stretching vibration.Polymer relaxation influenced transport of gas molecules through PBAT/PBS/EO matrices.Decreasedα-relaxation temperature suggested plasticization effects of the amorphous PBAT phase by EO,increasing oxygen and water vapor permeability by 2.52 and 1.16 times,respectively.Polymer relaxation and crystallinity influenced transport of non-polar oxygen through PBAT/PBS/EO matrices.Moreover,films containing EO effectively delayed fungal growth in pandan pudding and layered pudding by more than 3 days due to the release of volatiles that exhibited antifungal activities.Findings suggested potential of Ylang-ylang EO incorporated biodegradable films to produce active packaging for aroma release,extending product shelf-life.展开更多
Novel nanocomposite poly(butylene adipate-co-terephthalate)(PBAT)/polybutylene succinate(PBS)blend films functionalized with titanium dioxide(TiO_(2))nanoparticles(0,0.9,1.8,2.7,3.6 and 4.5%w/w)were produced using cas...Novel nanocomposite poly(butylene adipate-co-terephthalate)(PBAT)/polybutylene succinate(PBS)blend films functionalized with titanium dioxide(TiO_(2))nanoparticles(0,0.9,1.8,2.7,3.6 and 4.5%w/w)were produced using cast-sheet extrusion.Atomic force microscopy,X-ray diffraction(XRD),Fourier-transform infrared spectroscopy(FTIR)and dynamic mechanical thermal analysis were used to investigate film morphology and structure.The crystallinity of the films was modified due to interactions between the nanoparticles and the PBAT/PBS blends,as confirmed by FTIR and XRD.Tensile strength and elongation of films slightly reduced with TiO_(2)addition up to 4.5%in both machine direction(MD)and cross direction(CD).The tensile strength of the T5 films was nearly 25%less than the control films.Adding TiO_(2)gave excellent UV-blocking properties with slightly reduced water vapor by 16.5%and oxygen permeability by 4%for films with maximum loading.The film surface became more hydrophilic,as evidenced by the reduced contact angle.The results,as acquired from turbidity measurements,show that films with 3.6%TiO_(2)loading and above have high antimicrobial activity against both Bacillus cereus(Gram-positive)and Escherichia coli(Gram-negative).The relative area of microbial growth on agar media exhibited better antibacterial capacity against Escherichia coli than Bacillus cereus,with a sharp reduction of microbial growth at TiO_(2)contents above 2.7%.Films containing TiO_(2)(≥0.9%)effectively delayed ripening and increased peel yellowness of packaged bananas during storage for 6 days at room temperature.The developed PBAT/PBS/TiO_(2)nanocomposites films hence showed enhanced UV-resistance and antimicrobial properties,while maintaining adequate mechanical strength necessary for food packaging.The film is an eco-friendly alternative antimicrobial food packaging to extend the shelf-life of fresh produce.展开更多
Plasma-activated water(PAW)is increasingly recognized for its role in mitigating microbial contamination in fresh-cut produce,but its disinfection effectiveness can be limited under certain conditions.Notably,dissolvi...Plasma-activated water(PAW)is increasingly recognized for its role in mitigating microbial contamination in fresh-cut produce,but its disinfection effectiveness can be limited under certain conditions.Notably,dissolving organic acids in PAW is an effective way to boost its antimicrobial properties through a synergistic effect.This study examined the enhanced antimicrobial efficacy of PAW when combined with tartaric acid against Staphylococcus aureus and its application on fresh-cut asparagus lettuce.Results demonstrated that PAW combined with tartaric acid showed stronger antimicrobial efficacy than PAW alone(p<0.05).The addition of tartaric acid to PAW increased the oxidation-reduction potential and lowered the pH,contributing to its superior antimicrobial performance against S.aureus.The underlying antimicrobial mechanisms included the inactivation of Ca^(2+)-Mg^(2+)-ATPase and Na^(+)-K^(+)-ATPase accompanied by damage to bacterial cell membrane,enhanced oxidative damage due to the influx of extracellular reactive oxygen species such as H_(2)O_(2),the disrupted energy metabolic activities,and the mitigated bacterial defense system constructed by antioxidant enzymes,such as superoxide dismutase and catalase.Furthermore,the synergistic treatment improved the quality of fresh-cut asparagus lettuce by retarding browning,curbing microbial spoilage,and lessening weight loss.The preservation of color was largely due to the decreased activities of polyphenol oxidase and peroxidase,along with controlled chlorophyll degradation.These findings suggest that PAW enhanced with tartaric acid could be a promising,cost-effective disinfection strategy for fresh-cut asparagus lettuce.展开更多
基金the Natural Science Foundation of Tianjin (013605211)
文摘The thermal stress of the quartz oscillator module packaging isinvestigated using digital-im- age correlation method (DICM), and theexperimental results are given. Under the quartz oscillator modulepackaging, the quartz oscillator and the Fe-Sn-Cu alloy frame arejoined together with the electroconductive adhesive (PI), and theelectroconductive adhesive needs to be cured twice at 150 deg. C and275 deg. C respective- ly.
基金Funded by Guangdong Provincial Natural Science Foundation (No. 04105950)Specialized Research Fund for the Doctoral Program of Higher Education (No. 20050561017)Program for New Century Excellent Talents in University (No. NCET-04-0826)
文摘A procedure for preparing a nanofluid that a solid-liquid composite material consists of solid nanoparticles with sizes typically of 1-100 nm suspended in liquid was proposed. By means of the procedure, Cu-H2O nanofluids with and without dispersant were prepared, whose sediment pho-tographs and particle size distribution were given to illustrate the stability and evenness of suspension with dispersant. The viscosity of Cu-H2O nanofluid was measured using capillary viscometers. The mass fractions（w） of copper nanoparticles in the experiment varied between 0.04% and 0.16% with the temperature range of 30-70 ℃. The experimental results show that the temperature and SDBS concentration are the major factors affecting the viscosity of the nano-copper suspensions, while the effect of the mass fraction of Cu on the viscosity is not as obvious as that of the temperature and SDBS dispersant for the mass fraction chosen in the experiment. The apparent viscosity of the copper nano-suspensions decreases with the temperature increase, and increases slightly with the increase of the mass fraction of SDBS dispersant, and almost keeps invariability with increasing the mass fraction of Cu. The influence of SDBS concentration on the viscosity of nano-suspension was relatively large comparing with that of the nanoparticle concentration.
基金supported by the National Natural Science Foundation of China(No.51103129)the National Basic Research Program of China("973 Program",No.2010CB631105)+1 种基金the Ningbo Natural Science Foundation(No.2012A610084)the Open Fund of Zhejiang Provincial Top Key Discipline of New Materials and Process Engineering(No.20110939)
文摘Three kinds of novel aromatic diamine-based benzoxazines containing naphthalene, propane-2,2-diyldibenzene and neopentyl groups in the backbone, respectively （designated as BAPNCP, BAPBACP and BAPNPGCP, respectively）, were synthesized and characterized. In addition, the effects of backbone structures on curing behaviors of the monomers and thermal and flammability properties of the resulting polymers were systematically studied. The results indicated that BAPNPGCP displayed the highest enthalpy of the curing reaction associated with the ring-opening of benzoxazine, which was due to the effect of benzoxazine ring content per unit mass. Interestingly, the 5 wt% weight loss temperature and char residue after thermogravimetric test for poly（BAPNPGCP） were 8 ℃ and 7% higher than those of poly（BAPBACP）. Meanwhile, the total heat release of poly（BAPNPGCP） was less than half of that for poly（BAPBACP）, indicating the substantial effect of benzoxazine ring content on flammability and char formation. Furthermore, it was found that poly（BAPNCP） gave the best thermal stability and flame retardancy, which was due to the synergistic effect between naphthalene group and benzoxazine ring content. This study provides new insight into the curing behavior of benzoxazine and further understanding on the high performance of polybenzoxazine.
基金the Graduate School Kasetsart Universitythe Office of the National Research Council of Thailand for their financial support under a research plan "Increase the value through the production of agriculture"
文摘Titanium dioxide (TiO2) nano-particle is widely used in composite materials to its improved mechanical properties.TiO2 nano-particle was used in the composite material that consists of palm oil sludge from the palm oil production and activated sludge cake from a papermaking process.TiO2 was synthesized by a hydrolysis of titanium isopropoxide.The parameter was investigated by the mole ratio of reactant to different solvents (isopropanol and isobutanol).The solution was prepared by adjusting pH to acid solution,resulting in different sizes and distributions of precipitate which was heated at different temperatures.The obtained samples were then morphologically and structurally characterized using X-ray diffraction (XRD) and particle size distribution (PSD).The experimental results show that the TiO2 sample from isopropanol solvent with heated temperature of 600 °C exhibits the best results.Consequently,different mass fractions of TiO2 (0,0.5%,1.0%,2.0%,4.0% and 8.0%) were used for specimens that were made from palm oil sludge mixed with activated sludge cake.All samples were later characterized by 3-point bending test and compression test.The results indicate that the adding 0.5% and 1.0% TiO2 particles to the composite material outperforms the other fractions in terms of enhancing mechanical properties.Nonetheless,mechanical properties tends to decrease when adding 2.0% TiO2.
基金financially supported by the National Research Foundation of Korea Grant funded by the Korean Government(MEST)(NRF-2009-C1AAA001-2009-0092926)the National Research Foundation of Korea(NRF) grant funded by the Korea government(MEST)(No.2011-0016750)
文摘Partially exfoliated nanocomposite （2） has been synthesized by intercalation of poly（propylene carbonate） （PPC） into commercial clay, Cloisite 20B （PPC/C-20B）. Nanocomposite 2 was characterized phiso-chemically and exhibited high thermal, mechanical and anti-water sorption properties as compared to PPC and intercalated nanocomposite （1） of PPC/C- 20B having same amount of clay. TGA results revealed that the thermal decomposition temperature （Td, 50%） of 2 increased significantly, being 40 K and 17 K higher than that of pure PPC and 1, respectively, while DSC measurements indicated that the nano-filler dispersion of 2 increased the glass transition temperature from 21℃ to 31℃. Accordingly, 2 showed high elastic modulus, hardness and anti-water absorption capacity. These thermal, mechanical alad anti-water absorption improvements are of great importance for the application of PPC as packaging and biomaterials.
文摘Aiming at the dispersion stability of nanopartieles regarded as the guide of heat transfer enhancement, we investigate the viscosity and the thermal conductivity of Cu and Al2O3 nanoparticles in water under different pH values. The results show that there exists an optimal pH value for the lowest viscosity and the highest thermal conductivity, and that at the optimal pH value the nanofluids containing a small amount of nanoparticles have noticeably higher thermal conductivity than that of the base fluid without nanoparticles. For the two nanofluids the enhancements of thermal conductivity are observed up to 13% （Al2O3-water） or 15% （Cu-water） at 0.4 wt%, respectively. Therefore, adjusting the pH values is suggested to improve the stability and the thermal conductivity for practical applications of nanofluid.
基金by the National Natural Science Foundation of China under Grant No 11047021the Fund for Talent Introduction to Advanced Universities of Guangdong under Grant No 2009109and the Guangdong Natural Science Foundation under Grant No 10151064201000006.
文摘Aiming at the dispersion stability of nanofluids,we investigate the absorbency and the zeta potential of TiO_(2) and Al2O3 nanofluids under different pH values and different dispersant concentrations.The results show that in the mass fraction 0.05%alumina and 0.01%titanium dioxide nanosuspensions,the absolute value of the zeta potential and the absorbency of the two nanofluids with sodium dodecyl sulfate(SDS)dispersant are the highest at an optimal pH(pHAl_(2)O_(3)≈6.0,pHTiO2≈9.5)and that there is a good correlation between absorbency and zeta potential:the higher the absolute value of the zeta potential is,the greater the absorbency is,and the better the stability of the system is.The optimizing concentrations for SDS are 0.10%and 0.14%,respectively,at which the two nanofluids have the best dispersion results.The calculated DLVO interparticle interaction potentials verify the experimental results of the pH effect on the stability behavior.
基金supported by the Department of Packaging and Testing Institution of Sanechips。
文摘With the rapid increase in power density of electronic devices,thermal management has become urgent for the electronics industry.Controlling temperature in the back-end-of-line is crucial for maintaining the reliability of integrated circuits,where many atomic-scale interfaces exist.The theoretical models of interface thermal conductance not only accurately predict the values but also help to analyze the underlying mechanism.This review picks up and introduces some representative theoretical models considering interfacial roughness,elastic and inelastic processes,and electron–phonon couplings,etc.Moreover,the limitations and problems of these models are also discussed.
基金funded by the National Key Research and Development Program of China(2022YFA1203604 and 2023YFF1105200)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX24_2507).
文摘Postharvest seafood mushroom(Hypsizygus marmoreus)is highly susceptible to rapid dehydration,decay,and softening,rendering single preservation technologies insufficient to effectively address these issues.This study investigated a complementary strategy by integrating a low-voltage electrostatic field(LVEF)with biodegradable poly(butylene adipate-co-terephthalate)/polylactic acid(PBAT/PLA)packaging to extend the mushroom's shelf life.Results showed that compared with conventional low-density polyethylene(LDPE),PBAT/PLA film effec-tively prevented moisture condensation and maintained lower CO_(2)concentrations.In contrast,LVEF treatment could suppress respiratory intensity,modulate relevant enzyme activity,and significantly mitigate excessive moisture loss caused by PBAT/PLA films.The findings indicated that the combined treatment effectively increased the mushrooms'antioxidant capacity,maintained cell membrane stability,sustained cell wall poly-saccharide levels,and preserved optimal appearance and texture during storage.The combined application of LVEF and PBAT/PLA packaging effectively preserved quality and extended the shelf life at 4℃from 6 to 15 days,offering a promising,eco-friendly strategy for preserving high-respiration edible fungi.
基金supported by Kasetsart University Research and Development Institute(KURDI),Kasetsart University,Thailand,FF(KU)5.67Mettler-Toledo(Thailand)Ltd.,Thailand for the support of TGA/DSC3+.
文摘Maltol(MAL)and ethyl maltol(EMAL)are volatile flavor enhancers with antimicrobial properties,making them demonstrated candidates for bakery products.This study developed biodegradable films incorporating MAL and EMAL to enhance their antimicrobial function.Biodegradable films were produced via cast-extrusion by blending polybutylene adipate terephthalate(PBAT)with polybutylene succinate(PBS),incorporating MAL or EMAL at concentrations of 0,1.5,3,6,and 12%.Microstructures demonstrated good polymer compatibility and adhesion between the polymer and the MAL or EMAL,resulting in smooth,compact structures.Infrared absorption spectra indicated peak shifting in the C-H stretching region of the polyesters with added MAL and EMAL.This shift varied depending on the loading content and the recrystallization of MAL and EMAL,which caused phase separation from the polyester phase.The interactions between the polymer and volatile flavoring agents decreased oxygen permeability.Gas chromatography equipped with mass-spectrophotometry indicated a larger release of MAL than EMAL from PBAT/PBS matrix.Both MAL and EMAL exhibited antibacterial efficacy against Bacillus cereus,Staphylococcus aureus,and Escherichia coli,and delayed fungal growth(Aspergillus niger).However,EMAL had more antibacterial efficacy than MAL,while the MAL exhibited greater antifungal efficacy than EMAL.Moreover,the films containing MAL or EMAL effectively extended the shelf-life of packaged butter cake by more than 2-fold,with the effect increasing with loading content.The food industry will be significantly impacted by these results when it comes to improving packaging techniques to extend the shelf life of products and maintain quality.
基金supported by Kasetsart University Research and Development Institute(KURDI),Kasetsart University,Thailand,FF(KU)5.67.
文摘Poly(lactic acid)(PLA)has limited promise as a bio-based antimicrobial packaging material due to its lack of plasticization,which limits antimicrobial agent release and antimicrobial efficiency.PLA were plasticized with polyethylene glycol(PEG)and blended with ethyl maltol or ethylenediaminetetraacetic acid(EDTA)as antibacterial agents by melt extrusion.The effects of combining PEG,EDTA,and ethyl maltol on sheet properties and antibacterial activity were investigated.Incorporation of ethyl maltol created a dense and smooth homogeneous surface,while EDTA addition caused large pores in the PLA sheet microstructure impacting swelling degree,water solubility and surface hydrophilicity.Fourier transform infrared(FTIR)spectroscopy and differential scanning calorimetry(DSC)showed that both ethyl maltol and EDTA addition modified the amorphous and crystalline phases of plasticized PLA.FTIR results suggested interaction between the functional groups of PLA chains,PEG,ethyl maltol or EDTA which affected the glass transition temperature(T_(g)),degree of crystallinity,and thermal stability of PLA.Adding PEG into PLA-EDTA enhanced antibacterial activity against Gram-positive Staphylococcus aureus(reduction of 1.35 log CFU/mL from the initial inoculum).The higher water solubility of sheets corresponded to a suitable release rate and sufficient amounts of antimicrobial compounds against Staphylococcus aureus.In vitro antifungal testing,PLA-PEG-EDTA sheets did not exhibit a clear zone of inhibition but delayed Penicillium sp.spore formation until day 5 of incubation.PEG plasticized PLA sheets functionalized with ethyl maltol and EDTA showed potential as active biomaterials against food-borne pathogen bacteria Staphylococcus aureus.
文摘The market and the future trends of smart packaging show a tendency towards a continuous increase. Several reports have revealed about the increase of consumer concern for food quality and safety, which gives rise to the demand of intelligent packaging. Nano-enabled food packaging has attracted considerable interest and driven a variety of potential applications in the intelligent packaging. The presence of nanomaterials as nanodevices or nanosensors has been recognized as a part of the modern intelligent packaging for monitoring the condition of packaged food or the environment surrounding the product. Among of nanosensors, optical indicator has been widely applied in the market due to the convenient and easy to use. The utilization of nanomaterial such as metal nanoparticles or photonic nanocrystals shows superior performance in novel communicative functions than the traditional colorimetric indicator because of their unique optical properties and high surface reactivity. This review focuses exclusively on ongoing scientific research and recent technological breakthroughs related to nanotechnology-derived colorimetric indicators. The challenges of their application are highlighted and discussed to provide adequate information for future development.
基金Supported by the Hu'nan Natural Science Foundation(No.SSY2066).
文摘The average transient lifetime of a chaotic transient versus the Lyapunov dimension of a chaotic saddle is studied for high-dimensional nonlinear dynamical systems. Typically the average lifetime depends upon not only the system parameter but also the Lyapunov dimension of the chaotic saddle. The numerical example uses the delayed feedback differential equation.
基金financially supported by Kasetsart University Research and Development Institute(KURDI)FF(KU)25.64.
文摘Enhancing the antimicrobial functions of biodegradable polyesters facilitates the utilization of sustainable food packaging.Poly(butylene succinate)(PBS)and polybutylene adipate terephthalate(PBAT)blends were compounded with zinc oxide(ZnO)nanoparticles(up to 4.5%)into a master batch via twin-screw extrusion.Biodegradable films were produced via cast extrusion,and the morphologies and packaging properties were determined.Adding ZnO nanoparticles up to 2.7% modified the film’s surface topography,causing non-homogeneity and voids.ZnO tended to form aggregates at higher loading,while phase separation of metal oxide from PBAT/PBS matrices occurred.Dispersion of ZnO nanoparticles reduced water vapor permeability,with the lowest effects on oxygen permeability.Adding ZnO in combination with the molecular orientation of the polymer effectively reinforced the matrices and improved the mechanical properties of PBAT/PBS blends.PBAT/PBS/ZnO films exhibited antimicrobial capacity against Escherichia coli and Bacillus cereus.PBAT/PBS with ZnO>2.7% delayed discoloration of red pigments in packaged minced pork due to efficient inhibition of microbial growth and UV blocking.ZnO-loaded polyester enhanced antimicrobial functions,producing sustainable active nanocomposite packaging.
基金financially supported by Kasetsart University Research and Development Institute(KURDI)FF(KU)25.64the Office of the Ministry of Higher Education,Science,Research and InnovationThailand Science Research and Innovation through the Kasetsart University Re-inventing University Program 2022.
文摘Biodegradable polyester polymers including poly(butylene adipate-co-terephthalate)(PBAT)and poly(butylene succinate)(PBS)are used as sustainable and eco-friendly food packaging but poor water vapor barrier properties limit their applications with moisture-sensitive products.This research blended PBAT/PBS materials at 60/40 and 50/50 with silicon dioxide(SiO2)nanoparticles as master batch pellets via twin-screw extrusion before sheet-casting to improve food packaging barrier properties.PBAT/PBS/SiO2 nanocomposite films were investigated by X-ray diffraction(XRD)and Fourier transform infrared(FTIR)spectroscopy and also for mechanical relaxation,microstructure,surface topography,and barrier properties.Scanning electron microscopy-energy dispersive X-ray analysis(SEM-EDX)indicated dispersed SiO2 nanoparticle aggregation in polymer matrices at higher loading.FTIR spectroscopy results suggested modified C--O stretching vibrations in polyesters,concurrent with shifting X-ray diffraction angles depending on nanoparticle content and polymer blend ratios.Adding SiO2 nanoparticles at up to 1% exponentially reduced water vapor permeability by up to 26%,while decreasing oxygen permeability(up to 8%).Mechanical properties reduced when adding SiO2 nanoparticles but film stretching improved polymer orientation at higher loading,thereby increasing tensile strength and elongation.Compounding SiO2 nanoparticles with PBAT/PBS polyester polymer blends enhanced barrier properties for biodegradable food packaging.
基金supported by the Dr.Whiteside Laboratory in the Department of Food,Nutrition,and Packaging Science,Clemson University.
文摘Packaging material has an important role in extending the shelf-life of fruits.This study investigated the effectiveness of cellulose nanocrystals(CNCs)derived from Kudzu(Pueraria montana)vine to reinforce to starch-based films.In addition,the essential oil was incorporated into these nanocomposite films to evaluate further improvement in film properties and applications.Different packaging materials,including the pearl millet starch(PMS),PMS reinforced with Kudzu CNCs,and PMS reinforced with Kudzu CNCs stabilized pickering emulsion containing clove bud oil(CBO),was used to develop biodegradable nanocomposite films.The films were investigated for their thermal,morphological,mechanical,and barrier properties.In addition,the films were used as packaging material to improve the shelf life of the grapes for 15 days at 5℃.PMS films reinforced with Kudzu CNCs stabilized pickering emulsion of CBO were most effective in extending the shelf life of red grapes up to 15 days at 5℃ by maintaining the weight,firmness,and soluble solids in grapes for a longer duration during storage.The study suggests that PMS+Kudzu CNCs+EO films have the potential for commercial packaging of fruits during short storage periods without adversely affecting their quality and sensory attributes.
基金National Natural Science Foundation of China(No.51673177)National Key R&D Program of China(No.2017YFB0308500).
文摘Leather is a collagen-based biomass prepared from raw skins or hides by a series of unit operations, in which the unhairing and fiber opening are extremely important operations. However, the conventional Na2S/Ca(OH)2 system used in unhairing and fiber opening has given rise to the pollution to the environment. It is necessary to develop substitute technology for the Na2S/Ca(OH)2. In the present study, 1-allyl-3-methylimidazolium chloride ([AMIm]Cl) was used to cooperate with dispase for cycle unhairing and one-pot beamhouse to recycle waste bovine hides and com-pared with conventional processing. During those processes, the mechanism of [AMIm]Cl-dispase synergistic unhair-ing and collagen fibers opening were studied. Besides, plant hazard, organic matter and [AMIm]Cl of wastewater from [AMIm]Cl-dispase process were respectively investigated and separated to evaluate the environmental and economic benefits of the [AMIm]Cl-dispase process. As a result, enzyme activity after unhairing by [AMIm]Cl-diapase system for using 5 times is higher than that by KCl-dispase system, and needs lower unhairing time, which is because of rapid penetration of [AMIm]Cl-dispase solution in bovine hides. For this reason, the tensile strength and elastic modulus of tanned leather from [AMIm]Cl-dispase process are higher than those from the KCl-diapase and conventional pro-cesses, and its hydrothermal shrinkage temperature is comparable to that of the conventional one. Because of the 58.13% lower wastewater discharge (WD), 66.60% lower total solids (TS), 97.23% lower ammonia nitrogen (NH3-N), non-toxic wastewater and organic matter recovery in wastewater are reached from [AMIm]Cl-dispase process, which is expected to be an alternative to the conventional process to reduce environmental pollution and realize the sustainable development of technology for leather manufacturing.
基金supported by Kasetsart University Research and Development Institute(KURDI)FF(KU)25.64.
文摘Ylang-ylang(Cananga odorata)essential oils(EO)has several active components with flora odorants which are compatible with several foods and desserts.Incorporation of Ylang-ylang EO into biodegradable polymers potentially produce functional packaging,releasing desirable aroma which is attractive to consumers.This research aimed to enhance active function of biodegradable polyester blend films namely polybutylene adipateco-terephthalate(PBAT)and polybutylene succinate(PBS)using cast extrusion with Ylang-ylang EO.Characterizations of the film include morphology,relaxation,infrared absorption and packaging properties.Adding EO gave a smoother microstructure and surface topography and modified the crystal lattice of the PBS phase.Infrared absorption indicated EO-polymer interaction involving C-H stretching vibration.Polymer relaxation influenced transport of gas molecules through PBAT/PBS/EO matrices.Decreasedα-relaxation temperature suggested plasticization effects of the amorphous PBAT phase by EO,increasing oxygen and water vapor permeability by 2.52 and 1.16 times,respectively.Polymer relaxation and crystallinity influenced transport of non-polar oxygen through PBAT/PBS/EO matrices.Moreover,films containing EO effectively delayed fungal growth in pandan pudding and layered pudding by more than 3 days due to the release of volatiles that exhibited antifungal activities.Findings suggested potential of Ylang-ylang EO incorporated biodegradable films to produce active packaging for aroma release,extending product shelf-life.
基金financially supported by Kasetsart University Research and Development Institute(KURDI)FF(KU)25.64the Office of the Ministry of Higher Education,Science,Research and InnovationThailand Science Research and Innovation through the Kasetsart University Re-inventing University Program 2022.
文摘Novel nanocomposite poly(butylene adipate-co-terephthalate)(PBAT)/polybutylene succinate(PBS)blend films functionalized with titanium dioxide(TiO_(2))nanoparticles(0,0.9,1.8,2.7,3.6 and 4.5%w/w)were produced using cast-sheet extrusion.Atomic force microscopy,X-ray diffraction(XRD),Fourier-transform infrared spectroscopy(FTIR)and dynamic mechanical thermal analysis were used to investigate film morphology and structure.The crystallinity of the films was modified due to interactions between the nanoparticles and the PBAT/PBS blends,as confirmed by FTIR and XRD.Tensile strength and elongation of films slightly reduced with TiO_(2)addition up to 4.5%in both machine direction(MD)and cross direction(CD).The tensile strength of the T5 films was nearly 25%less than the control films.Adding TiO_(2)gave excellent UV-blocking properties with slightly reduced water vapor by 16.5%and oxygen permeability by 4%for films with maximum loading.The film surface became more hydrophilic,as evidenced by the reduced contact angle.The results,as acquired from turbidity measurements,show that films with 3.6%TiO_(2)loading and above have high antimicrobial activity against both Bacillus cereus(Gram-positive)and Escherichia coli(Gram-negative).The relative area of microbial growth on agar media exhibited better antibacterial capacity against Escherichia coli than Bacillus cereus,with a sharp reduction of microbial growth at TiO_(2)contents above 2.7%.Films containing TiO_(2)(≥0.9%)effectively delayed ripening and increased peel yellowness of packaged bananas during storage for 6 days at room temperature.The developed PBAT/PBS/TiO_(2)nanocomposites films hence showed enhanced UV-resistance and antimicrobial properties,while maintaining adequate mechanical strength necessary for food packaging.The film is an eco-friendly alternative antimicrobial food packaging to extend the shelf-life of fresh produce.
基金supported by the fundamental Research Funds for the Central Universities(JUSRP124028)the National Key R&D Program of China(2022YFF1100803)+3 种基金the Modern Agriculture Grant of Key Research and Development Program of Jiangsu Province(BE202331O)the Natural Science Foundation of China(32261133623)the Science and Technology Planning Project of Jiangsu Market Supervision and Administration Bureau(KJ21125006)the Open Project of Engineering Research Center of Dairy Quality and Safety Control Technology of Ministry of Education of China(R202101).
文摘Plasma-activated water(PAW)is increasingly recognized for its role in mitigating microbial contamination in fresh-cut produce,but its disinfection effectiveness can be limited under certain conditions.Notably,dissolving organic acids in PAW is an effective way to boost its antimicrobial properties through a synergistic effect.This study examined the enhanced antimicrobial efficacy of PAW when combined with tartaric acid against Staphylococcus aureus and its application on fresh-cut asparagus lettuce.Results demonstrated that PAW combined with tartaric acid showed stronger antimicrobial efficacy than PAW alone(p<0.05).The addition of tartaric acid to PAW increased the oxidation-reduction potential and lowered the pH,contributing to its superior antimicrobial performance against S.aureus.The underlying antimicrobial mechanisms included the inactivation of Ca^(2+)-Mg^(2+)-ATPase and Na^(+)-K^(+)-ATPase accompanied by damage to bacterial cell membrane,enhanced oxidative damage due to the influx of extracellular reactive oxygen species such as H_(2)O_(2),the disrupted energy metabolic activities,and the mitigated bacterial defense system constructed by antioxidant enzymes,such as superoxide dismutase and catalase.Furthermore,the synergistic treatment improved the quality of fresh-cut asparagus lettuce by retarding browning,curbing microbial spoilage,and lessening weight loss.The preservation of color was largely due to the decreased activities of polyphenol oxidase and peroxidase,along with controlled chlorophyll degradation.These findings suggest that PAW enhanced with tartaric acid could be a promising,cost-effective disinfection strategy for fresh-cut asparagus lettuce.
