A novel antibacterial material （L-PET） was prepared by immobilizing ε-polylysine on polyethylene terephthalate （PET） nonwoven fabrics. Surface modifications of the fabric were performed by using a chemical modifi...A novel antibacterial material （L-PET） was prepared by immobilizing ε-polylysine on polyethylene terephthalate （PET） nonwoven fabrics. Surface modifications of the fabric were performed by using a chemical modification procedure where carboxyl groups were prepared on the PET surface, a coupling agent was grafted, and the ε-polylysine was immobilized. Scanning electron microscopy （SEM） was used to analyze the surface morphology of the fabrics, while the toluidine blue method and X-ray photoelectron spectroscopy （XPS） were used to evaluate the grafting densities. The antibacterial activities of the L-PET were investigated by using the shaking-flask method. The electron micrographs showed that the surface of the blank PET and the modified fabrics did not change. The results of XPS analysis confirmed that ε-polylysine was successfully grafted onto the surface of PET. The results of the antibacterial experiments showed that L-PET fabrics had excellent antibacterial activity against Escherichia coli and Staphylococcus aureus, and that L-PET fabrics were stable in storage for at least two years.展开更多
As a leafy vegetable,dandelion(Taraxacum antungense Kitag.)leaves are subject to senescence,such as yellowing and even decay,during postharvest storage.Calcium chloride(CaCl_(2))andε-polylysine(ε-PL)treatments can s...As a leafy vegetable,dandelion(Taraxacum antungense Kitag.)leaves are subject to senescence,such as yellowing and even decay,during postharvest storage.Calcium chloride(CaCl_(2))andε-polylysine(ε-PL)treatments can safely and effectively improve the postharvest quality of fruits and vegetables.To improve the storage quality,dandelions were treated with 0.5%(mass concentration)CaCl_(2)and 0.9 g/Lε-PL and stored at 4±0.5℃.The results showed that the combination treatment of CaCl_(2)andε-PL(CaCl_(2)+ε-PL treatment)could effectively delay the yellowing and chlorophyll content decline,as well as reduce the browning index,when compared with those of the control and single treatments.The CaCl_(2)+ε-PL treatment also enhanced the synthesis and accumulation of secondary metabolites.The combination treatment could significantly enhance the enzyme activities of phenylalanine ammonia-lyase(PAL),4-coumarate-Co A ligase(4CL),and cinnamate-4-hydroxylase(C4H)in phenylpropanoid metabolism and upregulate the expression levels of Ta PAL,Ta4CL,and Ta C4H.Meanwhile,ε-PL treatment was more effective than CaCl_(2)treatment in promoting the expression of these genes.Correlation analysis indicates that the transcription levels and activities of the three enzymes,as well as the contents of secondary metabolites,are linked to the quality changes of dandelions treated with CaCl_(2)+ε-PL during cold storage.Principal component analysis was used to assess the storage quality of dandelions during cold storage,and the results showed the following rankings:CaCl_(2)+ε-PL>ε-PL>CaCl_(2)>control.These findings suggest that CaCl_(2)+ε-PL treatment can improve the postharvest storage quality of dandelions by modulating the phenylpropane metabolic pathway.展开更多
The current study investigated the utilization ofε-polylysine(ε-PL)and beetroot extract(BE)as suitable nitrite substitutes in frankfurter-type sausages packaged in vacuum polyethylene bags.The sample’s technologica...The current study investigated the utilization ofε-polylysine(ε-PL)and beetroot extract(BE)as suitable nitrite substitutes in frankfurter-type sausages packaged in vacuum polyethylene bags.The sample’s technological,safety,antimicrobial,and organoleptic attributes were analyzed during 30 days of storage at 4℃.Compared with controls,the sausages containingϵ-PL with BE had no significant differences in the water activity and proximate composition.The results showed that the T5 and T4 samples had the highest residual nitrite and total phenolic contents at day 45.Incorporatingε-PL and BE into frankfurter-type sausages prevented the increase of pH and maintained samples’pink color and texture consistency during storage.T3 and T4 samples could effectively delay the growth of total viable count,coliform,Clostridium perfringens,mold,and yeasts within acceptable limitations during refrigerated storage.展开更多
基金Funded by the National Major Science & Technology Specific Projects (2009ZX10004-703)
文摘A novel antibacterial material （L-PET） was prepared by immobilizing ε-polylysine on polyethylene terephthalate （PET） nonwoven fabrics. Surface modifications of the fabric were performed by using a chemical modification procedure where carboxyl groups were prepared on the PET surface, a coupling agent was grafted, and the ε-polylysine was immobilized. Scanning electron microscopy （SEM） was used to analyze the surface morphology of the fabrics, while the toluidine blue method and X-ray photoelectron spectroscopy （XPS） were used to evaluate the grafting densities. The antibacterial activities of the L-PET were investigated by using the shaking-flask method. The electron micrographs showed that the surface of the blank PET and the modified fabrics did not change. The results of XPS analysis confirmed that ε-polylysine was successfully grafted onto the surface of PET. The results of the antibacterial experiments showed that L-PET fabrics had excellent antibacterial activity against Escherichia coli and Staphylococcus aureus, and that L-PET fabrics were stable in storage for at least two years.
基金funded by the Liaoning Provincial Department of Education in 2023(No.JYTMS20231389)the Liaoning Provincial Science and Technology Department 2023 Joint Fund(No.2023-MSLH-297)+1 种基金the 2024 Shenyang Medical College Graduate Student Scientific and Technological Innovation Fund Project(No.Y20240533)the Liaoning Provincial Local Standards(DB/T 3476-2021),China。
文摘As a leafy vegetable,dandelion(Taraxacum antungense Kitag.)leaves are subject to senescence,such as yellowing and even decay,during postharvest storage.Calcium chloride(CaCl_(2))andε-polylysine(ε-PL)treatments can safely and effectively improve the postharvest quality of fruits and vegetables.To improve the storage quality,dandelions were treated with 0.5%(mass concentration)CaCl_(2)and 0.9 g/Lε-PL and stored at 4±0.5℃.The results showed that the combination treatment of CaCl_(2)andε-PL(CaCl_(2)+ε-PL treatment)could effectively delay the yellowing and chlorophyll content decline,as well as reduce the browning index,when compared with those of the control and single treatments.The CaCl_(2)+ε-PL treatment also enhanced the synthesis and accumulation of secondary metabolites.The combination treatment could significantly enhance the enzyme activities of phenylalanine ammonia-lyase(PAL),4-coumarate-Co A ligase(4CL),and cinnamate-4-hydroxylase(C4H)in phenylpropanoid metabolism and upregulate the expression levels of Ta PAL,Ta4CL,and Ta C4H.Meanwhile,ε-PL treatment was more effective than CaCl_(2)treatment in promoting the expression of these genes.Correlation analysis indicates that the transcription levels and activities of the three enzymes,as well as the contents of secondary metabolites,are linked to the quality changes of dandelions treated with CaCl_(2)+ε-PL during cold storage.Principal component analysis was used to assess the storage quality of dandelions during cold storage,and the results showed the following rankings:CaCl_(2)+ε-PL>ε-PL>CaCl_(2)>control.These findings suggest that CaCl_(2)+ε-PL treatment can improve the postharvest storage quality of dandelions by modulating the phenylpropane metabolic pathway.
文摘The current study investigated the utilization ofε-polylysine(ε-PL)and beetroot extract(BE)as suitable nitrite substitutes in frankfurter-type sausages packaged in vacuum polyethylene bags.The sample’s technological,safety,antimicrobial,and organoleptic attributes were analyzed during 30 days of storage at 4℃.Compared with controls,the sausages containingϵ-PL with BE had no significant differences in the water activity and proximate composition.The results showed that the T5 and T4 samples had the highest residual nitrite and total phenolic contents at day 45.Incorporatingε-PL and BE into frankfurter-type sausages prevented the increase of pH and maintained samples’pink color and texture consistency during storage.T3 and T4 samples could effectively delay the growth of total viable count,coliform,Clostridium perfringens,mold,and yeasts within acceptable limitations during refrigerated storage.
