In this study,freshness indicators were prepared through solvent casting method by anchoring black wolfberry anthocyanins into cassava starch/polyvinyl alcohol matrix and adjusting the pH value of film-forming solutio...In this study,freshness indicators were prepared through solvent casting method by anchoring black wolfberry anthocyanins into cassava starch/polyvinyl alcohol matrix and adjusting the pH value of film-forming solution.The aim of this study was to explore the impact of the pH value(3.0,4.0,5.0,6.0 and 7.0)of film-forming solution on the functionality of anthocyanins-based freshness indicators.The indicators were characterized by scanning electron microscopy,Fourier transform infrared spectroscopy,micrometer,UV-vis spectrophotometer,water vapor permeability tester,water contact analyzer,gas permeability tester,texture analyzer,thermogra-vimetric analyzer,differential scanning calorimeter and colorimeter.Meanwhile,the pH-responsive and ammonia-responsive properties of the indicators were determined.The indicators were finally used to indicate the freshness of shrimps.Results showed pH adjustment greatly changed the cross-sectional morphology and intermolecular hydrogen bonding strength of the indicators.The indicator prepared at pH 3.0 had the highest visible light/oxygen barrier ability and antioxidant activity,while the indicator prepared at pH 4.0 exhibited the highest water vapor barrier ability.The indicators prepared at pH 3.0,4.0 and 5.0 showed remarkable color changes when exposed to buffer solutions and ammonia gas.The indicator prepared at pH 3.0 could effectively indicate the freshness of chilled shrimp through color changes.This study reveals that the functionality of anthocyanins-based freshness indicators can be modulated by adjusting the pH value of film-forming solution.展开更多
Objectives:To deveop on-pack visual indicators for the real-time monitoring of raw beef steaks in a modified atmospheric packaging(MAP).Materials and Methods:Three indicators were prepared by spray deposition of a nan...Objectives:To deveop on-pack visual indicators for the real-time monitoring of raw beef steaks in a modified atmospheric packaging(MAP).Materials and Methods:Three indicators were prepared by spray deposition of a nanocellulose suspension(1.5%,in mass)with the desired concentration of the pH-sensitive indicators,either red cabbage(RC)extract,black carrot(BC)extract,or chlorophenol red(CPR).The responsiveness of the colorimetric pH indicators,assessed visually and by CiE-Lab quantitative analysis,to the freshness of raw beef steaks stored under MAP conditions at 4℃ or 20℃,was analysed over7d.Results:All the indicators showed a colour change for beef steak stored at 4℃ for 7 d that was noticeable with the naked eye and had a △E value>12.The sensitivity of the RC pH indicator was superior to that of the BC and CPR pH indicators.A study linking total microbial count(aerobic+Escherichia coli+coliform)and the quantitative colorimetric response of the indicators(△E)revealed a strong linear correlation.Conclusions:The developed colorimetric pH indicators could be used to monitor the freshness of raw beef and as an alternative to the bestbefore date commonly used in pre-packagedmeat.展开更多
The freshness and quality indices of whiting (Merlangius merlangus) influenced by a large number of chemical volatile compounds, are here analyzed in order to select the most relevant compounds as predictors for these...The freshness and quality indices of whiting (Merlangius merlangus) influenced by a large number of chemical volatile compounds, are here analyzed in order to select the most relevant compounds as predictors for these indices. The selection process was performed by means of recent statistical variable selection methods, namely robust model-free feature screening, based on quantile correlation and composite quantile correlation. On the one hand, compounds 2-Methyl-1-butanol, 3-Methyl-1-butanol, Ethanol, Trimethylamine, 3-Methyl butanal, 2-Methyl-1-propanol, Ethylacetate, 1-Butanol and 2,3-Butanedione were identified as major predictors for the freshness index and on the other hand, compounds 3-Methyl-1-butanol, 2-Methyl-1- butanol, Ethanol, 3-Methyl butanal, 3-Hydroxy-2-butanone, 1-Butanol, 2,3-Butane- dione, 3-Pentanol, 3-Pentanone and 2-Methyl-1-propanol were identified as major predictors for the quality index.展开更多
This study examined the freshness of minimally processed pomegranate arils(MPPAs)under refrigeration conditions(5±1◦C)stored in a polypropylene(PP)container sealed with PP nanocomposite multi-layered film(PP-NMF)...This study examined the freshness of minimally processed pomegranate arils(MPPAs)under refrigeration conditions(5±1◦C)stored in a polypropylene(PP)container sealed with PP nanocomposite multi-layered film(PP-NMF).The freshness indicator was fabricated using cellulose acetate coated with a combination of colorimetric pH dyes,which included bromocresol green(BCG),bromothymol blue(BTB)and methyl red(MR)in a ratio of 6:9:15.The fabricated indicator labels were attached inside the package headspace and observed an increase in CO_(2)(0.1±0.01 to 0.9±0.03%v/v)and a decrease in O_(2)(19.6±0.01 to 18.8±0.03%v/v)during storage(0-18 days).Color change of indicator labels was mainly caused by headspace concentrations that changed from dark to colorless for fresh and spoiled pomegranate arils.The PP-NMF used in MPPAs has high barrier properties,extending its shelf life in the refrigerator to over 15 days.The pomegranate arils stored for different periods of time showed significant changes in their physicochemical parameters.Over storage days,aerobic mesophilic bacteria(AMB)and yeast and mold count(YMC)increased to 4.90±0.20 and 4.50±0.20 log CFU g1.An indicator developed for monitoring pomegranate arils stored in the refrigerator can detect freshness efficiently.展开更多
基金funded by National Natural Science Foundation of China(31571788)Self-developing Instrument and Equipment Project of Yangzhou University(zzyq2022zy20).
文摘In this study,freshness indicators were prepared through solvent casting method by anchoring black wolfberry anthocyanins into cassava starch/polyvinyl alcohol matrix and adjusting the pH value of film-forming solution.The aim of this study was to explore the impact of the pH value(3.0,4.0,5.0,6.0 and 7.0)of film-forming solution on the functionality of anthocyanins-based freshness indicators.The indicators were characterized by scanning electron microscopy,Fourier transform infrared spectroscopy,micrometer,UV-vis spectrophotometer,water vapor permeability tester,water contact analyzer,gas permeability tester,texture analyzer,thermogra-vimetric analyzer,differential scanning calorimeter and colorimeter.Meanwhile,the pH-responsive and ammonia-responsive properties of the indicators were determined.The indicators were finally used to indicate the freshness of shrimps.Results showed pH adjustment greatly changed the cross-sectional morphology and intermolecular hydrogen bonding strength of the indicators.The indicator prepared at pH 3.0 had the highest visible light/oxygen barrier ability and antioxidant activity,while the indicator prepared at pH 4.0 exhibited the highest water vapor barrier ability.The indicators prepared at pH 3.0,4.0 and 5.0 showed remarkable color changes when exposed to buffer solutions and ammonia gas.The indicator prepared at pH 3.0 could effectively indicate the freshness of chilled shrimp through color changes.This study reveals that the functionality of anthocyanins-based freshness indicators can be modulated by adjusting the pH value of film-forming solution.
基金co-funded by Meat Livestock Australia(MLA)under the Monash Graduate Research Industry Partnership(GRIP)Program(project P.PSH.0889).
文摘Objectives:To deveop on-pack visual indicators for the real-time monitoring of raw beef steaks in a modified atmospheric packaging(MAP).Materials and Methods:Three indicators were prepared by spray deposition of a nanocellulose suspension(1.5%,in mass)with the desired concentration of the pH-sensitive indicators,either red cabbage(RC)extract,black carrot(BC)extract,or chlorophenol red(CPR).The responsiveness of the colorimetric pH indicators,assessed visually and by CiE-Lab quantitative analysis,to the freshness of raw beef steaks stored under MAP conditions at 4℃ or 20℃,was analysed over7d.Results:All the indicators showed a colour change for beef steak stored at 4℃ for 7 d that was noticeable with the naked eye and had a △E value>12.The sensitivity of the RC pH indicator was superior to that of the BC and CPR pH indicators.A study linking total microbial count(aerobic+Escherichia coli+coliform)and the quantitative colorimetric response of the indicators(△E)revealed a strong linear correlation.Conclusions:The developed colorimetric pH indicators could be used to monitor the freshness of raw beef and as an alternative to the bestbefore date commonly used in pre-packagedmeat.
文摘The freshness and quality indices of whiting (Merlangius merlangus) influenced by a large number of chemical volatile compounds, are here analyzed in order to select the most relevant compounds as predictors for these indices. The selection process was performed by means of recent statistical variable selection methods, namely robust model-free feature screening, based on quantile correlation and composite quantile correlation. On the one hand, compounds 2-Methyl-1-butanol, 3-Methyl-1-butanol, Ethanol, Trimethylamine, 3-Methyl butanal, 2-Methyl-1-propanol, Ethylacetate, 1-Butanol and 2,3-Butanedione were identified as major predictors for the freshness index and on the other hand, compounds 3-Methyl-1-butanol, 2-Methyl-1- butanol, Ethanol, 3-Methyl butanal, 3-Hydroxy-2-butanone, 1-Butanol, 2,3-Butane- dione, 3-Pentanol, 3-Pentanone and 2-Methyl-1-propanol were identified as major predictors for the quality index.
基金Financial assistance provided by the National Institute of Food Technology,Entrepreneurship and Management-Thanjavur(NIFTEM-T),Formerly Indian Institute of Food Processing Technology(IIFPT),Ministry of Food Processing Industries(MOFPI),Government of India(GOI),which is duly acknowledged.
文摘This study examined the freshness of minimally processed pomegranate arils(MPPAs)under refrigeration conditions(5±1◦C)stored in a polypropylene(PP)container sealed with PP nanocomposite multi-layered film(PP-NMF).The freshness indicator was fabricated using cellulose acetate coated with a combination of colorimetric pH dyes,which included bromocresol green(BCG),bromothymol blue(BTB)and methyl red(MR)in a ratio of 6:9:15.The fabricated indicator labels were attached inside the package headspace and observed an increase in CO_(2)(0.1±0.01 to 0.9±0.03%v/v)and a decrease in O_(2)(19.6±0.01 to 18.8±0.03%v/v)during storage(0-18 days).Color change of indicator labels was mainly caused by headspace concentrations that changed from dark to colorless for fresh and spoiled pomegranate arils.The PP-NMF used in MPPAs has high barrier properties,extending its shelf life in the refrigerator to over 15 days.The pomegranate arils stored for different periods of time showed significant changes in their physicochemical parameters.Over storage days,aerobic mesophilic bacteria(AMB)and yeast and mold count(YMC)increased to 4.90±0.20 and 4.50±0.20 log CFU g1.An indicator developed for monitoring pomegranate arils stored in the refrigerator can detect freshness efficiently.
