Food safety has become a major concern for consumers, as well as a priority for regulatory authorities. Faced with the growing industrial and domestic use of food additives, many questions are being asked and concerns...Food safety has become a major concern for consumers, as well as a priority for regulatory authorities. Faced with the growing industrial and domestic use of food additives, many questions are being asked and concerns are being felt by consumers around the world. Consumer perception defines the acceptability or rejection of food products, and has an impact on consumption patterns and behavior. To assess the level of knowledge and perception of food additives, a pilot study was carried out on a sample of 200 people in Dakar and Saint-Louis. A questionnaire was used to assess the acceptance or rejection, use and impact of food additives by consumers in Senegal. The results revealed several aspects. On the whole, the people surveyed expressed great mistrust and even rejection of these substances added to food products. This consumer perception is shared throughout the world, as indicated in numerous surveys. It also emerges from this study that, although most consumers are aware of the existence of these additives and their uses in the home, they feel that the use of these substances in industrial production is too excessive. What’s more, consumers associate food additives with numerous pathologies such as cancer, diabetes, hypertension, stroke and even sexual impotence. For some of these indexed pathologies, scientific studies have reached the same conclusions, although controversy still persists. On the other hand, for some of the other adverse effects mentioned, no cause-and-effect relationship has been scientifically demonstrated. In these latter cases, it seems that negative communication, misinformation and misconceptions have a major influence on consumer perception of food additives.展开更多
Terahertz time-domain spectroscopy is a kind of far-infrared spectroscopy technology,and its spectrum reflects the internal properties of substances with rich physical and chemical information,so the use of terahertz ...Terahertz time-domain spectroscopy is a kind of far-infrared spectroscopy technology,and its spectrum reflects the internal properties of substances with rich physical and chemical information,so the use of terahertz waves can be used to qualitatively identify food additives containing nitrogen elements.Analytic hierarchy process(AHP)was originally used to solve evaluation-type problems,and this paper introduces it into the field of terahertz spectral qualitative analysis,proposes a terahertz time-domain spectral qualitative identification method combined with analytic hierarchy process,and verifies the feasibility of the method by taking four common food additives(xylitol,L-alanine,sorbic acid,and benzoic acid)and two illegal additives(melamine,and Sudan Red No.I)as the objects of study.Firstly,the collected terahertz time-domain spectral data were pre-processed and transformed into a data set consisting of peaks,peak positions,peak numbers and overall trends;then,the data were divided into comparison and test sets,and a qualitative additive identification model incorporating analytic hierarchy process was constructed and parameter optimisation was performed.The results showed that the qualitative identification accuracies of additives based on single factors,i.e.,overall trend,peak value,peak position,and peak number,were 80.23%,70.93%,67.44%,and 40.70%,respectively,whereas the identification accuracy of the analytic hierarchy process qualitative identification method based on multi-factors could be improved to 92.44%.In addition,the fuzzy characterisation of the absorption spectrum data was binarised in the data pre-processing stage and used as the base data for the overall trend,and the recognition accuracy was improved to 94.19%by combining the fuzzy characterisation method of such data with the hierarchical analysis qualitative recognition model.The results show that it is feasible to use terahertz technology to identify different varieties of additives,and this paper constructs a hierarchical analytical qualitative model with better effect,which provides a new means for food additives detection,and the method is simple in steps,with a small demand for samples,which is suitable for the rapid detection of small samples.展开更多
This study was to analyze the risk of sulfites in food consumed by the Chinese people and assess the health protection capability of maximum-permitted level (MPL) of sulfites in GB 2760-2011. Sulfites as food additi...This study was to analyze the risk of sulfites in food consumed by the Chinese people and assess the health protection capability of maximum-permitted level (MPL) of sulfites in GB 2760-2011. Sulfites as food additives are overused or abused in many food categories. When the MPL in GB 2760-2011 was used as sulfites content in food, the intake of sulfites in most surveyed populations was lower than the acceptable daily intake (ADI). Excess intake of sulfites was found in all the surveyed groups when a high percentile of sulfites in food was intaken. Moreover, children aged 1-6 years are at a high risk to intake excess sulfites. The primary cause for the excess intake of sulfites in Chinese people is the overuse and abuse of sulfites by the food industry. The current MPL of sulfites in GB 2760-2011 protects the health of most populations.展开更多
With the vacuum freeze-drying technology, frozen dumpling wrappers were prepared, to investigate the effects of six kinds of food additives, including modified starch, compound phosphate, maltodextrin, guar gum, disti...With the vacuum freeze-drying technology, frozen dumpling wrappers were prepared, to investigate the effects of six kinds of food additives, including modified starch, compound phosphate, maltodextrin, guar gum, distilled monoglycerides and transglutaminase (TG enzyme), on the drying rate, rehydration ratio and sense value of the frozen dumpling wrappers. The results showed that, with respective addition of 6% modified starch, O. 1% compound phosphate, 10% maltodextrin, 0.4% guar gum, 0.4% distilled monoglyceride and 0.3% transglutaminase, the drying rate, rehydration ratio and sense value of the frozen dumpling wrappers were the highest.展开更多
An ion-exchange chromatography (IEC) followed by post-column derivatization method was validated for the determination of glutamine in food additive products. The chromatographic method was carried out on a sodium cat...An ion-exchange chromatography (IEC) followed by post-column derivatization method was validated for the determination of glutamine in food additive products. The chromatographic method was carried out on a sodium cation-exchange column and using detection at 570 nm. The mobile phase consisted of sodium eluant, pH 3.15, with 5% sulfolane, sodium eluant, pH 7.40 and sodium column regenerant. The method was linear in the range of 4 - 50 μg/mL (r2 = 0.9999). The accuracy was 99.78%. Moreover, method validation demonstrated acceptable results for precision and robustness. The method was found to be able to use for routine analysis of the glutamine.展开更多
An efficient and accurate analytical method was developed for the simultaneous determination of 20 synthetic food additives, including three sweeteners,seven food colorants,nine synthetic preservatives and caffeine,by...An efficient and accurate analytical method was developed for the simultaneous determination of 20 synthetic food additives, including three sweeteners,seven food colorants,nine synthetic preservatives and caffeine,by high performance liquid chromatography (HPLC) with photodiode array detector(PDA).This method permits the detection of food additives at very low concentrations(0.005-0.150μg/mL).The applicability was verified by the determination of food additives present in various foodstuffs.展开更多
The aim of this study was to revise the provisions for aluminum-containing food additives in GB 2760-2011 (The National Food Safety Standard for Use of Food Additives), in order to reduce aluminum exposure among the...The aim of this study was to revise the provisions for aluminum-containing food additives in GB 2760-2011 (The National Food Safety Standard for Use of Food Additives), in order to reduce aluminum exposure among the Chinese population. According to the latest risk assessment results of JECFA and China on aluminum and the actual use of aluminum-containing food additives in certain products, the aluminum-containing food additive-related provisions in GB 2760-2011 were revised. Those revisions included narrowing down the applicable food categories and adjusting the maximum use level of aluminum potassium sulfate and aluminum ammonium sulfate, repealing nine aluminum-containing food additives in puffed food and repealing the use of sodium aluminum phosphate, sodium aluminosilicate and starch aluminum octenylsuccinate in all food.展开更多
A simplex-lattice mixture design with response surface methodology was used to evaluate in vitro synergistic antioxidant activity of red, green, and brown Brazilian propolis extract blends. The in vitro antioxidant ca...A simplex-lattice mixture design with response surface methodology was used to evaluate in vitro synergistic antioxidant activity of red, green, and brown Brazilian propolis extract blends. The in vitro antioxidant capacity of propolis extract blends was measured using the fluorine method of oxygen radical absorption capacity assay (ORAC assay). A synergistic antioxidant interaction was identified between green and brown propolis extracts, and the predictive model accused a binary mixture composed of 59% green and 41% brown propolis extracts with increased antioxidant activity of about 54%. Our findings suggest a possible reduction in the dosages of these natural antioxidants in their various potential applications, including health and food, thereby proving to be a highly promising alternative for the rational use and valorization of propolis.展开更多
Food colorants are widely used in the food industry to maintain or enhance product color. However, as the use of these colorants can have negative impacts on health, it is essential to analyze the risks associated wit...Food colorants are widely used in the food industry to maintain or enhance product color. However, as the use of these colorants can have negative impacts on health, it is essential to analyze the risks associated with their consumption. This analysis requires, among other things, obtaining sufficient data on the presence of these colorants in foods, as well as their level of consumption. However, data on these colorants is often virtually non-existent in developing countries. The aim of this study was to determine the colorant profile of industrial products marketed in Senegal. Information on food additives was collected on 399 labels of different food product categories in shops located in Dakar. Data is recorded and processed using Excel software. Based on the Codex classification, analysis of the profile of additives identified on the labels of food samples revealed the presence of 31 colorants. The natural colorants identified are dominated by beta-carotene, widely present in beverages and dairy products, and paprika extract identified on cookies and industrial sauces. Artificial colors are dominated caramels present in several foods including bouillons, vinegars, sauces and hard candies. Secondly, there was a strong presence of the azo dye Sunset yellow FCF, widely found in samples of beverages, confectionery and cookies. The results of this case study enable us to appreciate the wide presence and diversity of colorants on the Senegalese market, and the importance of controlling them to guarantee consumer safety.展开更多
In exploring an autonomous independent water supply system, authors have realized the importance of the sustainable water supply utilizing regional features in isolated islands. This paper is further study from the pr...In exploring an autonomous independent water supply system, authors have realized the importance of the sustainable water supply utilizing regional features in isolated islands. This paper is further study from the previous one. This time we have narrowed down the mixing rate of mixed water. In this study, the mixed water less than 0.74% (blood concentration) has been prepared first, and then divided it into five kinds of the mixing rate of mixed water. And we have compared and examined the characteristics of the mixed water from the viewpoint of the relationship between salinity and pH, ORP and that of Dissolved Hydrogen, and examined the possibility of mixed water as a drinking water. As a result, we have obtained the new findings that suggest the possibility.展开更多
Due to human-caused deforestation,global warming,and other environmental factors,habitat fragmentation became widespread.This fragmentation has a variety of detrimental repercussions for many species as well as humans...Due to human-caused deforestation,global warming,and other environmental factors,habitat fragmentation became widespread.This fragmentation has a variety of detrimental repercussions for many species as well as humans,especially in the agricultural economy.It causes insect outbreaks,the expansion of alien species,and disrupts biological management by rendering the habitat unsuitable for natural enemies in agriculture.Providing natural enemies with additional food is one method to improve the ecosystem and support them.In this study,we assumed that the ecosystem is separated into two patches and that predators can easily migrate from one patch to the next,while prey stays inside its patch's territory.We looked at the impact of offering more food to predators in a patchy environment using dynamical systems theory.The permanence,stability,and various bifurcations that occur in the system are studied using a rigorous mathematical analysis.The study looks at how predator's access to other food sources affects pest management.By adjusting the provided food's characteristic qualities,such as(nutritional)quality and quantity,one can limit and manage the pest in one or both patches,as well as eliminate predators from the ecosystem.This research reveals that providing predators with additional food(of specified quality and quantity)can help in controlling chaotic behavior in the system.The findings of the study are supported by numerical simulations.展开更多
In this work,the nano-g-C_(3)N_(4)/Ui O-66-NH_(2)composite was prepared by one-step solvothermal method.The as-prepared composite was characterized by scanning electron microscopy,Brunner-Emmet-Teller measurement,ener...In this work,the nano-g-C_(3)N_(4)/Ui O-66-NH_(2)composite was prepared by one-step solvothermal method.The as-prepared composite was characterized by scanning electron microscopy,Brunner-Emmet-Teller measurement,energy dispersive spectrometer,X-ray diffraction,and Fourier transform infrared spectroscopy.By using nano-g-C_(3)N_(4)/Ui O-66-NH_(2)composite as sorbent,a dispersive solid-phase extraction coupled with high-performance liquid chromatography was developed to sensitive analysis of food colorants including tartrazine,amaranth,carmine,sunset yellow,allura red and bright blue.The experiment parameters including the amount of sorbent,adsorption time,the p H of adsorption solution,desorption time,desorption solvent,the p H of desorption solution as well as the proportion between desorption solvent and buffer solvent were investigated.Under the optimized conditions,the limits of detection(S/N=3) and limits of quantitation (S/N=10) were determined in the ranges of 0.08-0.8 and 0.2-2.0 ng/m L,respectively.With the developed sample pretreatment method,carmine and brilliant blue were determined from blueberry juice by HPLC-DAD.The contents were calculated as 1.53μg/m L and0.17μg/mL,respectively.展开更多
Based on the inhibition effect on the respiratory chain activity of microorganisms by toxicants, an electrochemical method has been developed to measure the current variation of a mediator in the presence of microorga...Based on the inhibition effect on the respiratory chain activity of microorganisms by toxicants, an electrochemical method has been developed to measure the current variation of a mediator in the presence of microorganisms contacted with a toxicant. Microelectrode arrays were adopted in this study, which can accelerate the mass transfer rate of an anaiyte to the electrode and also increase the total current signal, resulting in an improvement in detection sensitivity. We selected Escherichia coli as the testee and the standard glucose- glutamic acid as an exogenous material. Under oxygen restriction, the experiments in the presence of toxicant were performed at optimum conditions (solution pH 7.0, 37℃ and reaction for 3 hr). The resulting solution was then separated from the suspended microorganisms and was measured by an electrochemical method, using ferricyanide as a mediator. The current signal obtained represents the reoxidation of ferrocyanide, which was transformed to inhibiting efficiency, IC50, as a quantitative measure of toxicity. The IC50 values measured were 410, 570 and 830 mg/L for sodium nitrite, borax and aluminum potassium sulfate, respectively. The results show that the toxicity sequence for these three food additives is consistent with the value reported by other methods. Furthermore, the order of damage degree to the microorganism was also observed to be: sodium nitrite 〉 borax 〉 aluminum potassium sulfate 〉 blank, according to the atomic force microscopy images of E. coli after being incubated for 3 hr with the toxic compound in buffer solutions. The electrochemical method is expected to be a sensitive and simple alternative to toxicity screening for chemical food additives.展开更多
The rheological characteristic of soy protein isolate(SPI),is one of the most important properties in its application in food industry.The effects of different concentrations of guar gum(GG,polysaccharide)and sodium c...The rheological characteristic of soy protein isolate(SPI),is one of the most important properties in its application in food industry.The effects of different concentrations of guar gum(GG,polysaccharide)and sodium chloride(salt ion)on the rheological properties of SPI were studied in this research.Steady-state shear,strain sweep and frequency sweep tests(static and dynamic rheological tests)were performed,and the following phenomenon and conclusions were drawn:(1)The viscosity of the hybrid system increases with the GG addition.This trend could also be seen with the appropriate adding of salt ion;(2)As the applied frequency increases,the storage modulus G′and the loss modulus G″of the hybrid system increase at a similar rate.And the frequency sweep parameters of the hybrid system rise significantly with the increase of both GG and ionic concentration;The frequency dependence of the system varies significantly with the addition of salt ion;(3)With the concentration of the salt ion increase,the storage module G′of the hybrid system decrease indicating that salt ion destroyed the network structure of hybrid dispersion to a certain extent.展开更多
文摘Food safety has become a major concern for consumers, as well as a priority for regulatory authorities. Faced with the growing industrial and domestic use of food additives, many questions are being asked and concerns are being felt by consumers around the world. Consumer perception defines the acceptability or rejection of food products, and has an impact on consumption patterns and behavior. To assess the level of knowledge and perception of food additives, a pilot study was carried out on a sample of 200 people in Dakar and Saint-Louis. A questionnaire was used to assess the acceptance or rejection, use and impact of food additives by consumers in Senegal. The results revealed several aspects. On the whole, the people surveyed expressed great mistrust and even rejection of these substances added to food products. This consumer perception is shared throughout the world, as indicated in numerous surveys. It also emerges from this study that, although most consumers are aware of the existence of these additives and their uses in the home, they feel that the use of these substances in industrial production is too excessive. What’s more, consumers associate food additives with numerous pathologies such as cancer, diabetes, hypertension, stroke and even sexual impotence. For some of these indexed pathologies, scientific studies have reached the same conclusions, although controversy still persists. On the other hand, for some of the other adverse effects mentioned, no cause-and-effect relationship has been scientifically demonstrated. In these latter cases, it seems that negative communication, misinformation and misconceptions have a major influence on consumer perception of food additives.
基金funded by Key Technology Tackling Programme of Inner Mongolia,grant number2021GG0361funded by Basic Research Operating Costs of Colleges and Universities Directly Under the Inner Mongolia Autonomous Region Project。
文摘Terahertz time-domain spectroscopy is a kind of far-infrared spectroscopy technology,and its spectrum reflects the internal properties of substances with rich physical and chemical information,so the use of terahertz waves can be used to qualitatively identify food additives containing nitrogen elements.Analytic hierarchy process(AHP)was originally used to solve evaluation-type problems,and this paper introduces it into the field of terahertz spectral qualitative analysis,proposes a terahertz time-domain spectral qualitative identification method combined with analytic hierarchy process,and verifies the feasibility of the method by taking four common food additives(xylitol,L-alanine,sorbic acid,and benzoic acid)and two illegal additives(melamine,and Sudan Red No.I)as the objects of study.Firstly,the collected terahertz time-domain spectral data were pre-processed and transformed into a data set consisting of peaks,peak positions,peak numbers and overall trends;then,the data were divided into comparison and test sets,and a qualitative additive identification model incorporating analytic hierarchy process was constructed and parameter optimisation was performed.The results showed that the qualitative identification accuracies of additives based on single factors,i.e.,overall trend,peak value,peak position,and peak number,were 80.23%,70.93%,67.44%,and 40.70%,respectively,whereas the identification accuracy of the analytic hierarchy process qualitative identification method based on multi-factors could be improved to 92.44%.In addition,the fuzzy characterisation of the absorption spectrum data was binarised in the data pre-processing stage and used as the base data for the overall trend,and the recognition accuracy was improved to 94.19%by combining the fuzzy characterisation method of such data with the hierarchical analysis qualitative recognition model.The results show that it is feasible to use terahertz technology to identify different varieties of additives,and this paper constructs a hierarchical analytical qualitative model with better effect,which provides a new means for food additives detection,and the method is simple in steps,with a small demand for samples,which is suitable for the rapid detection of small samples.
文摘This study was to analyze the risk of sulfites in food consumed by the Chinese people and assess the health protection capability of maximum-permitted level (MPL) of sulfites in GB 2760-2011. Sulfites as food additives are overused or abused in many food categories. When the MPL in GB 2760-2011 was used as sulfites content in food, the intake of sulfites in most surveyed populations was lower than the acceptable daily intake (ADI). Excess intake of sulfites was found in all the surveyed groups when a high percentile of sulfites in food was intaken. Moreover, children aged 1-6 years are at a high risk to intake excess sulfites. The primary cause for the excess intake of sulfites in Chinese people is the overuse and abuse of sulfites by the food industry. The current MPL of sulfites in GB 2760-2011 protects the health of most populations.
基金Supported by National Undergraduate Training Program for Innovation and Entrepreneurship(201410459011)
文摘With the vacuum freeze-drying technology, frozen dumpling wrappers were prepared, to investigate the effects of six kinds of food additives, including modified starch, compound phosphate, maltodextrin, guar gum, distilled monoglycerides and transglutaminase (TG enzyme), on the drying rate, rehydration ratio and sense value of the frozen dumpling wrappers. The results showed that, with respective addition of 6% modified starch, O. 1% compound phosphate, 10% maltodextrin, 0.4% guar gum, 0.4% distilled monoglyceride and 0.3% transglutaminase, the drying rate, rehydration ratio and sense value of the frozen dumpling wrappers were the highest.
基金supported by CNPq-Brazil program and PACD-FCF-UNESP.
文摘An ion-exchange chromatography (IEC) followed by post-column derivatization method was validated for the determination of glutamine in food additive products. The chromatographic method was carried out on a sodium cation-exchange column and using detection at 570 nm. The mobile phase consisted of sodium eluant, pH 3.15, with 5% sulfolane, sodium eluant, pH 7.40 and sodium column regenerant. The method was linear in the range of 4 - 50 μg/mL (r2 = 0.9999). The accuracy was 99.78%. Moreover, method validation demonstrated acceptable results for precision and robustness. The method was found to be able to use for routine analysis of the glutamine.
基金the financial support by the Food Safety Fund of General Administration of Quality Supervision,Inspection and Quarantine of Chinathe Key Scientific Program of National Institute of Metrology of China(Nos.ASPAQ201010 and AJDYX1116)
文摘An efficient and accurate analytical method was developed for the simultaneous determination of 20 synthetic food additives, including three sweeteners,seven food colorants,nine synthetic preservatives and caffeine,by high performance liquid chromatography (HPLC) with photodiode array detector(PDA).This method permits the detection of food additives at very low concentrations(0.005-0.150μg/mL).The applicability was verified by the determination of food additives present in various foodstuffs.
文摘The aim of this study was to revise the provisions for aluminum-containing food additives in GB 2760-2011 (The National Food Safety Standard for Use of Food Additives), in order to reduce aluminum exposure among the Chinese population. According to the latest risk assessment results of JECFA and China on aluminum and the actual use of aluminum-containing food additives in certain products, the aluminum-containing food additive-related provisions in GB 2760-2011 were revised. Those revisions included narrowing down the applicable food categories and adjusting the maximum use level of aluminum potassium sulfate and aluminum ammonium sulfate, repealing nine aluminum-containing food additives in puffed food and repealing the use of sodium aluminum phosphate, sodium aluminosilicate and starch aluminum octenylsuccinate in all food.
文摘A simplex-lattice mixture design with response surface methodology was used to evaluate in vitro synergistic antioxidant activity of red, green, and brown Brazilian propolis extract blends. The in vitro antioxidant capacity of propolis extract blends was measured using the fluorine method of oxygen radical absorption capacity assay (ORAC assay). A synergistic antioxidant interaction was identified between green and brown propolis extracts, and the predictive model accused a binary mixture composed of 59% green and 41% brown propolis extracts with increased antioxidant activity of about 54%. Our findings suggest a possible reduction in the dosages of these natural antioxidants in their various potential applications, including health and food, thereby proving to be a highly promising alternative for the rational use and valorization of propolis.
文摘Food colorants are widely used in the food industry to maintain or enhance product color. However, as the use of these colorants can have negative impacts on health, it is essential to analyze the risks associated with their consumption. This analysis requires, among other things, obtaining sufficient data on the presence of these colorants in foods, as well as their level of consumption. However, data on these colorants is often virtually non-existent in developing countries. The aim of this study was to determine the colorant profile of industrial products marketed in Senegal. Information on food additives was collected on 399 labels of different food product categories in shops located in Dakar. Data is recorded and processed using Excel software. Based on the Codex classification, analysis of the profile of additives identified on the labels of food samples revealed the presence of 31 colorants. The natural colorants identified are dominated by beta-carotene, widely present in beverages and dairy products, and paprika extract identified on cookies and industrial sauces. Artificial colors are dominated caramels present in several foods including bouillons, vinegars, sauces and hard candies. Secondly, there was a strong presence of the azo dye Sunset yellow FCF, widely found in samples of beverages, confectionery and cookies. The results of this case study enable us to appreciate the wide presence and diversity of colorants on the Senegalese market, and the importance of controlling them to guarantee consumer safety.
文摘In exploring an autonomous independent water supply system, authors have realized the importance of the sustainable water supply utilizing regional features in isolated islands. This paper is further study from the previous one. This time we have narrowed down the mixing rate of mixed water. In this study, the mixed water less than 0.74% (blood concentration) has been prepared first, and then divided it into five kinds of the mixing rate of mixed water. And we have compared and examined the characteristics of the mixed water from the viewpoint of the relationship between salinity and pH, ORP and that of Dissolved Hydrogen, and examined the possibility of mixed water as a drinking water. As a result, we have obtained the new findings that suggest the possibility.
文摘Due to human-caused deforestation,global warming,and other environmental factors,habitat fragmentation became widespread.This fragmentation has a variety of detrimental repercussions for many species as well as humans,especially in the agricultural economy.It causes insect outbreaks,the expansion of alien species,and disrupts biological management by rendering the habitat unsuitable for natural enemies in agriculture.Providing natural enemies with additional food is one method to improve the ecosystem and support them.In this study,we assumed that the ecosystem is separated into two patches and that predators can easily migrate from one patch to the next,while prey stays inside its patch's territory.We looked at the impact of offering more food to predators in a patchy environment using dynamical systems theory.The permanence,stability,and various bifurcations that occur in the system are studied using a rigorous mathematical analysis.The study looks at how predator's access to other food sources affects pest management.By adjusting the provided food's characteristic qualities,such as(nutritional)quality and quantity,one can limit and manage the pest in one or both patches,as well as eliminate predators from the ecosystem.This research reveals that providing predators with additional food(of specified quality and quantity)can help in controlling chaotic behavior in the system.The findings of the study are supported by numerical simulations.
基金sponsored by the National Nature Science Foundation of China (No.22076038)Natural Science Foundation of Henan (No.202300410044)。
文摘In this work,the nano-g-C_(3)N_(4)/Ui O-66-NH_(2)composite was prepared by one-step solvothermal method.The as-prepared composite was characterized by scanning electron microscopy,Brunner-Emmet-Teller measurement,energy dispersive spectrometer,X-ray diffraction,and Fourier transform infrared spectroscopy.By using nano-g-C_(3)N_(4)/Ui O-66-NH_(2)composite as sorbent,a dispersive solid-phase extraction coupled with high-performance liquid chromatography was developed to sensitive analysis of food colorants including tartrazine,amaranth,carmine,sunset yellow,allura red and bright blue.The experiment parameters including the amount of sorbent,adsorption time,the p H of adsorption solution,desorption time,desorption solvent,the p H of desorption solution as well as the proportion between desorption solvent and buffer solvent were investigated.Under the optimized conditions,the limits of detection(S/N=3) and limits of quantitation (S/N=10) were determined in the ranges of 0.08-0.8 and 0.2-2.0 ng/m L,respectively.With the developed sample pretreatment method,carmine and brilliant blue were determined from blueberry juice by HPLC-DAD.The contents were calculated as 1.53μg/m L and0.17μg/mL,respectively.
基金supported by the National Natural Science Foundation of China (No. 20820102037,20935003)the National Basic Research Program (973) of China (No.2010CB933603)
文摘Based on the inhibition effect on the respiratory chain activity of microorganisms by toxicants, an electrochemical method has been developed to measure the current variation of a mediator in the presence of microorganisms contacted with a toxicant. Microelectrode arrays were adopted in this study, which can accelerate the mass transfer rate of an anaiyte to the electrode and also increase the total current signal, resulting in an improvement in detection sensitivity. We selected Escherichia coli as the testee and the standard glucose- glutamic acid as an exogenous material. Under oxygen restriction, the experiments in the presence of toxicant were performed at optimum conditions (solution pH 7.0, 37℃ and reaction for 3 hr). The resulting solution was then separated from the suspended microorganisms and was measured by an electrochemical method, using ferricyanide as a mediator. The current signal obtained represents the reoxidation of ferrocyanide, which was transformed to inhibiting efficiency, IC50, as a quantitative measure of toxicity. The IC50 values measured were 410, 570 and 830 mg/L for sodium nitrite, borax and aluminum potassium sulfate, respectively. The results show that the toxicity sequence for these three food additives is consistent with the value reported by other methods. Furthermore, the order of damage degree to the microorganism was also observed to be: sodium nitrite 〉 borax 〉 aluminum potassium sulfate 〉 blank, according to the atomic force microscopy images of E. coli after being incubated for 3 hr with the toxic compound in buffer solutions. The electrochemical method is expected to be a sensitive and simple alternative to toxicity screening for chemical food additives.
基金supported by the Research Foundation for Youth Scholars of Beijing Technology and Business University(QNJJ2016-17)supported by the National Natural Science Foundation of China(31301593)Research and Development Fund for University’s Doctoral Discipline of China(20130008120021).
文摘The rheological characteristic of soy protein isolate(SPI),is one of the most important properties in its application in food industry.The effects of different concentrations of guar gum(GG,polysaccharide)and sodium chloride(salt ion)on the rheological properties of SPI were studied in this research.Steady-state shear,strain sweep and frequency sweep tests(static and dynamic rheological tests)were performed,and the following phenomenon and conclusions were drawn:(1)The viscosity of the hybrid system increases with the GG addition.This trend could also be seen with the appropriate adding of salt ion;(2)As the applied frequency increases,the storage modulus G′and the loss modulus G″of the hybrid system increase at a similar rate.And the frequency sweep parameters of the hybrid system rise significantly with the increase of both GG and ionic concentration;The frequency dependence of the system varies significantly with the addition of salt ion;(3)With the concentration of the salt ion increase,the storage module G′of the hybrid system decrease indicating that salt ion destroyed the network structure of hybrid dispersion to a certain extent.