Monitoring biogenic amines,which are metabolic byproducts of shrimp spoilage,is crucial for assessing food quality.Currently,most detection methods for biogenic amines suffer from limitations such as time-consuming pr...Monitoring biogenic amines,which are metabolic byproducts of shrimp spoilage,is crucial for assessing food quality.Currently,most detection methods for biogenic amines suffer from limitations such as time-consuming procedures,complex operations,and delayed results.Colorimetric analysis techniques have gained attention in recent years due to their advantages of short analysis time,simple operation,and suitability for on-site testing.This study successfully developed a series of colorimetric sensor platforms for biogenic amines by loading the natural active ingredient curcumin(CUR)and its derivative of Boron complex BFCUR onto filter paper and electrospun nanofibre films(ENFs),respectively.By analyzing the color response differences of these sensors upon contact with biogenic amines,the colorimetric sensors with superior detection performance were selected and further applied to the visual monitoring and indication of shrimp spoilage processes.展开更多
The effect of freshness protection package on Chinese cabbage placed in the self-made shelf in ventilated storage was investigated, and the physiological-qual-ity indexes change were determined during the storage peri...The effect of freshness protection package on Chinese cabbage placed in the self-made shelf in ventilated storage was investigated, and the physiological-qual-ity indexes change were determined during the storage period. The results showed that the losses of weight and vitamin C were significantly reduced. The accumula-tion of crude fiber was effectively inhibited. But protein content was maintained at a low level and the rotting more serious of Chinese cabbage at the end of the stor-age packaged with the fresh keeping bags.展开更多
Salt tolerance and freeze preservation of crucian are always important concerns of people. There are rare reports on effect of different salinity on fresh- ness and quality. However, water salinity will directly affec...Salt tolerance and freeze preservation of crucian are always important concerns of people. There are rare reports on effect of different salinity on fresh- ness and quality. However, water salinity will directly affect osmotic pressure in fish, thereby affecting meat quality. In this study, the tolerance of crucian to different salinities （1‰, 2‰, 5‰, 8‰, 10‰ and 15‰） was investigated. In addition, the ef- fect of different salinity on freezing freshness and quality of crucian was studied. The results showed that the tolerance threshold of crucian to salinity was about 8‰, and the freezing quality of crucian in water with salinity of ‰ was significantly better than that in fresh water.展开更多
China is one of the largest meat producing countries in the wodd. With the growing concern for food safety more attention has been paid to meat quality. The application of conventional test methods for meat quality is...China is one of the largest meat producing countries in the wodd. With the growing concern for food safety more attention has been paid to meat quality. The application of conventional test methods for meat quality is limited by many factors, and subjectiveness, such as longer time to prepare samples and to test. A sensor matrix was constructed with several separate air sensors, and tests were conducted to detect the freshness of the beef. The results show that the air sensors TGS2610, TGS2600, TGS2611, TGS2620 and TGS2602 made by Tianjin Figaro Electronic Co, Ltd could be used to determine the degree of freshness but TGS2442 is not suitable. This study provides a foundation for designing and making an economical and practical detector for beef freshness.展开更多
Aquatic products are extremely perishable food commodities. Developing methods to keep the freshness of fish represents a major task of the fishery processing industry. Application of Lactic Acid Bacteria(LAB) as food...Aquatic products are extremely perishable food commodities. Developing methods to keep the freshness of fish represents a major task of the fishery processing industry. Application of Lactic Acid Bacteria(LAB) as food preservative is a novel approach. In the present study, the possibility of using lactic acid bacteria in freshness keeping of tilapia fillets as sashimi was examined. Fish fillets were dipped in Lactobacillus plantarum 1.19(obtained from China General Microbiological Culture Collection Center) suspension as LAB-treated group. Changes in K-value, APC, sensory properties and microbial flora were analyzed. Results showed that LAB treatment slowed the increase of K-value and APC in the earlier storage, and caused a smooth decrease in sensory score. Gram-negative bacteria dominated during refrigerated storage, with Pseudomonas and Aeromonas being relatively abundant. Lactobacillus plantarum 1.19 had no obvious inhibitory effect against these Gram-negatives. However, Lactobacillus plantarum 1.19 changed the composition of Gram-positive bacteria. No Micrococcus were detected and the proportion of Staphylococcus decreased in the spoiled LAB-treated samples. The period that tilapia fillets could be used as sashimi material extended from 24 h to 48 h after LAB treatment. The potential of using LAB in sashimi processing was confirmed.展开更多
The nutritional value of perishable food items,such as fruits and vegetables,depends on their freshness levels.The existing approaches solve a binary class problem by classifying a known fruit\vegetable class into fre...The nutritional value of perishable food items,such as fruits and vegetables,depends on their freshness levels.The existing approaches solve a binary class problem by classifying a known fruit\vegetable class into fresh or rotten only.We propose an automated fruits and vegetables categorization approach that first recognizes the class of object in an image and then categorizes that fruit or vegetable into one of the three categories:purefresh,medium-fresh,and rotten.We gathered a dataset comprising of 60K images of 11 fruits and vegetables,each is further divided into three categories of freshness,using hand-held cameras.The recognition and categorization of fruits and vegetables are performed through two deep learning models:Visual Geometry Group(VGG-16)and You Only Look Once(YOLO),and their results are compared.VGG-16 classifies fruits and vegetables and categorizes their freshness,while YOLO also localizes them within the image.Furthermore,we have developed an android based application that takes the image of the fruit or vegetable as input and returns its class label and its freshness degree.A comprehensive experimental evaluation of proposed approach demonstrates that the proposed approach can achieve a high accuracy and F1score on gathered FruitVeg Freshness dataset.The dataset is publicly available for further evaluation by the research community.展开更多
In this paper,multi-UAV trajectory planning and resource allocation are jointly investigated to improve the information freshness for vehicular networks,where the vehicles collect time-critical traffic information by ...In this paper,multi-UAV trajectory planning and resource allocation are jointly investigated to improve the information freshness for vehicular networks,where the vehicles collect time-critical traffic information by on-board sensors and upload to the UAVs through their allocated spectrum resource.We adopt the expected sum age of information(ESAoI)to measure the network-wide information freshness.ESAoI is jointly affected by both the UAVs trajectory and the resource allocation,which are coupled with each other and make the analysis of ESAoI challenging.To tackle this challenge,we introduce a joint trajectory planning and resource allocation procedure,where the UAVs firstly fly to their destinations and then hover to allocate resource blocks(RBs)during a time-slot.Based on this procedure,we formulate a trajectory planning and resource allocation problem for ESAoI minimization.To solve the mixed integer nonlinear programming(MINLP)problem with hybrid decision variables,we propose a TD3 trajectory planning and Round-robin resource allocation(TTPRRA).Specifically,we exploit the exploration and learning ability of the twin delayed deep deterministic policy gradient algorithm(TD3)for UAVs trajectory planning,and utilize Round Robin rule for the optimal resource allocation.With TTP-RRA,the UAVs obtain their flight velocities by sensing the locations and the age of information(AoI)of the vehicles,then allocate the RBs to the vehicles in a descending order of AoI until the remaining RBs are not sufficient to support another successful uploading.Simulation results demonstrate that TTP-RRA outperforms the baseline approaches in terms of ESAoI and average AoI(AAoI).展开更多
Major royal jelly protein 1（MRJP1）, designated apalbumin 1, has been regarded as a freshness marker of royal jelly（RJ）. A MRJP1-specific peptide（IKEALPHVPIFD） identified by bioinformatics analysis of homologous ...Major royal jelly protein 1（MRJP1）, designated apalbumin 1, has been regarded as a freshness marker of royal jelly（RJ）. A MRJP1-specific peptide（IKEALPHVPIFD） identified by bioinformatics analysis of homologous members of the major royal protein family was synthesized and used to raise polyclonal anti-MRJP1 antibody（antiSP-MRJP1 antibody）. Western blot analysis showed that anti-SP-MRJP1 antibody only reacted with MRJP1 in RJ. In contrast, the previously reported antibody against recombinant MRJP1（anti-R-MRJP1 antibody） reacted with other members of MRJP family in RJ. Enzyme-linked immunosorbent assay（ELISA） using anti-SP-MRJP1 antibody demonstrated that MRJP1 content in RJ stored at 40 °C significantly degraded by 37.3%, 55.9%, 58.0%, 60.6%, 65.7%, 72.7%, and 73.1% at 7, 14, 21, 28, 35, 42, and 49 d, respectively, when compared with MRJP1 content in fresh RJ（0 d）. Optical density analysis of MRJP bands from sodium dodecyl sulfate-polyacrylamide gel electrophoresis（SDS-PAGE） profiles demonstrated that the degradation of MRJP1, MRJP2, MRJP3, and MRJP5 in RJ was strongly and positively correlated with the period of storage（P〈0.0001）. Our results indicated anti-SP-MRJP1 antibody was highly specific for MRJP1, and ELISA using the antibody is a sensitive and easy-to-use method to determine the freshness and authenticity of RJ.展开更多
This study assessed the feasibility of developing a machine vision system equipped with ultraviolet (UV) light, using changes in fish-surface color to predict aerobic plate count (APC, a standard freshness indicator) ...This study assessed the feasibility of developing a machine vision system equipped with ultraviolet (UV) light, using changes in fish-surface color to predict aerobic plate count (APC, a standard freshness indicator) during storage. The APC values were tested and images of the fish surface were taken when fish were stored at room temperature. Then, images</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">’</span></span></span><span><span><span><span> color-space conversion among RGB, HSV, and L*a*b* color spaces was carried out and analyzed. The results revealed that a* and b* values from the UV-light image decreased linearly during storage. A further regression analysis of these two parameters with APC value demonstrated a good exponential relationship between the a* value and the APC value (R</span><sup><span>2</span></sup><span> = 0.97), followed by the b* (R</span><sup><span>2</span></sup><span> = 0.85). Therefore, our results suggest that the change in color of the fish surface under UV light can be used to assess fish freshness during storage.展开更多
Because the web is huge and web pages are updated frequently, the index maintained by a search engine has to refresh web pages periodically. This is extremely resource consuming because the search engine needs to craw...Because the web is huge and web pages are updated frequently, the index maintained by a search engine has to refresh web pages periodically. This is extremely resource consuming because the search engine needs to crawl the web and download web pages to refresh its index, Based on present technologies of web refreshing, we present a cooperative schema between web server and search engine for maintaining freshness of web repository. The web server provides metadata defined through XML standard to describe web sites. Before updating the web page the crawler visits the meta-data files. If the meta-data indicates that the page is not modified, then the crawler will not update it. So this schema can save bandwidth resource. A primitive model based on the schema is implemented. The cost and efficiency of the schema are analyzed.展开更多
The Internet of things(IoT)has become a key infrastructure providing up-to-date and fresh information for policy analysis and decision-making of upper-layer applications.However,there are limited sensing and communica...The Internet of things(IoT)has become a key infrastructure providing up-to-date and fresh information for policy analysis and decision-making of upper-layer applications.However,there are limited sensing and communication resources in IoT devices,which significantly affects the timeliness and freshness of the updated status.This work proposes two schemes,namely,the generation rate control and service rate reservation schemes,to improve the overall information freshness of multiple status update streams at the receiver.Specifically,using the recently proposed Age of Information(AoI)as the metric for evaluating information freshness,we characterized the overall information freshness,i.e.,the overall average AoI at the receiver for both schemes,by considering the urgency difference of status update and streams.Both schemes for status updates and streams,respectively,were formulated as two optimization problems.We proved that both problems are convex and the optimal generation and service rates for different streams are found by the standard convex optimization algorithm.Moreover,we proposed both approximate optimal generation and approximate optimal service rate for fast deployment in heavy and light load cases.Numerical results verify the theoretical findings and accuracy of the proposed approximate solutions,guiding the design and deployment of IoT.展开更多
As a novel food quality monitoring technology,intelligent freshness indicator has received wide attention in recent years.However,its poor safety and stability are the main problems hindering its practical application...As a novel food quality monitoring technology,intelligent freshness indicator has received wide attention in recent years.However,its poor safety and stability are the main problems hindering its practical application.Hence a new pH-sensing indicator based on bromocresol green(BCG)was developed in this study for nondestructive and real-time monitoring the freshness of marine fishes.The indicator was designed with a three-layer structure,using the polytetrafluoroethylene(PTFE)membrane with high hydrophobicity and air permeability as the inner layer to isolate the moisture in the package,BCG-coated filter paper as the colorchanging layer to indicate the freshness of fish,and a transparent unidirectional permeable(TUP)membrane with moisture resistance as the out layer to isolate the moisture in the environment.This contributed to weaken the influence of humidity and prevent dye migration,so as to improve the accuracy and safety of the indicator.Therefore,a highly sensitive and distinguished color variation response to trimethylamine(TMA)standard solution with different concentrations was observed on the indicator.Additionally,the indicator showed a high color stability at different storage temperatures up to 14 days with total color differences(ΔE)less than 5.0.The indicator presented visible color variations from yellow to green then eventually to blue when applied to monitor the freshness of sea bass and salmon stored at 4℃,implying that fish was spoiled.Meanwhile,indicatorsΔE value was significantly positively correlated with total volatile basic nitrogen(TVB-N)and total viable count(TVC)in sea bass and salmon samples.Thus,the pH-sensing indicator can be applied as a cost-effective and promising intelligent indicator for monitoring fish freshness.展开更多
A new method for determining the freshness of harvested carp using nuclear imaging technology is presented.This research attempted to determine the freshness of carp by measuring the radioactive area increase (RAI) va...A new method for determining the freshness of harvested carp using nuclear imaging technology is presented.This research attempted to determine the freshness of carp by measuring the radioactive area increase (RAI) value of fish.The carp samples were maintained under refrigerated condition for 12d, and RAI and total volatile base nitrogen (T-VBN)values were determined during the storage. The results showed that the RAI value increased with the T-VBN content duringthe storage. Also, there is a significant correlation between T-VBN content and RAI value of the carp kept in refrigeratedcondition. The results of this study suggest that the RAI value could be utilized to evaluate rapidly the freshness of carp.展开更多
The developed trend of novel intelligent packaging materials is changing from food traditional appearance detection to actual spoilage monitoring,aiming to supply a strategy to determine the edibility of food.In this ...The developed trend of novel intelligent packaging materials is changing from food traditional appearance detection to actual spoilage monitoring,aiming to supply a strategy to determine the edibility of food.In this work,a dual-functional electrospun nanofiber film(NFM)noted GZAT was prepared by the co-loading of anthocyanin(ANT)and thymol(THY)into polymer fibers of gelatin and zein.The prepared film was extensively characterized.The GZAT film displayed enhanced mechanical properties and decreased water vapor perme-ability(WVP)compared with gelatin/zein film(the control).The GZAT film also displayed excellent sensitive colorimetric responses to the pH solutions.Moreover,it exhibited excellent antioxidant property and antibac-terial behavior against Escherichia coli ATC25922(E.coli),Listeria monocytogenes ATCC 19115(L.monocytogenes)and Staphylococcus aureus ATCC 6538(S.aureus).Not only that,the dual functions of the GZAT film were confirmed that the shelf life of packaged shrimps was successfully extended to 11 days at 4℃along with the colorimetric response indicating the freshness of the shrimps.Based on the above characteristic,the prepared GZAT film exhibited great potential as an intelligent packaging film with both real-time freshness indicator and freshness preservation.展开更多
Aquatic products were susceptible to spoilage during storage due to microorganisms and enzymes,which could cause food safety problems.The electrospun nanofiber films,based on pullulan(PUL)and polyvinyl alcohol(PVA)inc...Aquatic products were susceptible to spoilage during storage due to microorganisms and enzymes,which could cause food safety problems.The electrospun nanofiber films,based on pullulan(PUL)and polyvinyl alcohol(PVA)incorporating bayberry pomace anthocyanin extract(BAE),were developed to monitor the freshness states of aquatic products in this study.The SEM results revealed that the electrospun nanofiber films exhibited a smooth surface,and the average diameter decreased from 481.56 nm to 237.68 nm as anthocyanin content increased from 0 to 20%.The FTIR and XRD results showed that there were no new characteristic peaks,confirming the successful loading of BAE.The incorporation of BAE decreased the water content(from 13.58%to 7.84%),swelling ratio(from 146.75%to 114.24%),water vapor permeability(from 3.38 g⋅mm⋅m^(-2)⋅Pa^(-1)⋅s^(-1)⋅10^(-5)to 2.00 g⋅mm⋅m^(-2)⋅Pa^(-1)⋅s^(-1)⋅10^(-5)),and elongation at break(from 24.67%to 14.90%),but increased water solubility(from 74.99%to 85.74%)and water contact angle(from 51.84◦to 63.73◦).The electrospun nanofiber films presented obvious color changes in buffer solutions(pH 2.0 to 12.0)or volatile ammonia and showed good reversibility.Besides,the electrospun nanofiber films were stable during storage at 4◦C or 25◦C for 20 days.Furthermore,PUL-PVA-A15 effectively distinguished the freshness states(fresh,sub-fresh and spoiled)of Penaeus vannamei during storage at 4◦C by showing different colors(from pink to grayish purple to green).Therefore,the electrospun nanofiber films showed great potential to real-time monitor the quality of aquatic foods as intelligent packaging.展开更多
Fresh beef is highly susceptible to spoilage during refrigerated storage,yet current freshness assessment ap-proaches remain limited by their invasiveness or low sensitivity.Beef exudate,a naturally released fluid enr...Fresh beef is highly susceptible to spoilage during refrigerated storage,yet current freshness assessment ap-proaches remain limited by their invasiveness or low sensitivity.Beef exudate,a naturally released fluid enriched with soluble metabolites,represents a promising yet underutilized matrix for non-invasive freshness assessment.This study applied non-targeted metabolomics to characterize spoilage-related metabolites in beef exudate and to clarify their association with freshness.Beef shank muscles were stored at 7±1℃,after which exudates were collected for physicochemical analyses and non-targeted metabolomic profiling using UHPLC-MS/MS.Comparative analyses revealed that metabolic variations in exudate closely mirrored physicochemical deterio-ration trends observed in the corresponding beef tissue.Among 1703 detected metabolites,62 changed signif-icantly during storage.Pathway enrichment identified the pivotal involvement of arginine metabolism and amino acid biosynthesis in spoilage progression.Correlation analysis further highlighted five key com-pounds-5′-methylthioadenosine,7-methylxanthine,N-methyltryptamine,L-phenylalanine,and spermine-as candidate freshness markers.Overall,this study demonstrates that exudate-based metabolomics offers an effective and non-invasive strategy for monitoring beef freshness,providing new insights for intelligent quality evaluation and spoilage prediction in the meat industry.展开更多
Amine-responsive fluorescent indicator films for meat freshness were constructed by incorporating β-glucan grafted with fluorescein isothiocyanate(FITC)in polyvinyl alcohol(PVA).The structural,thermal,and responsive ...Amine-responsive fluorescent indicator films for meat freshness were constructed by incorporating β-glucan grafted with fluorescein isothiocyanate(FITC)in polyvinyl alcohol(PVA).The structural,thermal,and responsive properties of grafted copolymers(βGlu-FITC)were investigated.The results of 1H NMR spectra showed that βGlu-FITC exhibited proton signals between 6.5 and 6.7 ppm,suggesting the successful grafting of FITC onto β-glucan.The fluorescence quantum yield of βGlu-FITC was 18.72%,which was higher than that of β-glucan of 12.94% at the optimum excitation wavelength of ultraviolet light of 365 nm.With the incorporation of PVA as a film-forming matrix,βGlu-FITC/PVA films showed high yellow-green fluorescent responsiveness under volatile ammonia and pH solution.When the film was used for meat freshness,the 0.06βGlu-FITC/PVA film provided a noticeable fluorescent indication of pork freshness that corresponded to increases in total volatile basic nitrogen,total colony counts,and drip loss,suggesting its potential for meat packaging and as a freshness indicator.展开更多
The authors regret an error in the vertical axis labels of Fig.7(f)and(g).Upon reviewing the published article,we discovered that due to our oversight,the vertical axis labels in Fig.7(f)and(g)were incorrectly labelle...The authors regret an error in the vertical axis labels of Fig.7(f)and(g).Upon reviewing the published article,we discovered that due to our oversight,the vertical axis labels in Fig.7(f)and(g)were incorrectly labelled as“ΔE”instead of“Swelling Ratio(%)”.This error has now been corrected.The relevant annotations,analyses,and underlying data remain unchanged and are accurate.展开更多
The authors regret an error in the vertical axis labels of Fig.7(f)and(g).Upon reviewing the published article,we discovered that due to our oversight,the vertical axis labels in Fig.7(f)and(g)were incorrectly labelle...The authors regret an error in the vertical axis labels of Fig.7(f)and(g).Upon reviewing the published article,we discovered that due to our oversight,the vertical axis labels in Fig.7(f)and(g)were incorrectly labelled as“ΔE”instead of“Swelling Ratio(%)”.This error has now been corrected.The relevant annotations,analyses,and underlying data remain unchanged and are accurate.展开更多
Carbon dots(CDs)have gained increasing attention across multiple disciplines due to their unique antibacterial activity,antioxidant properties,and tunable fluorescence characteristics.Particularly in the food industry...Carbon dots(CDs)have gained increasing attention across multiple disciplines due to their unique antibacterial activity,antioxidant properties,and tunable fluorescence characteristics.Particularly in the food industry,the incorporation of CDs-based detection platforms into food packaging materials has enabled the development of composite films with dual functionalities of food preservation and real-time monitoring.This review provides an overview of the synthesis methods of CDs,elucidates the antimicrobial and antioxidant mechanisms of CDs,and discusses their effective application strategies for extending food shelf life.The fluorescence properties of CDs are analyzed,and the potential of utilizing these properties for intelligent food freshness monitoring is explored.Furthermore,the challenges facing these technologies and future development trends are discussed,with a particular emphasis on the integration of CDs with Internet of Things and machine learning technologies for realtime monitoring of food quality,providing theoretical insights for the development of next-generation multi-functional active packaging materials.展开更多
基金Supported by the Guangdong-Hong Kong-Macao Joint Laboratory on Micro-Nano Manufacturing Technology,China(No.2021LSYS004)Guangdong Provincial Key Laboratory of Sustainable Biomimetic Materials and Green Energy,China(No.2024B1212010003)。
文摘Monitoring biogenic amines,which are metabolic byproducts of shrimp spoilage,is crucial for assessing food quality.Currently,most detection methods for biogenic amines suffer from limitations such as time-consuming procedures,complex operations,and delayed results.Colorimetric analysis techniques have gained attention in recent years due to their advantages of short analysis time,simple operation,and suitability for on-site testing.This study successfully developed a series of colorimetric sensor platforms for biogenic amines by loading the natural active ingredient curcumin(CUR)and its derivative of Boron complex BFCUR onto filter paper and electrospun nanofibre films(ENFs),respectively.By analyzing the color response differences of these sensors upon contact with biogenic amines,the colorimetric sensors with superior detection performance were selected and further applied to the visual monitoring and indication of shrimp spoilage processes.
基金Supported by the Major State Research Development Program of China(2016YFD04013)~~
文摘The effect of freshness protection package on Chinese cabbage placed in the self-made shelf in ventilated storage was investigated, and the physiological-qual-ity indexes change were determined during the storage period. The results showed that the losses of weight and vitamin C were significantly reduced. The accumula-tion of crude fiber was effectively inhibited. But protein content was maintained at a low level and the rotting more serious of Chinese cabbage at the end of the stor-age packaged with the fresh keeping bags.
基金Supported by Incentive Program Subsidized by Department of Science and Technology of Hebei Province(15926620H)Key Technology Research and Development Program of Science and Technology Bureau of Qinhuangdao City(201401A067201402B043)~~
文摘Salt tolerance and freeze preservation of crucian are always important concerns of people. There are rare reports on effect of different salinity on fresh- ness and quality. However, water salinity will directly affect osmotic pressure in fish, thereby affecting meat quality. In this study, the tolerance of crucian to different salinities （1‰, 2‰, 5‰, 8‰, 10‰ and 15‰） was investigated. In addition, the ef- fect of different salinity on freezing freshness and quality of crucian was studied. The results showed that the tolerance threshold of crucian to salinity was about 8‰, and the freezing quality of crucian in water with salinity of ‰ was significantly better than that in fresh water.
文摘China is one of the largest meat producing countries in the wodd. With the growing concern for food safety more attention has been paid to meat quality. The application of conventional test methods for meat quality is limited by many factors, and subjectiveness, such as longer time to prepare samples and to test. A sensor matrix was constructed with several separate air sensors, and tests were conducted to detect the freshness of the beef. The results show that the air sensors TGS2610, TGS2600, TGS2611, TGS2620 and TGS2602 made by Tianjin Figaro Electronic Co, Ltd could be used to determine the degree of freshness but TGS2442 is not suitable. This study provides a foundation for designing and making an economical and practical detector for beef freshness.
基金supported by the National Natural Science Foundation of China(No.31301587)Key Laboratory of Aquatic Product Processing,Ministry of Agriculture,China
文摘Aquatic products are extremely perishable food commodities. Developing methods to keep the freshness of fish represents a major task of the fishery processing industry. Application of Lactic Acid Bacteria(LAB) as food preservative is a novel approach. In the present study, the possibility of using lactic acid bacteria in freshness keeping of tilapia fillets as sashimi was examined. Fish fillets were dipped in Lactobacillus plantarum 1.19(obtained from China General Microbiological Culture Collection Center) suspension as LAB-treated group. Changes in K-value, APC, sensory properties and microbial flora were analyzed. Results showed that LAB treatment slowed the increase of K-value and APC in the earlier storage, and caused a smooth decrease in sensory score. Gram-negative bacteria dominated during refrigerated storage, with Pseudomonas and Aeromonas being relatively abundant. Lactobacillus plantarum 1.19 had no obvious inhibitory effect against these Gram-negatives. However, Lactobacillus plantarum 1.19 changed the composition of Gram-positive bacteria. No Micrococcus were detected and the proportion of Staphylococcus decreased in the spoiled LAB-treated samples. The period that tilapia fillets could be used as sashimi material extended from 24 h to 48 h after LAB treatment. The potential of using LAB in sashimi processing was confirmed.
文摘The nutritional value of perishable food items,such as fruits and vegetables,depends on their freshness levels.The existing approaches solve a binary class problem by classifying a known fruit\vegetable class into fresh or rotten only.We propose an automated fruits and vegetables categorization approach that first recognizes the class of object in an image and then categorizes that fruit or vegetable into one of the three categories:purefresh,medium-fresh,and rotten.We gathered a dataset comprising of 60K images of 11 fruits and vegetables,each is further divided into three categories of freshness,using hand-held cameras.The recognition and categorization of fruits and vegetables are performed through two deep learning models:Visual Geometry Group(VGG-16)and You Only Look Once(YOLO),and their results are compared.VGG-16 classifies fruits and vegetables and categorizes their freshness,while YOLO also localizes them within the image.Furthermore,we have developed an android based application that takes the image of the fruit or vegetable as input and returns its class label and its freshness degree.A comprehensive experimental evaluation of proposed approach demonstrates that the proposed approach can achieve a high accuracy and F1score on gathered FruitVeg Freshness dataset.The dataset is publicly available for further evaluation by the research community.
基金supported in part by the Project of International Cooperation and Exchanges NSFC under Grant No.61860206005in part by the Joint Funds of the NSFC under Grant No.U22A2003.
文摘In this paper,multi-UAV trajectory planning and resource allocation are jointly investigated to improve the information freshness for vehicular networks,where the vehicles collect time-critical traffic information by on-board sensors and upload to the UAVs through their allocated spectrum resource.We adopt the expected sum age of information(ESAoI)to measure the network-wide information freshness.ESAoI is jointly affected by both the UAVs trajectory and the resource allocation,which are coupled with each other and make the analysis of ESAoI challenging.To tackle this challenge,we introduce a joint trajectory planning and resource allocation procedure,where the UAVs firstly fly to their destinations and then hover to allocate resource blocks(RBs)during a time-slot.Based on this procedure,we formulate a trajectory planning and resource allocation problem for ESAoI minimization.To solve the mixed integer nonlinear programming(MINLP)problem with hybrid decision variables,we propose a TD3 trajectory planning and Round-robin resource allocation(TTPRRA).Specifically,we exploit the exploration and learning ability of the twin delayed deep deterministic policy gradient algorithm(TD3)for UAVs trajectory planning,and utilize Round Robin rule for the optimal resource allocation.With TTP-RRA,the UAVs obtain their flight velocities by sensing the locations and the age of information(AoI)of the vehicles,then allocate the RBs to the vehicles in a descending order of AoI until the remaining RBs are not sufficient to support another successful uploading.Simulation results demonstrate that TTP-RRA outperforms the baseline approaches in terms of ESAoI and average AoI(AAoI).
基金supported by the Public Beneficial Scientific&Technical Plan of Zhejiang(No.2011C22039)the Important Scientific & Technical Plan of Zhejiang(No.2011C12023)+2 种基金the Important Scientific & Technical Innovation Project of Hangzhou(No.20131812A25)the Foundation of Fuli Institute of Food Science of Zhejiang University(No.KY201404)the National Natural Science Foundation of China(No.31271848)
文摘Major royal jelly protein 1（MRJP1）, designated apalbumin 1, has been regarded as a freshness marker of royal jelly（RJ）. A MRJP1-specific peptide（IKEALPHVPIFD） identified by bioinformatics analysis of homologous members of the major royal protein family was synthesized and used to raise polyclonal anti-MRJP1 antibody（antiSP-MRJP1 antibody）. Western blot analysis showed that anti-SP-MRJP1 antibody only reacted with MRJP1 in RJ. In contrast, the previously reported antibody against recombinant MRJP1（anti-R-MRJP1 antibody） reacted with other members of MRJP family in RJ. Enzyme-linked immunosorbent assay（ELISA） using anti-SP-MRJP1 antibody demonstrated that MRJP1 content in RJ stored at 40 °C significantly degraded by 37.3%, 55.9%, 58.0%, 60.6%, 65.7%, 72.7%, and 73.1% at 7, 14, 21, 28, 35, 42, and 49 d, respectively, when compared with MRJP1 content in fresh RJ（0 d）. Optical density analysis of MRJP bands from sodium dodecyl sulfate-polyacrylamide gel electrophoresis（SDS-PAGE） profiles demonstrated that the degradation of MRJP1, MRJP2, MRJP3, and MRJP5 in RJ was strongly and positively correlated with the period of storage（P〈0.0001）. Our results indicated anti-SP-MRJP1 antibody was highly specific for MRJP1, and ELISA using the antibody is a sensitive and easy-to-use method to determine the freshness and authenticity of RJ.
文摘This study assessed the feasibility of developing a machine vision system equipped with ultraviolet (UV) light, using changes in fish-surface color to predict aerobic plate count (APC, a standard freshness indicator) during storage. The APC values were tested and images of the fish surface were taken when fish were stored at room temperature. Then, images</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">’</span></span></span><span><span><span><span> color-space conversion among RGB, HSV, and L*a*b* color spaces was carried out and analyzed. The results revealed that a* and b* values from the UV-light image decreased linearly during storage. A further regression analysis of these two parameters with APC value demonstrated a good exponential relationship between the a* value and the APC value (R</span><sup><span>2</span></sup><span> = 0.97), followed by the b* (R</span><sup><span>2</span></sup><span> = 0.85). Therefore, our results suggest that the change in color of the fish surface under UV light can be used to assess fish freshness during storage.
基金Supported by the National Natural Science Funda-tion of China (60403027)
文摘Because the web is huge and web pages are updated frequently, the index maintained by a search engine has to refresh web pages periodically. This is extremely resource consuming because the search engine needs to crawl the web and download web pages to refresh its index, Based on present technologies of web refreshing, we present a cooperative schema between web server and search engine for maintaining freshness of web repository. The web server provides metadata defined through XML standard to describe web sites. Before updating the web page the crawler visits the meta-data files. If the meta-data indicates that the page is not modified, then the crawler will not update it. So this schema can save bandwidth resource. A primitive model based on the schema is implemented. The cost and efficiency of the schema are analyzed.
基金sponsored by the National Natural Science Foundation of China under Grant 61901066,Grant 61971077sponsored by Natural Science Foundation of Chongqing,China under Grant cstc2019jcyjmsxmX0575,Grant cstc2021jcyj-msxmX0458+2 种基金in part by the Entrepreneurship and Innovation Support Plan of Chongqing for Returned Overseas Scholars under Grant cx2021092supported by the open research fund of National Mobile Communications Research Laboratory,Southeast University(No.2021D13,No.2022D06)the Industrial Internet innovation and development project(No.TC200A00M).
文摘The Internet of things(IoT)has become a key infrastructure providing up-to-date and fresh information for policy analysis and decision-making of upper-layer applications.However,there are limited sensing and communication resources in IoT devices,which significantly affects the timeliness and freshness of the updated status.This work proposes two schemes,namely,the generation rate control and service rate reservation schemes,to improve the overall information freshness of multiple status update streams at the receiver.Specifically,using the recently proposed Age of Information(AoI)as the metric for evaluating information freshness,we characterized the overall information freshness,i.e.,the overall average AoI at the receiver for both schemes,by considering the urgency difference of status update and streams.Both schemes for status updates and streams,respectively,were formulated as two optimization problems.We proved that both problems are convex and the optimal generation and service rates for different streams are found by the standard convex optimization algorithm.Moreover,we proposed both approximate optimal generation and approximate optimal service rate for fast deployment in heavy and light load cases.Numerical results verify the theoretical findings and accuracy of the proposed approximate solutions,guiding the design and deployment of IoT.
基金This work was supported by the National Key Research and Development Program(No.2019YFD0901705).
文摘As a novel food quality monitoring technology,intelligent freshness indicator has received wide attention in recent years.However,its poor safety and stability are the main problems hindering its practical application.Hence a new pH-sensing indicator based on bromocresol green(BCG)was developed in this study for nondestructive and real-time monitoring the freshness of marine fishes.The indicator was designed with a three-layer structure,using the polytetrafluoroethylene(PTFE)membrane with high hydrophobicity and air permeability as the inner layer to isolate the moisture in the package,BCG-coated filter paper as the colorchanging layer to indicate the freshness of fish,and a transparent unidirectional permeable(TUP)membrane with moisture resistance as the out layer to isolate the moisture in the environment.This contributed to weaken the influence of humidity and prevent dye migration,so as to improve the accuracy and safety of the indicator.Therefore,a highly sensitive and distinguished color variation response to trimethylamine(TMA)standard solution with different concentrations was observed on the indicator.Additionally,the indicator showed a high color stability at different storage temperatures up to 14 days with total color differences(ΔE)less than 5.0.The indicator presented visible color variations from yellow to green then eventually to blue when applied to monitor the freshness of sea bass and salmon stored at 4℃,implying that fish was spoiled.Meanwhile,indicatorsΔE value was significantly positively correlated with total volatile basic nitrogen(TVB-N)and total viable count(TVC)in sea bass and salmon samples.Thus,the pH-sensing indicator can be applied as a cost-effective and promising intelligent indicator for monitoring fish freshness.
文摘A new method for determining the freshness of harvested carp using nuclear imaging technology is presented.This research attempted to determine the freshness of carp by measuring the radioactive area increase (RAI) value of fish.The carp samples were maintained under refrigerated condition for 12d, and RAI and total volatile base nitrogen (T-VBN)values were determined during the storage. The results showed that the RAI value increased with the T-VBN content duringthe storage. Also, there is a significant correlation between T-VBN content and RAI value of the carp kept in refrigeratedcondition. The results of this study suggest that the RAI value could be utilized to evaluate rapidly the freshness of carp.
文摘The developed trend of novel intelligent packaging materials is changing from food traditional appearance detection to actual spoilage monitoring,aiming to supply a strategy to determine the edibility of food.In this work,a dual-functional electrospun nanofiber film(NFM)noted GZAT was prepared by the co-loading of anthocyanin(ANT)and thymol(THY)into polymer fibers of gelatin and zein.The prepared film was extensively characterized.The GZAT film displayed enhanced mechanical properties and decreased water vapor perme-ability(WVP)compared with gelatin/zein film(the control).The GZAT film also displayed excellent sensitive colorimetric responses to the pH solutions.Moreover,it exhibited excellent antioxidant property and antibac-terial behavior against Escherichia coli ATC25922(E.coli),Listeria monocytogenes ATCC 19115(L.monocytogenes)and Staphylococcus aureus ATCC 6538(S.aureus).Not only that,the dual functions of the GZAT film were confirmed that the shelf life of packaged shrimps was successfully extended to 11 days at 4℃along with the colorimetric response indicating the freshness of the shrimps.Based on the above characteristic,the prepared GZAT film exhibited great potential as an intelligent packaging film with both real-time freshness indicator and freshness preservation.
基金supported by the Zhejiang Provincial Natural Science Foundation of China under Grant No.LTGN23C200013the National Key R&D Program of China under Grants No.2021YFD2100504 and No.2020YFD0900900.
文摘Aquatic products were susceptible to spoilage during storage due to microorganisms and enzymes,which could cause food safety problems.The electrospun nanofiber films,based on pullulan(PUL)and polyvinyl alcohol(PVA)incorporating bayberry pomace anthocyanin extract(BAE),were developed to monitor the freshness states of aquatic products in this study.The SEM results revealed that the electrospun nanofiber films exhibited a smooth surface,and the average diameter decreased from 481.56 nm to 237.68 nm as anthocyanin content increased from 0 to 20%.The FTIR and XRD results showed that there were no new characteristic peaks,confirming the successful loading of BAE.The incorporation of BAE decreased the water content(from 13.58%to 7.84%),swelling ratio(from 146.75%to 114.24%),water vapor permeability(from 3.38 g⋅mm⋅m^(-2)⋅Pa^(-1)⋅s^(-1)⋅10^(-5)to 2.00 g⋅mm⋅m^(-2)⋅Pa^(-1)⋅s^(-1)⋅10^(-5)),and elongation at break(from 24.67%to 14.90%),but increased water solubility(from 74.99%to 85.74%)and water contact angle(from 51.84◦to 63.73◦).The electrospun nanofiber films presented obvious color changes in buffer solutions(pH 2.0 to 12.0)or volatile ammonia and showed good reversibility.Besides,the electrospun nanofiber films were stable during storage at 4◦C or 25◦C for 20 days.Furthermore,PUL-PVA-A15 effectively distinguished the freshness states(fresh,sub-fresh and spoiled)of Penaeus vannamei during storage at 4◦C by showing different colors(from pink to grayish purple to green).Therefore,the electrospun nanofiber films showed great potential to real-time monitor the quality of aquatic foods as intelligent packaging.
基金supported by the National Key Research and Development Program of China(2022YFD2100602).
文摘Fresh beef is highly susceptible to spoilage during refrigerated storage,yet current freshness assessment ap-proaches remain limited by their invasiveness or low sensitivity.Beef exudate,a naturally released fluid enriched with soluble metabolites,represents a promising yet underutilized matrix for non-invasive freshness assessment.This study applied non-targeted metabolomics to characterize spoilage-related metabolites in beef exudate and to clarify their association with freshness.Beef shank muscles were stored at 7±1℃,after which exudates were collected for physicochemical analyses and non-targeted metabolomic profiling using UHPLC-MS/MS.Comparative analyses revealed that metabolic variations in exudate closely mirrored physicochemical deterio-ration trends observed in the corresponding beef tissue.Among 1703 detected metabolites,62 changed signif-icantly during storage.Pathway enrichment identified the pivotal involvement of arginine metabolism and amino acid biosynthesis in spoilage progression.Correlation analysis further highlighted five key com-pounds-5′-methylthioadenosine,7-methylxanthine,N-methyltryptamine,L-phenylalanine,and spermine-as candidate freshness markers.Overall,this study demonstrates that exudate-based metabolomics offers an effective and non-invasive strategy for monitoring beef freshness,providing new insights for intelligent quality evaluation and spoilage prediction in the meat industry.
基金supported by The Basic Research Funds Project for Universities Directly under the Inner Mongolia Autonomous Region(BR230401)Outstanding Youth Incubation Project of College of Food Science of Inner Mongolia Agricultural University(SPYQ202101)+3 种基金Young Innovative Talent of Grassland Talent Project of Inner Mongolia(2020)Youth Science and Technology Talent Development Project of Inner Mongolia Autonomous Region(Innovation Team)(NMGIRT2310)Science and Technology Program Projects in the College of Food Science and Engineering(YLXKZX-NND-015)Science and Technology Project of Food Science and Engineering College,Inner Mongolia Agricultural University(SPKJ202405).
文摘Amine-responsive fluorescent indicator films for meat freshness were constructed by incorporating β-glucan grafted with fluorescein isothiocyanate(FITC)in polyvinyl alcohol(PVA).The structural,thermal,and responsive properties of grafted copolymers(βGlu-FITC)were investigated.The results of 1H NMR spectra showed that βGlu-FITC exhibited proton signals between 6.5 and 6.7 ppm,suggesting the successful grafting of FITC onto β-glucan.The fluorescence quantum yield of βGlu-FITC was 18.72%,which was higher than that of β-glucan of 12.94% at the optimum excitation wavelength of ultraviolet light of 365 nm.With the incorporation of PVA as a film-forming matrix,βGlu-FITC/PVA films showed high yellow-green fluorescent responsiveness under volatile ammonia and pH solution.When the film was used for meat freshness,the 0.06βGlu-FITC/PVA film provided a noticeable fluorescent indication of pork freshness that corresponded to increases in total volatile basic nitrogen,total colony counts,and drip loss,suggesting its potential for meat packaging and as a freshness indicator.
文摘The authors regret an error in the vertical axis labels of Fig.7(f)and(g).Upon reviewing the published article,we discovered that due to our oversight,the vertical axis labels in Fig.7(f)and(g)were incorrectly labelled as“ΔE”instead of“Swelling Ratio(%)”.This error has now been corrected.The relevant annotations,analyses,and underlying data remain unchanged and are accurate.
文摘The authors regret an error in the vertical axis labels of Fig.7(f)and(g).Upon reviewing the published article,we discovered that due to our oversight,the vertical axis labels in Fig.7(f)and(g)were incorrectly labelled as“ΔE”instead of“Swelling Ratio(%)”.This error has now been corrected.The relevant annotations,analyses,and underlying data remain unchanged and are accurate.
基金support from Natural Science Foundation of Hubei Province,China(2023AFB297).
文摘Carbon dots(CDs)have gained increasing attention across multiple disciplines due to their unique antibacterial activity,antioxidant properties,and tunable fluorescence characteristics.Particularly in the food industry,the incorporation of CDs-based detection platforms into food packaging materials has enabled the development of composite films with dual functionalities of food preservation and real-time monitoring.This review provides an overview of the synthesis methods of CDs,elucidates the antimicrobial and antioxidant mechanisms of CDs,and discusses their effective application strategies for extending food shelf life.The fluorescence properties of CDs are analyzed,and the potential of utilizing these properties for intelligent food freshness monitoring is explored.Furthermore,the challenges facing these technologies and future development trends are discussed,with a particular emphasis on the integration of CDs with Internet of Things and machine learning technologies for realtime monitoring of food quality,providing theoretical insights for the development of next-generation multi-functional active packaging materials.
