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 enhancement of the sensitivity for anthocyanin-based indicator films in food freshness monitoring in real time is important for application.In this study,hydrophilic silica aerogel(SiO2 NA)was incorporated into co...The enhancement of the sensitivity for anthocyanin-based indicator films in food freshness monitoring in real time is important for application.In this study,hydrophilic silica aerogel(SiO2 NA)was incorporated into corn starch(CS)/chitosan(CH)/rose anthocyanins(RACNs)-encapsulated potato amylopectin nanoparticles(APNPs)composite film to increase the sensitivity for shrimp freshness detection.The microstructure of films revealed that the gas absorption capacity was improved by amorphous SiO2 NA via hydrogen interactions.The pore size(1.74–5.60 times),pore volume(3.92–5.60 times),and specific surface area(2.21–2.34 times)of films increased with the addition of SiO2 NA.The sensing of NH3 and pH and the reversibility of films were also reinforced.Meanwhile,the pH-responsive films containing SiO2 NA changed visibly in color from purple–red to orange–gray and finally to gray,enabling effective monitoring of shrimp freshness during storage at 4°C.Thus,anthocyanin-based indicator films with improved sensitivity by adding SiO2 NA were successfully designed for monitoring shrimp freshness.展开更多
Indicating hydrogels have shown the advantages of being fast, sensitive, and real-time in demonstrating the freshness of aquatic products due to their noticeable color change. In this work, an anti-freezing hydrogel e...Indicating hydrogels have shown the advantages of being fast, sensitive, and real-time in demonstrating the freshness of aquatic products due to their noticeable color change. In this work, an anti-freezing hydrogel embedded with pH-sensitive alizarin was developed as an original colorimetric indicator for monitoring the corruption of aquatic products at low temperatures. The anti-freezing hydrogel was prepared from 2-carboxyethyl acrylate, [2-(methacryloyloxy)ethyl]-trimethylammonium chloride, and 2-hydroxyethyl methacrylate monomers with triethylene glycol dimethacrylate as cross-linking agent. The hydrogel showed excellent anti-freezing capability, which was further incorporated with the pH-sensitive dye alizarin to gain the indicating capability. When applied in the indication of the freshness of salmon under low-temperature storage, it was found that the color changes of the indicator corresponded with the total volatile basic nitrogen contents of salmon, the correlation coefficient of which was 0.959 6. These results indicated the application potential of the hydrogels as freshness indicators during low-temperature storage or cold-chain transportation.展开更多
There are many disadvantages such as small detection range and environmental restrictions on application conditions,when the single quantum dot powder or solution is used for fluorescent probe detection.In this paper,...There are many disadvantages such as small detection range and environmental restrictions on application conditions,when the single quantum dot powder or solution is used for fluorescent probe detection.In this paper,the blue fluorescent silicon quantum dots and green fluorescent carbon quantum dots were prepared,and their fluorescence color changes after mixing in different proportions were investigated under different pH conditions.When the two quantum dots were mixed with a concentration of 0.1 mg·mL^(-1) and a mass ratio of 1:1,the fluorescence color change could be better displayed at a pH from 1 to 14.Meanwhile,the double quantum dots were prepared into two forms(ink and film),successfully realizing the device application of the fluorescent probe.The films and inkjet-printed labels were used to test the spoilage of food(pork,milk,etc.),and the color change data of the labels were collected during the spoilage test.These data were used for neural network training to predict the spoilage changes of foods.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
Availability of inventory is a crucial issue while adopting a consignment strategy.The issue becomes paramount when demand depends on stock.To address the issue,a one-vendor one-buyer model under consignment stock(CS)...Availability of inventory is a crucial issue while adopting a consignment strategy.The issue becomes paramount when demand depends on stock.To address the issue,a one-vendor one-buyer model under consignment stock(CS)policy is addressed in this paper.Both the channel members are assumed to have space limitations in their respective warehouses.The display area for the buyer is also limited.The buyer receives the product from the vendor under consignment stock policy,and transfers it in small batches to the display area.The market demand is affected by the price,freshness and on-hand stock level.Price is assumed to be dynamic in order to accurately depict real-world scenarios and to exhibit its important role in driving demand and influencing other decision-making factors.This study derives the optimal decisions to maximize the total profit of the supply chain system.Numerical experiments illustrate the optimal strategies such as production rate,shipment sizes,warehouse space limit,and number of shipments.Managerial insights are provided to establish the applicability of the model.展开更多
With the rise in global meat consumption and chicken becoming a principal source of white meat,methods for efficiently and accurately determining the freshness of chicken are of increasing importance,since traditional...With the rise in global meat consumption and chicken becoming a principal source of white meat,methods for efficiently and accurately determining the freshness of chicken are of increasing importance,since traditional detection methods fail to satisfy modern production needs.A non-destructive method based on machine vision and machine learning technology was proposed for detecting chicken breast freshness.A self-designed machine vision system was first used to collect images of chicken breast samples stored at 4℃ for 1-7 d.The Region of Interest(ROI)for each image was then extracted and a total of 700 ROI images were obtained.Six color features were extracted from two different color spaces RGB(red,green,blue)and HSI(hue,saturation,intensity).Six main Gray Level Co-occurrence Matrix(GLCM)texture feature parameters were also calculated from four directions.Principal Component Analysis(PCA)was used to reduce the dimension of these 30 extracted feature parameters for multiple features image fusion.Four principal components were taken as input and chicken breast freshness level as output.A 10-fold cross-validation was used to partition the dataset.Four machine learning methods,Particle Swarm Optimization-Support Vector Machine(PSO-SVM),Random Forest(RF),Gradient Boosting Decision Tree(GBDT),and Naive Bayes Classifier(NBC),were used to establish a chicken breast freshness level prediction model.Among these,SVM had the best prediction effect with prediction accuracy reaching 0.9867.The results proved the feasibility of using a detection method based on multiple features image fusion and machine learning,providing a theoretical reference for the nondestructive detection of chicken breast freshness.展开更多
美国东部时间7月13日夜晚,美国新泽西州大都会人寿体育场内哨声长鸣,烟火照亮了2025世俱杯决赛现场的夜空!近年来历经波折的切尔西,将不可一世的新贵巴黎圣日耳曼斩于马下,收集齐了前无古人的“超级大满贯”。世界足球的狂热尚未褪去,...美国东部时间7月13日夜晚,美国新泽西州大都会人寿体育场内哨声长鸣,烟火照亮了2025世俱杯决赛现场的夜空!近年来历经波折的切尔西,将不可一世的新贵巴黎圣日耳曼斩于马下,收集齐了前无古人的“超级大满贯”。世界足球的狂热尚未褪去,中国海信的品牌故事依旧在绿茵殿堂闪耀。切尔西队员高举的金杯下,2025世俱杯上闪耀的海信冰箱“MVP OF FRESHNESS”醒目而有力。这样的荣耀不仅属于球员,同样也属于陪伴世界顶级足球赛事近十年的保鲜科技力量。展开更多
To monitor the freshness of chicken,a pH-sensitive film based on sodium alginate,gelatin,and plum peel extract(SGPE)was created.Thickness,color,water contact angle,mechanical characteristics,water content,water vapor ...To monitor the freshness of chicken,a pH-sensitive film based on sodium alginate,gelatin,and plum peel extract(SGPE)was created.Thickness,color,water contact angle,mechanical characteristics,water content,water vapor transmission,light transmission,and pH sensitivity were used to evaluate the performance of the film sample.SEM and FTIR graphs demonstrated that adding plum peel extract made the SGPE film’s internal structure more denser and increased its mechanical property,while decreasing the water contact angle,water content,and WVP value.The color of the SGPE15 film clearly changed from red to yellow-green in various buffer solutions(pH=1-14),demonstrating more pH sensitivity than the SG,SGPE5,and SGPE10 films.On day 6,when checking the freshness of chicken kept at 4℃,the SGPE15 film’s color changed from orange-pink to yellow-green with TVB-N level beyond the allowable limit(15 mg/100 g).The result revealed that the SGPE film might be applied to monitor the freshness of chicken breast flesh.展开更多
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.
基金Zhejiang Province Key Research and Development Programs(No.2023C02006),China.
文摘The enhancement of the sensitivity for anthocyanin-based indicator films in food freshness monitoring in real time is important for application.In this study,hydrophilic silica aerogel(SiO2 NA)was incorporated into corn starch(CS)/chitosan(CH)/rose anthocyanins(RACNs)-encapsulated potato amylopectin nanoparticles(APNPs)composite film to increase the sensitivity for shrimp freshness detection.The microstructure of films revealed that the gas absorption capacity was improved by amorphous SiO2 NA via hydrogen interactions.The pore size(1.74–5.60 times),pore volume(3.92–5.60 times),and specific surface area(2.21–2.34 times)of films increased with the addition of SiO2 NA.The sensing of NH3 and pH and the reversibility of films were also reinforced.Meanwhile,the pH-responsive films containing SiO2 NA changed visibly in color from purple–red to orange–gray and finally to gray,enabling effective monitoring of shrimp freshness during storage at 4°C.Thus,anthocyanin-based indicator films with improved sensitivity by adding SiO2 NA were successfully designed for monitoring shrimp freshness.
基金the Key Program of Natural Science Foundation of Zhejiang Province(LZ15C200001)the Zhejiang Provincial Department of Agriculture and Rural Affairs(2022SNJF0202022SNJF069).
文摘Indicating hydrogels have shown the advantages of being fast, sensitive, and real-time in demonstrating the freshness of aquatic products due to their noticeable color change. In this work, an anti-freezing hydrogel embedded with pH-sensitive alizarin was developed as an original colorimetric indicator for monitoring the corruption of aquatic products at low temperatures. The anti-freezing hydrogel was prepared from 2-carboxyethyl acrylate, [2-(methacryloyloxy)ethyl]-trimethylammonium chloride, and 2-hydroxyethyl methacrylate monomers with triethylene glycol dimethacrylate as cross-linking agent. The hydrogel showed excellent anti-freezing capability, which was further incorporated with the pH-sensitive dye alizarin to gain the indicating capability. When applied in the indication of the freshness of salmon under low-temperature storage, it was found that the color changes of the indicator corresponded with the total volatile basic nitrogen contents of salmon, the correlation coefficient of which was 0.959 6. These results indicated the application potential of the hydrogels as freshness indicators during low-temperature storage or cold-chain transportation.
基金the usage of all characterizations supported by the“14th Five-Year Plan”National Key Research and Development Plan Project(Grant No.2023YFE0105500)National Natural Science Foundation of China(Grant No.52173206)。
文摘There are many disadvantages such as small detection range and environmental restrictions on application conditions,when the single quantum dot powder or solution is used for fluorescent probe detection.In this paper,the blue fluorescent silicon quantum dots and green fluorescent carbon quantum dots were prepared,and their fluorescence color changes after mixing in different proportions were investigated under different pH conditions.When the two quantum dots were mixed with a concentration of 0.1 mg·mL^(-1) and a mass ratio of 1:1,the fluorescence color change could be better displayed at a pH from 1 to 14.Meanwhile,the double quantum dots were prepared into two forms(ink and film),successfully realizing the device application of the fluorescent probe.The films and inkjet-printed labels were used to test the spoilage of food(pork,milk,etc.),and the color change data of the labels were collected during the spoilage test.These data were used for neural network training to predict the spoilage changes of foods.
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Availability of inventory is a crucial issue while adopting a consignment strategy.The issue becomes paramount when demand depends on stock.To address the issue,a one-vendor one-buyer model under consignment stock(CS)policy is addressed in this paper.Both the channel members are assumed to have space limitations in their respective warehouses.The display area for the buyer is also limited.The buyer receives the product from the vendor under consignment stock policy,and transfers it in small batches to the display area.The market demand is affected by the price,freshness and on-hand stock level.Price is assumed to be dynamic in order to accurately depict real-world scenarios and to exhibit its important role in driving demand and influencing other decision-making factors.This study derives the optimal decisions to maximize the total profit of the supply chain system.Numerical experiments illustrate the optimal strategies such as production rate,shipment sizes,warehouse space limit,and number of shipments.Managerial insights are provided to establish the applicability of the model.
基金funded by the International Science and Technology Cooperation Program of Jiangsu Province(Grant No.BZ2023013)the Xuzhou Key Research and Development Project(Modern Agriculture)(Grant No.KC21135).
文摘With the rise in global meat consumption and chicken becoming a principal source of white meat,methods for efficiently and accurately determining the freshness of chicken are of increasing importance,since traditional detection methods fail to satisfy modern production needs.A non-destructive method based on machine vision and machine learning technology was proposed for detecting chicken breast freshness.A self-designed machine vision system was first used to collect images of chicken breast samples stored at 4℃ for 1-7 d.The Region of Interest(ROI)for each image was then extracted and a total of 700 ROI images were obtained.Six color features were extracted from two different color spaces RGB(red,green,blue)and HSI(hue,saturation,intensity).Six main Gray Level Co-occurrence Matrix(GLCM)texture feature parameters were also calculated from four directions.Principal Component Analysis(PCA)was used to reduce the dimension of these 30 extracted feature parameters for multiple features image fusion.Four principal components were taken as input and chicken breast freshness level as output.A 10-fold cross-validation was used to partition the dataset.Four machine learning methods,Particle Swarm Optimization-Support Vector Machine(PSO-SVM),Random Forest(RF),Gradient Boosting Decision Tree(GBDT),and Naive Bayes Classifier(NBC),were used to establish a chicken breast freshness level prediction model.Among these,SVM had the best prediction effect with prediction accuracy reaching 0.9867.The results proved the feasibility of using a detection method based on multiple features image fusion and machine learning,providing a theoretical reference for the nondestructive detection of chicken breast freshness.
文摘美国东部时间7月13日夜晚,美国新泽西州大都会人寿体育场内哨声长鸣,烟火照亮了2025世俱杯决赛现场的夜空!近年来历经波折的切尔西,将不可一世的新贵巴黎圣日耳曼斩于马下,收集齐了前无古人的“超级大满贯”。世界足球的狂热尚未褪去,中国海信的品牌故事依旧在绿茵殿堂闪耀。切尔西队员高举的金杯下,2025世俱杯上闪耀的海信冰箱“MVP OF FRESHNESS”醒目而有力。这样的荣耀不仅属于球员,同样也属于陪伴世界顶级足球赛事近十年的保鲜科技力量。
基金support from the National Natural Science Foundation of China(No.22268024,32060569,and 21576126).
文摘To monitor the freshness of chicken,a pH-sensitive film based on sodium alginate,gelatin,and plum peel extract(SGPE)was created.Thickness,color,water contact angle,mechanical characteristics,water content,water vapor transmission,light transmission,and pH sensitivity were used to evaluate the performance of the film sample.SEM and FTIR graphs demonstrated that adding plum peel extract made the SGPE film’s internal structure more denser and increased its mechanical property,while decreasing the water contact angle,water content,and WVP value.The color of the SGPE15 film clearly changed from red to yellow-green in various buffer solutions(pH=1-14),demonstrating more pH sensitivity than the SG,SGPE5,and SGPE10 films.On day 6,when checking the freshness of chicken kept at 4℃,the SGPE15 film’s color changed from orange-pink to yellow-green with TVB-N level beyond the allowable limit(15 mg/100 g).The result revealed that the SGPE film might be applied to monitor the freshness of chicken breast flesh.
