Effect Of Storage Conditions On The Respiration＆quality Of Eggs And Development Of Atmosphere Control System

Fresh eggs make up the majority of our egg consumption.Fresh eggs’quality is susceptible to deterioration during storage.Quality degradation not only results in significant financial losses,but it also compromises food safety.Refrigeration,film coating,and air conditioning are the most common egg storage methods.The idea behind these strategies is to prevent material from being exchanged between the egg and the environment outside the shell,so inhibiting the intensity of egg respiration is the key to decreasing variations in egg quality.In order to figure out what the ideal storage conditions are for eggs（temperature,humidity,carbon dioxide and oxygen concentration）.Using a variety of eggs as the subject of study,we analyze the mechanism of the effect of different gas conditioning methods on the intensity and quality of egg respiration during storage.To simulate the process,CFD techniques were used.The development of an air-cooling tank-based storage and preservation control system will give effective countermeasures to the severe difficulties of egg storage.The following are the main findings and conclusions of the study.（1）Eggshell is an important medium for egg respiration.The eggshell membrane which is the organic layer of the eggshell is the necessary channel for the egg respiration such that the study of the relationship between the ultrastructure of the eggshell membrane and the respiration intensity of the egg is of great significance for preservation and storage of eggs.In this research,the ultrastructure image of eggshell membranes was characterized by using scanning electron microscope（SEM）.After the ultrastructure image of the eggshell membrane was processed by an image processing software,relevant parameters could be achieved.The relationship between the fiber diameter,porosity and thickness of the eggshell membranes and the respiration intensity of the egg could be obtained according to the relevant parameters.The result showed that the fiber diameter,porosity and thickness of the eggshell membranes with strong respiration intensity（≥3 mg/kg·h）was significant different from that of the eggshell membranes with weak respiration intensity（≤1 mg/kg·h）.In addition,there was a Very significant positive correlation between the fiber diameter,porosity and thickness of the eggshell membranes and the respiration intensity（P<0.01）and a Very significant negative correlation between the fiber diameter,porosity and thickness of the eggshell membranes and the respiration intensity of the egg（P<0.01）.By analyzing the ultrastructure image of eggshell membranes under different respiration intensity of the egg,it was found that the arrangement of the eggshell membrane fibers was more disorderly and tighter and under the strong respiration intensity.There are obvious mucopolysaccharide tumor-like attachments on the outer membrane of eggs with weak and medium respiration strength,while mucopolysaccharide attachments on eggs with strong respiration strength are granular.The outer membrane fiber diameter of eggshell membrane is larger than the inner membrane,and the thickness is 3-4 times that of the inner membrane.The inner membrane fiber of the eggshell membrane is more slender and straighter than the outer membrane.Taking 10 characteristic parameters of porosity,fiber diameter and thickness on both sides of eggshell membrane as independent variables,and egg breathing intensity as dependent variable,partial least squares regression model was established.Test set correlation coefficient R_P was 0.976 7.The result shown that the ultrastructure of the eggshell membrane could well characterize the respiration intensity Taking respiration intensity as the classification basis,this paper establishes a partial least square discriminant analysis.The accuracy of the test set is 83.33%.And found that the outer surface porosity on the outside of outer membrane,the fiber diameter on the outside of inner membrane,the thickness of the outer membrane and the fiber diameter on the inside of outer membrane have a greater contribution to distinguish between different respiratory intensities.The porosity of the outer membrane is the main reason for the greater respiratory intensity.This conclusion shown that the ultrastructure of the eggshell membrane has a better discrimination effect on the respiration intensity of fresh eggs in an air environment of25℃.The conclusions of this study have good application prospects in the storage and preservation of eggs and the protein extraction process of eggshell membranes.（2）In order to explore the effect of carbon dioxide on the storage quality and extend the shelf-life of eggs.Fresh eggs,as the research subject in the study,were stored in the storage boxes with CO₂ concentration of 0.03%（air concentration）,5%,10%and 20%（divided into Group A,Group B,Group C and Group D respectively）.Furthermore,the study had an investigation into the impacts of CO₂ on the respiration intensity and freshness of eggs as well as the Grey Relational Analysis between index values and the respiration intensity,which will provide theoretical support for egg storage,transportation and preservation.The study had some findings as follows:in the general environment with 25℃and 65%humidity,the respiration of eggs in Group B,C and D were inhibited and the respiration intensity were weak;The respiration intensity of Group A gradually decreased from strong to weak over time.The p H value of Group A was higher than the other three groups.Colonies form in Group A after 5 days and in the other three groups after 15 days.Colonies count in Group A after storage of 45 days was about 60 times of that of the other three groups;In comparison with Group A,the rates of decrease of the egg Haugh units and egg yolk index in Group B,C and D were more gentle;shelf-life of Group A was longer then Group B,C and D.The results show that the storage condition with more than 5%CO₂concentration could effectively inhibit the respiration of eggs so as to achieve bacteriostat and preservation and the most suitable CO₂ concentration was 10%among the four groups.There was a strong correlation between the respiration intensity and Haugh unit,yolk index as well as p H value.And the colonies count had the least effect on the respiration intensity.（3）Fresh eggs were stored in boxes in a controlled atmosphere with an O₂concentration of 0%O₂+100%nitrogen（N₂）,5%O₂+95%N₂,10%O₂+90%N₂,15%O₂+85%N₂,and 20%O₂+80%N₂,and the effects of these storage conditions on large quantities of eggs were studied.The respiratory intensity and quality of eggs during storage were measured.We chose the weight loss rate of eggs,Haugh unit,p H,and the egg white total plate count as the characteristic indices of egg quality.We compared the changes in egg quality during and after storage at different O₂ concentrations versus that at 25℃.The stages were evaluated using the TOPSIS method to sort egg quality,and the optimal O₂concentration was selected.FLUENT was used to simulate and control the atmospheric requirements.Our findings showed that eggs stored in an air-conditioning chamber with O₂concentration≤10%exhibited weak respiratory intensity（0-1 mg/（kg·h））.The rates of decrease in loss of egg weight and Haugh units were smaller.There were significant differences in the p H of egg white stored in different O₂ concentrations（P<0.05）.Reducing the O₂ concentration in the egg-storage environment reduced the number of colonies in eggs and had a positive effect on egg preservation.The storage environment of 5%O₂+95%N₂ had the best preservation effect on eggs.This approach is associated with low costs in practical application and can potentially be used for egg storage and transport.（4）The impact of different egg types on storage was explored,and a respiratory intensity model was created.To investigate the impact of two gas conditioning procedures on egg storage:increasing CO₂ levels and lowering oxygen levels.Eggs from four different origins were used for storage testing.The pattern of variations in respiratory intensity of different types of eggs was consistent under the same storage conditions,according to the study.All four egg types demonstrated a consistent trend of decreasing respiratory intensity from strong to mild in the air environment.In storage conditions with low temperature,high carbon dioxide,and low oxygen,egg respiratory intensity was reduced;weight loss,Huff units,and yolk index of different types of eggs were not consistent across storage environments.Both aeration effects slowed the deterioration of egg freshness.The influence of temperature on oxygen gas conditioning was greater,whereas the impact on carbon dioxide gas conditioning was smaller.The freshness trends of various egg brands in various storage settings were associated with their own quality.Egg freshness was better preserved by both low temperature and gas conditioning;p H trends of different varieties of eggs in different storage settings were constant,and the p H of eggs was mostly controlled by carbon dioxide gas conditioning.The combined evaluation scores revealed that both carbon dioxide and oxygen gas conditioning improved storage,and that storage at a temperature of roughly 15°C was superior to storage in a 4°C refrigerated environment.With a prediction performance of R=0.9868 and RMSE=0.1664,the generalized model of egg respiration intensity created performed well.（5）Simulation of the gas diffusion process in egg gasification using fluids.The Fluent software is used to simulate the dynamic changes in gas distribution and concentration changes in the gas conditioning tank with a volume of 1.5m³,and to provide the optimization direction for the design of the structure,system,and performance of the gas conditioning tank,in order to extend the egg gas conditioning storage technology from the theoretical level to the production application level.To simulate the variations in oxygen,nitrogen,and carbon dioxide concentrations in two types of tanks during the egg storage process,a three-dimensional non-stationary numerical model of the gas flow in the tank was constructed.The following are the primary conclusions:From the air entrance,carbon dioxide enters the box and quickly sinks.After 1200 seconds of aeration,the upper layer can meet the set requirement（51 percent）,whereas the lower layer can reach the set requirement after 600 seconds of aeration.When considering the goods’own respiration,the carbon dioxide concentration in the air conditioning box can reach the 5%–10%range,and the carbon dioxide filling time is around 600s–1200s,which can match the production needs.Two concentrations of 95 percent and 98 percent nitrogen were chosen for simulation based on the nitrogen machine principle,and it was discovered that the overall inlet efficiency difference between the two filling methods is small,and the average concentration of oxygen can basically reach the storage requirements after 3600s of nitrogen filling.Nitrogen gas conditioning nitrogen production equipment and nitrogen filling operations are relatively simple,the amount of lower cost but slower rate.Carbon dioxide gas conditioning nitrogen production equipment and nitrogen filling operations are relatively simple,the amount of lower cost but slower rate.Both types of gas conditioning can successfully extend storage time.（6）Development of gas conditioning control system.Design and construct a gas conditioning storage and preservation control system based on the Internet of Things.The STM32F103C8T6 microcontroller is chosen as the controller based on the demand analysis,and it is paired with temperature,humidity,carbon dioxide,and oxygen sensors for data acquisition,as well as communicating with the One NET platform to enable remote online monitoring of the gas conditioning box environment.The Internet of Things（Io T）is used in the egg storage process to properly monitor environmental changes.Alarms and control measures are activated when abnormal conditions arise.The system has good application prospects after testing,delivering a good user experience while boosting security and realizing dynamic supervision of the egg tempering box.