Study On Shelf Life Prediction,Quality Rapid Detection And Shelf Life Extension Of Sichuan Sauerkraut

Sichuan sauerkraut is deeply loved by consumers because of its unique taste,flavor and nutritional value.It is widely accepted by people in many places because of its health care function,so it has a large trade market.According to the annual sales volume of Sichuan sauerkraut,the demand for sauerkraut is increasing year by year.However,this just increases the supply and demand of sauerkraut.It is very important to ensure the quality of sauerkraut to the greatest extent.During the production,transportation and storage of sauerkraut,it is vulnerable to changes in environmental conditions,especially temperature,which will lead to a serious decline in quality and affect the shelf life.Therefore,this study analyzed the main factors affecting the quality of sauerkraut during storage,established a shelf life model by measuring the relevant indicators of sauerkraut at different storage temperatures,explored the feasibility of CNN for rapid detection of sauerkraut,and tried to use expired sauerkraut to prepare CDs,CTS/PVA-CDs composite film packaging and optimizing storage conditions to extend the shelf life of sauerkraut.The main research contents and conclusions are as follows:（1）The texture,color,total acid,microorganism,near-infrared analysis,volatile components,taste and sensory evaluation of sauerkraut were determined at 25℃,35℃and45℃.According to the analysis of electronic tongue data by PCA and FDA,the critical value that the model can be used to determine various quality indicators is determined.In addition,the comparison shows that the zero-order kinetic reaction model（R²,0.8690-0.9895）fits better than the first-order kinetic reaction model.Arrhenius model(E_a value is 47.23 k J/mol-72.09k J/mol,k_ref value is 1.076×10⁶ d^-1-9.220×10¹⁰ d^-1)is better than Eyring model.On the basis of physical index analysis,the combination of zero-order kinetic reaction model and Arrhenius model can more accurately predict the shelf life of sauerkraut,while t BP-ANN model can better predict the chemical index.（2）The quality and flavor characteristics of 13 groups of sauerkraut samples with different storage times were evaluated by physicochemical parameters combined with electronic nose.It was concluded that there was a linear negative correlation between the oxidative decomposition of total phenols and flavor compounds.According to PCA and FDA,sauerkraut can be divided into three categories during storage（full acceptance stage,acceptable stage and unacceptable stage）.Based on the classification results,the CNN parameters are fine-tuned,and the output results can reflect the quality changes and flavor characteristics of the samples,and have better fitting and prediction ability.After epoch 50 stages of the model,the accuracy of the three sets of data（namely the training set,the verification set and the test set）was 94%,85%and 93%,respectively.In addition,the accuracy of CNN identification of different qualities of Sauerkraut was 95.30%,which proved that CNN had good performance and high reliability in predicting the quality of Sichuan sauerkraut.（3）The CDs and CTS/PVA-CDs composite films prepared from sauerkraut have antioxidant properties,UV blocking ability and photoluminescence.The film also has good mechanical properties and hydrophobic properties,which can extend the shelf life of sauerkraut and improve the quality of sauerkraut within the shelf life when used for packaging.The prediction and analysis of the quality of sauerkraut during the storage period by CNN showed that compared with PET packaging,the quality of sauerkraut could be extended by more than24%by CTS/PVA-CDs composite film packaging.（4）The quality change of Sichuan sauerkraut during storage was explored by changing the temperature and packaging materials.Low temperature combined with antioxidant packaging can slow down the change rate of quality indicators of sauerkraut during storage.At the same time,CNN predicted the quality of Sichuan sauerkraut under different storage conditions,and the results showed that the shelf life of high quality shelf life at 4℃,CTS/PVA-CDs could be increased by 34%compared with 25℃,PET packaging.