Rapid And Non-destructive Detection Of Soluble Sugars And Organic Acids Metabolism In Ripening Kiwifruit By Hyperspectral Imaging

Kiwifruit is one of nutritional and healthy fruits with a good reputation of the king of all fruits.China is one of the major countries for kiwi cultivation and exportation in the world.The quality and safety of fruits and vegetables are the most important issues for consumers.The process of sugar and acid metabolism in kiwi ripening process can be used as an important parameter to evaluate the edible quality of kiwifruit.However,the traditional detection methods are time-consuming and destructive detection technology.In recent years,with the rapid development of spectroscopy and imaging technology,hyperspectral imaging(HSI),combining the advantages of traditional imaging and spectroscopy techniques,which can not only be used to detect the external quality of fruits and vegetables,but also the internal quality,has become a hot spot both in domestic and abroad.In this study,the prediction model of glucose,fructose and sucrose,citric acid,quinic acid,malic acid and ascorbic acid in kiwifruit fruit as well as the mixed prediction model for different temperature was established by HSI technology.Monitoring in real-time the effects of 1-MCP on the sugar and acid metabolism of kiwifruit were studied.The main conclusions are as follows:(1)The prediction of three main soluble sugars and four main organic acids in fruit and fresh slices of kiwi fruit was realized by using visible-short wave near-infrared(400-1000 nm)HSI.The results showed that the Rp of the characteristic models of glucose,fructose and sucrose,citric acid,quinic acid,malic acid and ascorbic acid reached 0.87,0.87 and 0.84,0.79,0.87,0.85 and 0.85,respectively.The prediction of fresh slices is superior to the predictive model of complete fruit.(2)The accuracy of the predicted model of soluble sugar and organic acid in the kiwifruit fruit during the normal temperature and low temperature cryopreservation was compared,and the characteristics of sugar and acid content in the process of ripening and low temperature ripening were studied Model fusion.The results showed that the stability model of glucose,fructose and sucrose,citric acid,quinic acid,malic acid and ascorbic acid was good in the fusion model,and Rp reached 0.72,0.92 and 0.74,0.79,0.84,0.80 and 0.75 respectively.The final fusion model was used to detect the sugar and acid content in the process of ripening at different temperatures.(3)Based on the best feature prediction model,the changes of sugar and acid metabolism in fresh slices of kiwifruit treated with 1-MCP were visualized.The results showed that the distribution of soluble sugar and organic acid in different tissues of kiwifruit slices,the 1-MCP effect on the accumulation of soluble sugar and the degradation of organic acids in different tissues were different.In conclusion,HSI explored the mechanism of glucose,fructose and sucrose,citric acid,quinic acid,malic acid and ascorbic acid on the visible / near infrared reflectance spectra and images,as well as the external regulatory means(1-MCP)on the sugar and acid metabolism during the ripening of kiwifruit.The results of this study could be helpful for understanding the heterogeneity of sugar and acid metabolism in different tissues of kiwifruit and timely controlling the sugar and acid the of metabolism.