| Jujube originated in China, has a long history. It has been popular among the people with its excellent edible value and medicinal value. With the continuous improvement of living standards, people from the beginning of the single external quality requirements gradually turned to the emphasis both on external and internal quality in jujube. Three kinds of fresh jujube (Huping jujube, Lang jujube and Li jujube)were selected as the object in this experiment. The SSC content of single year, multi years and multi varieties were predicted and analyzed by using visible/near infrared spectroscopy technology. Each detection model of SSC content and its related characteristic wavelength established in this experiment, provided the theoretical foundation for the development of related equipment.The main research results and conclusions were as follows:(1) Compared the full wavelength (FS) with the other three kind of characteristic wavelengths extracted by methods (SPA, RC and CARS) based on the single year of SSC content of Huping jujube, the three kind of characteristic wavelengths reduced the amount of data significantly and improved the operational efficiency. The characteristic wavelengths in every single year both had some part of repeat by different methods of extraction. The results show that the extraction of characteristic wavelengths had representative.(2) Compared the prediction effect of each models were established by different years(2013,2014 and 2015), different modeling wavelength(SPA, RC, CARS and FS), and different model methods(PLS and LS-SVM), the characteristic wavelengths extracted by CARS had the best prediction effect. And The CARS-PLS models were the best model for the detection of SSC content of single year, because of its higher Rp and better stability. The best models and its Re, RMSEC, Rp, RMSEP were 2013-CARS-PLS (0.7835、1.0398*Brix、0.8166、1.0149* Brix)、2014-CARS-PLS (0.8889、1.1514* Brix、0.8536、 1.3601*Brix), and 2014-CARS-PLS (0.8753、1.4769* Brix、0.8970、1.3144* Brix), respectively.(3) Compared the CARS characteristic wavelengths extracted by combined years and the corresponding every single year, the number of characteristics wavelength had some part of repeat, and increased slightly. The results show that the extracted characteristic wavelengths between combined years and the corresponding every single year had certain correlation.(4) Compared the prediction effect of every CARS-PLS models established by combined years and the corresponding every single year, there were two conclusions. The CARS-PLS models based on the characteristic wavelengths extracted by single year had better prediction effect than the CARS-PLS models of corresponding combined years. The CARS-PLS models based on the single sample set had better prediction effect than the CARS-PLS models of corresponding combined sets. The prediction effect of combined detection models were not accurate as those single detection models, but it also had a good prediction effect and better versatility. The predicted effect of L13-14-15-CARS-PLS model, which built by three years sample set, for 2013,2014, and 2015 predicted sample set (Rp=0.7100, Rp=7396, Rp=0.8336) were less than that of 2013-CARS-PLS,2014-CARS-PLS, and 2015-CARS-PLS model (Rp=0.8166, Rp=0.8563, Rp=0.8970). But it had a good prediction effect and a better versatility. The predicted effect of L13-14-15-CARS-PLS model for combined sample as follow:(13-14-15:Rp=0.9150、13-14:Rp=0.9092, 14-15:Rp=0.8409; 13-15:Rp=0.8781)(5) Through the analysis of each detection models of SSC content of single and combined year of Lang jujube and Li jujube, determined the conclusions of Huping jujube were universal and could be extended. CARS-PLS model was the best detection model, because of its simplification and good prediction effect. The number of characteristics wavelength between the corresponding combined years and single year had some part of repeat, and increased slightly. The best detection models, which all established by single year, were LA-2014-CARS-PLS (Rc=0.9399, RMSEC=0.6531*Brix, Rp=0.9070, and RMSEP=0.7890*Brix), LA-2015-CARS-PLS(Rc=0.8578, RMSEC=1.7935-Brix, Rp=0.8373, and RMSEP 1.6282. Brix), Li-2014-CARS-PLS (Rc=0.8875, RMSEC=1.4248. Brix, Rp=0.8165, and RMSEP=1.8392* Brix), and Li-2015-CARS-PLS (Rc=0.9202, RMSEC=0.8789*Brix, Rp=0.8992, and RMSEP=0.9839* Brix), respectively. The combined years detection models had less accurate than that of single years(Lang jujube,2014:Rp=0.7581,2015:Rp=0.7711;Li jujube,2014:Rp=0.7992,2015:Rp=0.8394).But It had a good prediction effect and better versatility. The predicted effect of combined years detection model for combined sample as follow:(Lang jujube,14-15:Rp=0.7929、Li jujube,14-15:Rp=0.8697)(6) Through the comparison and analysis of each group characteristic wavelengths of detection models of SSC content of three kind of jujube established in this experiment, a theoretical basis had be provided for the development of related equipment. |
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