Abstract：In order to realize the real-time monitoring of hardness and predict the storage life of fresh jujubes in storage periods at room temperature, a kinetic model of hardness according to near-infrared (NIR) spectroscopy was established. The influence of integrated thickness on storage life of jujubes was explored using two dimensional correlation spectroscopy technology and the sensitive bands influenced by integrated thickness of 904, 980, 1 072, 1 200, 1 630，1 941 and 2 215 nm respectively. The average hardness of the jujube pulp per day during storage was analyzed and then a zero level reaction equation was fitted, which was A=0.549 8-0.009 6A0-0.023 2t. The result showed that the correlation coefficient of the zero level reaction was 0.991 3 and the standard error was 6.116×10-4. The content of main material changed during storage because of the complex physiological and chemical reaction in the fresh jujube fruits. And this is represented through spectral characteristics and hardness. Coupled the spectral information in the sensitive band and the hardness index of the storage period, a partial least squares (PLS) model of jujube flesh hardness was established. The prediction precision of the model was 0.942 7, and the root mean squared error of prediction (RMSEP) was 0.021 0. And then, a kinetic model of jujube’ flesh hardness according to near-infrared (NIR) spectroscopy (A=0.549 8-0.009 6(0.793 6+0.655 1X1-3.804 2X2+2.372 2X3-1.884 2X4+3.637 3X5-1.041 7X6-1.327 8X7)-0.023 2t) was established through multivariate regression analysis, in which the spectral reflectances of characteristic bands are independent variables and the hardness indexes of jujube fruits are dependent variables. The correlation coefficient of this model was 0.983 9 and standard error was 0.024 9. The linear relation between storage life and near-infrared(NIR) spectroscopy was found to be t=23.698 2-0.413 8(0.793 6+0.655 1X1-3.804 2X2+2.372 2X3-1.884 2X4+3.637 3X5-1.041 7X6-1.327 8X7)-43.103 4(0.793 6+0.655 1X1t-3.804 2X2t+2.372 2X3t-1.884 2X4t+3.637 3X5t-1.041 7X6t-1.327 8X7t). The study shows that the near-infrared (NIR) spectroscopy technology that combining kinetic model of hardness can realize rapidly nondestructive testing of jujube’ flesh hardness index and the prediction of the storage time.
Key words：Near-infrared spectroscopy; Jujube; Hardness; Kinetic model
刘蒋龙，张淑娟，孙海霞，薛建新，赵旭婷. 基于二维相关光谱的壶瓶枣室温贮藏硬度动力学模型研究[J]. 光谱学与光谱分析, 2018, 38(03): 813-817.
LIU Jiang-long, ZHANG Shu-juan, SUN Hai-xia, XUE Jian-xin, ZHAO Xu-ting. A Kinetic Model of Hardness in Storage Periods of Fresh Jujubes at Room Temperature Using Two Dimensional Correlation Spectroscopy. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2018, 38(03): 813-817.
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