该研究的目的是建立可见/近红外漫反射光谱无损检测甜柿果实硬度的数学模型,评价可见/近红外漫反射光谱无损检测甜柿果实硬度的应用价值。果实硬度采用果皮脆性、果皮强度和果肉平均硬度作为评价指标。在可见/近红外光谱区域(400～2 500 nm),采用改进偏最小二乘法,对比分析了不同导数处理、不同散射及标准化处理的甜柿果实硬度定标模型。结果表明,对于果皮强度和果皮脆性,采用最小偏二乘法、一阶导数处理和标准多元离散校正处理建立的定标模型预测效果较好,RP2分别为0.858和0.862,SEP分别为0.094和0.157,RPD分别为2.47和2.63。对于果肉平均硬度,采用改进偏最小二乘法、一阶导数处理和标准正常化和去散射处理建立的定标模型预测效果较好,RP2为0.82,SEP为0.063,RPD为2.35。因此,可见/近红外漫反射光谱无损检测技术可用于甜柿果实硬度的无损检测。

To establish a mathematical model of visible and near infrared diffuse reflection(VIS/NIR) spectroscopy and firmness of sweet persimmon,and to evaluate the applicability of VIS/NIR spectroscopy in non-destructive measurement of firmness of sweet persimmon.peel brittle,peel strength and the average hardness of flesh of the fruit were used as evaluation indexes.In the spectral region between 400～2500nm,calibration results for firmness of sweet persimmon were compared with different derivative treatments and different scatter and standard treatments with modified partial least squares(MPLS).The results showed that the MPLS model,with respect to the first derivative D1 Log(1/R)and standard multiple scatter correction,provided better prediction for peel brittle and peel strength,the correlation coefficient of prediction(R2P)was 0.858,0.858 respectively;the root mean square error of prediction(SEP)was 0.157,0.094 respectively;ratio performance deviation(RPD)was 2.63,2.47 respectively.The MPLS model,with respect to the first derivative D1 Log(1/R)and standard multiple scatter correction,provided better prediction performance for average hardness of the flesh,with R2P 0.82,SEP 0.063,and RPD 2.35.Therefore,this visible and near-infrared diffuse reflectance spectroscopy technique can be used for non-destructive testing of fruit firmness in sweet persimmon.