近红外光谱法检测婴幼儿营养米粉蛋白质含量

以160个婴幼儿营养米粉为样品,应用近红外光谱技术和偏最小二乘法建立了婴幼儿营养米粉中蛋白质含量的近红外模型。比较了2、3、4、5、6、7、8 mm不同装样厚度(即光程)下样品近红外光谱的稳定性,通过样品光谱在不同波数下的标准差选定了5 mm为最佳的装样厚度;比较了变量标准化、导数、多元散射校正和9点平滑预处理方法对模型建立的影响,根据模型的相关系数和均方根误差确定了最佳的预处理方法,为变量标准化、一阶导数和9点平滑,预处理后的光谱数据结合国标方法测定的蛋白质含量建立了婴幼儿营养米粉中蛋白质含量的近红外定量分析模型,定标集和验证集相关系数分别为0.9856、0.9841,均方根误差分别为0.2431%、0.2456%,对已建立的近红外光谱定量分析模型进行了外部样品验证,预测准确度达到96%,验证结果证明了近红外检测技术与国标方法一致性较好,速度快且不需要样品前处理,在婴幼儿营养米粉蛋白质含量分析中具有广泛的应用价值。

Determination of Protein Contents in Infant Nutritious Rice Flour by Near Infrared Spectroscopy

A near infrared analysis model of protein contents in nutritious infant rice flour was established by using near infrared spectroscopy and partial least square method.The spectral stability of the sample with different sample thickness 2,3,4,5,6,7,8 mm were compared.The standard deviation of the sample spectrum under different wave number determined that 5 mm was the best loading thickness. The effects of variable standardization,first order derivative,multivariate scattering correction and9-point smoothing preprocessing method on the model establishment were compared.According to the correlation coefficient and root mean square error of the model,the best pretreatment methods were variable standardization,first derivative and 9-point smoothing.The near infrared quantitative analysis model of protein contents in infant nutritious rice flour was established. The calibration correlation coefficients of calibration set and verification set were 0.9856,0.9841,and the root mean square error were 0.2431%,0.2456%,respectively. The established NIR quantitative analysis model was verified by external samples. The accuracy of prediction was 96%. The results showed that the near infrared detection method was consistent with the national standard method,and it was fast and didn’t need sample pretreatment.It would have wide application value in the analysis of protein content of infant nutritious rice flour.