蛋壳品质的近红外光谱检测分析

蛋壳品质对蛋品孵化、贮存和运输均有重要影响。为了探索近红外光谱技术快速检测蛋壳品质的方法，该文在鸡蛋蛋壳品质指标相关性分析的基础上进行了蛋壳品质的近红外光谱检测分析，研究比较了不同建模方法、不同光谱预处理方法和不同波段范围对预测结果的影响。结果表明：在5段特征波长范围内建立的经过多元散射校正的偏最小二乘回归（PLSR，partial least squares regression）模型对蛋壳强度的预测结果最好，相关系数r为0.86，校正、预测均方根误差分别为4.42、7.53 N；同时蛋壳百分比（蛋壳质量/蛋质量）的PLSR模型的相关系数r为0.92，校正、预测误差分别为0.313%、0.529%；蛋壳厚度的PLSR模型的相关系数r为0.81，校正、预测误差分别为0.0176、0.0234 mm。研究结果表明应用近红外光谱技术预测蛋壳品质是可行的，为蛋壳品质的快速无损检测提供了一种新的方法。

Detection of intact egg eggshell quality based on NIR spectra

The quality of eggshell is an important factor on egg hatching, storage and transport. In this research, it was tried to detect the quality of eggshells with near infrared spectroscopy on the basis of eggshell quality indicator correlation analysis. Different spectral preprocessing methods and modeling algorithms were tested in different band ranges. The results showed that the best result was gotten with the partial least square regression (PLSR) modeling method at 5 characteristic wavelengths with the multiplicative scatter correction (MSC) preprocessing method. The quality indexes of the best modeling result were: 0.86(correlation coefficient, r), 4.42 N (root mean standard error of calibration, RMSEC) and 7.53 N (root mean standard error of prediction, RMSEP) for the relation between the eggshell strength and their spectra; 0.92, 0.313% and 0.529% for the relation between the eggshell percentage and their spectra; 0.81, 0.0176 and 0.0234 mm for the relation between the eggshell thickness and their spectra. The correlation between conventional eggshell quality indicators was studied. The result showed that the correlation is big between eggshell strength with eggshell percentage, egg specific gravity and eggshell thickness, the correlation coefficient were 0.55, 0.49 and 0.43, respectively. They are three parameters that closely related to the eggshell strength. And the eggshell strength can be characterized by them to a certain extent. The near-infrared spectra of different eggshell strength were compared. The result showed that the average spectral reflectance of the high-intensity group was biggest, the medium-intensity group is in the second place, and the low-intensity group is smallest. The result showed that near-infrared spectral characteristic was affected by the eggshell surface structure. In order to research the influence of eggshell internal structure on near-infrared diffuse reflectance spectra of eggs samples with different eggshell strength, the eggshell ultra-microstructure of samples was compared between groups of high and low eggshell strength. The result showed that with the increase of the eggshell strength, the eggshell cross-sectional consistency and smoothness became better, the mastoid layer and fiber layer related more closely and the effective thickness of the mastoid became smaller, the outer surface of eggshell became smoother and denser, and cracks reduced; the eggshell fiber layer structure became closer, the primary and secondary branch was clearer, fiber gap became smaller. All the results show that detecting eggshell quality using NIR spectra is feasible, and provides a new method for rapid non-destructive testing of eggshell quality.