Feasibility of Detecting Aflatoxin B1 on Inoculated Maize Kernels Surface using Vis/NIR Hyperspectral Imaging

The feasibility of using a visible/near‐infrared hyperspectral imaging system with a wavelength range between 400 and 1000 nm to detect and differentiate different levels of aflatoxin B₁ (AFB₁) artificially titrated on maize kernel surface was examined. To reduce the color effects of maize kernels, image analysis was limited to a subset of original spectra (600 to 1000 nm). Residual staining from the AFB₁ on the kernels surface was selected as regions of interest for analysis. Principal components analysis (PCA) was applied to reduce the dimensionality of hyperspectral image data, and then a stepwise factorial discriminant analysis (FDA) was performed on latent PCA variables. The results indicated that discriminant factors F₂ can be used to separate control samples from all of the other groups of kernels with AFB₁ inoculated, whereas the discriminant factors F₁ can be used to identify maize kernels with levels of AFB₁ as low as 10 ppb. An overall classification accuracy of 98% was achieved. Finally, the peaks of β coefficients of the discrimination factors F₁ and F₂ were analyzed and several key wavelengths identified for differentiating maize kernels with and without AFB₁, as well as those with differing levels of AFB₁ inoculation. Results indicated that Vis/NIR hyperspectral imaging technology combined with the PCA–FDA was a practical method to detect and differentiate different levels of AFB₁ artificially inoculated on the maize kernels surface. However, indicated the potential to detect and differentiate naturally occurring toxins in maize kernel.