Correlation and classification of single kernel fluorescence hyperspectral data with aflatoxin concentration in corn kernels inoculated withAspergillus flavusspores

Abstract

The objective of this study was to examine the relationship between fluorescence emissions of corn kernels inoculated with Aspergillus flavus and aflatoxin contamination levels within the kernels. Aflatoxin contamination in corn has been a long-standing problem plaguing the grain industry with potentially devastating consequences to corn growers. In this study, aflatoxin-contaminated corn kernels were produced through artificial inoculation of corn ears in the field with toxigenic A. flavus spores. The kernel fluorescence emission data were taken with a fluorescence hyperspectral imaging system when corn kernels were excited with ultraviolet light. Raw fluorescence image data were preprocessed and regions of interest in each image were created for all kernels. The regions of interest were used to extract spectral signatures and statistical information. The aflatoxin contamination level of single corn kernels was then chemically measured using affinity column chromatography. A fluorescence peak shift phenomenon was noted among different groups of kernels with different aflatoxin contamination levels. The fluorescence peak shift was found to move more toward the longer wavelength in the blue region for the highly contaminated kernels and toward the shorter wavelengths for the clean kernels. Highly contaminated kernels were also found to have a lower fluorescence peak magnitude compared with the less contaminated kernels. It was also noted that a general negative correlation exists between measured aflatoxin and the fluorescence image bands in the blue and green regions. The correlation coefficients of determination, r(2), was 0.72 for the multiple linear regression model. The multivariate analysis of variance found that the fluorescence means of four aflatoxin groups, <1, 1-20, 20-100, and >or=100 ng g(-1) (parts per billion), were significantly different from each other at the 0.01 level of alpha. Classification accuracy under a two-class schema ranged from 0.84 to 0.91 when a threshold of either 20 or 100 ng g(-1) was used. Overall, the results indicate that fluorescence hyperspectral imaging may be applicable in estimating aflatoxin content in individual corn kernels.

Applying hyperspectral imaging to explore natural plant diversity towards improving salt stress tolerance

“…Application of HSI was done for food quality evaluation soybean seeds, wheat, barley grains and Portobello mushroom (Agaricus bisporu) (Taghizadeh et al, 2011, Tumuluru et al, 2010, Arngren et al, 2011, Huang et al, 2014a, 2014b and detection of defects in apple fruits and lettuce leaves (Baranowski et al, 2012, Simko et al, 2015. In parallel, experiments using HSI techniques for detection of fungal infections in fruits of citrus, leaves of sugar beet, wheat and maize have proven the applicability of the technique (Lorente et al, 2013, Mahlein et al, 2010Hillnhütter et al, 2011, Firrao et al, 2010Yao et al, 2010, Bauriegel and Herppich, 2014, Williams et al, 2012. Nowadays, HSI methodologies based on various indices have been mostly used for detection of photosynthetic pigments like chlorophylls, carotenoids as well as of the other major compounds in leaves and fruits, such as anthocyanins and flavonoids (Deepak et al, 2015;Matros and Mock, 2013, Hölscher et al, 2009, Zhao et al, 2005, Coops et al, 2003, Ferri et al, 2004.…”

Spectral Angle Mapper classification of fluorescence hyperspectral image for aflatoxin contaminated corn

“…In a recent study [11], a fluorescence peak shift was discovered in aflatoxin contaminated corn kernels. This spectral feature indicates that the spectral angle change in contaminated corn kernels may be an area suitable for further exploration using the SAM algorithm.…”

Aflatoxin Contamination Distribution Among Grains and Nuts

“…For Brazil nuts, the hand picking segregation based on segregation of kernels with fluorescence has been used in Bolívia as an aflatoxin decontamination technique. Yao et al (2010) reported good correlation between single kernel fluorescence hyperspectral data and aflatoxin concentration in maize.…”

“…Nowadays, BGYF is not currently used as a technique of decontamination of aflatoxin contaminated maize, it has been used as a technique for analyzing samples to detect aflatoxin contamination. Other types of fluorescence have been studied as a way to indicate contaminated peanuts, almonds, and maize (Pelletier & Reizner, 1992;Shade and King, 1984;Yao et al, 2010). A device capable of measuring fluorescence intensities from peanut surfaces and physically rejected peanuts having undesired fluorescence properties was described (Pelletier et al, 1991), however a comparison of the efficiency between it and the color sorting process in peanuts lots showed that it was not effective as an aflatoxin decontamination technique (Pelletier & Reizner, 1992).…”