Abstract
Since the 1800's, Fusarium Head Blight has deleteriously affected the yield and quality of small grain cereal crops such as wheat. This fungal disease is also a health concern due to the frequent production of the secondary metabolite, deoxynivalenol (DON), which is moderately toxic to humans and non-ruminant animals. Our study is a progress report on the effort to develop more efficient methods for separating Fusarium-damaged kernels from sound wheat kernels. Through the development of a high-powered pulsed LED system, we have demonstrated that Fusarium-damaged and sound individual wheat kernels can be correctly categorized at up to 91% average accuracy. The system is bichromatic in the sense that green and red LEDs are pulsed in sequence, which is similar to our recent work in the past year. In this study, however, the system illumination, signal acquisition, and analysis modules were integrated and improved. Two parameters (slope and r 2 ) from a regression analysis of the green response onto the red response were used as input parameters in a linear discriminant analysis (LDA). In agreement with our previous work, slope was the predominant classifier; so much so that it was used exclusively after preliminary analyses. The factors that affect the level of accuracy are the orientation of the optical probe with respect to the LED illumination source that strikes the free-falling kernel, and the color contrast of the two categories, which is observed to vary from sample to sample. Our previous research has shown that commercial high-speed optical sorters are, on average, 50 percent efficient at removing mold-damaged kernels; however, under more carefully controlled, kernel-at-rest, conditions in the laboratory, this efficiency can rise to 95 percent or better. Our present research on free-falling kernels is producing accuracies that are beginning to approach those of the controlled conditions. Knowledge gained from this research will provide design criteria for improvement of high-speed optical sorters for reduction of DON in raw cereal commodities, as well as in finished food products.