Near Infra Red Detection of Internally Moldy Nuts

Transmittance near infra red (NIR) spectra (500-1500 nm) of individual peanut was measured to detect the internally moldy nuts. The moldy nuts the appearance of which had little difference from the sound nuts by visual observations could be distinguished from each other by comparing the transmittance ratio of 700 nm to 1100 nm by NIR spectrometry. The fungal hydrolysis of the triglycerides that were contained in the nut seemed to account for these differences on the NIR spectra. Because of the higher incidence of aflatoxin (AF) contamination on these moldy nuts, taking out the internally moldy nuts detected by NIR, could drastically reduce the AF content of the overall lot of peanuts.