Researchers at the University of California, Davis have developed a nondestructive method for identifying raw nuts with concealed damage.
Concealed damage (CD) is a brown discoloration of nutmeat that appears after raw nuts are treated with heat. CD is frequently associated with bitter flavor and results in immediate consumer rejection. It significantly affects the quality of harvested nuts and reduces grower returns in subsequent years. Currently, there are no screening methods available to detect CD in raw nuts.
Researchers at the University of California, Davis have developed a nondestructive method for identifying raw nuts with CD. The method employs Near-Infrared Spectroscopy (NIR) at selected wavelength ranges to generate a discriminant analysis model. The model can be applied to an automated sorting system to rapidly identify raw nuts with CD prior to roasting. These method can be used to establish thresholds for the specific kernel moisture content, temperature, and the various time and storage management scenarios to improve quality of the nuts and improve grower returns. The method has already been tested and confirmed in raw almonds and can be extended to other CD afflicted raw nuts including macadamia nuts, walnuts, chestnuts, hazelnuts, and soybean seeds.
near-infrared spectroscopy, concealed damage, raw nuts, chemometrics, discriminant analysis