Low Cost Real Time Sorting of In-shell Pistachio Nuts from Kernels

Abstract

A high speed sorter for separating in-shell pistachio nuts from kernels is reported. Testing indicates 95% accuracy in removing kernels from the in-shell stream and 100% accuracy for the in-shells out of 1000 samples tested. Testing with 1000 each of in-shell, shell halves, and kernels resulted in an overall error of 3.3%, about twice the overall error rate achieved using a commercially available dual band VIS-NIR sorting device. The cost of materials for the sorter reported here was less than $500 US, compared to upward of $100,000 for commercially available sorters. The new sorter thus has approximately double the error rate while achieving a roughly two hundred fold savings in cost compared to currently used equipment. Since existing sorters can be trained to sort a variety of product streams, implementation of the new device in pistachio plants could free up machines for other sorting tasks, thus reducing the overall cost of pistachio processing.