A portable monitor for the rapid assessment of processing quality of stored potato tubers

The present study assessed a commercially available, enzymatically based blood glucose monitor for the rapid determination of processing quality of tuber samples taken directly from storage. This monitor is based on reflectance photometry of a disposable test strip for a chromogen produced during the oxidation of glucose. The influence of storage conditions, harvest location, cultivar, reconditioning effects and the monitoring environment were examined for their effects on glucose levels and chip color. Glucose concentrations were determined by blood glucose monitor, high performance liquid chromatography (HPLC) or YSI biochemical analyzer. Crude tuber extracts did not adversely affect the determination of glucose by the blood glucose monitor and there was no evidence of any interaction between glucose concentration and extract in terms of test strip color development. The test strips demonstrated stable color retention for over an hour although values remained slightly higher after the initial potato extract test. Reaction of test strips to glucose was sensitive to initial temperature of the tuber extract with greatest accuracy exhibited in the 15–22 C range. Chip color was inversely correlated with tuber glucose content regardless of detection method, cultivar, growing site or storage temperature. The highly portable glucose monitor provided a rapid, accurate and quantitative profile of chip processing quality.