Interrelation among measurements of browning of processed potatoes and sugar components

Summary

A principal factor in assessment of quality of processed potato products is the Maillard-reaction-induced brown color which develops during processing (chips) or during subsequent storage (dehydrated dice). The present paper constitutes a statistical appraisal of the relationship between this browning and the individual reducing-sugar components of the raw tubers and dehydrated potato dice. Although correlation coefficients were greater than 0.9 (except for sucrose) comparison of standard errors of estimate and application of a parameter referred to herein as the “discriminatory index” reveals that sugar measurements, or combinations thereof, do not yield sufficient information to establish an exclusively complete causal relationship between reducing sugar components and extent and rate of browning. This is true despite the control or elimination of several factors usually overlooked in the pertinent measurements which might lead to the observed scatter. Possible auxiliary factors operating during the browning reaction, other than sugars and amino compounds, are discussed. Application of discriminatory indices to the data reveals reducing-sugar and glucose measurements as a more sensitive index of browning in potato chips than of browning rate of dehydrated potato dice. On the other hand, measurements of fructose and total sugar constitute equally reliable indices of both types of browning but at a lower sensitivity level. From the standpoint of prediction of quality of processed potato products in general, this analysis leads to the conclusion that subjective or semiquantitative appraisal of chip color may constitute at least as adequate an index of quality as any of the more elaborate objective measurements undertaken in the laboratory.