ESTIMATION OF MOISTURE LOSS FROM THE COOLING DATA OF POTATOES

Abstract

ABSTRACT A procedure was developed to predict moisture loss from cooling data of potato packed in gunny bags and stacked on wooden platforms in commercial cold stores. To predict the moisture loss, mass transfer coefficients kcand kmwere estimated during the storage period, which were found to decrease with time. The calculated time average kcand kmvalues were 1.83 × 10−4 m/s and 2.31 × 10−10 kg/s·m2·Pa during the transient cooling period and 1.59 × 10−4 m/s and 2.27 × 10−10 kg/s·m2·Pa for the rest of the storage period, respectively. The estimated moisture losses were 4.8, 4.74 and 4.78%, at the center of three different stacks, for a storage period of 8 months. The corresponding experimentally measured weight losses at the center of the same stacks were 5.2, 5.1 and 5.26% with a variation of 11, 7.5 and 10.2%, respectively. Therefore, the procedure adopted in this study may be used to assess the moisture loss from potatoes under the different storage conditions. The effect of relative humidity (RH) and potato temperature on moisture loss was also predicted using the developed procedure. Decrease in RH of the storage air increased the moisture loss. The potatoes stored below 85% RH incurred more than 7% water loss. Therefore, 88–90% RH in the cold store may be used to limit the maximum moisture loss within the permissible limit of 5% even after 8 months of storage. It was also found that increasing the potato temperature exponentially increased the rate of moisture loss.