Effects of storage conditions on transpiration rate of pomegranate aril-sacs and arils

Abstract

This study investigated the effects of temperature (5, 10, 15 and 22 °C) and relative humidity (RH) (76%, 86% and 96%) on the transpiration rate (TR) of pomegranate (Punica granatum L.) cv. Bhagwa fruit fractions, namely arils and aril-sac. Both temperature and RH had significant effects on the TR of fruit fractions. The TR increased with an increase in temperature and decrease in RH, with the fruit fraction stored at 5 °C and 96% RH showing the lowest TR in comparison to other storage conditions. Arils showed higher TR than the aril-sac under all storage conditions. The TR of the arils at 96% RH was in the range 1.42–15.23 g kg⁻¹ d⁻¹, whereas that for the aril-sac was 0.63–9.95 g kg⁻¹ d⁻¹, respectively. The higher TR of fruit arils may be attributed to the larger surface area as compared to the aril-sac whereby some of the arils are covered with the membrane, albedo and peel. A mathematical model was applied and the model adequately predicted the TR for arils and aril-sacs stored at 22 °C and RH 76%, 86% and 96%, with a good correlation between experimental and predicted data.

Keywords: pomegranate aril-sac, relative humidity, storage temperature, transpiration rate

South African Journal of Plant and Soil 2014, 31(1): 7–11