Modelling the effects of storage temperature on the respiration rate of different pomegra nate fractions

Abstract

Temperature is one of the main factors that affects fresh produce respiration rate (RR). This study investigated the effects of storage temperature (5, 10, 15 and 22 °C) on the RRs of the pomegranate (Punica granatum L.) ‘Bhagwa’ whole fruit, aril-sacs and arils, and a mathematical model relating temperature to RR was applied. The aril-sacs had the highest RR at all storage temperatures in comparison to the whole fruit and arils. Overall, rates of carbon dioxide production (RCO2) and oxygen consumption (RO2) of the aril-sacs were in the range of 2.95–27.66 ml kg⁻¹ h⁻¹ and 5.49–48.44 ml kg⁻¹ h⁻¹, respectively, whereas those of the whole fruit ranged between 2.66 and 22.97 ml kg⁻¹ h⁻¹ and 3.71 and 33.3 ml kg⁻¹ h⁻¹, respectively, and those of arils were 1.96–18.64 ml kg⁻¹ h⁻¹ and 3.19–28.91 ml kg⁻¹ h⁻¹, respectively. Reducing storage temperature from 22 °C to 5 °C resulted in a reduction in RR of about 74.5% across all samples. Effect of temperature on RR of whole fruit, aril-sacs and arils were adequately predicted by an Arrhenius-type equation (R² > 97.1%). The model validated RR for arils stored at 22 °C and a good correlation was found between experimental and predicted data.

Keywords: aril-sacs, fresh-cut, mathematical model, pomegranate arils

South African Journal of Plant and Soil 2014, 31(4): 227–231