The anaerobic compensation point for fresh-cut watermelon and implications for postprocess handling

The influence of temperature and O-2 concentration on respiration and shelf life of fresh-cut watermelon was investigated. Product stored at selected temperatures from 1 to 30 degreesC showed increasing respiration and reduced shelf life with increasing temperature. Oxygen depletion and CO2 evolution were measured using a closed system method and rates of O-2 consumption and CO2 production were computed. A mathematical model found to predict the CO2 production as function of temperature and O-2 showed an elevated rate of CO2 production at about 14% O-2 or lower. A modified atmosphere trial that compared product stored at 7 to 9 degreesC in air with product at either 14% or 8% O-2 revealed increased respiration in the latter treatments, suggesting a relatively high anaerobic compensation point (ACP) at>14% O-2. Our results suggest limited applicability of modified atmosphere packaging (MAP) for this product. Fresh-cut watermelon had extended shelf life and reduced respiration rate when stored at 1 to 3 degreesC and in >14% O-2 atmospheres.