Bruise damage susceptibility of pomegranates (Punica granatum L.) and its impact on fruit physiological response
Fruit bruising results from excessive impact and compression forces due to improper handling between the point of harvest and consumption. This damage is one of the factors contributing to postharvest losses and decline in quality of produce. This study investigated the susceptibility of three pomegranate (Punica granatum L.) fruit cultivars 'Acco', 'Herskawitz' and 'Wonderful' to impact bruising by letting the fruit fall from selected heights onto a flat surface. The impact threshold level (based on minimal drop heights (10, 15, 20 cm)) required to cause bruising was investigated by determining the probability of bruise occurrence(PBO) from the population of randomly selected fruits of each cultivar. The effect of the storage temperature on bruise susceptibility and fruit physiological response was studied by impacting fruit equilibrated at 5 and 20°C from three drop heights (20, 40 and 60 cm) followed by storage for 10 d to monitor the weight loss and respiration rate of the fruit. The bruising susceptibility at higher drop heights (20, 40 and 60 cm) was cultivar dependent in the order of 'Wonderful'>'Herskawitz'>'Acco'. The cooler fruit had greater bruise sizes compared to the warmer fruit. The minimum drop height at which bruising was first observed and the associated bruising occurrence (PBO) was at 10 cm (0.44), 15 cm (0.50) and 15 cm (0.75) for 'Wonderful', 'Herskawitz' and 'Acco', respectively. The cultivar 'Wonderful' was most susceptible to bruising with the highest value of PBO corresponding to the minimal impact energy (371.87 mJ). The respiration rate was the highest in 'Herskawitz' (125 mL CO2 kg-1 h-1) followed by 'Acco' (113 mL CO2 kg-1 h-1). Mean percentage weight loss was 2.01, 2.41 and 2.75% for 'Wonderful', 'Herskawitz' and 'Acco' fruit, respectively. Overall, the measured physiological responses increased with the increasing level of impact bruising and storage temperatures in all cultivars. These findings provide science-based tools to assist in improving the postharvest handling of pomegranate fruit as part of the overall management strategy to reduce losses due to bruise damages.
Hussein, Z., Fawole, O.A. and Opara, U.L. (2018). Bruise damage susceptibility of pomegranates (Punica granatum L.) and its impact on fruit physiological response. Acta Hortic. 1201, 55-64
bruise susceptibility, cultivar, drop height, impact energy, pomegranate fruit