Characterising water loss in pomegranate fruit cultivars (‘Acco’, ‘Herskawitz’ & ‘Wonderful’) under cold and shelf storage conditions

Abstract Fruit water loss results in a huge financial loss to the industry due to loss of aesthetic appeal and direct loss of saleable fruit weight. There is currently a limited knowledge on the mechanism of water loss in pomegranate fruits, given their complex structure. Therefore, this study aimed to characterise water loss in the most common export pomegranate cultivars (‘Acco’, ‘Herskawitz’ and ‘Wonderful’) of South Africa. Fruits were stored for 42 d at 7 ºC and 90 % RH and thereafter transferred to shelf at 23 ºC and 58 % RH. Another batch of fruit was immediately stored under prolonged shelf conditions for 16 d. Water loss, respiration rate, arils-peel proportions and moisture content, peel thickness and colour attributes, puncture resistance property and chemical quality attributes of fruit juice were measured. The study revealed that despite the physiological and structural differences among pomegranate cultivars, water loss was similar during the 42 d of cold storage. However, the medium-sized fruits (‘Herskawitz’ and ‘Wonderful’) had significantly higher water loss (0.32 ± 0.01 g cm-2) than the small-sized fruits (‘Acco)’ (0.25 ± 0.01 g cm-2) during the prolonged 16 d of shelf storage. The observed maximum water loss of 24.2 % is mainly from the peel proportion. Therefore, research should primarily focus on the peel fraction in addressing the water loss problems of pomegranate fruits.