Cultivar and fruit size influence bruise susceptibility and some physical properties of apple fruit

For most fruit types, including apples, bruising is the most common type of postharvest mechanical injury. Bruise susceptibility was investigated in 3 commercial cultivars (‘JazzTM’, ‘Granny Smith’ and ‘Fuji’) and among a range of 4 different fruit sizes (commercial counts of 135, 120, 100, and 88) in each cultivar. Bruising was carried out by dropping a uniform round steel ball (110g) from a height of 30 cm through a vertical hollow PVC pipe onto the apples. Fruit physical properties and bruise assessments were evaluated. The results showed that ‘JazzTM’ and‘Granny Smith’ apples had the lowest and highest bruise susceptibility, respectively, indicating that ‘Granny Smith’ apple would be more likely to be bruised during harvest and post-harvest handling. Results also showed that smaller fruits were less susceptible to bruising. There was a positive significant correlation between fruit bruising and fruit volume; but, there were significant negative correlations between fruit bruising and fruit density, fruit firmness and fruit dry mater. These findings will be very useful to reduce the incidence of fruit damage of studied apple cultivars, which is of interest to both growers and operators of postharvest handling and marketing facilities.