Factors contributing to increased bruise expression in avocado (Persea americana M.) cv. ‘Hass’ fruit

• Published in: Postharvest biology and technology 2018-09, Vol.143, p.58-67
• Main Authors: Mazhar, M., Joyce, D., Hofman, P., Vu, N.
• Format: Article
• Language: English
• Subjects: Agricultural production; Bruising; Dry matter; Duration; Energy; Firmness; Fruits; Injuries; Maturity; Ripening; Supply chains; Temperature; Time
• ISSN: 0925-5214; 1873-2356
• DOI: 10.1016/j.postharvbio.2018.04.015

•Bruising susceptibility reduces by increasing dry matter concentration up to ≥23%.•Bruising susceptibility increases with longer pre-ripening fruit holding duration.•Bruising susceptibility increases with longer post-impact fruit holding duration.•Decreasing fruit firmness increases susceptibility to mesocarp bruising.•Holding and handling at temperature >5 °C increase susceptibility to bruising. Mesocarp bruising is an important postharvest problem of avocado fruit. Bruise expression may be influenced by inherent fruit characteristics, and pre- and postharvest handling practices and conditions. In this supply chain focused study, the putative effects on avocado cv. ‘Hass’ bruise expression and severity of fruit maturity, temporal duration before or after impact injury, fruit firmness, and fruit holding temperature were examined. Mesocarp bruising in ripening fruit decreased in a linear fashion with advancing fruit harvest maturity over 20 weeks. Bruise severity increased progressively in fruit kept for up to 5 weeks before impact injury and also for those kept for up to 7 days after injury. Hard green mature stage fruit did not express bruising at ≤100 cm drop height (∼1.36 J energy absorbed). However, softening, firm ripe, and soft ripe stage fruit impacted from 50 cm (∼0.8 J energy absorbed) developed progressively greater levels of bruising. Keeping fruit at temperatures of 2.5 °C and 5 °C as compared with 20 °C at the time of impact resulted in less bruise expression. Similarly, fruit kept at post-impact temperatures of 2.5 °C and 5 °C as compared with 7.5 °C, 10 °C, and 20 °C also resulted in less bruise expression. Fruit kept at 5 °C for the first 8 h after impact and then at 25 °C for 40 h developed less bruising than fruit kept at 25 °C for 8 h after impact and then at 5 °C for 40 h. Overall, it is proposed that harvesting fruit at ≥23% dry matter concentration, passing them quickly through the supply chain such that bruising has less time to express, and keeping the fruit ‘at’ or ‘below’ 5 °C in the supply chain could reduce bruise expression levels in ripening ‘Hass’ avocado fruit.