Understanding and managing avocado flesh bruising (AV12009)

What was it all about?

Flesh bruising is a significant postharvest concern for the avocado industry, reducing the value of produce. This project continued the work of an earlier investment to develop a better understanding of flesh bruising and to identify ways to avoid it.

This study had three parts, all conducted with Hass avocados.

In the first part of the study, researchers subjected individual fruit to a number of compression and impact levels and measured bruising in the hours afterwards. Trays of fruit were also dropped from various heights and various angles to find out how much bruising it caused.

Shoppers tend to assess avocados before purchase by squeezing to test for firmness, so in the second part of the study, researchers measured typical compression forces and pressures using sensors. They simulated the behaviour of shoppers in the lab using a silicone thumb and strain gauge assembly and assessed the damage to fruit.

In a third component, fruit was sampled at seven points along the supply chain including the ripening facility, distribution centre, retail store and the consumer’s home, and was assessed for bruising. Consumers were also given bruise free fruit at the retail store check-out point which was later collected to assess bruising sustained on the way home.

Key findings included…

• Flesh bruising worsened with increasing impact energy, with softer fruit being more affected
• Bruising increased as the fruit passed through each stage in the supply chain, particularly at the retail store display, and between the point of purchase and the point of consumption
• Each squeezing event by shoppers was found to potentially increase bruise severity in firm and soft ripe avocado fruit.

Since a lot of flesh bruising happens when the fruit is on retail display, researchers developed a prototype decision aid tool that helps shoppers to select fruit without squeezing it.

They recommended that the tool is assessed for usefulness and acceptance at retail level. This work was carried out through a further investment in the Hort Innovation Avocado Fund.