Improving consumer appeal of Honey Gold mango by reducing under skin browning and red lenticel discolouration (MG13016)

What was it all about?

Honey Gold mangoes are susceptible to two types of superficial defects that result in downgrading of produce and financial loss. These are…

• Under-skin browning, a type of lesion that shows up after harvesting
• Red lenticel spots, thought to be a wound response in the fruit, often associated with heavy rainfall prior to harvest.
• This project, which ran from 2013 to 2016, aimed to improve the consumer appeal and profitability of Honey Gold mango by…
• Reducing the occurrence of under-skin browning by exploring the influence of pre-harvest and harvest practices
• Identifying strategies to minimise red lenticels using inhibitors and promoters of red skin colour.

Researchers combined data from 40 previous studies to identify the most likely cause of under-skin browning. Experiments were then conducted to establish the factors that cause the bruising.

A literature review of red lenticel development informed another series of experiments to identify methods of preventing them.

Key findings included…

• Harvesting mangoes at night was the most effective practice for reducing the sensitivity of fruit to developing under-skin browning. Fruit harvested between 10 PM and 10 AM displayed 50-75 per cent reductions in browning compared to those picked at 2 PM.
• Pre-harvest bagging of fruit was the most reliable technique for reducing red lenticels. The bags block sunlight and, in turn, reduce red pigment production, including skin blush.
• Researchers also found that postharvest exposure of fruit to blue LED light for 3-4 weeks at 22°C enhanced skin blush, which could mask red lenticels.
• Preventing water entry into lenticels with pre-harvest applications of RainGard and carnauba wax also reduced red lenticel damage.

The project also confirmed previous findings that accumulated heat units is a reliable predictor for harvest dates.