Rotten mangoes often look ripe and smooth on the outside. WUR researchers have developed a way to detect whether the fruit is rotten without cutting it open.
Researchers at the post-harvest group of Food & Biobased Research had to cut hundreds of mangoes by hand to see if the pulp was rotten. "We even had a special cutting device developed at the workshop," says Suzan Gabriëls. But before the mangoes were cut open, the moisture and chemical composition were measured with a near infrared spectrometer (NIR).
Then all mangoes were cut and photographed in a standardised colour cabinet. Those images were then translated into values, with all brown and black pixels representing "rot" and all yellow pixels "healthy". From these values a "healthy-brown" ratio has been calculated for each mango. The higher the ratio, the less brown the mangoes were.
The researchers then tested whether the NIR measurements using this model could identify the mangoes with rotten pulp under the skin. This showed that in eighty percent of the cases they correctly predicted that the mango was brown inside.
Gabriëls thinks this is a good result that the large mango processors can use. With the spectrometer they can determine the quality of the mango, so that they can transport the good mangoes far away, sell the reasonable mangoes on the local market and throw away the rotten mangoes. Every year, 1.1 million tonnes of mangoes are traded globally with a value of around 2 billion Euro.
Source: Wageningen University & Research