Science - April 1, 2004

Special film prevents spots on bananas

Agrotechnology & Food Innovations has developed a special chloride packaging material jointly with the Kasersart University in Bangkok, Thailand. The film prevents the early formation of black spots on bananas, a welcome development for sweet banana growers.

The PVC film has optimal diffusion characteristics. It lets enough oxygen through for the bananas to ‘breathe’, but not enough to encourage the formation of black spots. Black patches on the banana are generally a useful sign that the banana is overripe. But the Chiquita banana that we are used to eating in the West is different from the common sweet bananas in Thailand and other Asian countries. “These Asian varieties develop patches more quickly, they may even be covered in them and still good to eat. The fruit itself is not necessarily overripe,” explains Dr Wouter van Doorn of A&F, and guest researcher at the Kasersart University in Bangkok.

Fruit sellers find it difficult to convince their customers that their spotty bananas are still alright to eat. The customers would rather have an evenly yellow banana. “We have tried all sorts of different packaging, but in the end the best was a film that allows just enough oxygen and just enough carbon dioxide through.” The low oxygen content delays the spot formation, but the fruit itself produces carbon dioxide and this must be able to escape otherwise the banana will ‘suffocate’. The higher humidity caused by the packaging has no detrimental effects.

The chloride film is suitable for bulk transport of bananas in sacks and also for covering bananas in the supermarket. The packaging has been tested on the sweet dessert banana Musa cavendishii, which is widely grown in Indonesia, Burma, India, Colombia and Brazil. | H.B.

Re:act