1Feb 2000

Banana republic science

by Kate Melville

Ever wondered about why your bananas are either squishy and overripe, or hard enough to double as sex toys?

Well wonder no more as the key factor seems to be the fruit's natural emissions of ethylene gas. How was this ground breaking discovery made? Students from the University of Maine have been trying to develop a fruit ripeness sensor that could growers and food processors can use.

Apparently in many fruits and vegetables ethylene is an indicator of the ripening process so a sensor that detects the telltale gas might just save money for the food industry by providing information about the best times to pick, store and process produce. For example, harvesting needs to be done at the peak of ripeness, but commercial operators are often forced to pick early, just as produce begins to ripen. This then causes a major danger in that if picked too early the fruit may not ripen at all.

The project is being run under the auspices of John Vetelino, a professor in the Department of Electrical and Computer Engineering. Vetelino said, "Our science is driven by practical applications, and this project has gotten lots of support from people in the food industry. As fruits and vegetables start ripening, they emit very small concentrations of ethylene, in the parts per million range. Our sensors have to be sensitive enough to detect that level."

"The benefit to industry would be having a non-destructive way to monitor food quality. The end result will be better products for the consumer," said Al Bushway of the UMaine Department of Food Science and Human Nutrition.

Researchers will use the data to calibrate sensors. The research students placed bananas in sealed jars and tested the gases emitted using high performance gas chromatography. The ultimate goal is to determine how ethylene gas concentrations correspond to different stages of ripeness.

While the project is still at an early stage it is hoped that the data collected from the sensors will help with the development of new software that is able to give a clear picture of ripeness or otherwise of bananas.

So, coming soon to a supermarket near you, bananas that are only suitable for eating.