Bremen 2000 – scientific programme

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UP: Umweltphysik

UP 12: Poster: Agrar-,Bodenphysik und Hydrologie

UP 12.3: Poster

Wednesday, March 22, 2000, 15:30–16:30, Foyer

Fruits and vegetables studied by thermal imaging — •Hans Juergen Hellebrand, Manfred Linke, Horst Beuche, Bernd Herold, and Martin Geyer — Institut fuer Agrartechnik Bornim e.V. (ATB), Max-Eyth-Allee 100, D-14469 Potsdam

The loss of water through transpiration causes a temperature gradient at the surface of horticultural products. This temperature gradient depends on the type and state of fruit (size, shape, skin, maturity, etc.), the temperature and humidity of the surrounding air, and on the air flow around and against the product. Thermal images have been taken using a commercial infrared camera with a temperature resolution of 0.1 K. The measured temperature differences can serve as a source to characterise plots of transpiration at the surface of the fruit, or, by using transpiration models, to determine transpiration coefficients quantitatively. The transpiration of a fruit and its metabolism depend on the degree of maturity. As a result, the temperature of the surface could be related to the ripeness of fruits, as indicated in preliminary studies. Products with defects or mechanical damage also gave variable surface temperature, or a measurable temperature reduction. Defective fruit skins can often be detected by a localised temperature decrease.