Measurement of Tomato Fruit Firmness

Flat-plate compression, constant area compression, and puncture tests were examined for their sensitivity in differentiating the firmness of previously chilled (6C, 85% RH, 15 days) and nonchilled mature-green tomato (Lycopersicon esculentum Mill cv . Caruso) fruit during 10 days of ripening at 22C. Firmness, as measured by each of the three methods, progressively decreased (P < 0.001) with ripening. Previously chilled tomatoes were initially softer (P < 0.01) than nonchilled tomatoes, as measured by puncture of whole fruit and constant area compression of pericarp tissue sections, but not by flat-plate compression of whole fruit. Flat-plate compression was therefore found to be a relatively insensitive method by which to measure differences in tomato firmness that are characteristic of slightly chilling-injured fruit.