Changes in the force relaxation and compression responses of tomatoes during ripening: The effect of continual testing and polygalacturonase activity

The response of tomato fruit compressed axially between flat plates was investigated under simple compression and under force relaxation conditions. These tests were able to follow the changes in fruit firmness during ripening, but could not be described as truly non-destructive as fruit tested daily became slightly firmer and more elastic when compared to a control group, which were tested only once in the ripening period, implying that the tests had an effect upon the fruit. While these tests could detect changes in Ailsa Craig and polygalacturonase-antisense fruit, no change could be detected in fruit from the rin mutant, and the polygalacturonase-antisense fruit could not be distinguished from the Ailsa Craig fruit. (C) 1997 Elsevier Science B.V.