A simple non-destructive method for laboratory evaluation of fruit firmness.
Macnish A. J., Joyce D. C., Shorter A. J.
Author Affiliation: Department of Plant Production, The University of Queensland, Gatton College, Qld 4345, Australia.
Australian Journal of Experimental Agriculture 37 : 709-13
Abstract : An analogue CSIRO Tomato Firmness Meter (AFM), which measures fruit deformation under a 500 g load applied for 30 s, was modified by replacing the analogue displacement gauge with a digital gauge and by using a laboratory jack for positioning the fruit in the vertical dimension. Non-destructive measurements of tomato fruit softening during ripening determined with the Digital Firmness Meter (DFM) were strongly correlated with both firmness measured with the AFM (rē=0.96, n=19) and with firmness determined subjectively by hand pressure (rē=0.93, n=19). Similarly, mango fruit softening during ripening was monitored and DFM and hand firmness measurements were well correlated (rē=0.95, n=10). The firmness of individual fruit could be measured around 20% faster with the DFM than with the AFM, and displacement was easier to read from the digital than from the analogue display. The DFM proved to be a suitable device for measuring fruit firmness in postharvest laboratory studies and warrants evaluation under commercial packing and handling conditions.