Comparison of nondestructive impact and acoustic techniques for measuring firmness in peaches

Abstract

Fruit firmness is one of the most important quality properties in peaches. Fruit firmness measurements can be destructive or nondestructive methods. Some nondestructive firmness sensors as lateral impact test (LPF), low mass impact methods (SIQ-FT) and acoustic impulse response (AFS) have been used to measure firmness. The objective of this study was to test nondestructive methods for the quality assessment of two peach varieties compared with destructive reference tests. It can be observed that all four devices are capable to sense the firmness decay of the peaches during the experiment. The correlations between destructive and nondestructive firmness measurements were significant (P<0.01) but too low. The best fit of the data was found between ME and the nondestructive lateral impact parameter A(max) (r = 0.652). The highest correlation in all parameters was found between A(max) and SIQ (r = 0.794). Nonlinear correlations between nondestructive firmness values and the destructive measurement values were significant (P<0.001) but low again. Coefficients of determination (r(2)) calculated for each variety and all data were as low as 0.22 and as high as 0.62.