Firmness Evaluation by Drop Impact Characteristics for Peach

Abstract

The peach dynamic resonance frequencies were obtained based on the analysis of dynamically measured response signal of an drop-excited peach with change in impacted orientation, drop height, material of impact surface, peach firmness, peach mass, and storage time of peach. After peach was impacted, response signals in time domain were detected, and transformed into frequency domain (by means of FFT). The dominant frequency (the response magnitude were the greatest) was obtained and significantly affected by peach firmness, mass, and storage time. The impacted orientation, drop height, and material of impact surface did not significantly affect the dominant frequency. The dominant frequency increased with increasing of peach firmness and decreased with increasing of peach mass. The relationships were obtained between dominant frequency and peach firmness or peach mass, and the stiffness coefficient (Sc = f²m^2/3 ) regressed on Magness-Taylor firmness had a better relationship. The peach firmness could be predicted by drop impacting method.

Keywords:

• Peach
• Dynamic
• Resonant frequency
• Firmness

ACKNOWLEDGEMENTS

The authors acknowledge the financial support of the Chinese National Foundation of Nature and Science through project 30170533 and 30570449 and the financial support of Program for New Century Excellent Talents in Chinese University through project NCET-04–0544.