Non-destructive determination of the optimum eating ripeness of pears and their texture measurements using acoustical vibration techniques
Mitsuru Taniwaki, Takanori Hanada, Minami Tohro and Naoki Sakurai
Postharvest Biology and Technology, Volume 51, Issue 3, March 2009, Pages 305-310
2009
บทคัดย่อ
Non-destructive determination of the optimum eating ripeness of pears and their texture measurements using acoustical vibration techniques
We investigated the time-course changes in the elasticity index (EI) and texture index (TI) of pears (Pyrus communis L. cv. La France) during the postharvest period. EI was determined using a formula EI = f22m2/3, where f2 is the pear sample's second resonance frequency and m is the sample mass. A non-destructive vibrational method using a laser Doppler vibrometer (LDV) was used to measure the pears’ second resonance frequency (f2). Changes in the EI of the pears showed bi-phasic decay. Along with sensory testing, we determined the period of optimum eating ripeness of the pears in terms of their EI to be 8.1 × 104–1.5 × 105 kg2/3 Hz2. Pre-determined EI of pears enables consumers to predict the time range of optimum eating ripeness. An improved device for texture measurement was used for measuring time-course changes in the texture of pears. The texture was quantified with TI, which was determined for 18 frequency bands through integration of squared amplitudes of texture signals multiplied using a factor of a frequency band. The TI declined gradually over a wide frequency range as the pear samples ripened.