Texture evaluation of cucumber by a new acoustic vibration method

Abstract

The texture of three cucumber cultivars was evaluated by an acoustic measurement of crispness (AMC). Piezoelectric film was sandwiched between a conical probe and a piston of a glass syringe. The probe was inserted into a cucumber at 35 mm/min by the delivery of water into a syringe and the acoustical vibration of the probe was directly detected by the piezoelectric film up to 10000 Hz. The vibration signals were transformed to spectrum data by fast Fourier transform. Difference in spectrum of different points and parts of three cucumber cultivars were found especially in the frequency range between 1 to 6 kHz. A new index to evaluate the texture was calculated by using intensities of each spectrum to emphasize the intensity of high frequency spectra ("Sharpness index"). Quantification of the crispy texture of an agricultural product by the new "Sharpness index" was discussed.