A method for quantifying the texture of fresh commodities was developed. The texture data were obtained by acoustic measurements using a piezoelectric sensor and knife edge probe. The signal amplitude density was computed by summing up the amplitude of the texture signals and dividing by the data length. We designated this value as the texture index. An octave multi-filter was used to analyze the texture signals in the frequency domain between 0 Hz and 6400 Hz. Also, a technique of reducing periodical noise in the texture signals was developed. The noise data before the probe was inserted into a sample were subtracted from the raw data that consisted of both texture signals and noise. The methodology was applied to blanched bunching onion samples. Their signal amplitude densities showed the characteristics of blanched bunching onion texture. Also, analyzing the texture signals in the lowest frequency band (0–50 Hz) revealed the leaf sheath structure of the blanched bunching onion tissue.