Use of the Acoustic Impulse-Response Technique for the Nondestructive Assessment of Manchego Cheese Texture

Set-up used in the acoustic measurements.

Change of surface and internal textural characteristics of Manchego cheese during ripening. MF = maximum force; MP = maximum in puncture. Maturity of pieces: batch 1 = 36 to 156 d; batch 2 = 140 to 218 d; and batch 3 = 219 to 336 d.

Principal component (PC) analysis loading plot of the surface and internal textural parameters of Manchego cheese. MF = Maximum force; WSD = downstroke compression work; DMF = distance to maximum force; WSU = upstroke work; SS = initial compression slope; MP = maximum in puncture; PW = puncture work; DMFP = distance maximum force to puncture; SP = slope in puncture; H = hardness; DMFC = distance to maximum force to compress; CW = compression work; DM = deformability modulus; subscript se = semispherical probe; sp = sperical probe.

Acoustic spectra of cheeses with different ripening times for impact probes A (top) and B (bottom). Probe A: segment 1 = 19 to 54Hz, segment 2 = 54 to 134Hz, segment 3 = 134 to 1,000Hz. Probe B: segment 1 = 93 to 815Hz, segment 2 = 815 to 2,000Hz.

Change of the acoustic characteristics of Manchego cheese during ripening. CF = central frequency. Maturity of pieces: batch 1 = 36 to 156 d; batch 2 = 140 to 218 d; and batch 3 = 219 to 336 d.

Principal component (PC) analysis loading plot of the acoustic parameters of Manchego cheese (subscript A denoting probe A and B probe B). M₁ = Moment of order 1 of the frequency spectrum; CF = central frequency of the entire spectrum; Var = variance of the frequency spectrum; M₀₁, M₀₂, M₀₃ = moments of order 0 in sections 1, 2, and 3 of the frequency spectrum; CF₁, CF₂, CF₃ = central frequencies of sections 1, 2, and 3; M₁₁, M₁₂ = moments of order 1 in sections 1 and 2 of the frequency spectrum.