Frequency analysis of Fourier spectra from ultrasonic signals was used
for predicting intramuscular fat content of beef tissue. The most sig
nificant parameter in the frequency domain for predicting intramuscula
r fat concentration in beef was the number of local maxima. It represe
nts the discontinuity of the Fourier spectrum caused by inhomogeneous
fat concentrations in the longissimus muscle; which had the correlatio
n coefficient .89 (P < .05) when a 2.25-MHz; shear probe was used. The
optimum frequency for predicting the amount of intramuscular fat cont
ent in the longissimus muscle was found to be 1.92 MHz. A multivariate
regression model was developed,using parameters in the frequency doma
in as follows: percentage of fat concentration 1.790 - 2.373x (lower f
requency) + .049x (bandwidth) + 1.178x (local maxima) (R(2) = .82), Va
lidation demonstrated that the multivariate model in the frequency dom
ain was capable of predicting intramuscular fat concentration with an
average of 1.17 percentage of fat error ( P < .05); The multivariate m
odel was most appropriate for predicting intramuscular fat below 4%. T
he mean accuracy of the model in the frequency domain was approximatel
y 79%.