MEASURING INTRAMUSCULAR FAT IN BEEF WITH ULTRASONIC FREQUENCY-ANALYSIS

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%.