Detection of lard mixed with body fats of chicken, lamb, and cow by Fourier transform infrared spectroscopy

Fourier transform infrared (FTIR) spectroscopy provides a simple and rapid means of detecting lard blended with chicken, lamb, and cow body fats. The spectral bands associated with chicken, lamb, and cow body fats and their l ard blends were recorded, interpreted, and identified. Qualitative differen ces between the spectra are proposed as a basis for differentiating between the pure animal fats and their blends. A serniquantitative approach is pro posed to measure the percent of lard in blends with lamb body fat (LBF) on the basis of the frequency shift of the band in the region 3009-3000 cm(-1) , using the equation y = 0.1616x + 3002.10. The coefficient of determinatio n (R-2) was 0.9457 with a standard error (SE) of 1.23. The percentage of la rd in lard/LBF blends was also correlated to the absorbance at 1417.89 and 966.39 cm(-1) by the equations y = 0.0061 x + 0.1404 (R-2 = 0.9388, SE = 0. 018) and y = 0.004x + 0.1117 (R-2 = 0.9715, SE = 0.009), respectively. For the qualitative determination of lard blended with chicken body fat (CF), t he FTIR spectral bands in the frequency ranges of 3008-3000, 1418-1417, 138 5-1370, and 1126-1085 cm(-1) were employed. Semiquantitative determination by measurement of the absorbance at 3005.6 cm(-1) is proposed, using the eq uation y = 0.0071 x + 0.1301 (R-2 = 0.983, SE = 0.012). The percentage of l ard in lard/GF blends was also correlated to the absorbance at 1417.85 cm(- 1) (y = 0.0053x + 0.0821, with R-2 = 0.9233, SE = 0.019) and at 1377.58 cm- 1 (y = 0.0069x + 0.1327, with R-2 = 0.9426, SE = 0.022). For blends of lard with cow body fat (CBF) bands in the range 3008-3006 cm(-1) and at 1417.8 and 966 cm(-1) were used for qualitative detection. The equation y = -0.005 x + 0.3188 with R-2 = 0.9831 and SE = 0.0086 was obtained for serniquantita tive determination at 966.22 cm(-1).