FTIR spectroscopy combined with chemometrics for analysis of lard in the mixtures with body fats of lamb, cow, and chicken

Fourier transform infrared (FTIR) spectroscopy combined with chemometrics of partial least square (PLS) and discriminant analysis (DA) has been developed for simple analysis of lard in the mixtures with body fats of lamb (LBF), cow (Cow-BF), and chicken (Ch-BF). The spectral bands correlated with lard, LBF, Cow- BF and Ch-BF as well as their lard blends were scanned, interpreted, and identified. Qualitative differences among FTIR spectra are proposed as a basis for differentiating between the lard and its blends. DA with Mahalanobis distance principle in entire range of mid infrared (3300 – 650 cm-1) was successfully provide an alternate method to differentiate lard and that in the mixtures with LBF, Cow-BF, and Ch-BF. Quantitative analysis using PLS calibration model is proposed to measure the percentages of lard in LBF, Cow-BF, and C-BF at selected fingerprint region (1500 – 900 cm-1). The equation obtained between actual lard concentration in the mixture with LBF and FTIR predicted concentration in calibration model is y = 0.995 x + 0.098 with coefficient of determination (R2) was 0.995 and root mean standard error of calibration (RMSEC) of 0.98. The actual percentages of lard mixed with Cow-BF and Ch-BF were also correlated to FTIR predicted percentages at 1500 – 900 cm-1 using equations of y = 0.999x + 0.016 (R2 = 0.999, RMSEC = 0.61); and y = 1.002x + 0.034 (R2 = 0.998, RMSEC = 0.73), respectively