On-line determination of fatty acid composition in intramuscular fat of Iberian pork loin by NIRs with a remote reflectance fibre optic probe.

A near infrared spectrometer equipped with a standard 210/210 bundle remote reflectance fibre-optic probe, with a 5×5 cm quartz window type, was used for the determination of fatty acids in the Longissimus dorsi muscle of Iberian breed swine. The fatty acids C14:0, C16:0, C16:1, C17:0, C17:1, C18:0, C18:1, C18:2, C18:3, Σpolyunsaturated, Σmonounsaturated and Σsaturated were determined in samples of intramuscular fat from Iberian breed swine by direct application of the fibre-optic probe onto the loin sample, with no treatment or manipulation of the sample. The regression method employed was modified partial least squares. The calibration results using the fibre-optic probe for 74 loin samples had multiple correlation coefficients (RSQ) for C14:0, C16:0, C16:1, C17:0, C17:1, C18:0, C18:1, C18:2, C18:3, Σpolyunsaturated, Σmonounsaturated and Σsaturated acid of 0.785, 0.798, 0.788, 0.825, 0.762, 0.765, 0.696, 0.859, 0.878, 0.807, 0.943, 0.858, respectively, and standard errors of prediction corrected for the same fatty acids (%) of 0.08, 0.63, 0.26, 0.02, 0.02, 0.51, 0,77, 0.64, 0.05, 1.06, 0.34, 0.70, respectively. The robustness of the method was checked by applying the fibre-optic probe to unknown samples of Iberian breed pork loin in a slaughterhouse, using 15 samples for the external validation.