Using portable near-infrared spectroscopy to predict pig subcutaneous fat composition and iodine value

This study tested the potential of portable near-infrared spectroscopy (NIRS) to predict fatty acids (FA) composition and iodine value (IV) of pig subcutaneous fat. Following carcass splitting, the inner layer of subcutaneous fat at the shoulder from the left carcass side was scanned using a hand-held NIRS probe (350 - 2500 nm) and analysed for FA composition using gas chromatography. The NIRS successfully predicted the total polysaturated fatty acids (PUFA) and n-3 FA proportions, polyunsaturated/saturated fatty acids (PUFA/SFA) ratio, and IV (R-2 = 0.90-0.95; root-mean-square error of prediction, RMSEP = 0.019%-1.03% total FA). This portable technology also met the requirements for a quick screening of the proportions of total SFA, monounsaturated fatty acids (MUFA) and n-6 FA, n-6/n-3 ratio, and some individual FA such as C18:2n-6 and C18: 3n-3 (R-2 = 0.80-0.89; RMSEP = 0.37%-1.11% total FA). However, unreliable predictions were found for other individual FA with low variability (coefficient of variation = 4%-8%) such as C16: 0, C18: 0, and C18: 1 (R-2 = 0.60 - 0.77; RMSEP = 0.76%-1.00% total FA). These results show portable NIRS as a suitable technology to predict pig fat quality. In addition, this study has been successful in implementing this portable NIRS technology in a research abattoir to collect spectra directly on the carcass, which would enable carcass sorting based on fat composition or hardness for marketing purposes.