Prediction of intramuscular fat content and major fatty acid groups of lamb M. longissimus lumborum using Raman spectroscopy

Abstract

A hand held Raman spectroscopic device was used to predict intramuscular fat (IMF) levels and the major fatty acid (FA) groups of fresh intact ovine M. longissimus lumborum (LL). IMF levels were determined using the Soxhlet method, while FA analysis was conducted using a rapid (KOH in water, methanol and sulphuric acid in water) extraction procedure. IMF levels and FA values were regressed against Raman spectra using partial least squares regression and against each other using linear regression. The results indicate that there is potential to predict PUFA (R2=0.93) and MUFA (R2=0.54) as well as SFA values that had been adjusted for IMF content (R2=0.54). However, this potential was significantly reduced when correlations between predicted and observed values were determined by cross validation (R2cv=0.21–0.00). Overall, the prediction of major FA groups using Raman spectra was more precise (relative reductions in error of 0.3–40.8%) compared to the null models.