Variabilità del profilo acidico del latte ovino prodotto in Sardegna: potenzialità della spettroscopia FT-MIR.

Variability of fatty acids profile in Sardinian sheep milk by FT-MIR spectroscopic
techniques. - The use of on-line aspecific spectroscopic methods in food analysis has
been constantly increasing. Mid-InfraRed (MIR) spectroscopic methods, combined with
multivariate analysis, has been used to build models that predict the concentration of an
analyte in a food matrix with good accuracy, in real time and at low cost. Been aware of the
growing importance of the fatty acid profile (at least in the categories of fatty acids) in the
enhancement of milk and its products, the aim of this work was to make objective the fat
variability of Sardinian sheep milk by using FT-MIR spectroscopic techniques. The study
was conducted on around 6000 Sardinian sheep milk samples collected between February
and June 2012 in different farms of the areas of Oristano, Nuoro and Cagliari. The FT-MIR
spectrum of each sample was acquired by using the spectrometer MilkoScan FT-6000 (FOSS)
used in the Milk Laboratory of the Regional Breeding Association (ARA Sardegna). Total
fat and the classes of Saturated Fatty Acids (SFA), Unsaturated Fatty Acids (UFA), Mono-
Unsaturated Fatty Acids (MUFA), and Poli-Unsaturated Fatty Acids (PUFA), were estimated
by using Partial Least Squares (PLS) models previously built and validated by our research
group. The predicted values were analyzed by the Principal Component Analysis (PCA) which
has allowed to evidence differences between samples in relation to geographical or seasonal
variability. The greatest separation has been noted between the samples of late winter and
early summer and between samples gathered, in the same period, in farms that differ for
altitude (high altitude, defined as “mountain”, versus low altitude, defined as “plane”)