Exploring the potential of tocols and retinoids in authenticating pasture-derived sheep milk and cheese

This study investigated the potential of tocols and retinoids to differentiate sheep milk and cheese from concentrate-feeding indoor farms and pasture-feeding extensive farms. A total of 94 milk and 90 cheese samples collected from intensive and extensive commercial farms were analyzed using high-performance liquid chromatography to quantify α- and γ-tocopherol, α- and β-tocotrienol, retinyl palmitate, and retinol. Higher concentrations of tocols and retinoids were found in the samples from extensive compared with intensive farms. The results of discriminant analysis showed that tocols and retinoids were able to clearly distinguish between the 2 farming systems. In this regard, a new multiple marker named vitamin-active lipid compounds indicator showed a strong discriminative power between intensive and extensive farms (91.4% correct classification for milk and 100% for cheese samples). These findings confirm that this indicator is a reliable tracer to authenticate dairy products according to production system, of particular interest for pasture-based foods.