Vitamin E and A Content in Raw Milk Cheeses from Mountain 
Grazing ewes
M.A. Bustamante, I. Valdivielso, J.C. Ruiz de Gordoa, L.J.R. Barron
Lactiker Research Group, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Paseo de la Universidad 7, 01006. Vitoria-Gasteiz, Spain
luisjavier.rbarron@ehu.es
 
Several studies reported that changes in animal diet composition affect the composition of the milk fat-soluble fraction [1]. Vitamins E and A are minor lipid-soluble compounds in milk, well-known for their antioxidant properties. Furthermore, it has been reported that these fat soluble vitamins could be potential biomarkers of milk and cheese derived from grazing animals [2].
The aim of this work was to compare the content of vitamins A and E in cheeses made with ewe’s raw milk depending on the feeding management throughout lactation. Three commercial flocks took part in this experience and all of them followed this feeding regime: from February to late-March (winter) animals were kept indoors and fed concentrate and forage; from April to early-May (spring), animals were fed under part-time grazing on cultivated valley grasslands; from mid-May to late-July (summer), animals were kept outdoors constantly on natural mountain pastures (Aralar mountains, Northern Spain). PDO Idiazabal cheeses were made in winter, spring and summer and ripened for 120 d. Vitamins E and A were extracted with saponification and analyzed by NP-HPLC with fluorescence detection [3]. α-Tocopherol (>70%), β-, γ-, and δ-tocopherol, and other unknown tocols, were found in the cheeses. α-Tocopherol content increases in the cheeses elaborated in summer when animals grazed on natural mountain pastures. However, no clear differences were observed for the content of vitamin A among the cheeses made with milk from different feeding regimes.

References:
[1] Calderon et al. J. Dairy Sci. 90 (2007) 5651-5664; [2] Prache et al. Small Rum. Res. 59 (2005) 157-168; [3] Bustamante et al. SECyTA, Tarragona (Spain) 2012.

Financial support: University of the Basque Country UPV/EHU UNESCO Cathedra (09/07) and Basque Government (IT766-13).