Author: Herr Dr. Amoneit
Last saved by: Saritas, Sevim
Company: Hewlett-Packard

Terpenoids as Potential Markers of Raw Milk from Sheep Reared on the Mountains
I. Valdivielso, N. Aldai, L.J.R. Barron
Lactiker Research Group, University of the Basque Country (UPV/EHU), 01006 Vitoria-Gasteiz, Spain.

Nowadays there is an increasing interest on authentication of foods derived from grazing livestock. Different types of lipids have been proposed as potential biomarkers for milk and cheese from grazing ruminants. Terpenoids, which originate from the secondary metabolism of plants, are particularly abundant in mountain pastures rich in dicotyledonae plants, and they can be rapidly transferred and deposited in milk of those animals that have ingested these pastures [1].
The aim of this work was to compare the content of terpenoids in milk depending on the feeding management throughout lactation period. The experimental design was composed by six commercial sheep flocks that 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 improved (cultivated) valley grasslands; and from mid-May to late-July (summer) animals were kept outdoors on natural mountain pastures (Aralar mountains, northern Spain). Terpenoids in milk were analyzed by SPME-GC-MS according to the method described by Abilleira et al. [2]. More than 25 terpenoids were identified in the mountain milk samples. Some of these compounds such as α-thujene, camphene, γ-terpinene, α-cubebene, β-bourbonene, linalool, β-cubebene, and 7-epi-α-selinene were found only in the milk produced by ewes reared in the mountains, although their amounts were close to the detection limit. The milk content of other terpenoids such as α-pinene, β-caryophyllene, α-amorphene, α-humulene, and γ-cadinene increased when flocks were allowed to graze in mountain pastures. Several of these terpenoids like β-caryophyllene, α-humulene and γ-cadinene could be considered as potential lipid markers for mountain milk due to their significantly higher content in summer than in spring or winter periods.

[1] Viallon et al. Lait 80, 635-641 (2000).
[2] Abilleira et al. Food Chem. 120, 1162-1169 (2010).