The inclusion of a daisy plant (Chrysanthemum coronarium) in dairy sheep diet: 2. Effect on the volatile fraction of milk and cheese

摘要

An experiment was undertaken to evaluate the effect on volatile fraction of milk and cheese of the inclusion of Chysanthemum coronarium (Asteracea) in the diet of grazing sheep. Plots sown either with a binary mixture consisting of Lolium rigidum Gaudin and Medicago polymorpha L, (LM) or a ternary mixture including the above species and C. coronarium L. (LMC) were grazed by groups of Sarda dairy ewes during May. This daisy plant contained several volatile compounds: the main were 1-methyl-4-(l-methylethylidene)-ciclohexene (terpinolene, 47%) and ethanol (36%). Among other volatile substances, terpenes such as a-pinene, triciclene and camphene; cyclic and unsaturated hydrocarbons and esters were detected. In contrast no volatile fraction was found inboth the grass and the legume. The inclusion of C. coronarium in sheep diet affected the composition of volatile fraction of milk and cheese. In particular LMC milk and cheese, unlike the counterparts, were featured by the occurrence of terpenes such asterpinolene, triciclene, 3,7-dimethyl-l,6-octadiene, a-pinene and camphene. A panel-test based on olfactory evaluation showed that the cheese obtained from sheep grazing the ternary mixture was distinguishable from that of counterparts grazing the grass-legume mixture (P<0.05). To conclude this daisy plant can be regarded as a putative tracer of dairy sheep production system.