Analyzing whether adding essential oils to sheep diet has effects on milk and cheese
José Pichel Andrés/ DICYT Isabel Revilla Martín, professor at the Escuela Politécnica Superior de Zamora (Spain), was awarded by the Fundación Científica Caja Rural in November 2012 for a research project that aims to analyze whether adding thyme and clove essential oils to sheep diet has any effect on the quality of milk and cheese. The researcher, from the Department of Food Technology at the Universidad de Salamanca, is trying to prove dietary compounds actually affect end products.
To conduct this study, thyme and clove essential oils were specifically chosen. “They are called oils because they look oily, but they are actually a mixture of substances that lend aroma to plants like thyme, cloves and rosemary, used as aromatic and preservative elements in traditional cooking,” Isabel Revilla explains to DiCYT.
These compounds synthesized by plants are diverse in nature, but from the scientific point of view, the most important is that they are antimicrobial and antioxidant elements. “Previous studies have proved that, when given to ruminants, digestive activity is changed,” the researcher states. In ruminants, microbial flora plays an important role in digestion, since it helps to better assimilate plant food eaten by animals. Microorganisms “break vegetable raw materials” into smaller molecules so bowels can assimilate them better. According to findings, essential oils may contribute by improving effectiveness of microbial flora and, ultimately, making digestion easier.
Nevertheless, there are not enough studies to prove whether this affects milk’s quality. Only a few studies have been conducted with cows and suggest that changes are minimal, but “more proteins and fat and a better lipid profile” were found overall. All in all, milk’s quality would be slightly better. This new study is aimed to analyze what happens in sheep.
In order to do so, 40-50 sheep from a livestock facility in Fariza (Spain) are to be selected. Animals are going to be separated into two groups immediately after birth: the first group is going to be given regular diet and the other is going to be given a diet with thyme and clove oils. Every five days, both groups will be milked and differences are going to be analyzed in the laboratory.
Most sheep’s milk goes to cheese manufacture, so researchers wanted to know if differences are perceptible in the end product. To do so, this project aims to elaborate small cheeses to analyze volatile organic compounds, that is, aromas.
Isabel Revilla appreciates the Fundación Científica Caja Rural’s contribution, because thanks to the financial support granted with the award, she is going to be able to perform some part of the study. Even if most of the analysis is carried out at the Campus Viriato (Zamora, Spain), the analysis of volatile compounds is expensive and must be done somewhere else.
In general terms, the entire project tackles “a very interesting area that has not been studied in depth”, as the researcher explains. Consumers increasingly demand better quality in products they consume and a way to achieve it is changing animals’ diet. In this regard, farmers are backed by science in order to set the most effective actions.