Résumé:
The objective of this study is to follow the evolution of the acidity of added yoghurt with
different concentrations (5%, 10%) of essential oils (HE) rosemary "Rosmarinus officinalis"
obtained from different parts of the plant (leaf, flower, stem and root).
The acidity of the yoghurt was measured during two periods, fermentation and post
acidification.
The results show that the concentration effect was not significant (p> 0.05), whereas the plant
part effect was significant (p <0.05).
the acidity values obtained on the yoghurt samples added to the HE of the roots were lower
during both periods (fermentation and post acidification), while the highest acidity values were
recorded on the added products with HE from the leaves, these results indicate generally that root
HE exhibits stronger inhibitory potency against lactic acid bacteria compared to other plant parts.
The results obtained are satisfactory to the extent that they make it possible to produce a product
more suitable for preservation.
This work always needs to be confirmed and deepened by other studies.
