Physicochemical and microbiological properties of Chaerophyllum, Oliveria and Zataria essential oils and their effects on the sensory properties of a fermented dairy drink, ‘doogh’

Abstract

In this present study, essential oils (EOs) were extracted from Chaerophyllum macropodum, Oliveria decumbents, and Zataria multiflora Boiss. The chemical composition and antimicrobial activity of the EOs were tested against Staphylococcus aureus (G+), Escherichia coli O157: H7 (G−), and three species of fungi (Rhodotorula glutinis, Kluyveromyces marxianus and Penicillium digitatum). The outcomes were evaluated in vitro and in a food model system for 28 days of storage. Carvacrol comprised 10.83, 22.51 and 73.66% of the EOs being extracted from Chaerophyllum, Oliveria and Zataria, respectively, while thymol comprised 9.57, 36.49 and 17.17%. By evaluating antibacterial properties in vitro, the bacteria were greatly inhibited by all of the three EOs with more sensitivity of S. aureus. Oliveria and Zataria EOs were more effective than Chaerophyllum EO in preventing the growth of the three fungi. Doogh samples were inoculated before receiving the EOs (1%) and stored at 4°C for 28 days. Chaerophyllum EO caused the highest value of pH in doogh. Viscosity was significantly higher (p < .05) in the treated samples than in the control. All three EOs inhibited the bacterial populations more effectively (p < .05) than fungal populations. Regarding sensory attributes, all fortified doogh samples received comparably higher scores than the doogh containing microorganisms. In summary, the present study revealed that Chaerophyllum, Oliveria and Zataria EOs can serve as natural antimicrobial agents in doogh.

Keywords

• dairy products
• essential oil
• doogh
• antimicrobial activity
• physicochemical properties