Effect of volatile oils from Petroselinum crispum and Foeniculum vulgare on the quality and shelf-life of steamed yoghurts

摘要

The main objective of this work was to investigate the effect of the parsley and fennel essential oils addition on the qualities of the steamed yoghurts stored during four weeks. The aerial plants were subjected to the hydrodistillation for 3h using a Clevenger-type apparatus. Three yoghurts were prepared: Control, yoghurt added with 5μL of parsley essential oil, and yoghurt treated with 5 μL of fennel essential oil. The addition of 5 μL of parsley and fennel essential oils causes certain stability after 29 days of storage of the acidity respectively (95, 83 °D), dry matter (9.2, 12%), sugar (94, 118 g/L), protein (4, 4.2 g/L), and ash contents (1.02, 1.14%) compared to the control (118 °D acidity, 4% dry matter, 42 g/L sugar, 1.05 g/L protein and 0.41% for ash content). A sharp decreases after 29 days of storage of the level of fat content from 14.2% for control yoghurt to respectively 5 and 0.1% for yoghurts treated by essential oil of parsley and fennel. Results indicated complete absence of the microorganisms in all treated yoghurts and sensory evaluation indicated that the highest acidity, taste and texture were obtained with yoghurts treated with essential oils. This study found that yoghurts treated with essential oils seem preserve the nutritional, microbiological and sensory parameters during 29 days of storage.