ORIGINAL ARTICLE |
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Year : 2020 | Volume
: 3
| Issue : 4 | Page : 265-269 |
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Effect of thyme (Thymus vulgaris L.) essential oil on the quality parameters of stirred yoghurt
Emad A H. Guirguis1, Mary G B. Meleka2
1 Department of Food Hygiene, National Nutrition Institute, General Organization of Teaching Hospitals and Institutes (GOTHI), Cairo, Egypt 2 Department of Plant Production, Desert Research Center, Cairo, Egypt
Correspondence Address:
Emad A H. Guirguis Assistant Consultant of Food Microbiology, Department of Food Hygiene, National Nutrition Institute, General Organization of Teaching Hospitals and Institutes (GOTHI), 391 Teraet El-Gabal Street, El-Zaytoon, Cairo Egypt
Source of Support: None, Conflict of Interest: None
DOI: 10.4103/JMISR.JMISR_60_20
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Aim
Stirred yoghurt was supplemented with thyme essential oil in an attempt to enhance its quality.
Materials and methods
Thyme (Thymus vulgaris L.) essential oil concentrations (0, 2, 4, 6, 8, and 10 μl/ml) were added to the prepared stirred yoghurt and then examined for microbiological count and mycotoxin quality during storage intervals following the Egyptian standards.
Results
Samples contained ≥ 6 μl/ml oil showed significant increase (p<0.05) of total viable bacterial count and lactic acid bacteria, whereas mold and yeast count was decreased. Pathogenic bacteria including Staphylococcus aureus, Bacillus cereus, Listeria monocytogenes, Salmonella spp., Escherichia coli, and coliform group were not detected in any of the samples, which complied with the standards. Moreover, aflatoxin M1 content was reduced by time in direct proportion to the thyme essential oil concentration.
Conclusion
The bioactive components in thyme act as a natural preservative in stirred yoghurt throughout the storage interval when the yogurt is fortified with hydro-distilled thyme essential oil.
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