Khaled El Omari
Industrial Development & Research Alimentary Center, Lebanon
Scientific Tracks Abstracts: J Food Process Technol
Yogurt is an ancient food that has been a part of the human meal for thousands of years. However, it�??s a living perishable product that will spoil or become unsafe to consume, if not kept refrigerated or not utilized within a certain period. The main aim of this study was to investigate the antimicrobial effect of an essential oil, extracted from a Micromeria Barbata (MB) plant, against spoilage microorganisms especially yeasts and molds in yogurt samples produced by fresh cow milk. We concentrated also on the prolongation of the shelf life and the evaluation of titratable acidity of yogurt by using two concentrations of this natural preservative (0.125 and 0.25 µL/100mL). The yogurt was prepared by heating the milk, cooling, adding the essential oil (EO) and incubating with the starter culture. As a result of our work, EO used at 0.125 µL/100mL can be used in order to increase the shelf life of yogurt for up to 70 days for sealed samples and 21 days for opening samples. The study also revealed that titratable acidity values after 70 days storage have increased from 0.9% (day 1) to 1.35±1% (day 70). It was observed that essential oil used at 0.125µL/100mL did not affect the growth of starter culture in yogurt samples but it showed the strongest antimicrobial (fungi, yeasts, and molds) activity compared with the control free oil samples. The use of essential oils is limited by their strong aroma, altering the taste of the food, therefore, to avoid this unwanted side effect, a sensorial analysis proved that yogurt containing 0.125µL/100mL EO was organoleptically acceptable and it had a good body and texture that was similar to the untreated one. According to the results of this study, the chemical, microbiological and organoleptic properties of the yogurt stored at 5±1ºC were determined. It can be concluded that 0.125µL/100mL of EO can be used in order to increase the shelf life of yogurt, with no growth of spoilage microorganisms.
Khaled El Omari is dedicated in improving the quality of water and food in Lebanon for more 15 years. He has completed his PhD in Food Engineer and Analytical Chemistry and MSc in Food safety and studied Lab accreditations (ISO 17025), he is also a certified food safety expert for WHO, EU and USAID projects. He is the Director of the Chamber of Commerce, Industry and Agriculture Laboratories in Tripoli & North Lebanon. He supports many businesses, NGOs and government to provide the highest quality of water and food. He is a Lecturer at Lebanese University and Researcher in the LMSE lab in the Doctorate School at Faculty of Health of Lebanese University.