بررسي اثر ضد ميكروبي و آنتي اكسيداني اسانس گياهان كاكوي، رزماري، شويد و مرزه، عليه استافيلوكوكوس اورئوس و اشريشيا كلي 157: 0، بر انبار ماني دوغ و خواص حسي آن

چكيده انگليسي :

74Evaluation of Antimicrobial and Antioxidant Effects of Plant ExtractsZiziphora Rosemary Anethum and Savory Against S aureus and E coli 0 157 on Doogh s Shelf life and Organoleptic Properties Sina Cheshmeh s cheshmeh@ag iut ac ir June 11 2014 Department of Food Science and Technology Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor S Soleimanian Zad Soleiman@cc iut ac irAbstractFor many centuries people have been using heat treatment for cooking and storing of food but withincreasing of people s awareness about the harmful effects of heat on food nutritional compounds tendency to use natural foods and beverages has been increased To prevent diseases caused byconsumption of contaminated foods food safety control systems have been created Today in foodindustry in addition to the severe thermal processes chemical preservatives are used to prevent thegrowth of spoilage and pathogenic microorganisms The use of chemical preservatives have unpleasantconsequences such as cancer and severe poisoning for human being Regarding the antimicrobial andantioxidant activity of herbs they are valuable alternative to chemical preservatives Therefore in additionto a mild thermal process one or more lateral processes can be used to ensure the reliability of the mildheat process Fermentation and use of plants medicinal essences are examples of these lateral processes Doogh is a traditional fermented beverage which is consumed for hundreds of years Application ofnatural preservatives such as plants essences in this beverage in addition to improving the flavor andnutritional properties of the product leads to severe reduction in thermal process In this study theessential oil of four native herbs Satureja hotensis L Rosemarinus officinalis L Anethum geraveolens L and Ziziphora tenuior L were used to prevent the growth of E coli 0 157 and S aureus in this product Initially plant oils were extracted using Clevenger apparatus and then to identify their active components they were injected into the GC MASS device Results showed that gamma terpinene in essence ofSatureja Bicyclo 3 1 1 heptane in rosemary essence Alpha phelandrene in essence of Anethum and 3 methyl 4 isopropyl phenol in Ziziphora tenuior essence are the dominant compounds The DPPH methodwas used to determine the antioxidant properties of the extracted essence and oil extract of Satureja with89 97 percent p 0 05 had the highest level of antioxidant activity To confirm the antimicrobialproperties of the extracts minimum inhibitory concentration method and disk diffusion method were usedagainst two main food poisoning microbes E coli 0 157 and Staphylococcus aureus Essence oil ofSatureja showed the highest germicidal activity p 0 05 using the first said method amongst all theessences tested Minimum inhibitory concentration using inoculation of pathogenic microbes into theDoogh as much as 107 cfu ml and adding the essence oils in concentration of 0 15 0 65 l ml weredetermined The Staphylococcus aureus bacterium showed an average decrease of 6 logarithmic cycles and the Escherichia 0 157 bacterium showed an average decrease of 4 logarithmic cycles in microbialpopulation during 8 weeks of storage p 0 05 It could be said that the tested essences are promisescompounds to increase the shelf life of doogh Keywords Minimum inhibitory concentrations Doogh Ziziphora Rosemary Anethum Savory

چشمه، سينا

بررسي اثر ضد ميكروبي و آنتي اكسيداني اسانس گياهان كاكوي، رزماري، شويد و مرزه، عليه استافيلوكوكوس اورئوس و اشريشيا كلي 157: 0، بر انبار ماني دوغ و خواص حسي آن

حداقل غلظت بازدارندگي , تيمار حرارتي , اسانس روغني