Controlled release of antifungal volatiles of thym

Authors: C L Del ToroSánchez J F AyalaZavala L Machi H Santacruz M A VillegasOchoa E AlvarezParrilla G A GonzálezAguilar

Publish Date: 2010/01/09

Volume: 67, Issue: 3-4, Pages: 431-441

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Abstract

Thyme essential oil TO is a good antimicrobial agent however its high volatility and reactivity limits its application as food preservative βcyclodextrin βCD is able to encapsulate organic molecules forming host–guest complexes with hydrophobic and volatile molecules such as TO constituents controlling volatility and reactivity In addition controlled released of the βCD trapped compounds could be possible by exposing the capsules to high relative humidity RH With this in mind the controlled release of antifungal volatiles throughout exposure of TOβCD capsules to high relative humidity was studied Thymol TOL was the major constituent of TO detected by gas chromatography before and after encapsulation Capsules of the 892 ratio TOβCD showed the highest TOL content Hydrogen bonds and hydrophobic interactions were detected between the oil constituent and βCD by IR and 1H NMR spectroscopy During moisture sorption the TO capsules showed a lower water uptake compared with free βCD Similar behavior was observed during water desorption In all cases a hysteresis process was observed when comparing sorption and desorption isotherms At high RH TOL is displaced and almost 76 is released to the headspace The growth of Alternaria alternata was inhibited significantly by the addition and exposure to TOβCD as measured by both the agar dilution and the headspace method respectively Therefore the encapsulation of antifungal volatile compounds as TO in βCD could be an alternative to control the release of natural antimicrobials that can be of interest to the agricultural area

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