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Tuesday, 15 November 2016

Quality preservation of deliberately contaminated milk using thyme free and nanoemulsified essential oils.

2017 Feb 15;217:726-34. doi: 10.1016/j.foodchem.2016.09.030. Epub 2016 Sep 7.


Ben Jemaa M1, Falleh H2, Neves MA3, Isoda H3, Nakajima M3, Ksouri R4.

  • 1Laboratory of Aromatic and Medicinal Plants, Biotechnology Center of Borj-Cédria, BP 901, 2050 Hammam-lif, Tunisia; Faculty of Life and Environmental Sciences, University of Tsukuba, Ibaraki 305-8572, Japan.
  • 2Laboratory of Aromatic and Medicinal Plants, Biotechnology Center of Borj-Cédria, BP 901, 2050 Hammam-lif, Tunisia. Electronic address: Hanenfalleh@gmail.com.
  • 3Faculty of Life and Environmental Sciences, University of Tsukuba, Ibaraki 305-8572, Japan.
  • 4Laboratory of Aromatic and Medicinal Plants, Biotechnology Center of Borj-Cédria, BP 901, 2050 Hammam-lif, Tunisia.

Abstract

The objective of this study is to evaluate the effect of either a solution of Thymus capitatus essential oil or its nanoemulsion on the quality of milk contaminated by bacteria. After 24h of S. aureus inoculation, bacterial growth reached 202×10(3)CFU/ml in the presence of the essential oil while it was limited to 132×10(3)CFU/ml when treated with nanoemulsion. The reduction of antioxidant capacity of milk treated with essential oil was higher when treated with nanoemulsion. Moreover, free essential oil was more efficient in protecting proteins from degradation than the nanoemulsion. For instance, after 24h of E. hirae contamination, 26% of the total proteins were consumed in the presence of nano-encapsulated essential oil, while only 14% of the initial content was consumed when free essential oil was added. Concerning milk acidity increase and the inhibition of peroxide production, no statistical differences have been recorded between the use of free essential oil or its nano-emulsion. In conclusion, bulk or nano-encapsulated T. capitatus essential oil preserve milk quality and can extend its shelf life.
Copyright © 2016 Elsevier Ltd. All rights reserved.

KEYWORDS:

Essential oil; Gram(+) bacteria; Milk quality; Nanoemulsion
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