African Journal of
Microbiology Research

  • Abbreviation: Afr. J. Microbiol. Res.
  • Language: English
  • ISSN: 1996-0808
  • DOI: 10.5897/AJMR
  • Start Year: 2007
  • Published Articles: 5210

Full Length Research Paper

Optimization of ultrasound-assisted extraction conditions using orthogonal matrix design to enhance the antimicrobial activity of extracts from Cichorium intybus root

  Quanzhen Wang1*, Haitao Liu1, Jinhong Du1, Jian Cui2, Guo Chen1 and Yuyan Liu1    
  1Department of Grassland Science, College of Animal Science and Technology, Northwest Agriculture and Forestry University, 712100 Yangling, Shanxi Province, P. R. China. 2Department of Plant Science, College of Life Science, Northwest Agriculture and Forestry University, 712100, Yangling, Shanxi Province, P. R. China.
Email: [email protected]

  •  Accepted: 30 July 2011
  •  Published: 18 August 2011



Plant-derived compounds used as alternatives to chemical preservatives have been extensively researched for use as natural medical ingredients or food preservatives. Conditions for the ultrasound-assisted extraction (UAE) of chicory (Cichorium intybus) root (including type of solvent, impregnation time, number of sonication steps and ultrasonic power) were optimized to determine the best extract antibacterial activity by using orthogonal matrix design [L16 (45)]. The combination of 70% ethanol v/v, a 36 h impregnation time, three sonication rounds and 300 W ultrasonic power input provided the best antimicrobial activity results. Our results demonstrate that solvent composition has the largest effect on antimicrobial activity. Several extracts demonstrated antibacterial activity against Escherichia coliStaphylococcus aureusBacillus thuringiensis andSalmonella typhi, and all extracts exhibited weak activity against Bacillus subtilis. To our knowledge, these results represent the first example of ultrasound-assisted chicory extracts aimed at increasing its potential for use in food industry.


Key words: Cichorium intybus, antibacterial, ultrasound-assistant extract, optimal conditions, orthogonal matrix design.