Formation, Characterization and Stability of Natural Antimicrobial-Cyclodextrin Complexes

As a response of the need for a natural antimicrobial to replace sodium benzoate's use as a preservative in beverages, twenty eight compounds known to have antimicrobial activity were evaluated to quantify their solubility. Twenty three of the compounds evaluated are components of plant essential oils and the remaining five compounds are alkyl esters of para-hydroxybenzoic acid. The test compounds were evaluated for aqueous solubility as well as their solubility in an acid-based beverage mixture. The compounds were found to be practically insoluble (< 100 mg/L), very slightly soluble (100 mg/L – 1,000 mg/L) or slightly soluble (1,000 mg/L to 10,000 mg/L). o-Methoxycinnamaldehyde, trans,trans-2,4-decadienal, cinnamic acid, and citronellol were complexed with α- and β-cyclodextrin and evaluated through phase solubility analyses. The complexes formed showed improved aqueous solubility for all compounds. Complexation with α-CD resulted in an increase of aqueous solubility of o-methoxycinnamaldehyde by 10-fold, trans,trans-2,4-decadienal by 3.2-fold, cinnamic acid by 6.3-fold, and citronellol by 8-fold. In addition, complexation with β-CD resulted in an increase of aqueous solubility of o-methoxycinnamaldehyde by 1.6-fold, trans,trans-2,4-decadienal by 3.1-fold, cinnamic acid by 1.7-fold, and citronellol by 1.6- fold. The storage stability of the α-CD complexes of o-methoxycinnamaldehyde trans,trans-2,4-decadienal and citronellol were evaluated for 7 days in an acid-based beverage solution by SPME GC-MS. The complexes exhibited varying levels of degradation throughout the duration of the study all. The concentration of o-methoxycinnamaldehyde detected by SPME GC-MS decreased by 61.7%. Similarly, the concentration of trans,trans-2,4-decadienal and that of citronellol decreased by 62.7% and 43% respectively. Additionally, a comparison by UV/Vis of the storage stability of the complexes stored in glass and PET containers was performed. The storage stability comparison proved that absorption into the PET polymer membrane did not occur.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Food Science and Technology

Department dc:contributor.department

Food Science and Technology

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2009

Author dc:creator

• Samperio, Cristian

Chair dc:contributor.committeechair

• Marcy, Joseph E.

Committee members dc:contributor.committeemember

• O'Keefe, Sean F.
• Eigel, William N. III

• essential oil
• cyclodextrin
• inclusion complex
• preservative
• solubility
• antimicrobial
• sodium benzoate

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

etd-08142009-151803

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/44251