Title page for ETD etd-02132003-124556


Type of Document Master's Thesis
Author Koontz, John L
Author's Email Address jkoontz@vt.edu
URN etd-02132003-124556
Title Improved Properties of Natamycin Upon Formation of Cyclodextrin Inclusion Complexes
Degree Master of Science
Department Food Science and Technology
Advisory Committee
Advisor Name Title
Marcy, Joseph E. Committee Chair
Barbeau, William E. Committee Member
Duncan, Susan E. Committee Member
Keywords
  • stability
  • photodegradation
  • antimycotic
  • polyene macrolide
  • cyclodextrin
  • pimaricin
  • antifungal
  • preservative
  • natamycin
  • inclusion complex
  • UV absorber
  • solubility
Date of Defense 2003-02-06
Availability unrestricted
Abstract
     

Natamycin is an antimycotic with very low water solubility and extremely high photosensitivity, which is used to extend the shelf life of shredded cheese products. The objectives of this research are: (a) to find a new delivery system for natamycin, which increases its aqueous solubility and (b) to increase the chemical stability of natamycin so that it has a prolonged antifungal effect on the surface of the shredded cheese.

      Molecular inclusion complexes of natamycin were formed with b-, hydroxypropyl b-, and g-cyclodextrins (CDs) which allowed large increases in aqueous solubility without the use of organic co-solvents or surfactants. The water solubility of natamycin was increased 16-fold, 73-fold, and 152-fold with b-CD, g-CD, and hydroxypropyl b-CD, respectively. The natamycin:CD inclusion complexes resulted in nearly equivalent in vitro antifungal activity as natamycin in its free state. Nuclear magnetic resonance (NMR) was utilized to prove the formation of true inclusion complexes. 1H NMR shift titrations of N-(3’-N-dimethylaminosuccimido) natamycin with b- and g-CDs enabled determination of the stoichiometry of both complexes as 1:1. Aqueous solutions of natamycin (20 mg/L) were found by quantitative HPLC to be completely degraded after 24 hours of exposure to 1000 lux fluorescent lighting at 4 °C. After 14 days of storage in darkness at 4 °C, 92.2% of natamycin remained in active form. Aqueous solutions of natamycin:b-CD complex and natamycin:g-CD complex were significantly more stable (p < 0.05) than natamycin in its free state when stored in darkness at 4 °C. Clear poly(ethylene terephthalate) packaging with an ultraviolet light absorber allowed 85.0% natamycin to remain after 14 days of storage under 1000 lux fluorescent lighting at 4 °C. Such dramatic increases in water solubility and light stability will enable natamycin to function as a more effective antimycotic in the food industry.

Files
  Filename       Size       Approximate Download Time (Hours:Minutes:Seconds) 
 
 28.8 Modem   56K Modem   ISDN (64 Kb)   ISDN (128 Kb)   Higher-speed Access 
  00_FrontMatter_etd.pdf 71.53 Kb 00:00:19 00:00:10 00:00:08 00:00:04 < 00:00:01
  01_Introduction_etd.pdf 17.67 Kb 00:00:04 00:00:02 00:00:02 00:00:01 < 00:00:01
  02_ReviewOfLiterature_etd.pdf 281.62 Kb 00:01:18 00:00:40 00:00:35 00:00:17 00:00:01
  03_Characterization_etd.pdf 223.05 Kb 00:01:01 00:00:31 00:00:27 00:00:13 00:00:01
  04_Stability_etd.pdf 161.09 Kb 00:00:44 00:00:23 00:00:20 00:00:10 < 00:00:01
  05_NMR_etd.pdf 372.07 Kb 00:01:43 00:00:53 00:00:46 00:00:23 00:00:01
  Vita_etd.pdf 4.54 Kb 00:00:01 < 00:00:01 < 00:00:01 < 00:00:01 < 00:00:01

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