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Article
Examination of the Interaction of Chitosan and Oil-in-Water Emulsions Under Conditions Simulating the Digestive System Using Confocal Microscopy
Journal of Aquatic Food Product Technology (2008)
  • T. Helgason
  • Jochen Weiss, University of Massachusetts - Amherst
  • D. Julian McClements, University of Massachusetts - Amherst
  • J. Gislason
  • J. M. Einarsson
  • F. R. Thormodsson
  • K. Kristbergsson
Abstract

Chitosan is a cationic biopolymer that has been used extensively in dietary supplements to reduce fat absorption in the fight against obesity. The mechanism of fat binding of chitosan is still not fully understood and has been the subject of controversy. This study was designed to improve the understanding of the underlying mechanism by investigating the interaction of chitosan with oil-in-water emulsion droplets. Our results indicated that (0.1% w/w) chitosan adsorbed to a 20% w/w phosphatidylcholine-stabilized anionic primary emulsion to form a secondary cationic emulsion by electrostatic attraction forces under conditions resembling the stomach (pH 2). Bile salts (6 mM) were added to simulate secretion in the small intestine and pH increase. Bile salts adsorbed to the chitosan secondary emulsion, which resulted in aggregation of oil droplets followed by coalescence due to close packing of droplets. Increased viscosity (267–2531 cp) and increased degree of deacetylation (40–92% DDA) of chitosan enhanced emulsion breakdown. Increasing the pH to 7.5 without addition of bile salts yielded little aggregation. Pronounced aggregation is thought to decrease the accessibility of lipase to the oil resulting in lower bioavailability and reduced caloric intake. Understanding how chitosan interacts with oil droplets in the digestive tract is vital to developing a comprehensive model of the influence of chitosan on the bioavailability of dietary lipids. The information gained in this study may be useful for the interpretation and experimental design of animal and human feeding studies and for the rational design of chitosan-based functional foods for fat reduction.

Keywords
  • Chitosan,
  • confogal microscopy,
  • lipid interaction,
  • obesity
Disciplines
Publication Date
2008
Publisher Statement
DOI: 10.1080/10498850802179784
Citation Information
T. Helgason, Jochen Weiss, D. Julian McClements, J. Gislason, et al.. "Examination of the Interaction of Chitosan and Oil-in-Water Emulsions Under Conditions Simulating the Digestive System Using Confocal Microscopy" Journal of Aquatic Food Product Technology Vol. 17 Iss. 3 (2008)
Available at: http://works.bepress.com/djulian_mcclements/65/