Chitosan-glucose conjugates: influence of extent of Maillard reaction on antioxidant properties.
Chitosan-glucose conjugates were prepared using Maillard reaction chemistry. Water-soluble and acid-soluble chitosan-glucose mixtures were heated at pH 4.9 and 6.0 at 98 °C. Mixtures at pH 6.0 containing acid-soluble chitosan gelled when heating was continued after reaching 98 °C and withstood gelation for only 30 min at pH 4.9. In contrast, mixtures containing water-soluble chitosan could be heated without gelation at pH 6.0 and 4.9. Examination of the extent of Maillard reaction and antioxidant properties showed that acid-soluble chitosan reacted for 30 min at pH 4.9 had the highest extent of reaction as judged by increased absorbance, the highest degree of modification to the amino group as evidenced by Fourier transform infrared and shifts of the endotherms by differential scanning calorimetry, and the highest antioxidant activity as indicated by ferric reducing power and oxygen radical absorbance capacity. There were significant correlations (p < 0.05) between indices of browning and antioxidant activity.
CSIRO Food and Nutritional Sciences, Private Bag 16, Werribee, Victoria 3030, Australia.
Shantha Lakshmi
SL
Kosaraju
Rangika
R
Weerakkody
Mary Ann
MA
Augustin
D000975:Antioxidants / Q000737:chemistry*; D048271:Chitosan / Q000737:chemistry*; D005947:Glucose / Q000737:chemistry*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D015416:Maillard Reaction; D010084:Oxidation-Reduction
D000975:Antioxidants; D048271:Chitosan; D005947:Glucose