Rheological Properties of dilute solution of chitosan and sodium alginate

• Main Author: 洪瑋婷
• Other Authors: 陳榮輝
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/79050352209146475759

碩士 === 國立海洋大學 === 食品科學系 === 91 === Abstract The objective of this study is to explore the physicochemical and rheological properties of chitosan — sodium alginate dilute solution. The dilute solution is definded as solution’s concenation lower than reciprocal of their characteristic concentration(c*). The characteristic concentration of chitosan and sodium alginate in acetic acid solutions were determined from their intrinsic viscosity([η]) by capillary viscometry. Chitin was extracted from red shrimp process wastes. 90% DD of chitosan were produced by hot alkaline deacetylation from chitin. The effect of ratio of chitosan and sodium alginate, their concentration, temperature, and ionic strength on rheological property of the dilute solutions of chitosan — sodium alginate solution were studied. The experimental results are as follow: The Mw of chitosan used were : 1.2 × 106 Da. The M/G ratio obtained by C13 NMR spectroscopy for the sodium alginate is 1.18, it Mw is 1 × 105 Da. The [η] and reduced viscosity (ηred) of mixture of chitosan and sodium alginate decreased with the chitosan, and sodium alginate the mixture minimum valuesηred was 1 : 1 ratio. [η] of chitosan decreased as pH increase, where sodium alginate as increased with solution pH. [η] of dilute solutions of chitosan — sodium alginate decreased with solution pH increases. ηred of dilute solutions of chitosan — sodium alginate as decrease as concentration increase at pH3.0, pH4.0. However, ηred raise to concentration at pH5.0. At pH4.0, 25 ± 1℃, [η] of chitosan , sodium alginate decrease with the increase in ion strength. ηred of dilute solution of chitosan — sodium alginate decrease as ionic strength increase. Increasing solution temperature rendered the decrease in [η] of the chitosan, sodium alginate, and dilute solution of chitosan — sodium alginate. The flow activation energies of chitosan(497.3 Jžg-1žmole-1), and sodium alginate(966.5 Jžg-1žmole-1) solution calculated by Arrhenius equation elevated. Relative siffnsses of chitosans and sodium alginate are 0.07 — 0.09 and 0.03 — 0.04 respectively.