In vitro binding of lipid [olive oil and ghee] with chitosan under the conditions mimicking the gastrointestinal tract

ABSTRACT

An in vitro binding study of chitosan with lipid was carried out under the conditions mimicking the gastrointestinal tract, with special reference to the pHs of stomach and duodenum. Olive oil and ghee were used to represent lipid components of diet, and chitosan [treated and untreated] was used to bind with the mentioned lipids. The results obtained from this study showed that the treated chitosan gave better binding to lipid [olive oil or ghee] compared with the untreated chitosan. Chitosan [treated or untreated] showed higher affinity towards olive oil than ghee. Incubation period accompanied with shaking also influenced the binding of lipid to chitosan and the maximum binding was attained after 2.5 hrs of incubation. The ratio of chitosan to lipid used was found to affect the amount of lipid bound per gram of chitosan. Olive oil bound per gram of chitosan was 4.6 +/- 0.28 -7.1 +/- 0.14 g while ghee was 3.6 +/- 0.28 - 6.2 +/- 0.28 g under 1100 experimental ratio of chitosan to lipid, and shaking for 2.5 hrs at physiological temperature of 37°C. Consideration of pKa value suggests that the predominated form of chitosan at duodenal pH [-7.0] is uncharged chitosan, which is precipitated along with the lipid adsorbed onto it