Bile acid-binding capacity of lobster shell-derived chitin, chitosan and chitooligosaccharides
Chitin, the second most abundant polysaccharide and its derivatives are known to have hypocholesterolaemic properties. In this study, chitin (~96.4% purity) extracted from lobster shells was converted to chitosan, with a high degree of deacetylation (DD, 90.9%) and a molecular weight (MW) of >500 kDa. The prepared chitooligosaccharides (COS) had a net positive surface charge of +37.6 mV, bimodal MW distribution (8.8 kDa and 0.6 kDa), and showed the highest bile acid-binding capacity against sodium deoxycholate (SDC) at the highest concentration (50 mg/mL). Results from this study suggest COS bind to bile acids by multiple different mechanisms; in fact, COS exhibited more complex binding than that of chitin and chitosan. The findings in this study will be useful in understand the hypocholesterolaemic properties of chitin and its derivatives. However, further studies elucidating the relationship between physicochemical properties of chitin and its derivatives and their bile acid-binding effects are essential.