Recent studies have focused on conversion of chitosan to
oligosaccharides (termed chitooligosaccharides, COS)—because
the latter are not only readily soluble in water due to their
shorter chain lengths (generally, the MW of COS is 10 kDa
or less) (Kim and Rajapakse, 2005) and free amino groups in
D-glucosamine units, but also easily absorbed through the
intestine, quickly getting into the blood flow