Chitosan with different molecular masses was reacted with sodium tripolyphosphate (STPP) to prepare
different size nanoparticles, in which vitamin C was encapsulated. The effect of molecular weight
(Mw) on nanoparticles efficiency, nanoparticles yield, size, and zeta potential was investigated in detail.
Low Mw chitosan generated nanoparticles with better size, morphology, and delivery rate. In addition,
the shelf life of encapsulated vitamin C increased as compared with its non-encapsulated counterpart.
The release of vitamin C from the nanoparticles was pH-dependent. Quick release took place in 0.1 M
phosphate buffer solution (PBS, pH 7.4), while the release was slow in 0.1 M HCl. In addition, in vivo
release rate in digestive tract of rainbow trout nearly showed the same trend as the in vitro one.
