waste treatment systems [28] is particularly eective in
removing proteins from wastes; the coagulated by-products
could serve as a source of protein in animal feed
[29]. Chitosan reduced the suspended solids of various food
processing wastes to dierent contents (Table 3). There
are two stages that result in destabilization of a colloidal
system; coagulation and ¯occulation. The former is the
process where the forces holding the particles in suspension
are neutralized, whereas ¯occulation is the process
in which destabilized suspended particles are
brought together to form larger aggregates [31, 35]. The
mechanism of ¯occulating lipids and proteins from food
processing waste is due to the pKa of the amino group
of glucosamine residue which is about 6.3 [91], hence
chitosan is polycationic at acidic pH values [33, 92].
Thus, in contrast to chitin, chitosan is soluble at pH
below 6.3 and precipitates at higher pH values [32].