This work evaluates the possibility of producing chitosan-based nanoparticles using food grade
ingredients from natural sources. Two ingredients with surface activity (lecithin and sodium
caseinate) were used for inducing particle formation and the addition of a surfactant (Tween
20) was also evaluated. Rotor-stator shearing and ultra-high pressure homogenization were
used in order to compare the effect of mechanical process in the properties of the manufactured
particles. Alcoholic lecithin and sodium caseinate (pH 7) solutions (2.5 % w/v) were prepared
separately. Chitosan solutions were firstly sheared in a rotor-stator device (Ultra Turrax), with
slow addition of caseinate or lecithin. These solutions were submitted to a two stage high
pressure homogenization. Samples were taken before and after high pressure homogenization
in order to evaluate the effect of this stage on the production of nanoparticles. Zeta potential
and hydrodynamic diameter of all samples were measured after preparation and after 20 days
under refrigerated storage. Particle sizes ranged from 50 to 200 nm, with smaller sizes obtained
for the samples produced with sodium caseinate. Even though zeta potential of both chitosanlecithin
and chitosan-caseinate samples were 28 and 17 mV respectively, almost all samples
showed to be stable after 20-day storage with no differences on their size observed within the
evaluated period. Exception for the samples produced without Tween 20 in the rotor-stator
device in which an increase of 50 % on particle size was observed after storage. Generally,
particle size was related to the binding properties of the ingredients. Such properties were
increased with shearing and modified by the co-surfactant. Such results show the possibility of
producing food grade stable particles at the nanoscale with simple processing techniques,
which could be further used as base systems for production of nanocapsules.