Micro and nanoparticles of native and modified cassava starches as carriers of the antimicrobial potassium sorbate

Cross-linked and/or acetylated cassava starches were synthesized and characterized. The acetylation increased the water retention capacity and the solubility in water while the higher level of cross-linking produced the opposite effect on starch. Native (NCS) and acetylated cassava starches (ACS) were used to generate starch micro-and nanoparticles by the dialysis technique. The nanoparticle fraction was around 1.8 g 100 g(-1) and 12 g 100 g(-1) (starch dry basis) for NCS and ACS, respectively. The nanoparticle sizes were around 23-255 nm with zeta potential extending from -4 to -44 mV, while the microscopic fractions ranged 5-87 mu m. In addition, the capacity of particles to support potassium sorbate (KS) was tested. NCS and ACS particles supported a similar quantity of KS (approximate to 1400 ppm) and the presence of antimicrobial decreased the particle size for NCS. The precipitation in ethanol technique was also used to generate microparticles where the particles generated from acetylated starches were smaller (8-58 mu m) than those from native ones (30-227 mu m). The KS content that these particles could incorporate was around 2020 ppm. The applied technique modulated the average dimension of the particles obtained, as well as the antimicrobial retention capacity. These innovative materials could be potentially helpful for shelf life extension by the contribution to the KS stabilization to be incorporated in the bulk of food products.