Ultrastructural, hydrodynamic, rheological, and emulsifying properties of chitin nanowhisker dispersions from commercial (C) and laboratory (L) origin were analyzed at pHs 2–3.5. Nanowhiskers were rod-like shaped and their hydrodynamic properties changed in range: particle size: 90–560 nm; ζ potential: 26–42 mV; polydispersity 0.175–0.850. Flow curves indicated a shear-thinning behavior for both samples. At pH 2 dispersions were more consistent than at pH 3.5, but in both cases L showed higher consistency than C. Both C and L exhibited a non-stationary (thixotropic) flow at pH ≥ 2.5. The coexistence of two shear-induced domains was found in the oscillatory tests. The emulsifying ability of both C and L samples at a low (0.5%) concentration was dependent on pH. So, at pH 2, the L sample showed a greater emulsifying ability (98%) and emulsion stability (92-90%) than the C sample (emulsion stability ≈74%).

This work was supported by the following projects: NANOALIVAL AGL2017-84161 funded by MCIN/AEI/10.13039/501100011033/and FEDER “Una manera de hacer Europa”; NANOBIOPACK PID2019-108361RB-I0 funded by MCIN/AEI/10.13039/501100011033; and project 202070E218 financed by CSIC, Spain.

Peer reviewed