关键词: 纳米甲壳素, 磷酸, 高效制备, Pickering乳液

Abstract:

Nano-chitin was prepared by treating raw chitin with phosphoric acid （H₃PO₄） for 40 min followed by high-pressure homogenization. This method could save chemical reagents, shorten the preparation process and increase the yield as compared with the previous preparation method. The chitin and regenerated nano-chitin （RCh） were characterized by XRD, TEM and inductively coupled plasma atomic emission spectrometry. The experimental conditions of preparation were optimized, such as the minimum concentration of phosphoric acid to dissolve chitin and the maximum concentration of chitin that could be dissolved by different concentrations of phosphoric acid. The RCh suspension thus prepared was used to stabilize caprylic/capric triglyceride （GTCC） to fabricate oil-in-water Pickering emulsions. The emulsions were characterized on an optical microscope, a dynamic laser scattering size analyzer and a rheometer. All the RCh prepared with this method could well stabilize Pickering emulsions （RCh content was only 0.2%）. The RCh adsorbed on the O/W interface could stabilize the Pickering emulsions. The rheological behaviors of Pickering emulsions indicated that, the entanglement of RCh enhanced the structure of the emulsions as well as their resistance to deformation. The energy storage modulus and loss modulus remained constant with the change of scanning frequency at a fixed stress, and no intersection point was found in the frequency range, which indicated that the emulsions were stable and had “gel-like” behavior. All emulsions showed shear thinning behavior. RCh was effective in preventing droplet coalescence and could form stable Pickering emulsions when GTCC mass fraction was not higher than 60%.

Key words: nano-chitin, phosphoric acid, efficient preparation, Pickering emulsion