Starch nanocrystals (SNCs) are a biodegradable polymer which has been widely studied and used in many fields. In this study, we have developed an efficient procedure for the preparation of SNCs. First, sodium hexametaphosphate (SHMP) and vinyl acetate (VAC) were used to modify waxy potato starch (WPS). Then, the modified starches were hydrolyzed with sulfuric acid to prepare SNCs. Results showed that SNCs prepared with modified starch had higher zeta potentials and better dispersion properties than the original starch. After modification, WPS still maintained its semi-crystalline structure, but the surface became rougher. SHMP-modified WPS showed a decrease in viscosity peak and an increase in gelatinization temperature. VAC-modified WPS showed increased swelling power. Additionally, SNCs prepared with VAC-modified WPS had better water redispersibility and dispersion stability than those from SHMP-modified starch—which will have broader application prospects in the field of safe and biodegradable food packaging.

Bacterial cellulose (BC) is a biomaterial with many excellent properties, but its application as a food packaging and biomedical material is limited due to its lack of antibacterial properties. In this study, ferulic acid (FA) grafted self-assembled bacterial cellulose-chitosan (BCF) membranes were prepared by soaking BC films in chitosan-ferulic acid (CF) solution to synthesize antibacterial biomaterials. 1 H NMR confirmed that FA grafted onto chitosan successfully. The results of field emission scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and tensile analysis showed that CF were successfully incorporated into BC matrix and the BCF membranes had good physical properties. The antibacterial experiments demonstrated that BCF membranes had an excellent antibacterial effect against Staphylococcus aureus and Escherichia coli. Therefore, combining all these properties, BCF composite membranes would have potential application in food packaging or wound-healing materials.