Natamycin-Loaded Ethyl Cellulose/PVP Films Developed by Microfluidic Spinning for Active Packaging.

The preparation of active packaging loaded with antimicrobial, antioxidant, and other functional agents has become a hot topic for food preservation in recent years. In this field, active fiber films based on spinning methods have attracted the interest of researchers owing to their high specific surface area, high porosity, high loading capacity, and good controlled release capacity. In the present work, neatly arranged ethyl cellulose (EC)/polyvinyl-pyrrolidone (PVP) fibrous films loaded with natamycin as an antimicrobial agent were prepared by microfluidic spinning. The encapsulation efficiency of natamycin was more than 90% in each group and the loading increased with increasing natamycin content. According to the characterization results of the natamycin-loaded EC/PVP fibrous films, hydrogen bonding was formed between natamycin and EC and PVP in the fibrous films. Meanwhile, the water contact angle of the fibrous films was increased, suggesting the improved hydrophobicity of the films. In the in vitro bacterial inhibition experiments, the active fiber films loaded with natamycin showed good antimicrobial activity, which could significantly inhibit the growth of gray mold. In conclusion, N-EC/PVP fibrous films with antimicrobial activity prepared by microfluidic spinning showed good potential in the field of active packaging.

Facile microfluidic fabrication and characterization of ethyl cellulose/PVP films with neatly arranged fibers.

Much attention and endeavor have been paid to developing biocompatible food packaging films. Here, ethyl cellulose (EC) and polyvinylpyrrolidone (PVP) were fabricated into films through a facile method, microfluidic spinning. Morphology observations showed that the fibers were neatly arranged with an average diameter of 1-4 µm. FTIR and X-ray diffraction analysis suggested the existence of good compatibility and interaction between EC and PVP. Thermogravimetric analysis demonstrated that PVP ameliorates the thermal properties; moreover, the tensile properties were improved, with tensile strength (TS) and Young's modulus up to 11.10 ± 1.04 MPa and 350.16 ± 45.46 MPa, respectively. The optimal formula was EC/PVP (2:3), of which the film displayed an enhanced TS of 4.61 ± 1.15 MPa and a modified water contact angle of 61.8 ± 4.4°, showing fine tensile and hydrophilic performance. This study provides a facile and green film fabrication method promising to be used for food wrapping.

Characterization of glycosylated gelatin/pullulan nanofibers fabricated by multi-fluid mixing solution blow spinning.

In this work, multi-fluid mixing solution blow spinning was applied to develop gelatin/pullulan composite nanofibers, and then the nanofibers were glycated to enhance the physical properties. The results show that the grafting degree of the nanofibers increased significantly from 17.5 % to 36.0 % as the glycation time increased, and the morphology results indicated that 72 h of glycation did not destroy the structure of the nanofibers. FTIR results show that the glycation consumed the the-NH2 groups, cleaved sugar units of polysaccharide, and affected the secondary structure of the protein. The glycation enhanced the thermal stability and improved the rigidity of the nanofibers. Besides, after 120 h of glycation, the water contact angle of nanofibers increased from 0° to 79.1°, and the water vapor transmission rates decreased from 12.49 to 8.97 g mm/m2 h kPa, indicating the enhanced hydrophobicity and barrier properties. In addition, the glycation improved the water stability of the nanofibers, which increased the applicability of the gelatin/pullulan nanofibers in food packaging. The present work provides a green and efficient method for improving the physical properties of gelatin/pullulan nanofibers.