ABSTRACT

The preparation of 3D printing ink with nanocellulose as the substrate is of positive significance to the development of the food industry. Herein, we have developed food 3D printing ink using nanocellulose, and explored its application in lactic acid bacteria delivery and smart food packaging through coaxial 3D printing technology. 
Bacterial cellulose was used as the matrix to combine with sodium alginate and k-carrageenan for the shell. Chitosan and lactic acid bacteria were co-cultured to be the core. Then, the lactic acid bacteria delivery composite was successfully constructed in one step by coaxial 3D printing technology. This composite has good texture and fermentation performance as well as excellent lactic acid bacteria protection and delivery efficiency.
For constructing an environmentally friendly degradable cushioning-antibacterial food packaging material to minimize the loss of fruit and vegetable during storage and transportation, a 3D printed cushioning food packaging material was prepared using carboxymethyl nanocellulose as a matrix, supplemented with acrylamide derivatives/glycerin. Then, with this material as the shell layer, silver nanoparticles were fixed as the core layer by coaxial 3D printing technology to prepare a cushioning-antibacterial dual-function food packaging material. The minimum cushioning factor of the material is 4.29 and its three-time compression rebound rate is above 90%. It also has obvious antibacterial effects on Escherichia coli and Staphylococcus aureus. Moreover, its degradation rate reaches 76.17% after 14 days.
Food packaging systems with single function of freshness keeping or monitoring may not be able to meet all practical needs. In this study, with nanocellulose/sodium alginate/k-carrageenan/blueberry anthocyanin as the shell material and chitosan/1-methylcyclopropene as the core material, the nanocellulose-based integrated smart label for fruit freshness keeping and visual monitoring was successfully constructed by coaxial 3D printing technology. The 3D printed label can extend the shelf life of litchi by 6 days and sensitively indicate the change in its freshness.

Note: The text of the abstract as well as the whole manuscript goes in single spacing.

Nanocellulose; 3D printing; delivery; antibacterial; freshness keeping/monitoring