Lipase etching effects-induced interaction between betanin nanocomplexes and polylactic acid and its 3D printing for food packaging

Abstract

Etching effects by lipase on polylactic acid (PLA) could induce the exposure of active sites and promote the attachment of betanin nanocomplexes (BR-Ch) to obtain red color. 3D printing, regarded as emerging, innovative packaging fabrication technique, was applied to potentially develop creative, red PLA products for food application. BR-Ch was prepared based on betanin and nano chitin (around 195 nm) via electrostatic interaction and hydrogen bonding, obtaining nanocomplexes (around 24 nm) with excellent thermal stability. Pre-treatments mattered greatly in PLA functionalization, and especially, lipase pre-treatment 30 min promoted BR-Ch modification on PLA. Final PLA exhibited excellent red color characteristics (CIElab, Hue-Saturation-Brightness, K/S and CMYK), elongation at break and stable thermal resistance, ultimately achieving outstanding dyeing effect. This work indicates that BR-Ch can potentially replace synthetic pigments to functionalize lipase-pretreated PLA, and the dyed PLA demonstrate the excellent packaging application prospects in food field by 3D-printed products.