Natural deep eutectic solvent polyphenol and cellulose from jackfruit peel as binary bio-fillers in jackfruit seed flour/poly (vinyl alcohol)-based sustainable composite films

Abstract

This study explores the use of natural deep eutectic solvent (NADES) polyphenolic extracts (E) and cellulose (C) from jackfruit peel as bio-fillers to enhance the properties of jackfruit seed flour/poly(vinyl alcohol) (JF/PVA)-based biocomposite films for food packaging. Nine composite samples (C0E0, C0E25, C0E50, C12.5E0, C12.5E25, C12.5E50, C25E0, C25E25, and C25E50) were prepared using solution casting. NADES demonstrated multiple roles, acting as a cross-linker, plasticizer, and particle size reducer. Lactic acid in NADES effectively cross-linked with PVA, leading to the C0E25 film exhibiting the highest hydrophobicity, water barrier properties, and thermal stability. The plasticizing effect of NADES reduced tensile strength and elastic modulus while increasing elongation at break. Additionally, increasing NADES content reduced the size of cellulose on the film surface. Hydrophilic cellulose, particularly in C25E0, enhanced mechanical properties and water uptake (223.96 ± 21.29%). Films with binary bio-fillers, especially C25E50, showed improved ultraviolet and visible light barrier properties, thermal stability, antioxidant activity, and antimicrobial activity. In olive oil packaging tests, high-antioxidant films (C0E50, C12.5E50, and C25E50) extended the shelf life of olive oil by 30 days compared to an open Petri dish and traditional PET/LDPE sachets. These findings highlight the potential of JF/PVA-based biocomposite films as sustainable alternatives for extending the shelf life of high-value food products like olive oil.