Coconut husk-lignin derived carbon dots incorporated carrageenan based functional film for intelligent food packaging

• Published in: International journal of biological macromolecules 2024-05, Vol.266 (Pt 1), p.131005-131005, Article 131005
• Main Authors: Sangeetha, U.K., Sudhakaran, Nandhana, Parvathy, P.A., Abraham, Malini, Das, Subrata, De, Sriparna, Sahoo, Sushanta K.
• Format: Article
• Language: English
• Subjects: Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - pharmacology; Antioxidants - chemistry; Antioxidants - pharmacology; Carbon - chemistry; Carbon dots (CDs); Carrageenan - chemistry; Coconut husk; Cocos - chemistry; Escherichia coli - drug effects; Fluorescence; Food Packaging - methods; Hydrogen-Ion Concentration; Intelligent packaging; Lignin; Lignin - chemistry; Permeability; pH responsiveness; Quantum Dots - chemistry; Staphylococcus aureus - drug effects
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2024.131005

Carbon dots (CDs) derived from sustainable natural feed-stocks like lignin have gained wide acceptance by virtue of their renewability and promising potential in intelligent sensing applications. The precursor lignin is isolated from agro-biomass waste, coconut husk through sodium hydroxide based extraction process. CDs are synthesised from amine functionalized lignin through solvothermal process and integrated into carrageenan biopolymer matrix (1, 2 and 3 wt%). The composite film with 2 wt% CDs (CARR2CD) showed optimum fluorescent emission intensity, excellent pH dependent fluorescent color change in the food pH range, reasonable tensile strength (46.50 ± 1.32 MPa) and 27 % increase in elongation at break. CDs imparted UV-light blocking properties (70 % UV-light) and enhanced hydrophobicity of the carrageenan matrix. CARR2CD film showed 84 % visible light transparency, 79 % reduction in oxygen transmittance rate (OTR), 81 % reduction in CO2 gas permeability and excellent antioxidant and antibacterial properties (against E. coli and S. aureus). As a practical application, the developed responsive packaging material is used to track pH change associated with milk spoilage via noticeable color change in fluorescent emission of the composite film. Thus, the developed responsive composite film paves a way for use as green and sustainable transparent intelligent food packaging material. [Display omitted] •Lignin is isolated from agrowaste coconut husk, through alkali based extraction process.•pH dependent fluorescent emission is observed for carbon dots (CDs) prepared from aminated lignin.•CDs incorporated carrageenan matrix exhibits UV blocking, antioxidant, antibacterial and gas barrier properties.•Carrageenan-CDs composite film is used to monitor the milk spoilage through pH dependent fluorescent emission.