Physicochemical Characteristics and Antioxidant Activity of Coconut Shell Liquid Smoke and Its Potential as a Solvent for Chitosan

Abstract

Liquid smoke is a product obtained from the condensation of biomass pyrolysis at high temperatures and is widely applied in the food industry and biopolymer-based material development. Coconut shell is a potential raw material due to its high lignocellulosic content, which decomposes into phenolic compounds, carbonyls, and organic acids during pyrolysis. The research aims to investigate the chemical characteristics and antioxidant activity of liquid smoke derived from coconut shell, as well as to evaluate its effectiveness as a chitosan solvent. The analyzed parameters included acetic acid content, pH, total phenolic content, antioxidant activity using the DPPH method, and chitosan solubility at various liquid smoke concentrations (5%, 10%, 15%, and 20%). The results showed the total acid content of liquid smoke was 6.798 ± 0.398% g AAE/mL, with a pH value of 2.42 ± 0.04. The total phenolic content was 4.715 ± 0.878% g GAE/mL. Antioxidant activity testing resulted in an IC₅₀ value of 0.53%, indicating strong antioxidant capacity. Chitosan dissolved optimally in 20% liquid smoke, comparable to dissolution in 2% acetic acid. These findings demonstrate that coconut shell liquid smoke has significant antioxidant potential and can serve as an environmentally friendly alternative solvent for chitosan dissolution.