Chikuwa preservation by edible coating from a combination of young coconut shell liquid smoke and chitosan

Abstract

This study aimed to preserve the quality of chikuwa during storage through the application of an edible coating derived from a combination of liquid smoke extracted from young coconut shell pyrolysis and chitosan. Liquid smoke was obtained through pyrolysis at temperatures of 300 °C (T1), 340 °C (T2), 380 °C (T3), and 420 °C (T4), followed by distillation to remove tar and other contaminants. A solution comprising 2 % liquid smoke was utilized to dissolve chitosan (0.5–1.5 % w/w), creating an edible coating, which was then applied to chikuwa samples through a 15-minute immersion process. Throughout the storage period, the quality of the chikuwa was evaluated using total volatile base nitrogen (TVB-N), total plate count (TPC), most probable number (MPN) Escherichia coli testing, as well as minimum inhibitory concentration (MIC), and minimum killing concentration (MKC) tests against Gram-negative bacteria (E. coli and Salmonella enterica sv Typhimurium). Results from the TVB test indicated that chikuwa treated with an edible coating, particularly at T4, maintained freshness for up to 168 h. Microbiological analyses revealed that TPC and MPN E. coli values remained compliant with Indonesian National Standards (SNI) for up to 120 h of storage in T4-treated samples, with values of <4.72 × 10⁴ CFU/g and 460 MPN/g, respectively. Furthermore, MIC and MKC values demonstrated the inhibitory and bactericidal effects of young coconut shell liquid smoke against E. coli and S. typhimurium. Overall, the findings suggest that the application of an edible coating effectively mitigates the deterioration of chikuwa quality during storage, extending up to 120 h.