The effect of reduced acetic acid concentration on nano-chitosan formulation as fish preservative

Abstract

Nano-chitosan has antibacterial activity and can be used as fish preservative. Acetic acid concentration of 1% is commonly used to produce nano-chitosan but it affected consumer acceptance because of its acidity. This study aimed to reduce the concentration of acetic acid and observed its effects on particle size, pH, and bacterial growth inhibition activity. Besides, it was also observed the effect of nano-chitosan with acetic acid concentration reduction on total bacteria and sensory value when applied on tilapia fillets. The results showed that the higher concentration of acetic acid resulted smaller particle size of chitosan and higher bacterial growth inhibition. The similar trend was also shown by acetic acid solution in same concentration. However, the bacterial inhibition zone of nano-chitosan solution was higher than acetic acid solution for each variation of acetic acid concentrations. This was evidenced by the observation of the clear zone formation of Gram positive and negative bacteria culture grown on nutrient agar. The optimum acetic acid concentration in nano-chitosan production was 0.43% because it was able to inhibit the growth of bacteria on the tilapia fillet and resulted in good consumer acceptance even when tilapia fillet was soaked up to 25 minutes in the nano-chitosan solution.