Aplikasi Khitosan sebagai Bahan Edible Coating pada Produk Ikan Beku

Abstract

Frozen process and storage is one of best method to keep fresheness of food during storage. Fish that processed and stored in frozen is potential for dehydration and microbial growth. Due to its antimicrobial agent, film formable, and good barrier of gas and moisture, chitosan try to be applied to frozen fish. This study consists of two steps, preliminary and main. Preliminary step was done to test pH of chitosan solution, antimicrobial, and water vapor permeability. Main step was done to test moisture content, total plate count, and organoleptic. This step used fish that filleted and coated by chitosan then stored in cold storage (-20 °C) for 15 days. The species of fish used is Sweetlips (Plectorhynchus sp.) with size 100-200 g (± 20 x 10 cm). Experimental design used in this research is Complete Random Factorial Design consisting of two factors. The first factor is the concentration of chitosan consisting of a three level, 1,0; 1,5; and 2.0% (b/v). Second factor is the concentration glycerol consisting of two level, 0,25 and 0,50 ml/g chitosan. The best combination of chitosan-glycerol then applied to the main step. The main step used fillet fish without coating and 0,4 mm thickness plastic (polypropylene/PP) wrapped as a benchmark. The preliminary step resulted chitosan with the concentration of 1,0% (b/v) and glycerol 0,25 ml/g chitosan as the best combination. This combination has pH value of 4,59; index of inhibition of E. coli 0,00; index of inhibition of S. aureus 0,03, and water vapor permeability (WVP) 1,6548 g.m-1.atm-1.day-1. Coating application on the frozen fish was done with the dipping method. The fish dipped for 30 seconds, then drained and kept in cold storage. The test of moisture content shows that in all samples of fish tend to show a decrease in moisture content. The value of moisture content of fish coated by chitosan is still lower then others. However, the value of the moisture content of the samples are still in tolerance of frozen fish (± 80%). For total plate count, the sample of fish coated by chitosan has a total value of microbes that lower than others. If compared with fish without coating, the value become 8-28 percent. If compared with the fish that wrapped with plastic, the value become 16-44 percent. In organoleptic (hedonic) test, by 17 panelists, the assessment indicates that the sample of the coating chitosan average ranged between normal (biasa) and quite like (agak suka). This range describes that the score of the assesment is above the average (score of 3-4).