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Chitosan is a potential preservative agent to be applied on fish because of its anti-microbial function with additional beneficial characteristics for food application, e.g. biocompatibility, biodegradability and edibility. The particle size modification of chitosan will improve its anti-microbial performance because smaller particle size of chitosan can much better cover the surface of the preserved products with more concentrated positive charges on particle size of chitosan. With these special characteristics, modified chitosan is more effective in destroying bacterial cell walls to be compared to simple chitosan solution. In this study, chitosan modification was carried out using precipitation method with the addition of ammonia. This study aimed to prolong the shelf life of fish with variations in immersion time at room temperature. This prediction is important to develop effective standard operating procedures (SOP) for the preservation of fresh fish using modified chitosan-ammonia. Fish was soaked with immersion time variations (1, 15, 30, 45 and 60 minutes). The level of fish damage was measured by the total number of plates (TPC), number of base volatiles (TVB), and sensory evaluation by trained panelists. To quantify the effect of modified chitosan application in this preservation of fish in this study, the TPC data were analyzed using kinetics model. The kinetics model for predicting the level of deterioration in this study was the three-parameter logistic model. The kinetics parameter showed that the modification of chitosan improved the performance of chitosan as antibacterial agent that inhibited bacterial activity as the main source of deterioration on fish. The immersion time which was the best for inhibiting bacterial growth was 1 minute up to 45 minutes in room temperature. [ABSTRACT FROM AUTHOR]

The polyelectrolyte complexes (PECs) of chitosan with various polysaccharides such as alginate, carrageenan, Arabic gum, carboxymethylcellulose (CMC), pectin, and glucomannan were prepared and characterized. The complexation was performed by addition of polysaccharide solution as crosslinking agent into chitosan solution (0.01% and 2 %) wider magnetic stirring. The size of the obtained modified chitosan was analyzed by Particle Size Analyzer (PSA). The turbidity and pH were measured to observe the stability of the modified chitosan during the storage. The stability of the complexes was investigated at room temperature (37°C) for 3 weeks. The existence of glucomannan and arabic gum resulted PECs when it reacted with the chitosan solution using ratio 1:1. The changed crosslinker resulted a hydrogel after it blended. The obtained PECs could be affected by the ratio between chitosan and polysaccharide and the molecular weight of both polymers. The crosslinker concentration gave a significantly influenced the obtained particle size at the chitosan concentration 0.01 % and 2%. [ABSTRACT FROM AUTHOR]