Effect of chitosan, sodium lactate and sodium acetate on shelf-life of hot smoked and vacuum packed rainbow trout fillets

This thesis has been conducted to determine the effects of chitosan (Ch), sodium lactate (SL) and sodium diacetate (SD) on the shelf life of hot smoked rainbow trout. During the thesis work, 20 trout fillet samples for each of the control, 2% chitosan applied, 2% sodium lactate applied and 0.2% sodium diacetate applied groups, in total 80 samples, were obtained from a company located in Aydın/Bozdoğan. Effect of applied compounds on the product's shelf life was examined by microbiological (TMC, TPC) and chemical (TVB-N, PH) analyses. In the control group, TMC amount was determined as 2.70 log10 kob/g and TPC amount was determined as 2.68 log10 kob/g at the beginning of the analysis. The TMC amount exceeded 7.00 log10 kob/g level which is the comestible value for fisheries at the 14th-16th day (according to ICMSF 1986). In the same manner, TPC amount exceeded 7.00 log10 kob/g threshold value which is the comestible value for fisheries at 14th day (according to ICMSF 1986). The limit value of TMC was exceeded by; 2% chitosan applied samples on the 26th day, 2% sodium lactate applied samples on the 22nd day and 0.2% sodium diacetate applied samples on the 20th day. The limit value of TPC was exceeded by; 2% chitosan applied samples on the 24th day, 2% sodium lactate applied samples on the 22nd day and 0.2% sodium diacetate applied samples on the 22nd day. To determine quality control of fishery, at the beginning of the analysis, TVB-N amount was determined as 8.43 mg/1000g for all samples in all groups. The TVB-N value was determined as; 29.4 mg/1000g in control samples on 14th day, 30 mg/1000g in 2% chitosan applied samples on 26th day, 32.4 mg/1000g in 2% sodium lactate applied samples on 22nd day and 34.1 mg/1000g in 0.2% sodium acetate applied samples on 22nd day. PH measurements gave lower results on the first few days of the analysis and higher results on the latter days. PH value at the beginning was determined as 5.98; this value was decreased in all groups at first, and on the next days of storage, it increased. As a result of the research, shelf life of hot smoked, vacuum packed rainbow trouts was successfully increased from 14-15 days up to 24-26 days.