Abstract:
Production and shelf-life of fish powder for gel forming product were studied. Threadfin bream, Nemipterus spp., meat used was composed of 79.84% moisture, 15.89% protein, 2.78% fat, 0.98% ash, 0.51% carbohydrate and 48.80% of the salt soluble protein (SSP) to total protein. The total volatile base (TVB) and trimethylamine (TMA) contents of the fish flesh were 17.54 and 5.62 mg/100 g respectively while its pH was 6.75. The significant steps in the preparation of the fish powder were washing, slurry preparation and spray drying. After washing the fat content in the flesh reducced to 0.40% while its SSP increased 70.00%. Four levels of the solid contents, 10, 20, 30 and 40%, were studied in the slurry preparation. The highest yield was obtained at 30% solid content and 62.50 min. of spray drying. The spray-drying experiment on 3 levels of inlet temperature, 150, 170, 190 ํC and 3 levels of sucrose, 0, 3, 5% by weight, were conducted. The result indicated that with 5% sucrose and 150 ํC inlet temp., the value of gel strength, folding ability, water holding capacity (WHC), emulsion capacity (EC), yield and whiteness of the resulting gel were the highest. The study on improving of gel forming ability of the fish powder was later conducted. Potato starch at 2, 5, 8 and 11% by weight and Tranglutaminase (TGase) at 0.01, 0.02, 0.03 and 0.04% by weight were selected as additives in this study. The results revealed that potato starch at 11% provided the fish gel with the highest whiteness value while the TGase at 0.03% provided the product with the highest gel strength, folding ability and WHC. The sensory evaluation results also confirmed those of the objective tests. For the shelf-life study, the fish powder vacuum packaged in linear low density polyethylene coated with nylon bag, at 5 ํC can be kept for 12 weeks.