Study On Fish Sauce Fermentation With Tilapia Wastes

Fish sauce fermentation technology was studied with wastes after sliced tilapia production to enhance the utilization ratio of fish protein.First,liquid koji was made with Aspergillus oryzae (As3.951) from tilapia waste. the optimum conditions were as follows:tilapia waste was firstly mixed with water in the ratio of 1:1,and heated to 80℃for 5 min and cooled ,and then inculated with 4% liquid starter of Asp. oryzae (As3.951) ,and kept at 40℃for 12h, the protease activity of liquid koji-making obtained was 1270u/mL.Then ,fish sauce fermentation technology was investigated , and the optimal fermentation conditions were as follows: tilapia waste was added with 150% water and blended, boiled for 10min, and then added with 20% soya koji, 15% liquid koji and 9% salt. Then the mixture was fermented at 40℃for 12d.The fermented product contained 0.77g/100mL aimino nitrogen, and 1.69g/100mL total nitrogen.To enhance the flavor ,the mixed culture of Saccharomyces rouxii As2.180 and Torulopsis globosa As2.202(As2.180∶As2.202=1∶1) was added by 10% to the product obtained above ,and re fermented at 12% of salt content for another 12d ,and the flavor was improved with the alcohol content being 4.670g/L.The deodorizing effects ofβ-cyclodextrin,active carbon ,the fucose and on fish sauce were compared using the lose of dissociative amino-nitrogen and the content of TMA as assay parameters. The results indicated that the fishy smell removing effect of active carbon,the fucose were better thanβ-cyclodextrin .Through the L9 (33) orthogonal test, the best deodorizing effect was obtained when fish sauce was treated with 6% fucose at 40℃f or 120 min followed by adding 0.5% active carbon at 35℃for 20 min.After the experiments, the fish sauce is rich in tasty amino acid ,and the fish odour was removed .