REDUCING OFF-FLAVOUR COMPOUNDS GEOSMIN AND 2-METHYLISOBORNEOL IN TILAPIA THROUGH DIFFERENT CULTIVATION TECHNOLOGIES

LIU Liping1∗, ZHANG Kai1, LI Kang1, ZHOU Menghai1, ZHAN Jia2，LIANG Qinlang2, WU Zongwen2
 
(1. Key Laboratory of Freshwater Fishery Germplasm Resources, Ministry of Agriculture, Shanghai Ocean University, Shanghai 201306, China; 2. Ningbo Academy of Inspection and Quarantine of the P.R. China, Ningbo 315012, China; 3. Tongwei Group Co. Ltd, Sichuan, Chengdu 610041, China)
E-mail: lp-liu@shou.edu.cn
 

Off flavor in aquatic products is a rising concern among consumers and researchers. This study compares the effects of four different tilapia cultivation systems, namely tilapia-water spinach integrated system, sewage discharging system, sewage discharging and tilapia-water spinach integrated system with tilapia monoculture system as control on the water quality, tilapia production and off-flavor contents in water and tilapia. Using gas chromatography and mass spectrum (GC-MS) based on microwave assisted distillation followed by purge-and-trap, the off-flavor compounds geosmin (GSM) and 2-methylisobomeol (2-MIB) were determined in water and tilapia tissue. The results showed that the production of the tilapia-water spinach integrated system was the highest among the systems (P <0.05). The contents of ammonia nitrogen and nitrite in the sewage discharging and tilapia-water spinach integrated system were significantly lower (0.64±0.06mg/L and 0.086±0.005mg/L, respectively). In addition, the concentration of 2-MIB and GSM in the tilapia muscle of the sewage discharging and tilapia-water spinach integrated system (0.31±0.02 μg/kg and 0.53±0.042 μg/kg respectively) were significantly lower than in the control group (0.67 ± 0.022 μg/kg and 0.87±0.018 μg/kg respectively). The results indicated that the sewage discharging and tilapia-water spinach integrated system reduced the accumulation of off-flavor compounds in water and tilapia muscle in the intensive tilapia farming system.