PROPOSED NEW COLOR RETENTION METHOD FOR TILAPIA FILLETS (O. NILOTICUS[female symbol] x O. AUREUS[male symbol]) BY EUTHANATIZING WITH REDUCED CARBON MONOXIDE

• Published in: Journal of food processing and preservation Vol. 32; no. 5; pp. 729 - 739
• Main Authors: LI, LAIHAO, HAO, SHUXIAN, DIAO, SHIQIANG, CEN, JIANWEI, YANG, XIANQING, SHI, HONG, CHEN, SHENGJUN
• Format: Journal Article
• Language: English
• Published: Malden, USA Malden, USA : Blackwell Publishing Inc 01.10.2008; Blackwell Publishing Inc; Blackwell Publishing
• Subjects: Biological and medical sciences; Food industries; Fundamental and applied biological sciences. Psychology; Tilapia; Vertebrata; Pisces; Color; Tilapia; Carbon monoxide; Method; Retention
• ISSN: 0145-8892; 1745-4549
• DOI: 10.1111/j.1745-4549.2008.00209.x

The conditions of color retention for tilapia fillets (O. niloticus[female symbol] x O. aureus[male symbol]) treated by euthanatizing with reduced carbon monoxide (CO) were investigated. Live tilapias were first exposed to water saturated with CO. After a certain amount of CO-saturated water had been pumped through the gills, the tilapias were timely picked out and killed following the industry guidelines. The color value of fillets was measured by colorimeter to evaluate the color retention. The results showed that (1) temperature did not have a significant effect on the color of the fillets; (2) the optimal conditions were a ratio of 3:1, v/w between water and fish, a CO flow rate of 80 mL/min and 10 min CO injection followed by 5 min air exposure. Under these conditions, a higher a*value (redness 19.44) and a better sensory evaluation value (4.8) were obtained; and (3) the proposed method shortened processing time by 30-35 min, reduced the frequency of sterilization to only once, significantly lowered microbial counts from 82.33 x 10² to 56.33 x 10² and reduced the CO requirement 25-fold, which has significant occupation, health, safety, and environmental implications. Color retention for tilapias is conventionally accomplished by treating fillets with CO. Recently, euthanatizing tilapias with CO has been assumed to be an effective way to shorten processing time and to lessen product handling process. Many factories have been searching for a way to solve the problem of color retention for tilapias or other red muscle treatment, but there has been a lack of information on how euthanasia affects fish quality, especially red muscle color. The objective of this experiment was to explore the application of the new method.