Effect of met-myoglobin reductase on the color stability of blue fin tuna during refrigerated storage

Abstract

To investigate the reducing ability of met‐myoglobin (metMb) reductase, browned tuna meat was immersed with/without metMb reductase (0.103 unit/mL) for 120 min at 4°C. The metMb reductase activity of browned tuna meat significantly increased, whereas no significant change was observed in the control sample for the first 10 min of immersion (P > 0.05). After comparing the changes in metMb reductase activity, metMb content, Hunter’s ‘a’ and color, it was observed that the reductase did recover the bright red color. To further confirm the role of metMb reductase in color stability, fresh tuna meat was first immersed in metMb reductase (0.503 unit/mL) or a mixture of reductase and nicotinamide adenine dinucleotide (NADH) (1 mM) solutions at 5°C for 10 min, and then stored at 4°C and relative humidity 100%. No significant changes in metMb accumulation and in metMb reductase activity were observed between samples treated with enzyme alone and enzyme + NADPH (P > 0.05). Changes in metMb reductase activity, metMb, Hunter’s ‘a’ value and color for both the control and treated samples suggested that immersion in metMb reductase could extend the color stability of tuna meat, and that the enzymatic reduction of metMb by its reductase occurred during refrigerated storage.

Chemical compositions and characteristics of farm raised giant catfish (Pangasianodon gigas) muscle

“…Myoglobin is an important chromoprotein which gives the redness to muscle. Generally, the redness of dorsal and ventral ordinary muscles is an important indicator of the quality of bluefin tuna, and the meat colour of tuna muscle changes from red to brown during chilled storage (Chiou, Pong, Nieh, & Jiang, 2001). The change of meat colour after slaughter is due to the increase of met-myoglobin which is produced by autoxidation of myoglobin.…”

Improving the Color Shelf Life of Farmed Southern Bluefin Tuna (Thunnus maccoyii)Flesh with Dietary Supplements of Vitamins E and C and Selenium

“…The importance of metmyoglobin in tuna flesh discoloration has been demonstrated by Chiou et al (2001) in studies with the closely related northern bluefin tuna. Chiou et al (2001) showed that addition of the enzyme metmyoglobin reductase to the surface of browned tuna meat could increase the redness of the meat by reducing the amount of metmyoglobin.…”

“…Chiou et al (2001) showed that addition of the enzyme metmyoglobin reductase to the surface of browned tuna meat could increase the redness of the meat by reducing the amount of metmyoglobin. This approach, like that of the present study, increases the color shelf life of tuna meat.…”

Use of “filtered smoke” and carbon monoxide with fish

“…in respect of the colour. While Livingston and Brown (1981) still question the physiological importance of such enzymatic activities, it has been established by the working group of Jiang (Pong et al, 2000;Chiou et al, 2001) that met-Mb reductase influences the accumulation of met-Mb in chilled-stored tuna meat as an essential factor. Furthermore, it was found that immersion in met-Mb reductase could extend the colour stability of tuna meat, and that the enzymatic reduction of metMb by its reductase occurred during refrigerated storage (Chiou et al, 2001).…”