42-5 |
The effect of carbon monoxide on autoxidation, peroxidase and pro-oxidative activity of hemoglobin from tilapia |
K. S. GARNER, S. Mony, and H. G. Kristinsson. Dept. of Food Science & Human Nutrition, Univ. of Florida, 359 FSHN Bldg., Newell Dr., PO Box 110370, Gainesville, FL 32611-0370 Hemoglobin plays an important role in color and lipid peroxidation of fish muscle. Recently carbon monoxide (CO) has been used to stabilize the color of fish muscle, including tilapia. Carbon monoxide binds to hemoglobin (Hb) with greater affinity than oxygen and is expected to alter the properties of this protein. There is a lack of information how CO will affect the properties of fish hemoglobin. The objective was to compare CO-Hb with oxy-Hb from tilapia for rate of autoxidation, peroxidase and pro-oxidative activities under different environmental conditions. Oxy-Hb and CO-Hb were prepared from tilapia blood. Hemoglobin solutions (pH 6-8) were kept at -30°C (frozen storage), 4°C (cold storage) and 20°C (room temperature) and autoxidation of Hb monitored at select time intervals by scanning the samples from 350-700 nm in a spectrophotometer. The peroxidase activity of Hb was assayed (pH 6-8) using guaiacol as the substrate and monitoring the reaction at 470 nm. The pro-oxidative activity of Hb (pH 6-8) at 4°C was determined in a fish membrane lipid system by measuring TBARS formation and also in a linoleic acid emulsion by following conjugated diene formation. CO significantly stabilized hemoglobin against autoxidation at all temperatures and pH’s studied. CO-Hb had significantly less peroxidase activity than oxy-Hb. CO-Hb oxidized the fish membrane lipids at a slower rate than oxy-Hb and led to a significantly lower formation of conjugated dienes in the linoleic acid emulsion, thus having less pro-oxidative activity than oxy-Hb. These results show that CO provides significant stability to the Hb molecule which may lead to less quality problems arising from CO-Hb compared to oxy-Hb in fish muscle. Better understanding on the effect CO has on Hb will aid in developments
Session 42, Food Chemistry: Proteins II
|