76D-6 |
Role of deoxyhemoglobin in lipid oxidation of washed cod muscle mediated by trout, poultry and beef hemoglobins |
M. P. RICHARDS, Animal Science-Food Science, U. Wisconsin-Madison, Meat Science and Muscle Biology Lab, 1805 Linden Dr. West, Madison, WI 53706, R. Li, Food Science, U. Wisconsin Madison, Meat Science and Muscle Biology Lab, 1805 Linden Dr. W., Madison, WI 53706, and I. Undeland, Food Science, Chalmers University of Technology, PO Box 5401, S-402, 29 Göteborg, Sweden. Lipid oxidation is a major cause of quality deterioration in muscle foods. Quality defects that occur due to lipid oxidation include off-odors, off-flavors and poor texture. Hemoglobin and myoglobin are likely catalysts of lipid oxidation in muscle foods. A better understanding of the role of heme proteins in lipid oxidation could lead to improvements in quality of muscle foods. The objective was to investigate the relationship between deoxyhemoglobin content and lipid oxidation using hemoglobins from aquatic and terrestrial animals as catalysts and washed cod muscle as a lipid substrate. Relative oxygenation of trout, chicken, turkey and beef hemoglobins at pH 5.5 to 7.5 was determined. Hemoglobin oxygenation was assessed by spectral changes in the soret band and visible range. Each hemoglobin was added separately to washed cod muscle at pH 6.3 and stored at 2°C for up to 7 days. Thiobarbituric reactive substances (TBARS) and lipid hydroperoxides were used as indicators of lipid oxidation. Loss of redness was measured by a-value determination with a Minolta CR-200 chroma meter. At pH 6.3, deoxyhemoglobin content was highest in trout hemglobin, low to intermediate in poultry, and lowest in beef hemoglobin. The lipid oxidation rate at pH 6.3 was trout >> chicken=turkey > beef. Hemoglobins from trout appeared to oxidize more rapidly compared to chicken hemoglobin in the washed cod muscle model system, as measured by a decrease in redness during storage. Loss of red color was slowest in beef samples. These studies suggest that deoxyhemoglobin may be a major catalyst of lipid oxidation at post mortem pH values found in muscle foods, especially in trout and poultry compared to beef. The more rapid loss of red color from poorly oxygenated hemoglobins could be due to more rapid hemoglobin autoxidation or changes in heme-globin stability.
Session 76D, Muscle Foods II
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