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Low fat ground beef patties have increased oxidation compared with high fat ground beef patties
Meat oxidation is caused by several factors including light source, oxygen incorporation during grinding, and degree of fat saturation. The objective of this study was to determine the impact of fat percentage on color and lipid oxidation in ground beef. Subcutaneous fat was removed from top rounds (n = 20) which were ground to produce patties (113.4 g) with either 5 or 25% fat. No additional fat was added to patties containing 5% fat. Subcutaneous fat from each top round was added back to achieve 25% fat content. Patties were packaged in Styrofoam trays with oxygen permeable overwrap and then assigned into deli cases (5ºC) with one of three lighting conditions: low UV fluorescent, Light Emitting Diode (LED), or no light (negative control). Patties were removed from storage on days 1, 3, 5, and 7 for evaluation of objective color measurements L*, a* and b* and lipid oxidation determination by thiobarbituric acid reactive substances (TBAR). Myoglobin states were calculated using selected wavelengths. Means were separated using GLIMMIX on SAS. Patties with 5% fat had greater a* values (P < 0.05) than 25% for storage days 1, 3, and 7; the exception was day 5 where there was no difference (P > 0.05). Metmyoglobin (MMb) percentage increased by storage day for both 5 and 25% fat with a difference (P < 0.05) on day 7 of storage where patties with 25% fat had a greater percentage (45.28) MMb than patties with 5% fat (44.14). Conversely, oxymyoglobin (MbO2) percentage decreased by storage day for both 5 and 25% fat with a difference (P < 0.05) on day 7 of storage where 5% fat patties had a greater MbO2 percentage (53.71) than patties with 25% fat (52.43). TBAR values increased by day for each fat percentage (P< 0.0001). After storage day 1 (P > 0.05), means were consistently lower (P < 0.05) on storage day 3, 5, and 7 for patties with 25% fat. Data from this study confirmed the phospholipid membrane layer plays a larger role in lipid oxidation than additional added subcutaneous fat in ground beef.
Keywords:
Ground beef, oxidation, myoglobin, fat percentage