RESUMO
Following storage at 32 degrees or 42 degrees +/- 1 degrees F. for zero (4 hr.), and one, two, four, seven, and nine days, beef loaves which had either been cooked; cooked and pasteurized; or cooked, frozen, and thawed prior to storage were compared with a freshly prepared, freshly cooked loaf. Loaves were initially cooked to an internal temperature of 165 degrees F. and reheated to the same temperature prior to testing. A freshly prepared loaf cooked immediately prior to evaluation statistically had a shorter heating time, less cooking losses, higher moisture content, lower thiobarbituric acid (TBA) scores, and higher taste panel scores for odor, juiciness, flavor, and appearance. In all quality-related properties evaluated, the reference loaf rated higher. Pasteurized loaves were not significantly different from refrigerated loaves. Frozen, thawed loaves had significantly different values for TBA scores for all taste panel evaluations; these differences were indicative of reduced quality. Taste panel scores decreased and TBA scores increased significantly over nine-day storage. The hypothesis that changes over time were linear was not rejected. The only significant difference noted for the two storage temperatures of 32 degrees and 42 degrees F. was for total heating time. Standard plate counts for aerobic bacteria were extremely low when samples were taken after storage and after reheating. Only two loaves sampled had counts per gram above 100. The absence of microbial growth pattern indicated that increases in TBA scores and decreases in odor and flavor scores were produced by autoxidation of lipids.
