TEXTURAL CHANGES IN GROUND BEEF PATTIES DURING COOKING

Ground beef patties were cooked in a convection oven or on a flat-top electric grill using a 3 x 5 factorial arrangement of treatments in a split plot design (rep = 3). Each cook method was compared at three temperatures (121, 148 and 177(DEGREES)C). Five internal patty temperatures (10, 25, 40, 55 and 70(DEGREES)C) were evaluated. Meat blocks were adjusted to 18% fat prior to final grinding and patty formation. Data were collected on cook yield, dimension alterations, and color score. Laboratory analyses consisted of proximate composition, pH, water-holding capacity, Instron textural measurements, protein solubility and hydroxyproline content. As cooking time and internal patty temperature increased, patty yield significantly (P \u3c 0.01) decreased for both grill and oven cooked patties. Higher cooking temperatures result in greater (P \u3c 0.01) yields for both methods of cooking. Diameter was less (P \u3c 0.05) for patties grilled at 177(DEGREES)C than at lower grill temperatures and greater (P \u3c 0.05) for oven cooked patties at 177(DEGREES)C than at lower oven temperatures. Protein solubility decreased (P \u3c 0.01) as internal patty temperature increased. Myofibrillar proteins heated at low temperatures, were less soluble (P \u3c 0.05) at 55(DEGREES)C than at high temperatures. Patties cooked at 121(DEGREES)C had less (P \u3c 0.01) expressible moisture than patties cooked at higher temperatures. Oven cooked patties exhibited an increase (P \u3c 0.01) in expressible moisture. Low oven temperatures (121(DEGREES)C) yielded greater (P \u3c 0.05) expressible moisture than higher oven temperatures. Oven cooked patties at low temperature (121(DEGREES)C) exhibited less springiness than at higher temperatures. Cohesiveness in grilled and oven cooked patties increased (P \u3c 0.05) as internal temperature increased except for patties grilled at 177(DEGREES)C where no change was shown. No difference in Kramer peak height or compression hardness were observed. Differences exist in the time-temperature relationship when different methods of cooking are used. This affects the extent of protein denaturation and the subsequent effects on water-holding capacity, yield and texture. Patties are more tender and juicy when cooked at high oven temperatures while tests on grilled patties indicate a more desirable product at lower cooking temperatures