Designing Next Generation of Grills for Cooking Hamburger and Meat Patties
カリフォルニア大学 生物農業工学部 食品工学研究室(米国)
R. Paul Singh and Gail Bornhorst
Understanding heat and mass transfer during cooking of hamburger patties in a grill is essential to ensure food safety and quality. This study was focused on determining the role of design and operating conditions of a cooking grill on selected measurable indices describing quality of hamburger patties. For a double-sided grill, commonly used in cooking hamburger patties, the influence of the separation between the upper and lower plates, called gap thickness, and the plate temperatures set during cooking were studied for their effects on textural quality of cooked hamburger patties.
A commercial, double-sided, clamshell grill (Taylor, Rockton, IL) was used with has two separate top heating plates covered with Teflon release sheets and one common bottom heating plate. Type “K” thermocouples were inserted by the grill manufacturer at 14 different positions in the top and bottom plates. The top and bottom plates were heated to set temperatures. Temperatures were monitored using a data acquisition system (21X Micrologger, Campbell Scientific, Edmonton, Canada). Experiments were conducted using four different gap thicknesses of 0.965, 1.003, 1.054, and 1.105 cm, and four plate temperatures 177, 191, 205, and 219 C, resulting in 16 treatments, which were randomized and replicated. A cooking cycle of 120 s was used for all experiments. The quality of the cooked hamburger patties was evaluated by measuring the cooking loss, and press juice. In addition, texture profile analysis was conducted using a Texture Analyzer (TA-XT2, Texture Technologies Corp. Scottsdale, NY) for 23-mm diameter cylindrical samples obtained from each patty. Each sample was compressed twice to 5 mm height using a 40 mm diameter aluminum cylinder probe at a speed of 5 mm/s. Hardness, cohesiveness, springiness, and chewiness (n=18 for each treatment) were determined using Texture Expert software (ver 1.22).
In general, cooking loss (24 to 36 %) and press juice values (8 to 25%) increased significantly (p<0.05) with increase in temperature or decrease in gap thickness. Similarly, hardness values (24 to 34 N), cohesiveness (0.76 to 0.83) and chewiness (107 to 152 Nmm) increased with increase in plate temperature or decrease in gap thickness.
With trials conducted to study heat transfer, temperature profiles measured during the cooking cycle can help to identify optimal locations where heating elements may be embedded in the grill plates during manufacturing.
The results of this study provide new information on the design features of double-sided grills that ensure improved and consistent quality of cooked hamburgers.