Background

The high value of beef trimmings has motivated major beef packers to merchandise a larger proportion of the carcass as beef trimmings for grinding operations. Additionally, the success of premium hamburger chains has increased demand for specialty blends as well as increased utilization of whole muscle cuts as grindable items. Many restaurant chains and mail-order, online meat businesses advertise specialty ground beef blends of whole muscle cuts or sub-primals, including briskets, short ribs, and chuck clods among others. Additionally, these same businesses are marketing dry- and wet-aged ground beef from sub-primal sources. In all of these instances, ground beef and hamburgers sell for a price that rivals premium steaks from the same company. Although numerous restaurant chains are marketing gourmet burgers, their ground beef blends and formulations remain proprietary. Little published scientific research exists to back up these marketing claims.  

A better understanding of the factors influencing the performance of ground beef products as well as the development of industry standards that could be utilized to develop premium ground beef specifications for flavor and texture could greatly contribute the demand for ground beef products and the profitability of the beef industry. This research will assist in determining the validity of various production and premium ground beef marketing claims. The objectives of the current study were to evaluate the flavor effects of individual muscles as grind sources and dry-aging techniques. Objectives also included evaluating the effects of grinder plate size, blend time, patty-forming technique, and chub packaging verses fresh grinds on ground beef texture.  

Methodology

Four independent experiments were conducted to evaluate performance of ground beef from various sources and production techniques. Flavor and texture of 7 different beef products and the effects of dry-aging were evaluated and quantified by descriptive sensory analysis. Beef products evaluated included chuck shoulder clods (NAMP 114), chuck boneless short ribs (NAMP 130), whole briskets (NAMP 120), loin tenderloin tips (NAMP 1190C), loin top sirloin caps (NAMP 184D), round sirloin tip knuckles (NAMP 167), and 81/19 chuck sourced trimmings. Fresh (100% un-aged), 100% dry-aged, and 50% fresh/50% dry-aged trimmings were used to evaluate the effects of dry-aging on ground beef performance.  

Furthermore, the effects of grinder plate size, blend time, and patty-forming technique were evaluated and quantified by descriptive sensory analysis and objective instrument measurement. Additional treatments compared common grocery store practices of grinding bench trimmings versus re-grinding previously ground chubs.  

Trained panelists evaluated ground beef patties from each treatment for 10 different flavor notes, including beefy/brothy, browned/grilled, buttery/beef fat, bloody/metallic, gamey, earthy/mushroom, nutty/roasted nut, livery, sour/acidic, and bitter, as well as 7 different texture characteristics, including hardness, cohesiveness, tenderness, connective tissue, particle size, moisture content, and beef fat/oily mouthfeel. In addition, samples were analyzed to determine fatty acid composition of raw products and volatile compounds formed during cooking. 

Findings 

No single trimming source evaluated in this study outperformed patties comprised of 81/19 chuck sourced trimmings. Notably, briskets and sirloin caps were ranked comparably to 81/19 trimmings in the desirable flavor attributes of beefy/brothy, browned/grilled, and buttery/beef fat, whereas tenderloin tips were rated lowest in the same desirable flavors. Tenderloins were rated lowest in beefy/brothy, browned/grilled, and buttery/beef fat, as well as highest in sour/acidic off-flavors. Tenderloins were also the softest, least cohesive, and perceived to have the smallest particle size. Panelists did not detect many differences among other muscle source treatments.  

Dry-aged beef samples produced the most complex flavor profile with the highest panel ratings for earthy/mushroom and nutty/roasted nut flavors and had high scores for browned/grilled flavor. However, panelists also detected some incidence of sour/acidic and bitter off-flavors in dry-aged ground beef samples. Relationships between sensory flavor characteristics and fatty acid composition show opposite results of commonly cited literature, in that beef flavor notes such as browned/grilled, nutty/roasted nut, and earthy/mushroom were associated with increased proportions of C18:0 and decreased proportions of monounsaturated fatty acids including C14:1, C16:1, C17:1, C18:1C9. Aldehydes and ketones were present in increased concentrations in dry-aged samples and positively associated with browned/grilled, nutty/roasted nut, and earthy/mushroom flavors.  

Panelists detected significant differences between grind size effects as well as effects of patty-forming device. Ground beef patties fabricated with smaller sized grind plates were perceived softer, more tender, and had a smaller particle size. Objective texture measurements agreed, showing lower peak loads for patties produced with smaller sized grind plates. Detectible differences also existed in ground beef patties fabricated with different patty-forming techniques. Patties made with a Formax (Formax F6, equipped with the 2874-6 plate, Mokena, IL) were softer and more cohesive, while patties made with the vacuum stuffer (Model VF50, Handtmann, Germany) equipped with a portioning device were more crumbly but also ranked higher for moisture content and oily mouthfeel.  

The last comparison was between common grocery store practices of grinding bench trimmings versus re-grinding large chubs and packaging into smaller quantities. Ground beef patties resulting from the re-ground chubs were perceived to have a greater amount of connective tissue, a larger particle size, greater moisture content, and a greater beef fat/oily mouthfeel. Additionally, objective measures of texture showed greater peak loads for patties from re-ground chubs. 

Implications 

Results of this project can assist in developing premium ground beef specifications for flavor and texture.