Background 

To help fulfill goals outlined in the Beef Industry Long Range Plan (2001) to increase consumer demand for beef, the National Cattlemen’s Beef Association (NCBA), a contractor to the Beef Checkoff, coordinated a research project that profiled the physical, chemical and organoleptic properties of individual beef muscles. That research is the most comprehensive of its kind to date and was designed to explore new ways of fabricating beef carcasses that might lead to increased value, especially for the round and the chuck.   

The study identified several muscles that possessed sufficient tenderness and flavor attributes to be marketed as individual cuts, but there are still several individual muscles that remain underutilized in retail and foodservice markets. To continue to build on the initial success of the checkoff-funded muscle profiling study in introducing new cuts such as the Flat Iron to the marketplace, it is important to review other research that evaluated the attributes of individual muscles. To accomplish this task Colorado State University researchers compiled a literature review that represents a comprehensive summary of all muscle-specific research, including NCBA’s muscle profiling work, for both fed and non-fed cattle. 

Methodology

Fed Cattle More than one hundred peer-reviewed research studies were included in this compilation. Characterizations of individual muscles, based on the research available, included the following:

The longissimus dorsi was used as a reference point to compare across the various studies. From those comparisons, tenderness and juiciness indexes were developed to aid in identifying muscles that have been found to perform similarly to the longissimus dorsi.   

Non-fed Cattle 
A similar compilation of research associated with older animals, or non-fed cattle was also done. However, the literature is much more limited, so only the following muscles were described:   

• Longissimus dorsi 
• Biceps femoris 
• Gluteus medius 
• Psoas major 
• Rectus femoris 
• Semimembranosus 
• Semitendinosus

Findings 

Fed Cattle In all of the literature reviewed, researchers conducted all, or some of the following evaluations, to accurately assess individual muscles: 

• Warner-Bratzler Shear Force (WBSF) 
  
• Sensory panel evaluations, which typically assess palatability attributes such as tenderness, juiciness and flavor. Connective tissue amount was sometimes part of a panel evaluation. 
  
• Chemical and physical attributes 
  
• Consumer evaluation 
  
• Optimum aging for individual muscles, however most of this work has only focused on the longissimus dorsi 

Non-fed Cattle 

Almost 20 percent of the cattle slaughtered under federal inspection are cows and bulls. As a result, beef from non-fed market animals represents a substantial portion of U.S. beef production. The Cow Muscle Profiling study conducted by the National Cattlemen's Beef Association, a Contrator to the Beef Checkoff, in 2002 represents the most complete collection of muscle profiling research for older animals. The project profiled 21 individual muscles from beef and dairy cows, so that processors had more information to better utilize product from these animals. Beyond that study, there is limited information available about muscles from mature carcasses.   

Most of the present knowledge pertaining to the age-related effects on beef and the palatability improvement processes applied to beef from mature cattle is based on studies that focused on the longissimus dorsi. Sensory panel scores for the juiciness and flavor of the longissimus dorsi vary widely, depending on the study and the range in carcass maturity being studied. 

There are several limitations that do not allow for broad-based interpretations of the available research on individual muscles from non-fed cattle:   

1. Available literature focuses on the longissimus dorsi (from the loin or rib) and minimal data is available for muscles from the chuck and round   
2. The majority of the research has specified the use of muscles based on USDA quality grade (i.e. U.S. Commercial or Utility), which encompasses three maturity scores (C, D, or E). USDA quality grades, which are based on marbling and maturity, are almost never used by packers who process mature non-fed cattle. Most packers of market cows segregate carcasses into marketing groups based on evaluations of marbling, maturity, color of fat and lean, degree of fatness, and/or muscle thickness. 

Implications