Beef Flavor Evaluation on Top Loin Steaks, Sirloin Steaks, Chuck Roasts, and 80/20 Ground Beef Over The Retail Case

ObjectivesConsumer acceptability in meat flavor is one of the driving factors of acceptability. Many studies have found factors that affect beef flavor, but little is known about variability of major beef cuts in the retail meat case where meat is displayed, and customers can choose from.Materials and MethodsFour beef cuts (chuck roast, top sirloin steaks, top loin steaks, and 80/20 ground beef) were obtained from retail stores in Miami, Los Angeles, Portland, New York, and Denver within a 2-mo period. The study wanted a variety of samples that were from different production systems or contained certain claims that would be available to customers. The meat was shipped with dry ice and stored at –9°C. For evaluation steaks, roasts, and ground beef were thawed 24 h at 4°C. Prior to cooking, chuck roasts were cut 10.16 × 12.7cm from the center of the roast. Each ground beef sample was formulated into 3, approximately 150 g patties. Chuck roasts were placed in a roasting pan on a roasting rack and 2 cups of water. Beef steaks and ground beef patties were cooked on a stovetop grill and cooked to 71°C, steaks and patties were flipped when temperature reached 35°F. Chuck roasts were cut into 1.27cm cubes with no visible connective tissue, fat, or outside browning. Steaks were cut into 1.27cm cubes with no connective tissue or fat. Ground beef patties were cut into 6 wedges. Panelists were served either 2 wedges or 2 1.27 cm samples for evaluation. An expert trained descriptive flavor and texture sensory panel was conducted where panelists evaluated beef flavors and textures. Beef flavor and texture attributes were analyzed using SAS (version 9.4, SAS Institute, Inc., Cary, NC) and principal component (PCA) bi-plots were generated using XLSTAT (Addinsoft, Inc., Long Island City, NY) using P < 0.05.ResultsChuck roasts were associated with bloody/serumy flavor aromatics. Ground beef patties were clustered with fat-like, overall sweet, green hay, and buttery flavor aromatics. Top sirloin steaks samples were more highly associated with off flavors such as liver, cardboardy, and sour flavor aromatics. Top loin steaks were clustered with positive attributes such as umami, beef flavor identity, and brown, roasted flavor aromatics. For the PCA biplot, factor 1 accounted for 60% and factor 2 accounted for 28% of variation. Ground beef was higher (P < 0.0001) in brown, fat like, green hay, sour milk/sour dairy, flavor aromatics, and had more salty and sweet basic taste than the other cuts. Ground beef patties had the least amount (P < 0.0001) of bloody/serumy, metallic, and liver like flavor aromatics. Chuck roasts had the least (P < 0.0001) beef flavor id, brown, roasted flavor aromatics and salt and umami basic taste. Sirloin steaks had the lowest (P < 0.0001) fat like flavor aromatic and the highest levels (P < 0.0001) of burnt and cardboardy flavor aromatics and bitter and sour basic taste. Sirloin steaks and chuck roasts had more metallic and liver like (P < 0.0001) flavor aromatics than other cuts. Top loin steaks were intermediate in flavor attributes.ConclusionFlavor descriptive attributes of four beef cuts differed. Results indicated that chuck roasts and top sirloin steaks were associated with negative flavor attributes. Ground beef contained sweeter, fat like attributes with exceptions of green hay, while top loin steaks were associated with more positive beef flavor attributes.

The Influence of Mitochondria Enzyme Activity on Beef Tenderness

ObjectivesAmong all eating quality attributes, tenderness is often described as the most important factor dictating the overall acceptance of cooked beef, as well as, future decision to repeat purchase. While many intrinsic and extrinsic factors impact end-product tenderness, variation in tenderness is usually attributed to the extent of postmortem proteolysis occurring during meat aging. Evidence from the literature indicates that muscle fiber type composition is a major source of variation in the rate and extent of postmortem proteolysis. One of the major differences that distinguishes muscle fibers is the content of mitochondria. Typically, red muscle (slow-oxidative) is characterized by greater amounts of mitochondria than white muscle (fast-glycolytic). As part of the calcium buffering system, mitochondria sequester large quantities of calcium to maintain a constant cytosolic calcium level. We hypothesized that mitochondria may delay the activation of µ-calpain, the major protease responsible for postmortem proteolysis, through preventing the increase in cytosolic calcium concentration.Materials and MethodsTo test our hypothesis, beef longissimus thoracis muscle samples were collected at 30 min and 16 d postmortem. The 30 min samples were immediately snap frozen in liquid nitrogen and stored at – 80°C, while the 16 d samples were used to determine Warner-Bratzler shear force (WBSF) values. Based on WBSF values, the samples were allocated into less tender (average WBSF = 5.3 kg; n = 8) or more tender (average WBSF = 2.3 kg; n = 8) categories. Succinate dehydrogenase (SDH) abundance, citrate synthase (CS) activity, phosphofructokinase (PFK) activity, and glycogen phosphorylase (GP) activity were compared between the two categories using the 30 min samples. Collected data were analyzed using a Student’s t test and considered significant at P ≤ 0.05.ResultsOur results showed that SDH abundance and CS activity (mitochondrial biomarkers) were significantly greater (P = 0.01 and 0.003, respectively) in less tender samples when compared to more tender samples. On the other hand, PFK and GP activities (glycolytic biomarkers) were greater (P < 0.05) in the more tender than less tender steaks.ConclusionWhile not a cause and effect relationship, these data indicate that mitochondria content likely plays a role in development of beef tenderness.