EFFECTS OF FAT TRIM ON THE COMPOSITION OF BEEF RETAIL CUTS – 2. FAT AND MOISTURE CONTENT OF THE SEPARABLE LEAN

Thirty beef carcass sides varying in USDA quality and yield grade were fabricated into various steaks and roasts. The retail cuts were assigned serially to the following treatments: (A) raw, trimmed to 0.6 cm external fat; (B) trimmed to 0.6 cm external fat, cooked; (C) trimmed to 0.0 cm external fat, cooked. The 0.0 cm and 0.6 cm, cooked treatments were prepared by appropriate cookery methods, and the separable lean and separable fat were analyzed for chemical fat and moisture content. Regression analyses were used to predict values for the percentage chemical fat and moisture content at each treatment as influenced by marbling and USDA yield grade. Retail cuts that were braised had the lowest (P < 0.05) predicted moisture content of the separable lean, while roasted cuts had the highest (P< 0.05) predicted percentage moisture content of the lean. Trimming retail cuts to 0.0 cm external fat before cooking decreased the predicted percentage chemical fat of the lean as compared to retail cuts trimmed to 0.6 cm before cooking.     

EFFECTS OF FAT TRIM ON THE COMPOSITION OF BEEF RETAIL CUTS – 3. COOKING YIELDS AND FAT RETENTION OF THE SEPARABLE LEAN

Thirty beef carcass sides varying in USDA quality and yield grade were fabricated into various steaks and roasts. The retail cuts were assigned serially to the following treatments: (A) raw, trimmed to 0.6 cm external fat; (b) trimmed to 0.6 cm external fat, cooked; (C) trimmed to 0.0 cm external fat, cooked. The separable lean was analyzed for chemical fat. Regression analyses were used to predict percentage cooking yields and fat retention of the separable lean. Generally, cooking yield was not influenced by USDA grade, but retail cuts cooked with 0.6 cm external fat usually had numerically higher predicted values for cooking yield than cuts trimmed to 0.0 cm before cooking. Braising of thin (< 2.5 cm thick), single-muscle retail cuts decreased the predicted percentage of chemical fat retention of the separable lean. Trimming of retail cuts to 0.0 cm external fat before cooking decreased (compared to the 0.6 cm cuts) the predicted percentage of chemical fat retention of the separable lean as compared to cuts that were trimmed to 0.6 cm.     

DETERMINATION OF THE TOTAL LIPID CONTENT OF PORK RETAIL CUTS AT TWO EXTERNAL FAT TRIM LEVELS

Currently, retailers are required to conduct semi-annual or annual analyses of their labeled products under the USDA's Nutritional Labeling Verification procedures. The following study analyzed pork retail cuts that were trimmed to 0.0 cm or 0.64 cm external fat remaining. Lipid content was analyzed to determine the cuts that met "lean" (<10% total fat) and "extra-lean" (<5% total fat) specifications. The tenderloin, inside ham steak, and inside ham roast trimmed to 0.0 cm external fat remaining met the requirements for "extra-lean" labeling. The loin chop, loin roast, tip steak and tip roast trimmed to 0.0 cm external fat remaining, and the inside ham steak and inside ham roast trimmed to 0.64 cm external fat remaining, met the specifications for "lean" labeling.     

EFFECTS OF SOLUTION ENHANCEMENT ON PALATABILITY AND SHELF-LIFE CHARACTERISTICS OF LAMB RETAIL CUTS

The low demand for lamb in the U.S.A. requires the sheep industry to focus on the development of a means to simultaneously protect fresh lamb consumption from deteriorating and entice new consumer purchases based on palatability characteristics. Thus, the shelf-life and palatability attributes of lamb enhanced with salt, phosphate and rosemary were compared with traditional, fresh, nonenhanced lamb cuts. Wholesale loins and legs (n  =  30/subprimal) were either injected to 112.5% of raw weight with the enhancement treatment (ENH) or not (Ctrl), and both ENH and Ctrl cuts were vacuum-packaged and stored 24 h before fabrication into 2.54-cm-thick chops/steaks. While color scores decreased (P  <  0.05) for both loin chops and leg steaks over the 7-day display period, sensory panelists preferred (P  <  0.05) ENH lamb over Ctrl chops and steaks. Results indicate that enhancement can improve the palatability attributes of lamb without detrimental effects on product shelf life.

PRACTICAL APPLICATIONS

Information presented in the current experiment can be used as a tool to define the sensory taste and color quality characteristics of solution-enhanced lamb retail cuts. More specifically, this information could be used to support future studies in the areas of color stability/packaging applications and a means to identify a threshold for solution enhancement of lamb muscles. With an industry that relies on the identification of new cuts for the retail market, and consumers placing tremendous emphasis on muscle color at the time of purchase, a thorough understanding of color stability for solution-enhanced lamb is necessary. Lastly, this information can be used to further enhance the potential marketability of such muscles from the lamb carcass that tend to receive severe discounts as a result of a lack in consumer preference for lamb products in the retail setting.     

ENHANCEMENT EFFECTS ON SENSORY AND RETAIL DISPLAY CHARACTERISTICS OF BEEF ROUNDS

Beef round roasts were injected (to 110% of original weight) to result in 0.4% sodium chloride and 0.4% phosphate on a finished weight basis. Steaks from enhanced roasts were more (P<0.05) juicy, tender and salty than those from control roasts. However, enhancement had a detrimental effect on the color of the steaks during retail display. After two days in display, enhanced steaks had lower visual color scores indicating darkening and discoloration. At 4 days, a* and b* values were lower for enhanced steaks indicating that they were less red and yellow than controls. Aerobic plate counts suggested that enhanced steaks were more susceptible to microbial growth during retail display. Although enhancement positively affected sensory characteristics, the negative effect of a shortened shelf-life was apparent.     

QUALITY ATTRIBUTES OF GROUND BEEF ON THE RETAIL MARKET

Each of three ground beef products, varying in price (based on lipid content) were purchased from each of three retail stores. Patties of each product were modified broiled at 177°C for 35 min. Products containing 10–20% lipid had less cooking loss than those containing 25–30% lipid, but lower-lipid, higher-priced beef cost more per 100g of cooked meat than higher-lipid, lower-priced beef. Percentage ether extract decreased after broiling raw ground beef containing 20–30% lipid, and increased slightly after broiling raw ground beef containing less than 12% lipid. Over-all acceptability was similar for all three products, but the leanest, highest-priced product rated less juicy, more mealy and lower in flavor than higher-lipid, lower-priced products.     

EFFECTS OF END-POINT TEMPERATURE AND FAT LEVEL ON THE RESIDUAL CHOLESTEROL IN GROUND BEEF PATTIES1

Patties of lean ground beef with 2% fat (L2PF) and 6% fat (L6PF) were used to study the fat and cholesterol composition of raw and cooked ground beef and to determine how the end-point cooking temperature affects the amount of fat and cholesterol in a lean ground beef patty as it would be eaten by the consumer. The two patty types were obtained from the longissimus muscle of steers with marbling scores associated with “Standard” to “Select” and “Select” to “Choice” U.S. carcass grades of beef, respectively. All steers were fed a diet of roughage and concentrates to ensure fat deposition over the 12th and 13th ribs; longissimus muscles between the 7th and 10th ribs were removed, trimmed of all external fat, ground and formed into three 130-g patties. One patty was fried to an internal temperature of 60C, another to 71C and the third was uncooked. After frying, the patties were measured for drip loss, moisture and total fat. The fat extract was used for cholesterol analysis. The cooked L2PF sample had significantly less fat than the cooked L6PF samples, but there was no difference between the L2PF and L6PF in cholesterol. End-point temperature had no effect on the fat and cholesterol contents for either L2PF or L6PF samples, but the higher end-point temperature resulted in a significant loss of moisture.     

NATIONAL CONSUMER RETAIL BEEF STUDY: INTERACTION OF TRIM LEVEL, PRICE AND GRADE ON CONSUMER ACCEPTANCE OF BEEF STEAKS AND ROASTS

Consumers in San Francisco, California and Philadelphia, Pennsylvania, USA were asked to purchase, in simulated retail markets, beef retail cuts of different grades, Choice versus Select (equivalent to Good), or of different trim levels, Regular Trim (no more than 13 mm of external fat; Philadelphia only), Extra Trim (no more than 8 mm of external fat) or Super Trim (no external fat), all priced at Parity or Premium (Parity plus 10%) prices. Consumers in Philadelphia purchased significantly more Extra Trim and Super Trim steaks and roasts than Regular Trim. At the time of purchase, consumers in both cities could not detect the visual differences in Choice versus Select, but upon eating them found that Choice cuts were better tasting, but also fatter, and that Select cuts were leaner, but had problems with taste and texture. Both Choice and Select were rated high for consumer acceptance, but for different reasons, taste for Choice, leanness for Select.     

FACTORS AFFECTING THE HARDNESS OF FAT ON SIDES OF CHILLED BEEF

The influence of some factors on the hardness of subcutaneous fat on sides of chilled beef as measured by the average force resisting movement of a cutting pin (Ff) was investigated. Values of Ff determined at a fat temperature of 10°C on grass-fed animals denied water 24 h preslaughter were not significantly influenced by moisture content (5-11%) or fat depth (2-27 mm). There was a quadratic relationship (P<0.001) between the age of animals at slaughter (31-141 months) and Ff, and a linear one (P<0.001) between saturated fatty acid content (35-50%) and Ff. Values of Ffat a fat temperature of 5°C were not significantly related to moisture content (1-22%) but there was a linear relationship (P<0.01) with fat depth (5-13 mm). This had a common slope for the three feeding patterns: (1) grass-fed animals denied water 24 h preslaughter; (2) grass-fed animals given access to water 24 h preslaughter, and; (3) lot-fed animals given access to water 24 h preslaughter.     

DIETARY EFFECTS ON BEEF COMPOSITION. 4. Processing and Palatability Attributes

SUMMARY– The influence of dietary regimen of 104 half-sib Angus steers allotted to 1 of 13 combinations of hay, corn silage and corn concentrate, and of slaughter weights of 284 vs. 340 kg and 409 vs. 454 kg (live weight) on processing qualities and palatability of beef was studied. Measurements included postmortem glycolytic activity, water- and fat-binding capacity, textural properties, cooking losses, flavor and juiciness of selected muscles. Results showed that feeding regimens had a greater effect than did slaughter weight on qualities studied. Corn silage in the early dietary regimen of cattle weighing 284 and 340 kg resulted in significantly lower pH values (5 and 45 min post-mortem), higher amounts of glycogen at slaughter and greater water- and fat-binding capacity as compared to hay. Similar effects of early diet were noted for 5- and 45-min pH and water-binding capacity in cattle fed to heavier weights (409 and 454 kg); however, in these animals the early-hay diet resulted in greater muscle glycogen deposition than the early-silage diet. Steaks from animals fed corn silage in the early period were determined to be more tender by both shear values and panel scores and were more juicy and flavorful than those from hay-fed animals. These differences in palatability due to early diet were still evident after the cattle had been fed to heavier (409 and 454 kg) weights. When steers weighing 409 and 454 kg were grouped together, the effects of feeding regimen during the intermediate period were considerably less pronounced than those of the early feeding period.     

AN INSTRUMENT FOR THE MEASUREMENT OF THE HARDNESS OF FAT ON SIDES OF CHILLED BEEF

An instrument has been developed to measure the hardness of fat on sides of chilled beef. A 0.97 mm diameter cutting pin, 3.76 mm long, is inserted perpendicular to the subcutaneous fat and moved through the fat a fixed distance in a direction parallel to its surface by a pretensioned spring. The time for the pin to travel this distance is measured electronically. Times are recorded for the pin to travel through both air and fat and the average force to cut through the fat is then calculated from these readings. There was a linear relationship between the average force resisting the pin travel and the subjective ratings of fat hardness by five experienced boning room personnel. The instrument offers a simple, rapid and portable method of measuring fat hardness in abattoirs.     

EFFECTS OF DIFFERENT AGING PROCEDURES ON THE PALATABILITY OF BEEF

Ten pairs of beef strip loins were obtained 48 h postmortem from ten good grade beef carcasses. Three steaks (2.5 cm thick) were cut from the loin end of each strip loin and the remaining portion retained as the subprimal. Steaks and subprimals were aged for 7 days at 2°C in the following treatments: polyvinyl chloride overwrapped steaks (PVC-ST), vacuum packaged steaks (VP-ST), vacuum packaged subprimals (VP-SP), and subprimals held in air (Air-SP). After aging of the subprimal, 3 additional steaks were cut for evaluation. The steaks from all treatments were evaluated for palatability and chemical characteristics. Palatability characteristics did not differ significantly (P > 0.05) between treatments with the exception of the off-flavor intensity of PVC-ST which was higher (P < 0.05) than other treatments. Warner-Bratzler shear values were similar for all treatments. No significant differences (P > 0.05) were observed between treatments for percent moisture, percent lipid, pH or TBA number. The results of this study indicate that aging method (air or vacuum) or type of cut (steaks or subprimals) had little effect on the palatability attributes or chemical characteristics of the beef strip loins.     

EFFECTS OF FAT LEVEL AND COOKING METHODS ON PHYSICAL AND SENSORY CHARACTERISTICS OF RESTRUCTURED BEEF STEAKS

Trimmed top rounds from 9 Angus steers were flaked and formed into restructured steaks containing 15, 20, or 25% fat. The steaks were cooked in a microwave oven (MW) on a preheated browning dish or broiled in a conventional oven (CO). Microwave cooking required less time and energy. Decreased time and energy for cooking also related to increased fat levels. Cooking losses and penetration hardness values were greater for the MW steaks. Cooking losses increased and penetration hardness values decreased with increasing fat level. MW steaks appeared more well-done and were harder, less moist, and more resistant to chewing. As fat level increased softness and moistness scores also increased. Consumer panelists found all steaks to be equally acceptable, suggesting the potential for the development of portion- and fat-controlled restructured steaks for microwave cooking.     

EFFECTS OF SOY PROTEIN AND FREEZING TREATMENTS ON COOKING LOSS AND COMPOSITION OF BEEF PATTIES

All-beef and soy-extended patties were frozen to −18°C in either 24, 48, 72 or 96h and stored at −23, −18 or −7°C for 6, 9, 12, 18 or 24 months. The addition of soy resulted in a substantial reduction in cooking loss for patties cooked from the frozen state with a greater retention of moisture in cooked patties. Freezing reduced cooking loss for soy-extended patties, but increased cooking loss for all-beef patties. Faster freezing (-18°C in 24 h vs. −18°C in 96 h) reduced cooking loss and produced higher moisture values in all-beef patties. Patties stored at –7°C lost more moisture during cooking. Increased frozen storage time had a minimal effect on cooking losses, moisture and fat levels. Where it is essential for frozen patties to sustain minimal cooking losses with maximal moisture in cooked patties, the inclusion of soy protein concentrate, faster freezing, and storage at –18°C or colder are suggested.