Electrical Stimulation and Hot Boning: Cooking Losses, Sensory Properties, and Microbial Counts of Ground Beef

Six batches of ground beef, approximately 10, 15, or 20% fat, were fabricated from flanks (lean and fat trim) of electrically stimulated-hot boned (ESHB) or conventionally chilled (CC) beef sides. Patties (2.5 × 7.6 × 8.2 cm) from each batch were modified broiled for 35 min at 177°C. Generally, ESHB and CC products were comparable in cooking and sensory properties and in microbial counts of raw products. ESHB products had slightly higher cooking losses, more intense beef flavor, and were slightly juicier than CC products. Small differences between ESHB and CC products more often were attributable to fat content than to processing treatment (ESHB or CC).     

Effects of Electrical Stimulation and Hot-Boning on Physical Changes, Cooking Time and Losses, and Tenderness of Beet Roasts

Beef semimembranosus and semitendinosus muscles were removed prerigor (1 hr postmortem) and postrigor (7 days postmortem) after one-half of the left and right sides were electrically stimulated. The influence of electrical stimulation and hot-boning upon physical changes; cooking losses; shear force; taste panel evaluation; and time required to heat product to an internal temperature of 63°C was studied. There was no consistent influence of electrical stimulation upon physical changes of prerigor muscles or upon tenderness of pre– or postrigor roasts. Hot-boned and precooked roasts were less tender than cold-boned counterparts. Cooking yields were not altered by electrical stimulation. Prerigor roasts had 9% higher yields than postrigor roasts. Prerigor roasts from electrically stimulated sides required a longer time to cook to 63°C than roasts from the control sides. Hot-boning reduced the length of time of cooking (95 min/kg to 72 mm/kg of raw weight).     

Effects of Electrical Stimulation, Temperature of Boning and Storage Time on Bacterial Counts and Shelf-Life Characteristics of Beef Cuts

Strip loins and eye of rounds from 16 beef carcasses were used to study the effects of electrical stimulation (ES), no stimulation (NS), hot-boning (HB), and cold-boning (CB) on bacteriological and shelf-life evaluations. Following 7 days of vacuum-packaged storage, coliform counts were higher in the drip fluid from strip loins and lean surfaces of eye of rounds from ES compared to NS carcasses. A major advantage for HB in this study was the additional time required in retail display before the occurrence of lean surface discoloration. A previously identified benefit of lighter lean color with ES beef in carcass and primal cut form was also found in this study during display of retail cuts.     

Effect of Electrical Stimulation and Postmortem Boning Time on Sensory and Cookery Properties of Ground Beef

Ground beef was prepared from electrically stimulated and nonstimulated sides of 24 U.S. Utility grade carcasses that were boned 1, 3 or 24 hr postmortem. Postmortem electrical stimulation had no negative effects or, the physical, sensory or cooking properties of ground beef patties. Time of boning had significant effects on percent height change during cooking, total cooking loss, tenderness, and juiciness. As cooning time increased, the effects on the traits were negative.     

Effects of Electrical Stimulation, Boning Temperature, Formulation and Rate of Freezing on Sensory, Cooking, Chemical and Physical Properties of Ground Beef Patties

The effects of electrical stimulation vs nonstimulation, temperature of boning (hot vs cold), formulation (USDA Choice chucks with USDA Choice plates vs imported cow lean with USDA Choice plates) and rate of freezing (fast = -50°C vs slow = -20°C) were determined on sensory, cooking, chemical, and physical properties of ground beef patties. Sensory panel ratings for tenderness were highest in patties from formulations processed with either nonstimulated beef, hot-boned beef or Choice chucks. The substitution of imported cow lean for Choice chucks generally reduced cooking losses and changes in patty height during cooking. Fat losses during cooking were higher in patties made from electrically stimulated than nonstimulated beef, while moisture losses during cooking were greater for patties from nonstimulated than stimulated beef. Of the factors involved in this study, hot boning produced the most beneficial results in beef patties. Boneless chucks and plates from electrically stimualted Choice carcasses appear to be suitable raw materials for production of ground beef patties.     

Simulation of Cooking Cylindrical Beef Roasts

A mathematical model was developed to predict temperature and mass transfer of cylindrical beef roasts cooked in a forced-air-convection oven. The finite difference method was used to solve the simultaneous heat and mass transfer equations. Dynamic transport properties were estimated during the cooking process. The model was tested using beef semitendinosus muscles. No difference (P>0.05) occurred between the predicted and observed cooking times. Moisture loss generally was underestimated because of the lack of compensation for dripped moisture loss during cooking. Our model is suitable for predicting cooking times.     

Effects of Beef Carcass Electrical Stimulation and Hot Boning on Display Color of Unfrozen Vacuum Packaged Steaks

Ninety-six beef sides from 48 carcasses were used to determine effects of control (C, chilled 48 hr at 5°C), electrical stimulation (ES, 45 min postmortem, 400 volts for 2 min, pulsed), and hot boning (HB, 2 hr postmortem), and combination (ESHB) treatments on muscle color of longissimus (LD) and semimembranosus (SM), vacuum packaged steaks. HB muscles frequently were visually brighter purplish-red than other treatments. Compared to ESHB, ES LD was not different, but ES SM was duller purplish-red in color. Reflectance indicators of reduced myoglobin and metmyoglobin were essentially the same across treatments in both muscles. Vacuum packaged fresh beef steaks from all treatments were acceptable in color at 0, 3, 7, and 14 days of display. Vacuum packaging appears suitable for steaks from any of these carcass treatments but is especially useful for steaks from hot boned cuts.     

Effects of Electrical Stimulation and Hot Boning on Functional Characteristics of Preblended Beef Muscle in Model Systems

Thirty beef carcasses were used to determine the effects of electrical stimulation (ES) and hot boning on the emulsifying capacity (EC) and thermal emulsion stability (TES) of preblended Triceps brachii (TB) muscle (long head) from sides assigned to one of four treatments: (1) conventionally boned after chilling at 2–8°C until 48 hr postmortem (CB); (2) hot boned at 1 hr postmortem (HB); (3) ES during bleeding and conventionally boned at 48 hr postmortem (ESCB); and (4) ES during bleeding and hot boned at 1 hr postmortem (ESHB). HB preblended samples had greater EC and TES values than CB preblended samples in both nonstimulated (P < 0.05) and stimulated carcasses. When compared to nonstimulated sides, ES decreased (P < 0.05) these values in both ESHB and ESCB sides.     

Effects of Beef Carcass Electrical Stimulation and Hot Boning on Muscle Display Color of Polyvinylchloride Packaged Steaks

Ninety-six beef sides from 48 carcasses were used to determine the effects of control (C, chilled 48 hr at 5°C), electrical stimulation (ES, 45 min postmortem, 400 volts for 2 min, pulsed), hot boning (HB, 2 hr postmortem), and combination (ESHB) treatments on muscle color of longissimus (LD) and semimembranosus (SM) steaks packaged in polyvinylchloride film. LD from HB was mostly visually darker, had less oxymyoglobin, and more metmyoglobin than other treatments as was the SM, but SM had fewer differences between HB and ESHB. ES and ESHB muscles were visually similar, suggesting ES minimized the darkening effect of HB. Regardless of treatment, muscle color was acceptable at 0, 1, 3 and 5 days of display.     

Effects of Electrical Stimulation and Hot Boning on Color Stability of Aerobic and Vacuum Packaged Restructured Beef Steaks

Color stability of restructured beef steaks processed from beef boned 4 hr postmortem (HB) and 96 hr postmortem (CB) was determined using a Hunter color difference meter and a semi-trained color evaluation panel. Steaks were formulated using ground tenderized (2.5 cm) restructurable meat (75% of formulation), salted preblended meat (3% NaCl + 0.267% BHA, 25% of formulation) and enough ground fat to form steaks of 10% fat. Steaks were aerobically wrapped and vacuum packaged. Hunter L, a, b, a/b values and color panel scores during a 7-day retail display revealed that HB steaks had superior color stability. This was attributed to the ability of NaCl to inhibit glycolysis in the HB preblended meat and to act as a prooxidant of myoglobin in the CB preblended meat.     

Effects of Beef Carcass Electrical Stimulation, Hot Boning, and Aging on Unfrozen and Frozen Longissimus dorsi and Semimembranosus Steaks

Ninety-six sides from 48 beef carcasses were used to study the effects of hot boning (HB), electrical stimulation (ES), a combination of electrical stimulation and hot boning (ESHB), and steak storage treatments on longissimus dorsi and semimembranosus steaks. Steak storage treatments were: unfrozen (aged until 6 days postmortem) or frozen (ES, HB, and ESHB frozen 24 hr and controls 48 hr postmortem). ES did not improve taste panel ratings or consistently lower shear force values when compared with control counterparts. Storing carcasses at 5°C for the first 24 hr postmortem and freezing ES steaks at 24 hr versus 48 hr postmortem for the control possibly diluted the effectiveness of ES. However, ES did eliminate any toughening due to HB.     

Effects of Electrical Stimulation, Hot Boning and Chilling on Bull Semimembranosus Muscle

Taste panel, Warner-Bratzler shear force (WBS) and cooking loss characteristics of semimembranosus (SM) muscles from thirty electrically stimulated and hot-boned (ESHB) or control young bull sides were evaluated. At 2 hr postmortem, muscles were excised from electrically stimulated sides and chilled in a tray or in a cardboard box. All control sides and ESHB muscles were chilled at 5–7°C until 24 hr postmortem; then 2–4°C for 24 hr. At 48 hr postmortem, steaks were cut, vacuum packaged and aged (2–4°C) for 4 days. Beef flavor was more intense for control steaks than for steaks from either ESHB chilling treatment. No other differences were noted.     

Glucose and Internal Cooking Temperature Effects on Low Fat, Pre- and Post-Rigor, Restructured Beef Roasts

Muscles were excised pre-rigor (hot-boned, HB) or post-rigor (conventionally boned, CB), chunked, and were subjected to four ingredient treatments: (SPE) 2% NaCl, 0.5% NaCl, 0.5% phosphate, 2% glucose (SP 2% NaCl, 0.5% phosphate (SG) 2% NaCl, 2% glucose and (PG) 0.5% phosphate, 2% glucose to produce low fat, restructured, beef roasts, which were cooked to an internal temperature of 63 or 93°C. Addition of glucose to a salt and phosphate (LEM-O-FOS¹) ingredient treatment as well as cooking to 93°C helped maintain low warmed-over flavor (WOF) scores and kept thiobarbituric acid values below threshold (< 1.0) while maintaining desirable consumer acceptability scores.     

Textural and Chemical Characteristics of Recombined Precooked Beef Chuck Roasts as Influenced by Boning Time and Salt Level

The effects of hot-boning (HB) and salt level (SL) (0, 0.5, 1.0%) on recombined precooked roasts from three beef chuck recombined whole muscles were investigated using a system that employed electrical stimulation, blade tenderization, vacuum massage and the addition of phosphate. SL and muscle type (MT) significantly affected proximate composition (protein, fat and moisture). Maximum yields were obtained with hot-boned treatments at the highest salt level. Instron measurements were affected by MT, HB and SL. Results of this study indicate that binding of large meat pieces together to form low calorie recombined, precooked roasts can be achieved.     

Effect of Cooking Method on the Texture of Epimysial Tissue and Rancidity in Beef Roasts

Twelve top round roasts from two Utility-grade cows were randomized and cooked by microwave, convection or conventional methods after epimysial tissue had been inserted into each roast. The freshly cooked and stored roasts were evaluated for rancidity using three TBA methods, and textural determinations were made on epimysial tissue. TBA numbers increased from day 0 through day 11. Shear values for epimysial tissue from 8-year old animals cooked by microwave tended to be lower than those for tissues cooked by convection or conventional methods, but no differences in cooking method were observed for tissue from l-year old animals.     

Electrical Stimulation and Hot Boning: Color Stability of Ground Beef in a Model System

Lean and fat trim of flanks from electrically stimulated, hot boned (ESHB) or conventionally chilled (CC) beef sides were used to fabricate six batches of ground beef with three levels of fat (ESHB 10, 15, or 20% fat; CC 10, 15, or 20% fat). Raw samples were evaluated for color stability in a model system, pH, and microbial counts. After 4 hr exposure to radiant energy, percentage reflectance for 630 – 580 nm, HunterLab spectrophotometer a values, HunterLab a/b ratios, and visual color scores indicated the ESHB samples were more (P < 0.05) sensitive to metmyoglobin formation, had slightly lower pH, and had lower microbial counts than did CC samples.     

Hot-Fat Trimming and Electrical Stimulation Effects on Beef Quality

We evaluated the effects of hot-fat trimming, low-voltage electrical stimulation (ES) and storage time (3, 7 or 14 days) on quality of beef longissimus dorsi, psoas major, biceps femoris and supraspinatus muscles. Prior to chilling, beef carcasses (n = 32) were either subjected to ES or not stimulated before alternating sides were hot-fat trimmed. Temperature decline, pH, sarcomere length and USDA yield and quality grades were obtained on each carcass side. Muscles were removed from each side and evaluated for quality factors related to storage life and sensory analysis. Generally, no adverse effects of hot-fat trimming, with or without ES, or increased storage time, were observed. Results indicate that hot-fat trimming may be practiced at the industry level without affecting overall quality.     

Reducing Postmortem Aging Time of Beef with Electrical Stimulation

Two studies (Study 1 = 23 forage-fed steers; Study 2 = 20 grain-fed steers and heifers) were conducted to determine relationships of electrical stimulation (ES) and/or postmortem aging (PA) to tenderness of beef. For Study 1, steaks from ES sides had lower (P < 0.05) Warner-Bratzler shear (WBS) values than steaks from not-ES sides for each PA period. In addition, the percentage reduction in WBS values was greater for the steaks from the ES-Day 2 group (–29.5%) than for steaks from even the longest PA period (14 days) from the not-ES group (–25.8%). For Study 2, during the fist three PA periods (1, 2 and 5 days), ES resulted in more desirable (P < 0.05) flavor ratings (Day l), higher (P < 0.05) tenderness ratings and lower (P < 0.05) WBS values (Day 1, 2, 5) and more desirable (P < 0.05) overall palatability ratings (Day 1, 2). During the last three PA periods (8, 11 and 14 days), ES resulted in higher (P < 0.05) tenderness ratings (Day 8), lower (P < 0.05) juiciness ratings (Day 11, 14) and lower (P < 0.05) WBS values (Day 8). Based on these results, ES had the greatest impact on beef palatability if the period of aging was 8 days or less; with additional aging time, ES effects on palatability were negated. When each treatment (ES, not-ES) was divided into two groups based on median tenderness ratings for the not-ES group, ES had the greatest impact on those carcasses in the “tough” group while ES had little impact on those carcasses in the “tender” group. ES will accelerate the postmortem aging of beef but the aging time reduction and extent of ultimate tenderization appears to be affected by the inherent tenderness of the beef.     

Oxidative Stability of Restructured Beef Roasts As Affected by Cooking Temperature

Restructured beef roasts (2.5 kg) were cooked in a water bath at 70, 85, and l00°C to an internal temperature of 65°C, then stored at 4°C for 0 and 3 days. Storage increased (p ≤ 0.05) oxidation; after 3 days storage, roasts cooked at higher temperatures had higher (p ≤ 0.05) TBA values. Sensory panelists detected more (p ≤ 0.05) warmedover flavor (WOF) due to storage; however, after 3 days there was less (p ≤ 0.05) WOF in samples cooked at 70°C than in samples cooked at 85 or 100°C. Interaction (p ≤ 0.05) between cooking temperature and storage indicated oxidation proceeded more rapidly with higher cooking temperatures during refrigerated storage. Cook yield decreased as cooking temperature increased and expressible moisture was lower (p ≤ 0.05) at 100°C than at 70°C.     

Influence of Storage Times After Cooking on Warner-Bratzler Shear Values of Beef Roasts

Fifty longissimus and 49 biceps femoris roasts were cut from five Choice-grade steer carcasses and used to evaluate differences in Warner-Bratzler shear values at different times after cooking. Five longissimus roasts and four or five biceps femoris roasts were cut from both sides of each carcass. Roasts were cooked to an internal temperature of 71°C then wrapped in aluminum foil and chilled (4°C) for 2, 24, 48, 72 or 168 hr prior to shear analysis. No differences in shear values by carcass side or by length of chill after cooking existed for biceps femoris roasts. Longissimus roasts were more tender when taken from the left side and when chilled for 2 hr vs longer chill periods. Roasts chilled for 24, 48, 72 or 168 hr had similar shear values. Cores taken from the medial portion of the longissimus roasts had lower shear values than cores taken from the central or lateral portions. Longissimus roasts were always more tender than roasts from the biceps femoris muscle and they were less variable in tenderness.