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.     

Heating and Texture Profiles of Packaged Pasteurized Beef Loin Steaks from Precooked Roasts

Precooked beef loin steaks obtained from waterbath cooked roasts, were oasteurized usinge three different temoeratures (65° 85° and 100°C) and rimoved after reaching internal temperatures of 60°, 70° and 80°C. Temperatures of the steaks were monitored at three locations during heating and cooling. Steaks heated to internal temperatures close to the cooking water temperatures had the least differences in temperature between layers. Total cooking losses increased (P<0.05) as internal endpoint temperatures and pasteurization water temperature increased. Texture profiles of steaks cut from precooked roasts were similar to pasteurized steaks.     

Sensory and Chemical Characteristics of Fresh Pork Roasts Cooked to Different Endpoint Temperatures

Pork roasts cooked to various endpoint temperatures were evaluated by sensory and chemical analyses. Increased endpoint temperatures were associated with increased cooking losses; decreased juiciness, pink color, and metallic flavor; increased graininess, brown color, and pork flavor. Increased endpoint temperatures also led to a concentration of lipid, protein and certain fatty acids. Cholesterol levels were not significantly influenced by endpoint temperature. Lipid content was decreased by removal of external fat before cooking. To minimize pink color in some muscles and maximize other sensory characteristics and yield of cooked meat, at least 71.1°C and no more than 76.6°C is recommended as the endpoint temperature for fresh pork roasts.     

Differences Between Conventionally Cooked Top Round Roasts and Semimembranosus Muscle Strips Cooked in a Model System

Roasts cooked at 177°C by dry (OR) or moist (OFB) heat to 60°C were compared with muscle strips cooked in a model system to 60°C at a rate similar to oven raosting 1.4-kg roasts at 177°C. OFB roasts were less tender, less juicy, had less rare beef flavor, less red and yellow color, more total cooking loss, and shorter cooking time than did OR roasts. Strips had lower values for Instron measurements of hardness, chewiness, shear cohesiveness, and firmness than did OR or OFB roasts. Although strips were cooked in a moist atmosphere, they were more like OR roasts than like OFB roasts. Variance for a given measurement was similar between roasts and strips.     

LOW TEMPERATURE ROASTING OF THAWED OR FROZEN PORK LOINS

The effects of oven temperature (93, 121, 149, or 163°C) and state (thawed or frozen) on 64 loin roasts from 8 pigs were studied. Frozen roasts required 1.3 times longer to cook, were more juicy and acceptable, and contained more moisture than thawed roasts. Roasting at 121°C produced the least losses and no difference in meat palatability from the higher oven temperatures. The 93°C oven temperature produced the least juicy but the most tender muscle with the longest cooking times and highest losses. Animals were the largest source of variance in 14 of the 19 cooking and palatability traits studied.     

Cooked yields, color, tenderness, and sensory traits of beef roasts cooked in an oven with steam generation versus a commercial convection oven to different endpoint temperatures

A CVap steam generation oven was compared with a Blodgett convection oven to examine effects on yields, cooked color, tenderness, and sensory traits of beef Longissimus lumborum (LL), Deep pectoralis (DP), and Biceps femoris (BF) muscles cooked to 1 of 3 temperatures (65.6, 71.1, or 76.7°C). Four roasts were cooked in the CVap for a constant time, and 2 roasts were cooked in the Blodgett until they reached target temperatures (3 replications). Cooking yields were higher (P<0.05) for BF and LL roasts in the CVap. Slice shear force (SSF) for BF roasts was lowest (P<0.05) in the CVap but lowest (P<0.05) for DP roasts in the Blodgett. No oven effect (P>0.05) was found for LL roasts. Sensory tenderness for BF roasts in the CVap was higher (P<0.05) than those in the Blodgett. Juiciness was higher (P<0.05) for LL roasts in the Blodgett. The CVap oven offers some tenderization (BF) and cooking yield advantages (BF and DP) over forced-air convection cooking.     

Thiamin Retention and Other Characteristics of Cooked Beef Loin Roasts

Beef loin roasts were prepared by three procedures that simulated home, foodservice or commercial methods for precooking meat prior to vacuum packaging. Roasts were prepared by conventional electric (176.5°C), cook-in-package waterbath (70°C water), or smokehouse (ambient temperature) heating. Yield, thiamin, fat, water content, and Instron tenderness of roasts were determined. Raw roasts had higher (P<0.05) water and free water content. All cooked roasts were significantly lower in thiamin content (dry, fat free basis) and thiamin retention (true and dry, fat free basis) than raw roasts (P<0.05). No differences were observed between cooking procedures evaluated (P>0.05), suggesting that most heat processing treatments used for precooking packaged meat result in similar quality products.     

Evaluation of Microwave Cooking Procedures and Ovens for Devitalizing Trichinae in Pork Roasts

Pork roasts from pigs experimentally infected with Trichinella spiralis were cooked in five microwave ovens. Twenty-nine procedures, generally recommended by the oven manufacturers or pork interest groups, were used. Infective trichinae were present after cooking in 50 of 189 roasts. Factors affecting infectivity included procedure used, use or nonuse of post-cooking standing or temperature holding, weight of roast, and internal temperatures attained. Five visually well done roasts contained infective trichinae including one in which all five temperatures taken exceeded 76.7°C. One other infective roast, with a small red spot, also had all temperatures at or above the 76.7°C level. Recommendations are made to minimize the potential that trichinae may survive in microwaved-cooked pork.     

Physical and Sensory Characteristics of Fresh Pork Leg Roasts Cooked at Low Temperatures

The effects of oven temperatures of 82, 93, 121 and 163°C were studied using 31 fresh pork leg roasts cooked to 74°C in oven bags. Warmed-over-flavor (WOF) was measured by sensory analysis after holding 3 hr at 68°C and after holding 24 hr at 2°C and then reheating to 68°C prior to serving. Roasts cooked at 82 and 93°C tended to have less WOF after refrigeration and reheating than roasts cooked at 121 and 163°C. Roasts cooked at 93°C had fewer aerobic mesophilic bacteria than those cooked at 121 and 163°C. In general, objective and sensory perception measurements indicated that roasts cooked at 82 and 93°C were of higher quality.     

Spectra of Pigments Responsible for Pink Color in Pork Roasts Cooked to 65 or 82°C

Undenatured oxymyoglobin and deoxymyoglobin were the pigments responsible for pink color in pork roasts cooked to 65°C. Roasts cooked to 82°C had gray internal color after cooking, but panelists noted development of pink internal color after refrigerated storage. Reflectance spectra of pink slices from roasts cooked to 82°C, then stored for 12 days at 2°C, were characteristic of denatured globin hemo-chromes or related nonnitrosyl hemochromes.     

Effect of marination and microwave heating on the quality of Semimembranosus and Semitendinosus muscles from Friesian mature cows

Semimembranosus (SM) and Semitendinosus (ST) muscles from 8 mature cows were used to evaluate the effect of marination, power of microwave heating, and internal temperature of cooking on the quality of calibrated beef roasts. Four treatments, using combinations of power (182W and 654W) and temperature (60 and 80°C) were applied to marinated (10% added brine: salt, sodium lactate, lactose, and ascorbate) and control roasts from SM (15×5×3cm) and ST (10×4×3cm) muscles in a 2×2×2 factorial arrangement. Microwave cooking was heterogeneous resulting in a gradient of temperatures within the roasts. Either high or low microwave power were appropriate for cooking ST roasts, but SM roasts cooked at 654W showed higher cooking losses, and lighter and less red cooked color than 182W. Cooking to 80°C increased cooking and color losses in both muscles and decreased tenderness of SM roasts compared with 60°C. Marination can be used successfully to enhance beef tenderness of ST and SM muscles cooked in microwave.     

Prediction of Pork and Lamb Meat Quality Characteristics

A two-factor central composite rotatable design and corresponding response surface analysis were successfully applied to data from pork and lamb loin roasts, using cooking temperature and endpoint temperature as the two independent variables. Heating rate (°C/min), evaporation loss, cooking time, total moisture, and chromaticity coordinate (z) were found to be significantly affected (p ≤ 0.10) by different combinations of cooking temperatures and endpoint temperatures in pork and lamb. Additional significant variables for pork were total nitrogen, remaining protein fraction and sensory panel juiciness; and for lamb, heating rate (°C/g), drip loss, total cooking loss, expressible moisture index, total nitrogen, chromaticity coordinate (×), saturation index, and sensory panel doneness and color. Response surfaces were useful in evaluating results.     

External Fat Cover Influence on Raw and Cooked Beef 2. Cooking Time, Losses, Press Fluid and Shear Force Values

SUMMARY: The semitendinosus muscle was used in a study of the influence of the external fat cover and the oven temperature on the characteristics of cooked beef. Roasts were cooked either with or without the external fat cover to an internal temperature of 58°C (rare). Two oven temperatures, 163° or 218°C, were used. The roasts cooked at 218°C required a shorter time in the oven than did the roasts cooked at 163°C but the presence or absence of the external fat cover had very little effect on the min per lb. Roasting at an oven temperature of 218°C caused significantly greater total cooking losses than roasting at 163°C. The cooking losses were increased significantly by cooking the roasts with the fat cover on, as compared with removing the external fat The increase was mainly due to an increase in the drip losses. The presence or absence of the external fat cover had a significant influence on the quantity of press fluid obtained from the samples. A greater amount of fluid was pressed from the roasts without the fat cover. The posterior ends of the muscle were more tender (as indicated by Warner Bratzler shear force values) than the anteriomr ends. The lower oven temperature also caused significantly more tender roasts.     

Clostridium sporogenes and Listeria monocytogenes: Survival and Inhibition in Microwave-ready Beef Roasts Containing Selected Antimicrobials

Beef roasts were pumped with brines containing phosphates and acetic acid, sodium lactate, potassium sorbate, or glycerol monolaurin, and cooked in-the-bag once or twice to 62.8°C. Samples were examined during storage at 2, 5, and 10°C and after mishandling at 25°C for survival of inoculated Clostridium sporogenes spores and Listeria monocytogenes. Clostridia and listeriae survived one cooking when surface inoculated and two cookings in roasts inoculated internally. Lactate in brine afforded protection against clostridial survival and growth in temperature-abused roasts. Clostridia grew after 24 hr at 25°C in untreated roasts cooked once, and after 48 hr of abuse in most others except those with lactate or monolaurin. Listeria survival was reduced by lactate and monolaurin in recooked surface-inoculated roasts.     

Palatability and Storage Characteristics of Precooked Beef Roasts

The palatability and storage characteristics of fresh, frozen and precooked beef chuck roasts prepared using added phosphate-salt and vacuum cooking bags were evaluated. Palatability attributes (tenderness, juiciness, beef flavor intensity, and off-flavor intensity) of precooked roasts prepared in vacuum cooking bags with phosphate-salt were as good or better than freshly cooked roasts. Precooked roasts in vacuum cooking bags had the lowest total bacterial counts after storage for 14 and 28 days. A palatable precooked roast beef product was developed that can be stored for 28 days at 4°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.     

Influence of Rate and Length of Cookery upon Product Attributes of Pre- and Post-Rigor Beef

Paired sides of 15 steer carcasses were used to determine the effects of low temperature, long duration cooking upon muscle (semimembranosus, SM; semitendinosus, ST) shortening, cooking and tenderness attributes of beef roasts that were removed 1 hr (hot-boned, HB) and 48 hr postmortem (cold-boned, CB). The cooking treatments were: (1) 1st hr at 47°C then raised 5.6°C/hr through the 5th hr (69°C); (2) 1st hr at 52°C then raised 5.6°C/hr through the 4th hr (69°C); and (3) 1st hr at 58°C then raised 5.6°C/hr through the 3rd hr (69°C) and thereafter at 80°C until an internal temperature of 66°C was reached. Shear values and panel ratings showed HB roasts to be slightly less tender than CB roasts. Cooking yields were higher for HB than CB roasts.     

Palatability of bison semimembranosus and effects of marination

The present study was conducted to investigate the palatability of bison semimembranosus muscle (SM) and the effects of injection with sodium chloride and sodium tripolyphosphate on cooking yield, colour, shear force and consumer acceptability. Twenty paired SM were obtained from 10 intact male bison (aged 24-30 months); each of these muscles was divided longitudinally into two sections. One section was injected to 110% of its original weight to contain 0.5% sodium chloride and 0.3% sodium tripolyphosphate, while the other was kept as a non-injected control. HunterLab a* (redness) and b* (yellowness) values did not differ (P>0.05) between injection treatments; however, injected steaks had lower L* values (darker) compared to controls. Control samples from bison SM were very lean and high in protein but not very tender. Marination by injection was able to significantly reduce shear force values of SM; that is, injected steaks/roasts had significantly (P<0.001) lower shear force values (63.9 N) compared to control samples (102.3 N). Cooking yields for the steaks/roasts from the injected sections were significantly (P<0.001) higher compared to those from control non-injected sections when cooked to either 71 or 77?°C. Bison samples cooked by moist-heat had significantly (P<0.001) lower cooking losses and shear force values compared to those cooked by dry-heat. As expected, steaks/roasts were more tender and had higher cooking yields when cooked to a medium level of doneness (71?°C) compared to an internal temperature of 77?°C (well done). A panel of 80 consumers preferred injected steaks cooked to 77?°C endpoint over other combinations, followed by non-injected steaks cooked to 71?°C, whereas injected steaks cooked to 71?°C and non-injected steaks cooked to 77?°C were equally but least preferred. Hence, injection seems to be protecting against moisture loss at high end-point cooking temperatures.     

The Effects of Marination and Cooking Regimes on the Waterbinding Properties and Tenderness of Beef and Bison Top Round Roasts

ABSTRACT: The combined effect of marination and different cooking regimes on the cooking yield and palat-ability of bison and beef top round roasts was investigated. Semimembranosus (SM) muscles from beef and bison top rounds were injected with a marinade to achieve 20% extension by weight and 0.5% sodium chloride and 0.3% sodium tripolyphosphate levels and then subdivided into 4 roasts and cooked by following 4 cooking regimes: cooking at a constant temperature of 75°C (control; C); similar to the control treatment except that roasts were held at an internal temperature of 55°C for 45 min (Hold45) or 90 min (Hold90) prior to final cooking at 75°C; initial cooking at 55°C with a 5°C increase in oven temperature every hour (Step-up) until the 71°C internal temperature was achieved. Cooking yield, expressible moisture, purge, and shear force of processed roasts were determined. Marination by injection improved the yield and tenderness of beef and bison SM roasts. The cooking yield for injected samples (78%) was significantly (P < 0.05) higher compared with noninjected controls (68%). Injected SM roasts from bison had lower cooking losses than those from beef, whereas control samples from these 2 species did not differ in their cooking yields. Injected beef SM was more tender than bison SM; however, marination significantly reduced the shear force values of SM roasts for both species (i.e., shear force values of 82 N in control samples was reduced to 63 N in injected ones). The cooking regimes, Hold45, Hold90, and Step-up (which allowed a longer time at 55 to 60°C), gave products with lower ( P < 0.05) shear force values than those of the controls. Based on the cooking yield and time involved, the Hold 45 treatment performed the best.     

Microwave Recooking of Pork Roasts To Attain 76.7°C Throughout

Sixteen trichina-infected pork roasts were cooked at 30% power in two microwave ovens for 48.4 min/kg. Seven roasts attained or closely approached 76.7°C thoughout and were not recooked. Nine roasts whose initial post-cooking low temperatures varied from 42.8–72.8°C were recooked one to three times at 8.8 min/kg. One of the roasts recooked three times probably would have required two more recookings at 8.8 min/kg to obtain 76.7°C throughout. Eight of the 16 roasts were underdone and should have been recooked. Trichinae in all sixteen roasts, irrespective of temperatures or degree of doneness attained, were noninfective to rats.