Power and Cooking Time Relationships for Devitalization of Trichinae in Pork Roasts Cooked in Microwave Ovens

Power and cooking time combinations necessary to devitalize trichinae in pork roasts were determined using three power levels in each of two microwave ovens. The combinations obtained for an oven listed as producing 700 watts were: 100% power, 19.8 min/kg; 70%, 24.2 min/kg; and 30%. 55.0 min/kg. Those for a listed 625 watt oven were: 100% power, 24.2 min/kg; 70%, 26.4 min/kg; and 30%, 55.0 min/kg. Inadequate doneness in many roasts cooked with the safe combinations would necessitate additional cooking time before procedures could be recommended. Post-cooking temperatures during a 20-min standing period may either increase or decrease with no predictability.     

An Approach to Safe Microwave Cooking of Pork Roasts Containing Trichinella spiralis

Pork roasts, obtained from pigs experimentally infected with Trichinella spiralis, were cooked at 50% power in four microwave ovens. The attainment of consistently well done roasts is the primary requisite for development of safe cooking methods. Recommendations for cooking of trichinous pork roasts, with adequate margins of safety, are made for each oven.     

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.     

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.     

Palatability and Storage Characteristics of Precooked Pork Roasts

Pairs of boneless pork loins (n=10) were pumped to contain 0.5% tripolyphosphate or water and allotted to three treatments: PVC wrapped, convection oven cookery (CO); vacuum packaged, precooked and reheated in a water bath (PC); and vacuum packaged and cooked in a water bath (VP). Paired loins (n = 30) were injected with tripolyphosphate and allotted to the following treatments and storage (0, 14 or 28 days) conditions: Control (?20°C) [CO]; precooked (?20°C) [PCPR]; precooked (4°C) [PCRF]; vacuum packaged (?20°C) [VPFR]. VP and PC phosphate injected roasts were more tender and had lower cooking losses than CO roasts. After 28 days, all PC roasts had lower microbial counts than other treatments, and PC and VP roasts had improved palatability compared with CO roasts.     

Sensory and Chemical Characteristics of Precooked Mircrowave-Reheatable Pork Roasts

Boneless pork shoulder pieces were pumped to 10% of original weight with brine to give 1% salt and one of the following at 0.3% in the final product: phosphate, ascorbic acid or sodium ascorbate. Sensory evaluation and TBA assay were done on precooked microwave reheated roasts that had been stored for 7, 14, and 28 days at 4°C. Phosphate-treated roasts were scored significantly more tender, juicy, flavorful and palatable than the other treatments and control. TBA numbers were lower for ascorbic acid-treated and sodium ascorbate-treated roasts than for phosphate-treated and control roasts. An acceptably palatable, value-added, precooked, boneless pork shoulder roast designed for microwave cookery was produced.     

National In-Home Consumer Evaluation of Pork Roasts From Pigs Administered Porcine Somatotropin (pSt)

Boneless pork loin (longissimus) or ham (semimembranosus) roasts from 60 control and 60 porcine somatotropin-produced (pSt) pigs (3 mg daily) were analyzed for composition and evaluated by 120 families in each of three major cities. In San Antonio and Portland each family received a loin roast from a control pig and a pSt-treated pig. In Buffalo, each family received a fresh ham roast from a control pig and a pSt-treated pig. Consumers were asked to evaluate the roasts during conventional in-home meal preparation and consumption. Overall, pSt roasts contained less intramuscular fat and no differences were noted in acceptability scores when control loin or ham roasts were compared with pSt-produced loin or ham roasts. No differences were noted in the preference scores for the loin roasts; however, consumers preferred the tenderness, juiciness and flavor of the control ham roasts.     

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.     

纯瘦猪肉丸的组分配比及工艺标准

对烹饪不常用的纯瘦猪肉丸的调配工艺进行优化,以用量配比以及加热时间对内丸质量的影响进行比较试验,通过对内丸弹性、口味、形态的感官综合评价结果分析,找出纯瘦猪肉丸配比的优化参数.首先进行单因素试验分析,分别对盐浓度、水浓度、淀粉浓度、加热时间对内丸感官质量的影响进行对比试验.得出盐、水、淀粉、加热时间的基本范围.在单因素分析的基础上,再进行正交试验,找出肉丸调配的最佳配比组合和加热时间,在对样品进行弹性和硬度分析,将检测结果与感官鉴别结果进行综合评估,最终得出纯瘦猪肉丸的工艺参数即水用量220 g、盐用量4 g、淀粉用量20g、加热时间50mim.     

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.     

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.     

Cholesterol and Selected Attributes of Pork Tenderloin Steaks Heated by Conventional, Convection, and Microwave Ovens to Two Internal Endpoint Temperatures

Six treatment combinations for determination of cholesterol and selected quality attributes of pork tenderloin steaks were studied with three oven types (conventional, convection and microwave) and two internal endpoint temperatures (71°C and 77°C). In general, pork tenderloin steaks heated in the microwave oven had lower evaporative loss and higher drip loss. Cholesterol (wet weight basis) of the pork steaks was not affected by oven type; however, heating to the higher internal endpoint temperature (77°C) increased (concentrated) the cholesterol. On a dry weight basis, microwave-heated steaks contained more cholesterol when compared to conventional and convection-heated samples.     

Effects of Sodium Tripolyphosphate on Physical and Sensory Properties of Beef and Pork Roasts

Six paired beef round and pork loin roasts were used to determine the effects of sodium tripolyphosphate (STPP) on fresh and reheated roasts. Roasts were pumped 10% of their weight with distilled water (control) or with distilled water containing 4.75% STPP. Roasts were cooked to internal temperatures of 70°C (beef) or 75°C (pork) and evaluated after 0, 1 or 3 days (roasts were reheated to cooked temperatures). This study indicates that phosphate in pork and beef roasts allowed them to be reheated after 1 and 3 days of refrigeration with minimal losses of juiciness, tenderness or flavor intensity, Phosphate injection reduced warmed-over flavor in reheated pork roasts but was not successful in decreasing the incidence of warmedover flavors in reheated beef roasts.     

Effects of Electrical Stimulation, Boning Time and Cooking Method on Beef Roasts

Sixteen steer carcasses were selected to study effects of electrical stimulation, boning time and cooking methods on palatability traits, cooking loss and chemical composition of beef biceps femoris muscle. Eight carcasses were electrically stimulated and eight carcasses served as controls. The biceps femoris muscle was removed from one side of each carcass within 2 hr of exsanguination and from the remaining side following a 48-hr chill. Muscles were subdivided and cooked in either a convectional electric or a microwave oven. Electrical stimulation resulted in longer (P < 0.01) sarcomeres for cooked product but did not affect palatability traits, cooking loss or chemical content. Hot boning reduced (P < 0.01) cooking loss and tenderness, resulted in less (P < 0.05) total, soluble and insoluble collagen and increased the juiciness score and moisture percentage when compared with 48-hr boning. Microwave cooking produced a greater (P < 0.01) cooking loss and a higher shear force value than convectional electric cooking.     

Sensory and Cooking Properties of Beef Steaks and Roasts Cooked with and without External Fat

The effects of removal of external fat prior to cooking on fat and moisture content and sensory properties of cooked beef lean were investigated. Twelve pairs of beef strip loin steaks, eye of round roasts, top round roasts, briskets and arm pot roasts fabricated from USDA Choice carcasses were used. True fat retention was also determined for 36 strip loin steaks trimmed to either 0, 0.6 or 1.3 cm external fat. Cooking yield and sensory traits were adversely affected, by the fat removal, only in those cuts (briskets and arm pot roasts) which were cooked by braising. Fat content of the cooked lean was numerically higher in all cuts cooked with an external fat layer. Retention of intramuscular fat was also higher in strip steaks cooked with an external fat layer.     

Destruction of Pathogenic Bacteria in Turkeys Roasted in Microwave Ovens

Whole turkeys inoculated with Salmonella typhimurium, Staphylococcus aureus, or Clostridium perfringens were cooked in a microwave oven (2450 MHz) to an end-point temperature of 76.6°C. The cooking procedure did not completely eliminate any of the three pathogenic bcteria from the turkeys. The extent of survival of C perfringens on the cooked unstuffed turkeys was proportional to the number of spores in the initial inoculum. Similar results were observed when turkeys stuffed with inoculated stuffing were cooked in microwave ovens. Cooking in brown-in-bags increased the destruction of C. perfringens and S. typhimuriun in unstuffed turkeys even though the end-point temperature was only 68.3°C.     

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.     

POULTRY PRODUCT QUALITY. 1. Compositional Changes During Cooking of Turkey Roasts

SUMMARY: White and dark turkey roasts, averaging 7.1 and 3.1 lb respectively, were made with meat taken from selected samples of the various entries in the Pennsylvania Turkey Random Sample Meat Test. Additional róasts were made from sample birds from the University research flock. Roasts were wrapped in aluminum foil, then cooked in a Telkes oven. All roasts were cooked to an internal temperature of 170°F. There were no sex differences in cooking losses except when skin was examined separately. Differences in cooking losses were observed in the breast meat but not in the thigh meat of roasts prepared from Bronze and White turkeys. Losses were higher for breast meat than for thigh meat. There was an indication that size of bird was not a significant factor in determining percentage cooking losses for breast and thigh roasts. When fat drippings from cooked skin were analyzed for carbonyl content high skin yielding males were characterized by the high concentration of the 2-enals in relation to the methyl ketones. Low skin groups consisted mainly of methyl ketones.     

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.