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.     

鱼香肉丝在烹饪前后营养成分的评价

为系统评价中国传统菜肴鱼香肉丝的营养品质以及烹饪前后的营养成分变化,将用于制作鱼香肉丝的原材料平均分成2组,每组3份,分别是生原料组和成品组。对其22种营养素指标进行检测,并分别对常规营养素、氨基酸、脂肪酸、矿质元素以及维生素进行营养评价。结果表明,在烹饪后鱼香肉丝的蛋白质显著升高(P<0.05),脂肪、磷、和铁的含量极显著升高(P<0.01),但氨基酸组成和脂肪酸总量无显著变化,维生素B₁显著降低(P<0.01)。蛋白质的氨基酸组成合理,必需氨基酸指数达到了85.91%;且多不饱和脂肪酸含量丰富,占总脂肪酸的58.36%。此外,矿质元素的营养质量指数均大于1(除钙以外),基本满足人体需求,但鱼香肉丝的维生素A和维生D含量较为缺乏,B族维生素(B₁、B₃、B₁₂)含量也低于中国居民膳食营养素摄入量的推荐值。综上,鱼香肉丝是一道营养丰富、均衡的菜肴,它具有优质的蛋白质、脂肪酸和丰富的矿质元素。烹饪会造成其维生素B₁的损失,而大大增加铁元素的含量,并且蛋白质和脂肪的含量会升高。本研究为膳食记录提供了更为准确的营养数据。     

间歇式蒸微组合加热对排骨品质的影响

组合应用气蒸和微波两种方式对排骨进行加热处理,研究间歇式蒸微组合方式对烹饪排骨理化指标、营养成分质量分数及组成、蛋白消化率等品质特性的影响。结果表明:相比于单独的微波和蒸制,间歇式蒸微组合(先微4 min再蒸6 min)烹饪条件下,排骨中水分质量分数、嫩度、油酸、棕榈酸、胶原蛋白质量分数和胰蛋白消化率有明显提高。在此条件下,排骨中总巯基质量分数相比于单独的蒸制提高了60.1%,羰基质量分数降低了约35.3%。与传统蒸制排骨相比,适当的间歇式蒸微组合加热不仅可以显著提高排骨烹饪效率,而且烹制排骨具有较好嫩度和营养价值。     

Microwave Cooking Properties of Ground Pork Patties as Affected by Various Fat Levels

ABSTRACT: Ground pork patties were processed from pork hams to achieve fat levels of 5%, 10%, 15%, 20%, and 25%. Each patty was cooked in a microwave oven to 75 °C from a thawed state. As fat levels increased, cooking time decreased. Total cooking loss and drip loss were highest for 25% fat patties and lowest for 5% fat patties. High-fat patties (20% and 25%) had greater reductions in dia than did 5% to 15% fat patties, but had less change in patty thickness. Shear force values decreased as fat levels increased. Visual evaluations also indicated a greater presence of air pockets in high-fat patties. In raw patties, low-fat samples were darker (had lower L * values) and were redder (had higher a * values) than patties with more fat. However, these differences were relatively smaller when the patties were cooked. As fat levels increased, flavor, tenderness, juiciness, and oiliness ratings increased. These differences were not as apparent when comparing among low-fat patties or high-fat patties. Keyword: microwave, cooking, fat, pork patty     

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.     

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.     

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.     

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 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.     

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.     

Concentration of Umami Compounds in Pork Meat and Cooking Juice with Different Cooking Times and Temperatures

This study examined the concentrations of umami compounds in pork loins cooked at 3 different temperatures and 3 different lengths of cooking times. The pork loins were cooked with the sous vide technique. The free amino acids (FAAs), glutamic acid and aspartic acid; the 5′‐nucleotides, inosine‐5′‐monophosphate (IMP) and adenosine‐5′‐monophosphate (AMP); and corresponding nucleoside inosine of the cooked meat and its released juice were determined by high‐performance liquid chromatography. Under the experimental conditions used, the cooking temperature played a more important role than the cooking time in the concentration of the analyzed compounds. The amino acid concentrations in the meat did not remain constant under these experimental conditions. The most notable effect observed was that of the cooking temperature and the higher amino acid concentrations in the released juice of meat cooked at 80 °C compared with 60 and 70 °C. This is most likely due to the heat induced hydrolysis of proteins and peptides releasing water soluble FAAs from the meat into the cooking juice. In this experiment, the cooking time and temperature had no influence on the IMP concentrations observed. However, the AMP concentrations increased with the increasing temperature and time. This suggests that the choice of time and temperature in sous vide cooking affects the nucleotide concentration of pork meat. The Sous vide technique proved to be a good technique to preserve the cooking juice and the results presented here show that cooking juice is rich in umami compounds, which can be used to provide a savory or brothy taste.     

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.