Cholesterol Content of Raw and Cooked Beef Longissimus Muscles with Different Degrees of Marbling

The relationships of marbling level (eight levels from “Moderately Abundant” to “Practically Devoid”) and cooking to cholesterol content of beef longissimus muscle steaks were studied. Only raw steaks with “Practically Devoid” marbling contained significantly less cholesterol (wet basis) than did raw steaks with any of the other seven marbling scores. However, steaks cooked to an internal temperature of 60° or 75°C showed no significant differences in cholesterol content among any of the eight marbling groups. The cholesterol content of cooked steaks was 22–48% higher than that of raw steaks when cooked to 60°C and 38–65% higher when cooked to 75°C; cooking reduced the weight of each steak, thereby increasing the cholesterol content of the steak expressed as a percentage of the cooked weight.     

Oxidative Stability and Sensory Attributes of Prerigor Cooked Beef Steak

Beef sirloin tip steaks from 12 steer carcasses were cooked prerigor and postrigor using three heating methods and stored at 4 °C or ‐20 °C. Prerigor cooked steak had lower cook loss, higher pH, higher shear force, and sensory hardness than postrigor cooked steak. Conventional oven cooking produced the lowest cook loss for prerigor steak. Prerigor cooked steak had lower thiobarbituric acid value than postrigor cooked samples after 2 wks at 4 °C or 3 mo at ‐20 °C. Sensory warmed‐over flavor intensity scores were low and showed no differences between prerigor and postrigor cooked steaks for refrigerated or frozen samples.     

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.     

Effects of Preslaughter Exercise, Electrical Stimulation, Type of Packaging Tray, Display Temperature, and Time on Acceptance and Shelflife of Beef Steaks

Eight steers, of which four were exercised prior to slaughter, were slaughtered and one side of each carcass electrically stimulated (ES). Steaks from combined wingrib and sirloin were packaged in two types of plastic foam trays, overwrapped with PVC and displayed in refrigerated display cabinets either at 0°C or 5°C meat surface temperature. Display temperature and period of display significantly influenced shelflife and overall appearance of steaks. ES enhanced tenderness and improved muscle color but caused more weight loss during display when compared with steaks from unstimulated carcasses. All factors investigated had a significant influence on percentage weight loss during display while stress and tray depth also negatively influenced cooking weight loss encountered during cooking.     

Predicting temperature profiles to determine degree of doneness for beef biceps femoris and longissimus lumborum steaks

The degree of steak doneness is an important factor in providing consumers with a satisfying eating experience. Endpoint temperature and cooking rate are the determinants of degree of doneness. Our objectives were to predict internal temperature profiles and cooking times for longissimus lumborum and biceps femoris steaks. Each biceps femoris and longissimus lumborum steak was cooked individually in a gas-fired, forced-air-convection oven at 163 °C until the center temperature of each steak reached 70 °C. Temperature profiles were recorded by a Doric temperature recorder and the recorded time and temperature data were imported into a spreadsheet. A prediction method was then implemented to predict cooking times and temperature profiles. No significant differences (p<0.05) were found in cooking times between experimental and predicted values for either longissimus lumborum or biceps femoris steaks. Good agreement was found between experimental and predicted temperature profiles for the longissimus lumborum muscle. However, predicted temperature profiles were consistently higher (except for the beginning of the cooking cycle) than the experimental values up to 65 °C in the cooking cycle for biceps femoris steaks. A highly positive linear relationship was found between experimental and modeled temperature profiles for longissimus lumborum (R(2)=0.99), whereas a high quadratic (R(2)=0.99) relationship was found for biceps femoris steaks. Our method for predicting temperature profiles of steaks for a specified cooking time to attain a given degree of doneness should increase consumer satisfaction by reducing variation in meat sensory traits related to an expected degree of doneness.     

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, 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.     

不同熟制方式下调理鸡排蛋白质结构及水相分布的变化

为了探究熟制方式对调理鸡排蛋白质结构和水相分布的变化的影响,以预制的调理鸡排为研究对象,用三种不同的熟制方式（香煎熟制、鼓风烤制、普通烤制）进行熟制（生鸡排为对照）,测定蛋白质二级结构,观察肌纤维微观结构并分析水分迁移情况。结果表明：蛋白质二级结构中酰胺I带变化量为9.64 cm-1（普通烤制）、11.579 cm-1（鼓风烤制）、13.49 cm-1（香煎熟制）;呈凝胶网状的蛋白质微观结构由疏松到紧密的大小为：普通烤制>鼓风烤制>香煎熟制;各组自由水峰面积P23分别为0.31%（生鸡排）、1.85%（普通烤制）、2.97%（鼓风烤制）、3.56%（香煎熟制）;系水力大小为：普通烤制>鼓风烤制>香煎熟制。以上结果为明确不同熟制方式对调理鸡排食用品质的影响提供理论指导依据。     

Physical-Chemical Properties and Cooking Yield of Hamburgers Prepared from Accelerated Processed Beef

The effect of time of processing, pre- vs post-rigor, on quality of hamburgers prepared from electrically stimulated beef was investigated. Within 2 hr postmortem flanks of right sides of 8 electrically stimulated (85 V, 14 Hz, 30 s) and 8 nonstimulated cow carcasses were hot-processed into hamburgers. Flanks of left sides were cold-processed after 20 hr at 1 ± 1°C. Electrical stimulation resulted in significantly higher cooking losses than no stimulation. Hot processed hamburgers from nonstimulated beef had lowest cooking losses whilst hot-processing virtually nullified adverse effects of stimulation on cooking yield. Irrespective of electrical stimulation, shear forces for hot-processed hamburgers were lower than shear forces for cold processed hamburgers. Increased brightness (higher L*-values) observed in hot-processed hamburgers was a result of fat-smearing.     

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.     

Cooking loss and juiciness of pork in relation to raw meat quality and cooking procedure

The study comprised two experiments with the aim to investigate the influence of raw meat quality and cooking procedure on cooking loss and juiciness of pork. The first experiment determined the cooking loss at 60, 70 and 80 °C centre temperature of 10 raw meat qualities (defined according to ultimate pH, drip loss, breed and rearing conditions) when cooked as steaks on a pan or as a roast in oven at a oven temperature of 90 or 190 °C. The differences in cooking loss between the raw meat qualities and the cooking procedures did decrease as the centre temperature increased and were almost negligble at 80 °C. Low water holding capacity (WHC) and low pH resulted in high cooking loss while no difference in cooking loss was observed between meat having medium or high WHC and pH. In the second experiment four raw meat qualities (standard, Duroc, low pH and heavy carcass weight) chosen from the first experiment to ensure a wide variation in cooking loss, were cooked in oven at 90 or 190 °C oven temperature. Juiciness was assessed three times during the chewing process. The results suggested that juiciness experienced initially in the chewing process depended only on the water content of the meat, whereas juiciness experienced later in the chewing process was determined by a combination of the water and intramuscular fat contents and the saliva production during chewing.     

Effect of Storage and Cooking on Qualities of Loin and Top-Wound Steaks

SUMMARY— Boneless, trimmed steaks (U. S. Good) from the longissimns dorsi muscle (loin) and semimembranosus muscle (top-round) and conventionally cut loin steaks were removed 8 days post-mortem, quick-frozen and stored at −18°C to −23°C for three storage periods, 0, 6, and 9 months. Steaks were sampled at each storage period and cooked to an internal temperature of 70°C in a microwave oven and electric range. Quality was evaluated by chemical tests, sensory evaluations and cooking loss data.
Storage up to 6 months had little effect on loin steaks with the exception of TBA values, but significant changes occurred between 6 and 9 months. Loin steaks had increased cooking losses and decreased juiciness scores, percent moisture, and juice content. TBA values increased with each storage period. Top-round steaks at the 9-month period showed a decrease in collagen content and juiciness and flavor scores, and an increase in TBA values. Storage up to 9 months did not influence tenderness in either muscle.
Conventionally broiled loin steaks had higher palatability scores, cooking losses, percent moisture, percent total proteins, and lower percent total lipids than did microwave cooked loin steaks. Electronically cooked top-round steaks had higher total cooking losses and percent total proteins and lower collagen values than did conventionally roasted top-round steaks.
The qualities of boneless loin steaks did not differ significantly from those of conventionally cut loin steaks when compared at each storage period.     

The effect of marinading on beef

Beef sternomandibularis muscle was tenderised by marinading in 1.5% acetic acid. The effect was marked whatever the cooking temperature, but greatest with mild or severe cooking (60 or 100°C). Addition of 12% sucrose further increased tenderness. Juiciness was not improved, with or without sucrose. Longissimus dorsi steaks when marinaded and grilled showed only a small increase in tenderness. Lengthy soaking of a thick steak is necessary to achieve full penetration of the marinade. Marinading appears to be particularly effective in tenderising muscles containing a large amount of connective tissue, but the benefit is marginal in top quality cuts.     

Effect of Steam-Assisted Hybrid Cooking on Textural Quality Characteristics,Cooking Loss,and Free Moisture Content of Beef

Semitendinosus muscles were cooked in a steam-assisted hybrid oven and also convection ovens at three different oven temperatures (180, 210, and 240°C) until three different end point temperatures [65°C (medium-rare), 72°C (medium), 80°C (medium-well)] were reached. Textural properties of cooked beef were investigated by the Warner Bratzler shear test and texture profile analysis. Cooking loss and free moisture content of muscle tissue was determined for each cooking condition. In addition, sensory analysis was carried out in order to compare with the instrumental results and correlations between instrumental texture parameters and sensory results. Steam-assisted hybrid oven cooking of beef resulted in a tougher texture, higher cooking loss, and lower free moisture content than convection cooking. High correlation coefficients (r² > 0.70) were observed between instrumental texture measurements and sensory results for all ovens, especially in terms of tenderness. The free moisture content and adhesiveness values were also correlated well with juiciness (r² > 0.70) for all oven types.     

Cooking qualities of parboiled rices produced at low and high temperatures

The cooking characteristics of parboiled rice are related to (i) its hydration behaviour at temperatures above and below the gelatinisation point; (ii) to kernel elongation on cooking; and (iii) to the extent of amylose solubility. These properties differ among samples, depending on the parboiling conditions. Samples were prepared by parboiling paddy at 70, 80, 90, 100, 110 and 120°C. The kernel elongation on cooking and the amount of soluble amylose in the gruel were then determined. The water uptake values for raw and parboiled rice samples were determined by hydrating them at room temperature (25-30), 60 and 98°C (boiling temperature) for optimal cooking times. The rate of hydration at temperatures below the gelatinisation point increased on parboiling and, conversely, a reverse pattern above this point. Close correlations existed between the temperature of parboiling and the properties studied. The different properties studied also correlated well. The temperature of parboiling influenced the linear elongation of the kernel after cooking. The soluble amylose content was negatively correlated with the temperature of parboiling. Though the hydration properties of different parboiled samples differed among themselves, depending on the degree of parboiling, they fell into two distinct classes, viz. the samples parboiled at a temperature close to the gelatinisation point having cooking qualities similar to raw rice, and above this point qualities differing from raw rice. The water uptake values at room temperature and at 60°C, and the ratio of water uptake at 98°C and optimum cooking time to that at 60°C were found to be useful in differentiating the parboiled rices into the two classes.     

Effects of Rapid Processing on the Chemical and Sensory Properties of Restructured Steak Made From Bull and Steer Meat

South Devon cattle (10 bulls, 10 steers) were slaughtered to determine effects of sex condition and postmortem temperature conditioning on the chemical and sensory properties of restructured beefsteak. Chucks from each left side were boned following a 4 hr delayed chill (DC, 13°C) period, while chucks from right sides were boned following a 48 hr conventional chill (CC. 2°C). Chucks were mechanically tenderized and formulated into restructured steaks. Bulls produced restructured steaks less prone to oxidative rancidity. Restructured steaks from bulls exhibited higher (P<0.01) cooking losses and Kramer Shear values. There were no differences between treatments in tenderness, juiciness, flavor, and connective tissue residue ratings; however, DC restructured steaks had lower (P<0.05) bind values than CC restructured steaks.     

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.     

Effect of Cooking Temperature and Time on the Shear Properties of Meat

The effect of cooking temperature in the range 40–95°C on Warner-Bratzler shear force-deformation curves, obtained for stretched and cold-shortened meat samples from young and old bovine animals, has been investigated. The results were interpreted as indicating that the relative contributions of the connective tissue and myofibrillar structures to the peak shear force values were markedly altered as cooking temperature was increased. The changes of the myofibrillar structure were reflected by the changes in initial yield force values. In general, the initial yield force increased about three- to fourfold between 40°C and 60°C for both stretched and cold-shortened meat but between 60°C and 80°C the increase was about twice for the former and about fivefold for the latter. The connective tissue contribution decreased as cooking temperature was raised above 50°C for meat for young animals and above 60°C for very old animals–the contribution at temperatures above 70°C being very small for the former but still relatively large for the latter.     

Yield and Quality of Soymilk Processed by Steam-Infusion Cooking

Traditional soymilk is boiled for approximately 60 min at 99°C pH 6.7, which reduces trypsin inhibitor (TI) activity by more than 90% to improve nutritional value. We evaluated continuous, direct steam-infusion cooking that facilitated higher temperatures (99-154°C) than that traditionally used for cooking soymilk. At temperatures above 120°C in steam-infusion cooking we observed consistent temperature-dependent patterns in yields of soymilk, solids, and protein, characterized by an initial decrease, followed by a rise to maximum recovery, then by a final decrease. At 154°C, pH 6.7, maximum recovery occurred at the same point as did adequate in-activation of TI. As much as 90% of the slurry, 86% of the soybean solids, and 90% of the protein were recovered as soymilk after centrifuging at 1050 × G for 5 min. Under optimum conditions for steam-infusion cooking the soymilk also retained less than 8% residual TI activity, and less chemical browning. Using traditional cooking methods, about 72% of the slurry, 61% of soybean solids, and 73% of the protein are recovered.     

Effect of Soybean Cooking Temperature on the Texture and Protein Digestibility of Miso

Miso samples were prepared with soybeans cooked for 10 min at different temperatures (up to 100°C). Appreciable changes in the amount of 0.2 M trichloroacetic acid-soluble nitrogen (TCA-soluble N) and the pattern of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) of fermented miso samples were observed in the temperature range between 90°C and 100°C. No further changes in the TCA-soluble N and SDS-PAGE pattern of miso were observed when the cooking time was prolonged up to 3 hr at 100°C. On the other hand, a 2 hr cooking period at 100°C was required to achieve a level of softness for cooked soybeans to give an acceptable texture of miso.