RELATIONSHIPS of PHYSICAL PROPERTIES of FAT-SUBSTITUTES, COOKING METHODS and FAT LEVELS WITH QUALITY of GROUND BEEF PATTIES

Ground beef patties containing 2 fat levels (5%, 10%), and 3 fat-substitutes (LeanBind, Rice* Complete 3, and Sta-Slim 171) were processed using 3 cooking methods (microwave, roasting, and pan-frying). Correlation analyses between patty quality and the physical properties of the fat-substitutes, as well as the composition of both raw and cooked patties were conducted. Regression models of patty quality parameters as functions of the physical properties of the fat-substitutes, and as the function of the patty composition were developed. This work demonstrated that the fat-substitutes can be evaluated based on regression models relating patty quality to the physical properties of the fat-substitutes.     

EFFECTS OF FAT LEVEL AND COOKING METHODS ON PHYSICAL AND SENSORY CHARACTERISTICS OF RESTRUCTURED BEEF STEAKS

Trimmed top rounds from 9 Angus steers were flaked and formed into restructured steaks containing 15, 20, or 25% fat. The steaks were cooked in a microwave oven (MW) on a preheated browning dish or broiled in a conventional oven (CO). Microwave cooking required less time and energy. Decreased time and energy for cooking also related to increased fat levels. Cooking losses and penetration hardness values were greater for the MW steaks. Cooking losses increased and penetration hardness values decreased with increasing fat level. MW steaks appeared more well-done and were harder, less moist, and more resistant to chewing. As fat level increased softness and moistness scores also increased. Consumer panelists found all steaks to be equally acceptable, suggesting the potential for the development of portion- and fat-controlled restructured steaks for microwave cooking.     

EFFECTS OF COOKING AND SUBSEQUENT REHEATING ON THE PROPERTIES OF LOW-FAT BEEF PATTIES

Low-fat (10%) beef patties manufactured with 0.5% iota carrageenan, were subjected to one-time cooking from the raw to fully cooked state or precooking and later reheating before evaluating sensory, shear force and cooking properties. The samples were reheated in a convection oven or in a simultaneous top and bottom contact grill set either at 121 or 191C. Precooking followed by reheating produced only slight changes in sensory properties (reduced tenderness, increased juiciness and increased beef flavor). Convection oven cooking improved tenderness only for one-time cooked patties. With the double contact grilling system, the 121C surface temperature enhanced tenderness (sensory and shear force) and cooking yields of precooked-reheated patties. Low-fat beef patties formulated with iota carrageenan appear capable of being subjected to a variety of cooking approaches and temperatures without major changes in cooked patty properties.     

EFFECTS OF SOY PROTEIN AND FREEZING TREATMENTS ON COOKING LOSS AND COMPOSITION OF BEEF PATTIES

All-beef and soy-extended patties were frozen to −18°C in either 24, 48, 72 or 96h and stored at −23, −18 or −7°C for 6, 9, 12, 18 or 24 months. The addition of soy resulted in a substantial reduction in cooking loss for patties cooked from the frozen state with a greater retention of moisture in cooked patties. Freezing reduced cooking loss for soy-extended patties, but increased cooking loss for all-beef patties. Faster freezing (-18°C in 24 h vs. −18°C in 96 h) reduced cooking loss and produced higher moisture values in all-beef patties. Patties stored at –7°C lost more moisture during cooking. Increased frozen storage time had a minimal effect on cooking losses, moisture and fat levels. Where it is essential for frozen patties to sustain minimal cooking losses with maximal moisture in cooked patties, the inclusion of soy protein concentrate, faster freezing, and storage at –18°C or colder are suggested.     

EFFECT OF PROTEIN EXTENDERS ON FATTY ACIDS,CHOLESTEROL, SENSORY QUALITY AND COOKING LOSS OF BEEF PATTIES1

Ten different formulations of beef patties were processed to contain 20–50% fat from lean beef containing not more than 7% fat and beef fat consisting of not less than 90% fat and were extended with different levels of textured soy protein (TSP) at 5, 10 and 20% and single cell protein (SCP) at 2.5, 5 and 7.5%. The patties were stored at ?18°C for 6 months. Sensory quality evaluation showed that patties with 80% lean and 20% fat and patties with 40% lean, 40% fat and 20% TSP were the least acceptable, but lower levels of TSP and SCP addition were found to improve panel rating. A 17% increase in protein content and a reduction of about 13.5% in fat content was observed due to TSP and SCP incorporation. An average cooking loss in the different formulations was 33%, addition of protein extenders was found to reduce cooking loss by about 22% while fat loss averages 30.2%. A reduction of 21.1% of 18:1 and a reduction of approximately 18.7% of total FAME and 32% cholesterol were observed due to the addition of TSP and SCP.     

EFFECTS OF END-POINT TEMPERATURE AND FAT LEVEL ON THE RESIDUAL CHOLESTEROL IN GROUND BEEF PATTIES1

Patties of lean ground beef with 2% fat (L2PF) and 6% fat (L6PF) were used to study the fat and cholesterol composition of raw and cooked ground beef and to determine how the end-point cooking temperature affects the amount of fat and cholesterol in a lean ground beef patty as it would be eaten by the consumer. The two patty types were obtained from the longissimus muscle of steers with marbling scores associated with “Standard” to “Select” and “Select” to “Choice” U.S. carcass grades of beef, respectively. All steers were fed a diet of roughage and concentrates to ensure fat deposition over the 12th and 13th ribs; longissimus muscles between the 7th and 10th ribs were removed, trimmed of all external fat, ground and formed into three 130-g patties. One patty was fried to an internal temperature of 60C, another to 71C and the third was uncooked. After frying, the patties were measured for drip loss, moisture and total fat. The fat extract was used for cholesterol analysis. The cooked L2PF sample had significantly less fat than the cooked L6PF samples, but there was no difference between the L2PF and L6PF in cholesterol. End-point temperature had no effect on the fat and cholesterol contents for either L2PF or L6PF samples, but the higher end-point temperature resulted in a significant loss of moisture.     

THE INFLUENCE OF COOKING METHOD ON THE QUALITY OF PORK PATTIES

Pork patties were subjected to traditional frying, cooking in a microwave oven (microwaves  +  grill), hot air cooking in a cyclojet (Electrim JI-9101 RP, Taiwan) and cooking in a steam-convection (combi) oven (hot air  +  30% steam) (BECK FCV 4 EDS, BECK GmbH, Jagsthausen, Germany). Products cooked in the combi oven (BECK FCV 4 EDS) were characterized by the smallest cooking loss, the highest retention of water and the lowest content of fat compared to other samples. The content of hydroxymethylfurfural in fried and cyclojet-cooked patties was almost twofold higher than in microwave and combi oven-cooked samples. The intensity of lipid oxidation was also higher in fried and cyclojet-cooked meat than in the other two products. The intensity of meat flavor was the strongest in the combi oven-cooked patties. All products were characterized by a low intensity of fatty flavor. The highest scores for overall acceptability were given to the combi oven-cooked patties, whereas the lowest scores were given by the panelists to the microwave-cooked patties.

PRACTICAL APPLICATIONS

Pork patties are an important meat product both in catering production for direct consumption and in convenience food industry when intended for refrigerated or frozen storage. As cooking is a main stage in preparation of patties for consumption, it is essential to use a method of cooking that ensures the high nutritional and sensory quality of products. Most often, pork patties are subjected to deep frying or traditional frying; however, several other cooking methods can be used. The present work shows that the combi oven cooking enables production of patties of desirable nutritional and sensory characteristics and low content of unfavorable compounds.     

EFFECTS OF MICROWAVE COOKING ON FISH QUALITY

Changes in tenderness, unit proteolytic activity, protein denaturation and fatty acid content of trout (Onchorhyncus mykiss) cooked in microwave oven for different time-power combinations were studied and the relationship between protein denaturation and textural changes was investigated. Trout was cooked in the microwave oven at 20, 40 and 60% powers for 10, 20, 30, 40 s. As a control uncooked fish was used. Proteolysis was controlled by using microwave energy. Texture degradation due to proteolytic enzymes was reduced as microwave power increased. As cooking time and/or power of the microwave oven increased, proteolytic activity decreased which was a sign of the increase in enzyme inactivation. A correlation was found between the variation of texture and proteolytic activity (r = 0.973). It was observed that proteolytic enzymes were effective especially on myosin. Most of the fatty acids were not destroyed during microwave cooking. The optimum cooking conditions in microwave oven were determined as 60% power for 20 s of cooking time.     

COOKING EFFECTS ON TITIN IN FRESH AND PROCESSED BEEF PRODUCTS

Fresh bovine longissimus thoracis muscle samples, heated at 73C for 0, 5, 15, 30, 45, 60, 90 and 120 min, were subjected to sodium dodecyl sulfate polyacrylamide gel electrophoresis and western blot analysis. Titin was both aggregated into large protein masses and degraded into smaller fragments (two apparently independent processes) in fresh muscle samples heated 15 min or more at 73C. Samples removed at various points during the manufacture of a tumbled cured beef product were also subjected to electrophoresis and western blot analysis. Titin was primarily degraded into smaller polypeptide fragments during the manufacture of this product with no large titin aggregates observed. Commercially manufactured meat products, when examined by these techniques, contained both titin aggregates and degradation products. These results suggest that titin can be aggregated into large protein masses and degraded into smaller polypeptide fragments during the heating of fresh or processed meat products.     

EFFECTS OF PREFRY DRYING METHODS ON THE QUALITY OF DEEP FAT FRIED ONION SLICES

Deep fat fried onion slices are used widely as a condiment for hot-dogs and other types of bread and meat combinations in Denmark, Netherlands and Germany. Since there is a consumer demand for food products, high in both sensory and nutritional quality, the effect of prefry drying on the oil content and the color of the fried product was investigated. In order to reduce the oil content in the fried product, raw sliced onions were prefry dried by (1) hot air in a forced air convection oven, (2) microwaving in an oven with a conveyor belt, or (3) freeze dried. For each of the three methods a series of eight batches ranging from 13–30 % dry matter content in the raw onions were obtained. The product that was dried by hot air before frying was lighter than the product prefry dried by microwaving. The product of the freeze dried material was heterogeneous, and the results were excluded. The fried product from dried raw onions, showed the moisture content to be independent of the manipulated dry matter content. The oil content was reduced from about 55% to about 49%, as a result of increasing the dry matter content; however the surface color became darker (L-value was reduced about 6 point).     

EFFECTS OF TOCOPHEROLS AND β-CAROTENE ON BEEF PATTIES OXIDATION

The effect of a tocopherol mixture (mainly composed of γ and Ø isomers) and β-carotene on lipid oxidation in cooked beef patties was studied. Ground beef was mixed with each or both compounds at designated concentrations. After mixing, cooking and storing at 4 ° 1C for 0, 2 and 5 days, the 2-thiobarbituric acid reactive substances (TBARS) and hexanal peak areas were determined. The results slowed that β-carotene had no antioxidant activity in this system. The tocopherol mixture at 200 ppm level slowed down the lipid oxidation by 56.7% for 2 days and 61% for 5 days of storage in cooked meat at 4 ° 1C, respectively.     

EFFECTS OF SOY CURD ON THE ACCEPTABILITY AND CHARACTERISTICS OF BEEF PATTIES

Soy curd-beef patties were made containing 0%, 5%, 10%, 20%, 75% and 100% (w/w) of curds which had been pressed at 300 psi, 600 psi and 1100 psi during manufacture. Taste panel tests showed that by increasing pressure on the soy curd or by the addition of flavoring to the curd before patty formation, increases in soy concentration became less detectable and the acceptability of the patties was drastically increased. Soy curd-beef patties made with 1100 psi curd and with color and flavor added were favorably accepted even at levels as high as 75% curd (w/w). The easy detectability of flavored soy in patties did not greatly change the high acceptability of the patties. The chemical composition, functional characteristics and physical properties of the soy-beef patties were also studied.     

EFFECTS OF FAT TRIM ON THE COMPOSITION OF BEEF RETAIL CUTS – 3. COOKING YIELDS AND FAT RETENTION OF THE SEPARABLE LEAN

Thirty beef carcass sides varying in USDA quality and yield grade were fabricated into various steaks and roasts. The retail cuts were assigned serially to the following treatments: (A) raw, trimmed to 0.6 cm external fat; (b) trimmed to 0.6 cm external fat, cooked; (C) trimmed to 0.0 cm external fat, cooked. The separable lean was analyzed for chemical fat. Regression analyses were used to predict percentage cooking yields and fat retention of the separable lean. Generally, cooking yield was not influenced by USDA grade, but retail cuts cooked with 0.6 cm external fat usually had numerically higher predicted values for cooking yield than cuts trimmed to 0.0 cm before cooking. Braising of thin (< 2.5 cm thick), single-muscle retail cuts decreased the predicted percentage of chemical fat retention of the separable lean. Trimming of retail cuts to 0.0 cm external fat before cooking decreased (compared to the 0.6 cm cuts) the predicted percentage of chemical fat retention of the separable lean as compared to cuts that were trimmed to 0.6 cm.     

PATTY FORMATION METHOD, THICKNESS AND WEIGHT EFFECTS ON PROPERTIES OF COOKED LOW-FAT BEEF PATTIES

Effects of patty thickness (0.95 and 1.27 cm), weight (90 and 113 g) and type of patty fill method (traditional gravity fill = FF and twisted through holes into mold = TF) were evaluated using low-fat (10%) ground beef. An increase in patty thickness from 0.95 cm to 1.27 cm, resulted in a decreased (P<0.01) sensory firmness and peak load (Newtons) and increased (P<0.01) initial juiciness. TF fill method and 1.27 cm thick FF treatments improved tenderness and juiciness over 0.95 cm thick FF patties. This study revealed that improvements in tenderness and juiciness of low-fat beef patties can be attained through use of appropriate patty formation procedures.