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Factors associated with microbial growth in ground beef extended with varying levels of textured soy protein.
Three separate batches of ground beef containing 25% fat were extended to 0, 10, 20 and 30% by weight with rehydrated defatted textureed soy protein (TSP). Five samples of each soy level were wrapped in a polyethylene oxygen-permeable fim and stored at 5ºC for 4 days. Samples were analyzed daily for changes in bacterial numbers (total plate counts and coloforms), pH, titratable acidity, proximate analysis, ninhydrin reactive material, carbohydrate content, and gas liquid chromatographic (GLC) analysis of individual amino acids to assess spoilage in TSP extended groung beef. Total bacterial numbers increased significantly as days of storage progressed and in proportion to added TSP. Coliforms increased during storage, but not proportional to increased levels of soy protein. Spoilage in soy extended samples, as determined by off-odors and bacterial numbers, was evident by day 4 as total bacterial counts approached 108 bacteria/g. The differences were noted for percent protein. Total carbohydrate as determined by proximate analysis increased with TSP levels. Concentration values for carbohydrates were proportionately larger with added amounts of TSP, but varied little during 4 days of storage. Ninhydrin reactive material differed significantly among samples, but not proportionate to added TSP, and decreased in the 30% soy level between days 3 and 4. Decreases in individual amino acids could not be shown from the qualitative results obtained by GLC analysis. Further investigation is suggested using more difinitive measuring techniques to determine the factor(s) causing accelerated spoilage in soy extended ground beef.
Effect of sodium acid pyrophosphate on sensory, chemical and physical properties of frankfurters.
Sodium acid pyrophosphate (SAPP) is currently used by the sausage industry to accelerate development of cured meat color. The cured color accelerator was examined, through sensory evaluation and instrumental measurements, for its effects on the texture of frankfurters. The effects of SAPP on other sensory properties and on chemical and physical characteristics were also examined. SAPP was found to slightly improve texture by increasing springiness, hardness, and awareness of skin, and by reducing oiliness. SAPP had no detrimental effects on texture. SAPP caused a slight improvement in flavor by enhancing beef, salt, smoke and seasoning flavors, and by diminishing fat flavor and mouthfeel. However, the presence of SAPP resulted in intensified sour flavor and decreased aroma and flavor of pork. SAPP did not greatly reduce residual nitrite levels or increase the development of meat color. SAPP effectively lowered viscosity of the emulsion and held emulsion temperature down during emulsification. Unlike alkaline phosphates, SAPP did not improve moisture retention or cook yields; it had no effect on proximate analysis. SAPP did cause an increase in exudate formation in stored vacuum-sealed packages of frankfurters.
Effects of fat and NaCl/phosphate levels on the chemical and sensory properties of pork patties
Ground pork shoulders were combined with 50/50 pork trimmings to achieve fat levels of 20.0, 23.3, 26.6, and 30.0%. Salt/phosphate (NaCl/PO4) combinations of 0/0, 1/0, 1/0.25 and 2%/0.5% were blended with each fat level. Each treatment combination was stored at 3°C for 7 days in air-permeable film (AP), 21 days in vacuum pouches (VP) and at -23°C for 90 days in double-wrapped (DW) freezer paper. Fat level did not effect pH, expressed moisture (EM), peroxide value (PV), 2-thiobarbituric acid (TBA) values or cooking losses. Patties with 30.0% fat were juicier and required less energy to compress. A combination of 1% NaCl/0.25% PO4 reduced cooking losses, enhanced sensory properties and moderated the oxidation effects of NaCl up to 60 days of frozen storage. The NaCl treatment accelerated lipid oxidation most during all storage conditions while the control remained the least oxidized.
Effects of potassium chloride on properties of country-style hams
Sixteen fresh hams were dry-cured over a 90-day period using four curing formulations based on total and partial replacement of NaCl with KCl (0, 33.3, 66.7, and 100.0%). Total weight loss, moisture, fat, pH, firmness, color, total Cl- and residual NO-2 were not different among treatments at the end of the aging period. Hams with replacement levels of 66.7 and 100% KCl, when compared to the control, had higher levels of residual NO-3, less aged flavor, were more cohesive and were unacceptable due to extreme bitterness. Samples cured with 33.3% KCl were not different from the control, except for a slight degree of bitterness. Replacement of up to one-third of the NaCl in country-style hams with KCl appears feasible and could substantially lower the total Na+ content.
A comparison of non-meat proteins, sodium tripolyphosphate and processing temperature effects on physical and sensory properties of frankfurters.
Frankfruters, with and without 0.5% sodium tripolyphosphate (STPP), containing 3.5% vital wheat gluten (VWG), calcium reduced nonfat dry milk (RNFDM) and soy concentrate (SPC) were processed to an internal temperature of 72º or 82ºC and compared to an all-meat control. Processing yields, textural profile analysis (TPA) and sensory textural attributes were not different among protein treatments, but SPC and VWG contributed slight-to-moderate off-flavor. VWG and SPC franks were acceptable, but slightly less desirable than the control and RNFDM treatments. Franks processed to 82ºC were more desirable, but at the expense of reduced yields. STPP did not affect yields, but increased sensory firmness and TPA fracturability and hardness. VWG, RNFDM and SPC were comparable to the control for most traits studied, but alterations in spice formulation are needed ti improve VWG and SPC flavor.
Microbiological and shelf-life properties of ground beef containing glandless cottonseed flour
Ground beef with or without 3% added glandless cottonseed flour (GCF) was over-wrapped with polyvinyl chloride film and displayed up to 6 days in a retail case. Aerobic plate counts were slightly higher (P<0.05) for ground beef with GCF at day 0, with no difference (P>0.05) found at days 3 and 6. At day 6, a combination of Pseudomonas and heterofermentative Lactobacillus spp. made up a major part of the microflora of ground beef without GCF whereas heterofermentative Lactobacillus spp. constituted a dominant part of the microflora of ground beef with GCF. Discoloration and lipid oxidation in ground beef during display were markedly reduced by addition of 3% GCF.
Automated methods for determination of fat and moisture in meat and poultry products: Collaborative study.
A collaborative study was conducted to compare automated methods for rapid determination of fat and moisture in meat and poultry poducts with the official AOAC solvent extraction and forced-air oven methods, respectively. Fourteen products were tested, with fat and moisture contents ranging from 2 to 43% and 44 to 74%, respectively. Eight of the collaborating laboratories analyzed to the products by using a moisture/fat analyzer; 4 laboratories used the AOAC methods. Standard deviations for within-laboratory repeatability, between-laboratory reproducibility, and bias for each product indicated that the rapid methods were acceptable. The moisture/fat analyzer methods have been adopted official first action for fat and moisture analyses in meat and poultry products.
Sensory and physical attributes of frankfurters with reduced fat and elevated monounsaturated fats.
Instrumental and sensory evaluations were conducted on frankfurters manufactured with an increased monounsaturated/saturated (M/S) lipid ratio and 25% less fat than control. The M/S ratio was altered by using lean and fat from pigs fed 0%, 10%, or 20% canola oil (CO) which is high in oleic acid. Incorporation of 10% and 20% CO pork tissue into the product decreased saturated fat by 11.0% and 18.6%, respectively. Instron texture analysis indicated slight increases in cohesiveness with elevated CO, whereas decreasing fat increased gumminess and chewiness. Sensory evaluation demonstrated that the overall palability ratings of the test frankfurters were similar to the control product. Frankfurters with significantly less total fat and saturated fatty acids without adverse sensory and storage characteristics were produced.
Effects of zeranol and trenbolone acetate on testis function, live weight gain and carcass traits of bulls
The ability of zeranol and trenbolone acetate (trenbolone) to alter testis function, weight gain and carcass traits of young bulls was studied. In Exp. 1, the effects of age at initial zeranol implantation was determined. After a 235-d experimental period, sequential implantation (56-d intervals) beginning at 100 or 150 d of age had reduced testis growth (P<.01), sperm production (P<.01) and serum testosterone concentration in response to gonadotropin releasing hormone (GnRH; P<.01). The 200-d age group was partially suppressed, while the 250-d age group was not affected. Body weights were similar to controls in all groups. In Exp. 2, bulls previously implanted with zeranol at 175 and 231 d of age received single implants of zeranol, trenbolone or trenbolone plus zeranol at approximately 300 d of age. At slaughter (135 d later), body weight and carcass characteristics in all treatments were similar to controls. However, trenbolone reduced sperm production (P<.05), zeranol reduced sperm production and testes weight (P<.05), but trenbolone plus zeranol was similar to controls. Mean testosterone response to GnRH was suppressed in all implant groups on d 65 (P<.01), but only in trenbolone or trenbolone plus zeranol groups on d 112 (P<.05). Results indicate that zeranol suppresses spermatogenesis and testosterone production if implanted before approximately 200 d of age. Reduction of endogenous testosterone without alteration of weight gain or carcass characteristics may be of benefit if behavioral or masculinity traits of bulls are altered. Also, it appears that no benefit is derived from implanting bulls with both trenbolone and zeranol.
Effects of cryoprotectants in minimizing physical/chemical changes in bovine natural actomyosin during frozen storage.
Physiochemical changes in bovine natural actomyosin extracted from prerigor semimembranosus muscle were investigated during frozen storage at -28ºC as affected by the addition of cryoprotectants (5.6% Polydextrose® or 5.6% mixture (1:1) of sucrose and sorbitol). Proteins were destabilized during freezing and frozen storage as reflected by decreases in protein solubility, the visual appearance of aggregates in protein sols, decrease in intensity of flow birefringence, intrinsic viscosity and ATPase activity, and changes in size, shape, or charge of the protein (especially myosin) as evidenced by nondenaturing electrophoresis. These effects were reduced to some extent by the two cryoprotectant treatments.
Use of cryoprotectants to stabilize functional properties of prerigor salted beef during frozen storage
Changes in functional properties (gel-forming ability, water-holding capacity, and protein solubility) of salted prerigor beef and postrigor beef were measured over 6 months frozen storage at -28°C, as affected by addition of 5.6% cryoprotectants [Polydextrose‚ or 5.6% a mixture (1:1) of sucrose and sorbitol]. Addition of NaCl to comminuted muscle prior to freezing accelerated destabilization of muscle proteins with respect to functional properties. This effect was reduced by cryoprotectants; most effectively by sucrose/sorbitol and only slightly less effectively by polydextrose. As evidenced by the parameters investigated, quality of prerigor salted muscle treated with cryoprotectants and stored 6 months was approximately equal to that of untreated postrigor meat prior to freezing.
Physical and sensory characteristics of vacuum packaged beef steaks and roasts treated with an edible acetylated monoglyceride
Vacuum packaged strip loins and top rounds were fabricated into loin steaks and round roasts and treated, respectively, with 3 and 2% Dermatex‚ Food Grade (DFG), an acetylated monoglyceride. Samples were then vacuum packaged and stored at 2± 2°C for up to 49 (steaks) and 56 (roasts) d. Mean lean color (vacuum packaged and oxygenated), surface discoloration and overall appearance scores were not consistently different between treated and control steaks and roasts regardless of storage time. No consistent differences were observed in pH values of the lean and purge, percentage moisture or sensory evaluations of steaks and roasts treated with DFG before storage.
Consumer evaluation of sodium reduced, restructured lamb roasts
The longissimus dorsi (LD) and psoas major (PM) muscles were removed from the racks and loins of nine lamb carcasses (18 sides). Each LD was cut in half to yield 36 pieces of each muscle. Three defatted LD pieces and one PM were randomly grouped together (4 replications) and assigned to the following treatments at 1.5% of the fresh muscle weight: (1) 100% NaCl (control); (2) 75% NaCl + 25% KCl; (3) 50% NaCl + 50% KCl. Water (5%) and sodium tripolyphosphate (.3%) were also added. Muscle pieces were tumbled for 2h, tied into roasts, cooked and smoked. Proximate analysis results showed no significant differences (P>0.05) among treatment groups for percentage moisture and fat. The 100% NaCl control had significantly higher (P<0.05) cooking yields than the 50% KCl replacement treatment. A consumer sensory panel found no consistent differences among treatments for juiciness, flavor desirability, off-flavor, or overall acceptability among treatments. Consumer panel responses indicate that the low-fat (5.3-6.8%), low sodium (455-744 mg/100g), restructured lamb roasts evaluated in this experiment would be an acceptable new processed lamb product.
Evaluation of fresh vacuum-packaged beef steaks coated with an acetylated monoglyceride
Fresh beef loin steaks were coated with 3% (w/w) acetylated monoglyceride (DFG), vacuum-packaged and held at 2 ± 2°C for weekly evaluation during a 49-day storage period. When compared to control steaks, DFG had little effect on lean color, surface discoloration, overall appearance, moisture, pH, and sensory characteristics. DFG maintained an acceptable fat color longer and tended to reduce purge and microbial counts (aerobic, APT, and coliform) during storage. After 49 days, Lactobacillus cellobiosis was the dominant microorganism on treated and control steaks. The uncharacteristic aroma, oily coating and cost of application might outweigh the benefits derived from the use of DFG as an edible coating on steaks.
Evaluation of the physical and sensory properties of jerky processed from beef heart and tongue
Eighteen beef jerky formulations (nine treatments, 3 muscle types x 3 cooking times x 2 replications) were prepared from USDA Good top rounds, hearts, and tongues obtained from a commercial source. Muscles were sliced, cured for 3 days and cooked at 64°C for 12, 14 and 16 h. All treatments were evaluated for visual, sensory, chemical and cost analysis. Jerky produced from beef heart reduced final cost by 43%; however, visual and flavor properties of beef heart jerky were less desirable than jerky prepared from top round. Tongue jerky products were high in fat, extremely expensive and would be undesirable for today's health-oriented consumer. Top round beef jerky was the most desirable based upon sensory analysis, but heart jerky was highest in protein and lowest in fat. Further work may increase the possibility of reducing jerky costs by improving the color and flavor of beef heart jerky.
Minimization of oxidative flavor deterioration in refrigerated, batter-breaded restructured pork nuggets by glandless cottonseed flour in meat or coating
Pork shoulders were restructured into nuggets with 0.5% NaCl, 0.25% polyphosphate and 3.0% water or with the three additives plus 1.5% defatted glandless cottonseed flour (GCF). Restructured nuggets were batter-breaded with either commercial coating ingredients or commercial ingredients plus GCF. The coated nuggets were prefried in vegetable oil and stored at 4°C for 0 or 9 days before reheating when needed. Thiobarbituric acid values and sensory warmed-over flavor scores of products showed that oxidative flavor deterioration in batter-breaded pork nuggets can be minimized by incorporating GCF into either the meat or the coating system. The GCF additions did not have adverse effects on coating pick-up and palatability.
Oxidative stability of batter-breaded restructured nuggets processed from prerigor pork
Restructured pork slices made with either prerigor or postrigor meat, with or without 1.5% of defatted glandless cottonseed flour (GCF), were batter-breaded with or without GCF in predust and batter-mix. Prerigor products had less cooking losses than postrigor products; GCF in the meat or coating reduced cooking losses. Prefried prerigor products were more susceptible to lipid oxidation and warmed-over flavor development than prefried postrigor products. GCF in the meat or coating markedly reduced the oxidative deterioration in nuggets stored at 4°C or -20°C, regardless of the rigor state of meat used for restructuring. Little lipid oxidation occurred in vacuum-packaged raw nuggets stored at -20°C.
Comparisons of carboxymethyl cellulose with differing molecular features in low-fat frankfurters
Four types of carboxymethyl cellulose (CMC) with varying degrees of substitution (DS) and molecular weights were incorporated into low-fat, high moisture and high protein frankfurters. Emulsion stability (ES), chemical composition, processing yield and texture profile analysis were evaluated for frankfurters with 0.25% CMC and compared to an all-meat control. Generally, as the molecular weight of the CMC decreased the ES decreased; however, the processing yield and proximate composition of the products were no affected (P< 0.05) by the treatments. With the exception of springiness and cohesiveness, addition of the CMC significantly decreased textural parameters, but there were no textural differences in frankfurters due to molecular weights or DS of the CMC.
The influence of heat and cure preservatives on residues of sulfamethazine, chloramphenicol and cyromazine in muscle tissue.
Animals were given medications to produce incurred residues of sulfamethazine or chloramphenicol in swine and cyromazine and melamine metabolite residues in cattle. This muscle tissue was subjected to combinations of curing or noncuring and temperatures of 2-3, 68 (casing), and 122ºC (canning) with the analytes of interest quantitated before and after processing. Sulfamethazine survived in pork cured and thermally processed, although losses of up to 50% were observed. Half the chloramphenicol concentration in pork was lost in uncured processed tissue, with greater losses observed after curing and complete loss for canned product. Cyromazine losses of approximately 35% occurred in beef after processing and curing. Cyromazine levels increased when the beef was processed at 68ºC in casing, due to water loss. In canned product, melamine was present at 1 ppm for the dosed and nondosed tissue. The melamine contamination may be due to the melamine-formaldehyde resin in the can lining.
Microbiological characteristics of precooked, vacuum-packaged uncured beef and pork
Microbiological examination of 29 packages of precooked, vacuum-packaged beef and pork products purchased at local and regional supermarkets along with 110 packages of precooked, vacuum-packaged, sliced roast beef obtained from a major meat processor did not disclose the presence of Escherichia coli, coagulase-positive Staphylococcus aureus, Clostridium perfringens or Salmonella. The effects of storage temperature and length of storage on the microflora of 110 packages of sliced roast beef were determined at specific intervals of storage up to 84 days at 1° and 5°C, and up to 28 days at 10°C. The microflora of samples stored at 1°C and 5°C was dominated by Lactobacillus spp. when examined on day 28 and throughout the remainder of the 84-day test period. The microflora of samples held at 10°C was dominated by Lactobacillus spp. until late in storage when Hafnia alvei became a major portion of the bacterial population. Precooked, sliced roast beef had a longer shelf life in laboratory controlled evaluations when stored at 1°C as opposed to 5° or 10°C.
Impact of sodium ascorbate and sodium erythorbate used in meat processing on the Vitamin B12 contents of cured ham
Effects of sodium ascorbate (Na ascorbate) and sodium erythorbate (Na erythorbate) on vitamin B12 content of cured, cooked ham were investigated. Paired hams were injected with cure solution containing no curing accelerators or with cure solution containing Na ascorbate or Na erythorbate (3.28, 6.56, 9.84 g/L). There were no differences between vitamin B12 contents of hams containing added curing accelerators and paired controls, indicating that B12 was not destroyed by either Na ascorbate or Na erythorbate. Analysis of ascorbate, dehydroascorbate, isoascorbate and dehydroisoascorbate showed ascorbate to be the only substance present in Na ascorbate-treated hams and isoascorbic acid to be the only substance present in Na erythorbate-treated hams.
Properties of low-fat frankfurters containing monounsaturated and omega-3 polyunsaturated oils
Properties of low-fat (<18%) frankfurters containing high-oleic acid sunflower oil (HOSO) and fish oil were studied. Replacement of animal fats by the oils had little effect on emulsion stability. Frankfurters with 5% fish oil had very low sensory scores due to undesirable fish flavor. Incorporation of maximum amounts of HOSO into low-fat beef/pork and all-beef frankfurters increased oleic acid by 34% and 62%, respectively, and the monounsaturated/saturated fatty acid ratio by 178% and 468%, respectively, compared to regular (30% fat) product containing only animal fats. Sensory evaluation and instrumental texture profile analysis showed that the reduction in total fat caused texture problems, especially increased firmness and springiness and decreased juiciness.
Bioassay analysis of dry-cure ham processed to affect Trichinella spiralis.
Effects of curing time and temperature to destroy Trichinella spiralis in dry-cured hams were evaluated. Five muscle groups from small, medium and large, short-cure hams and large, bag-cure hams were subjected to a digestion technique to determine the number of T. spiralis larvae. Trichinae in small held at 10ºC for 90 days, in medium hams at 23.9 and 32.2ºC for 35 and 11 days, and in large hams at 10 and 23.9ºC for 90 and 35 days, respectively, were rendered non-infective. Medium hams contained a number of trichinae after 90 days at 10ºC. Bag-cure hams aged at 23.9 days at186;C for 35 days were free of trichinae. Results could indicate insufficient aging time at 10ºC for medium hams and the need for reviewing current USDA-FSIS regulations for the destruction of T. spiralis.
Physiochemical composition of dry-cured ham processed under minimal aging time/temperature conditions
Effects of ham size, aging time and temperature on the physiochemical composition of trichina-infected dry-cured hams were studied. Five muscle groups from small, medium and large short-cure hams and large bag-cure hams were analyzed for aw, moisture, NaCl and brine concentration. Semimembranosus/Adductor and Rectus femoris groups from the center has the lowest aw and moisture, and highest NaCl and brine concentrations compared to Biceps femoris + bottom Gastrocnemius groups from the hock. Aging at 32.2°C resulted in higher moisture and lower NaCl and brine percentages. Bag-cured hams were similar to the short-cure hams at 23.9°C. These results provide a detailed dataset of physiochemical analyses for dry-cured hams by individual muscle groups under minimal curing conditions.
Pathogen survival in precooked beef products and determination of critical control points in processing
Surfaces of precooked, roast beef slices were inoculated with Clostridium perfringens, Staphyloccuccus aureus, Escherichia coli, Salmonella typhimurium, or Listeria monocytogenes, vacuum packaged and then stored at 3°C for 70 d to determine survival of pathogens under extended refrigerated storage in the presence of natural competing microflora. S. typhimurium and L. monocytogenes remained present on the slices for the duration of the experiment. Numbers of S. aureus did not decrease significantly (P>0.05), and counts of C. perfringens decreased steadily over the 70-d storage period. Numbers of E. coli also declined, but more rapidly than the other pathogens during initial storage of the product. Total bacterial numbers for both uninoculated (control) and inoculated slices were similar. Samples obtained at selected locations in the processing sequence of a commercial restructured beef product contained L. monocytogenes at most sampling locations prior to heat processing, but not after heating. Salmonella bacterial numbers decreased as processing day progressed, as did counts for S. aureus, E. coli, and coliforms. Counts of S. aureus and total bacterial numbers increased after the cooked product was removed from the package and coated with a seasoning mix. Data collected in this study support the designation of the following locations as critical control points: initial bacterial levels on raw products, cooking temperature and time, proper cooling after cooking, sanitation after opening the package (rubbing with seasonings and rebagging), and temperature control of the final product.
Fat substitutes and fat modification in processing
(no abstract available)
Lactate dehydrogenase activity in bovine muscle as a potential heating endpoint indicator
Lactate dehydrogenase (LDH) activity was measured in heated extracts of cooked bovine muscle tissues to evaluate the potential for developing a rapid, accurate assay to verify cooking endpoint temperatures in beef. Adductor and semimembranosus muscles from six Angus steers were assigned to one of four treatments: fresh, frozen, frozen-thawed, or aged. Each treatment was applied to beef rounds that did or did not receive electrical stimulation. LDH activity rates were monitored in heated and unheated samples following 3 weeks of vacuum-packaged storage at 4°C. Treatments other than heating showed little effect on LDH activity. A major portion of activity was lost upon heating to 63°C, and only marginal activity was detectable at 66°C. Extractable protein decreased with increasing temperature. Decreases in LDH activity with increasing temperature may result from heat denaturation of the enzyme and/or from increased amounts of extractable protein.
Evaluation of partially defatted chopped beef in a fermented beef snack sausage.
Five levels (0, 5, 10, 15, 20%) of partially defatted chopped beef (PDCB) were substituted for lean in fermented beef stick sausage to evaluate changes over a 90 day period (24ºC). Replacement of 0, 5, 10, 15, and 20% of the lean with PDCB did not affect percentage of fat, moisture, protein, moisture:protein ratio, or aw of the final product. TBA values were different (P<0.05) between storage periods, but were all lower than those associated with oxidative rancidity. Warner-Bratzler shear values increased incrementally with increasing PDCB but were still within acceptable limits. Sensory profiles indicated that concentration of PDCB in the formulation had no effect on aroma, mouthfeel, taste, or texture of the product over storage time.
Lactate dehydrogenase enzyme activity in raw, cured, and heated porcine muscle
Semimembranosus, semitendinosus, biceps femoris, rectus femoris, and adductor muscles were dissected from nine fresh hams. Each muscle was analyzed for lactate dehydrogenase (LDH) activity after receiving one of the following treatments: fresh, aged, frozen, frozen-thawed, heated, cured, and cured-heated. Aging resulted in an increase in LDH activity, while freezing and freezing-thawing resulted in a marked decrease in activity. Heating fresh tissue to 65-68°C resulted in large activity losses. Heating to 68°C and above significantly inactivated the enzyme. Curing and heating to 63.8°C eliminated almost all LDH activity. Pyruvate kinase, malate dehydrogenase, adenylate kinase, isocitrate dehydrogenase, creatine kinase, aspartate aminotransferase, fructose-1, 6-bisphosphate aldolase, citrate synthase, and glutamate-oxaloacetate transminase activities were monitored in cured ham muscle heated to 64.5 and 68.8°C. No appreciable enzyme activity was detected in any cured/heated samples.
Lactate dehydrogenase activity in bovine muscle as a means of determining heating endpoint
Influence of pH, salt, phosphate, cooking temperature, muscle variation, carcass sex and maturity on lactate dehydrogenase (LDH, E.C. 1.1.1.27) activity in bovine tissue slurries was investigated. LDH activity declined sharply as temperature neared 63°C at pH 5., but no activity was detected at pH 4.8. As salt and phosphate concentrations increased, LDH activity decreased. LDH activity varied greatly from muscle to muscle. Carcasses did not differ in LDH activity by sex, but showed a decrease in activity as maturity increased. LDH has potential as a determinant of the minimum heating endpoint in precooked beef and a rapid analytical test could be developed.
Altering fat composition of read meat and fish products
Meat products have been implicated in contributing to the incidence of heart disease. Recommendations from health care professionals, the Surgeon General, the USDA Dietary Guidelines, and the American Heart Association have emphasized consuming meat products with less fat. Recent purchasing trends suggest that consumers have become more conscious of the amount and type of fat in their diet and have tended to increase their purchases of foods that claim decreases in fat, calories, sodium, and cholesterol. Pork and beef carcasses have become leaner over the past two decades, and, in combination with trimming of retail cuts, over 42% of beef cuts recently surveyed had no external fat and the over all fat thickness for steaks and roasts from the chuck, rib, loin, and round averaged 0.14 in. To optimize palatability and limit fat in beef cuts and fresh pork cuts, an intramuscular fat content of 3% on an uncooked basis is necessary for minimal acceptable palatability, whereas no more than 7.3% fat should be present to meet the nutritional requirements of lean meat.Decreasing the fat content of red meats and fish can be accomplished by (1) using leaner raw materials, (2) including non-meat ingredients in processed meats that serve as fat replacements, and (3) applying new process technologies that decrease the fat and cholesterol content of meat tissues. Increased use of more lean meats and fish may require removing individual muscle groups from carcasses and grouping according to product categories while also including less caloric dense meat ingredients, such as fat-reduced beef/pork, partially defatted chopped beef/pork, mechanically separated meats, and surimi. Fat replacements that offer a great deal of promise include ingredients such as added water or high protein meat slurries; protein-based flours, concentrates or isolates; carbohydrate-based starches, gums maltodextrins, or dextrins; and new-generation synthetic compounds.
Low-fat meat products &endash; technological problems with processing
Diet and health advice serves as a driving force to redirect the types of foods considered to be most beneficial in terms of improved health and quality of life for Americans. Although meat cuts have become leaner, products such as ground beef, fresh pork sausage, coarse ground sausages and emulsified sausages traditionally have higher levels of fat. However, these products offer the greatest opportunity for fat reduction by reformulation with fat substitutes. Fat replacements should contribute a minimum of calories to a product and should not be detrimental to organoleptic qualities. Most substitutes can be categorized as: leaner meats, added water, protein-based substitutes, carbohydrate-based substitutes and synthetic compounds. Reducing the fat content to ~10% often results in cooked ground beef that is bland and dry with a hard, rubbery or mealy texture. Reformulation with fat substitutes can cause a reduction in particle binding, darker product color, lack of beef flavor, reduced browning reactions and shorter microbiological shelf-life. Other problems that occur with low-fat (5-10%) fresh or cooked/smoked sausages are reduced cook yields, soft mushy interiors, rubbery skin formation, excessive purge in vacuum packages, shorter shelf-life and changes in sensory qualities after cooking or reheating. However, some combinations of fat replacements that mimic the mouthfeel and textural characteristics of fat offer potential for development of low-fat meat products.
Determination of optimum particle size for low-fat, precooked ground beef patties
Low-fat (10%) beef patties varying in particle size, C (Comitrol‚ flaked), CG (mixture of flaked and ground) and G (coarse-ground) were precooked, frozen and microwave reheated for sensory, instrumental and compositional evaluations. Treatment G had higher cooking and reheating losses, higher shear values and lower final yields. Additionally, G was harder, denser, more easily fractured, and less juicy than other treatments. All treatments were similar in sensory flavor attributes. C had the least cooking and reheating losses, lower shear values and higher final yields; however, it also showed surface "puffing" and an internal air pocket after microwave reheating which could be a disadvantage. Results indicated that physical shape, size or density of meat particles played a major role in textural traits. For optimum yield and textural properties, low-fat, precooked beef patties targeted for the frozen market probably should be manufactured using a Comitrol‚-grinding (CG) combination.
Konjac flour gel as fat substitute in low-fat prerigor fresh pork sausage
Prerigor trimmings from four lean cuts of pork carcasses (n=3) were used to manufacture three replications of low-fat (10%) fresh pork sausage containing konjac flour gel, at 0, 10 or 20% levels and compared to a 40% fat control. Treatment sausages showed equal or improved cooked yields, slightly higher shear force (kg/g) and sensory textural attributes, but rated slightly lower in juiciness. As konjac flour gel levels increased, shear force and sensory textural attributes became more like the control. Storage time had minimal effect on quality and shelf life. Acceptable low-fat, prerigor pork sausage can be produced with 10-20% incorporation of konjac flour gel.
Sodium lactate and sodium tripolyphosphate effects on oxidative stability and sensory properties of precooked reduced-fat pork sausage with carrageenan
One 40% fat, three 10% fat, and three 17% fat ground pork sausage products were manufactured. Within each reduced-fat level, these products contained 0.5% carrageenan, carrageenan and 3% sodium lactate (SL), and carrageenan, SL and 0.25% sodium tripolyphosphate (SP). Precooked patties packaged with oxygen-permeable PVC film were stored at 4°C and &endash;20° C for up to 6 days and 252 days, respectively. Vacuum-packaged patties were stored up to 84 days and 252 days at the respective temperatures. All reduced-fat products were harder, more dense, and less juicy than the 40% fat product. Total aerobic microbial plate counts determined on PVC packaged samples stored at 4°C were similar among the 7 products. SL acted as a prooxidant as evaluated by 2-thiobarbituric acid values. SP used with SL tended to overcome the prooxidive effect of SL but increased springiness, hardness, and fracturability sensory scores.
Fish oil dietary effects on fatty acid composition and flavor of channel catfish
A typical channel catfish diet was supplemented with 0, 1.5 and 3% menhaden oil. Fillets were subjected to lipid, fatty acid, and TBA analyses. After 6 mo storage at &endash;18°C, fillets were again analyzed for TBA value and flavor panel profile. Fillets from catfish fed diets with 1.5 and 3% supplemental fish oil had elevated levels of n-3 fatty acids (P<0.05). TBA number and off-flavor attributes were not affected by treatments. Menhaden oil supplementation up to 3% enhanced the content of n-3 fatty acids in channel catfish fillets without adversely affecting flavor attributes or storage quality.
Ostrich slaughter and fabrication: 1. Slaughter yields of carcasses and effects of electrical stimulation on post-mortem pH
A commercial ostrich slaughter protocol was developed. Ostriches (n=7 males and n=7 females) averaged 95.54 kg live weight and yielded 55.91-kg carcasses. By product yields were measured. The most significant by-products by weight were full viscera (8.29 kg), hide (6.71 kg), full gizzard and crop (5.80 kg), and abdominal fat (4.11 kg). Sex had no effect on slaughter yields. Post-mortem temperature declines were measured on five separate muscles and showed that chilling for 24 h was sufficient to adequately chill the deep muscle temperature to under 4°C. The effect of electrical stimulation on post-mortem pH decline also was investigated and had no effect.
Qualitative and quantitative textural assessment of cooked ground beef patties
Cohesiveness of extruded, sliced hamburger patties from two manufacturers was studied in relation to cooking performance. Tensile determinations of ultimate strength and toughness were related to cohesiveness as measured with an Instron Universal Testing Machine. Light and environmental scanning electron microscopy was used to relate physical and macroscopic observations. Very cohesive samples had values of ultimate strength > 1.45N and toughness < 1.50 x 10-4J. Tensile results allowed discrimination between levels of cohesiveness among ground beef patties and could serve as a monitoring device to ensure consistency and indicate failure of the product at the serving outlet.
Reduction of drying time for pepperoni by vacuum-drying
Commercial pepperoni was dried under vacuum (100 kPa) at three temperatures (17°, 19°, and 22°C) and matching controls were dried under commercial conditions. Vacuum-dried pepperoni achieved a moisture:protein (M:P) ratio of 1.6:1 after 9 to 12 days drying, compared to 18 days for the control. Overall drying time was reduced 30%. Among temperature treatments, 17°C treatment had more weight loss and darker color (P<0.05) than others. Weight loss and Kramer shear force were higher (P<0.05) for vacuum-dried pepperoni, whereas Hunter a and b values tended to be higher for the control throughout the drying period.
Sarcoplasmic enzymes as potential indicators of heating endpoints in meat products
Recent outbreaks of foodborne illness caused by Escherichia coli O157:H7, Listeria monocytogenes and Salmonella have raised concerns about the safety of prepared meats. The USDA-FSIS has responded by requiring safe handling labels on fresh meat products, increased surveillance of prepared meat products, higher heating endpoint temperatures and has proposed to declare E. coli O156:H7 an adulterant. As a result, accurate and rapid methods for monitoring prepared meats to ensure pathogen destruction are required. Enzymes and proteins play an essential role as diagnostic tools and monitoring devices for food components and contaminants. The application of enzyme techniques or other protein identification procedures could verify if sufficient heat has been applied to meat products to destroy pathogens. Several enzymes from various muscles have been screened for loss activity within the range of processing temperatures deemed safe. Enzyme candidates from bovine, porcine and avian muscles which could likely be developed into rapid enzyme or immunoassays are discussed.
Lactate dehydrogenase activity as an endpoint heating indicator in cooked beef
Lactate dehydrogenase (LDH, E:C 1.1.1.27) activity, specifically LDH5 isoenzyme, declined significantly when bovine Semimembranosus (SM) slurries were heated from 57° to 66°. When SM whole muscle roasts were brine pumped and oven-cooked, total LDH and specific activities declined proportionately from 57° to 63°C resulting in almost no activity at 63°± 0.5°C. LDH activities were consistently higher in younger cattle and lower in older cattle for SM, Infraspinatus (IN) and Longissimus dorsi (LD) muscles and were lowest overall in the IN. LDH colorimetric and fluorescent assays were more accurate indicators for predicting beef roast heating temperature endpoints between 60° and 63°C than the USDA-FSIS method.
Functional, textural and microstructural properties of low-fat bologna (model system) with a konjac blend
The form (dry vs prehydrated) and level (0, 0.5, 1.0 and 1.5%) of a konjac blend (KB) were evaluated to determine their effects on the characteristics of a low-fat bologna model system (LFBMS). The system had a pH range of 6.01 to 6.12, moisture 74 to 76%, fat <2.0% and protein 17 to 18%. Prehydrated KB had higher (P<0.05) texture profile analysis (TPA) hardness values than dry addition, whereas lower TPA values (P<0.05) were observed as the level of KB increased. In microstructural observation, the addition of prehydrated KB gels caused the protein matrix to appear more swollen in structure as compared to that after inclusion of a dry powder.
Low-fat bologna in a model system with varying types and levels of konjac blends
A low-fat bologna model systems (LFBMS) with a konjac blend (KB) level of 0.5% had higher moisture content and shear stress values (P<0.5) than a 1.0% KB. Increasing moisture:protein (M:P) ratios from 5.0 to 6.0 had the greatest effect on chemical and physical parameters. Three konjac types (KSS, KHC and KNC) had varying effects on these parameters. Allo-Kramer shear, texture profile analysis (TPA) and torsion tests indicated that LFBMS with a 0.5% konjac level and a M:P ration of 6.0 or a 1.0% konjac level and M:P ratios of 5.5 or 6.0 yielded similar products to the control (30% fat).
Meat fermentation research opportunities
(no abstract available)
Textural and physicochemical properties of low-fat, precooked ground beef patties containing carrageenan and sodium alginate
Textural and physicochemical characteristics of selected hydrocolloids incorporated into low-fat, precooked, beef patties were investigated. Patties with alginate/carrageenan combination had higher yields and percent moisture but lower shear force values than those of alginate or carrageenan treatments within the same fat level. Alginate appeared to improve the texture slightly more than carrageenan, but carrageenan tended to release more free water after cooking and reheating. Patties with 10% fat were generally lower in shear value, cooking yield and percentage free water released as compared to their 5% fat counterparts with the same added ingredient. Low-fat, precooked, ground beef patties containing alginate/carrageenan combinations were comparable to regular beef patties (20% fat control) regarding yields and textural properties.
Utilization of soy protein isolate and konjac blends in a low-fat bologna (model system)
Low-fat bologna formulations (LFBMS, <2.0% fat) were manufactured in a model system with two levels (0.5 or 1%) of two konjac blends (KB: KSS=konjac flour/starch and KNC=konjac flour/carrageenan/starch), and three levels (0, 2.2, 4,4%, DWB) of prehydrated soy protein isolate (SPI) to replace 0, 2 and 4% of the meat protein, respectively. Compared to 0.5% KB, the 1% level reduced (p<0.05) protein solubility (PS), vacuum purge (VP, %) and texture profile analysis (TPA) hardness. LFBMS containing KNC had higher (p<0.05) cooking yields, TPA fracturability and shear stress, but lower (p<0.05) expressible moisture (EM), VP values and TPA cohesiveness than KSS. Replacement of 4% meat protein with SPI increased (p<0.05) pH and yellowness (b*), but decreased (p<0.05) redness (a*), PS, EM and most textural characteristics, whereas no differences (p>0.05) were observed between 1 and 2% of meat protein replacements with SPI for most characteristics.
Evaluation of konjac blends and soy protein isolate as fat replacements in low-fat bologna
Low-fat bolognas (LFB, <2.0% fat) were developed with 2 levels (0.5% or 1.0%) of konjac blends (KB, KSS=konjac flour/starch and KNC=konjac flour/carrageenan/starch) and the replacement of meat proteins with 2% soy protein isolate (SPI, DWB). Increased levels of KB decreased (P<0.05) lightness and yellowness, and most texture profile analysis (TPA) values. LFB containing 1.0% KB with 2% SPI addition had TPA values and sensory flavor/taste attributes similar to the control (CTL II, 30% fat), where as LFB formulated with KSS had textural characteristics more similar to CTL II than those with KNC, based on sensory evaluation.