Quality changes in beef gluteus medius, infraspinatus, psoas major, rectus femoris, and teres major enhanced prior to aging

ABSTRACT:  The objective of this study was to evaluate the effects of enhancement and aging on quality characteristics of the gluteus medius (round), rectus femoris (round), teres major (chuck), infraspinatus (chuck), and psoas major (loin). Muscles were enhanced, vacuum packaged, and aged for 7 or 14 d. Aging affected enhanced compared with nonenhanced beef differently. After 7 d of aging, enhanced beef experienced more cook loss and was less red (higher hue angle, lower a * values, and chroma) than did nonenhanced beef; after 14 d of aging, these differences were lost. Enhancement increased tenderness and brown color of the gluteus medius (round); however, it decreased visual green and red colors. Enhanced gluteus medius experienced 3.1% lower purge losses, lower L * values, and chroma than their nonenhanced counterparts. Enhancement increased infraspinatus (chuck) tenderness and visual brown color, and decreased visual red and green colors, purge loss, L * value, a * value, and chroma. The enhanced infraspinatus was substantially more tender than the other muscles evaluated, other than the gluteus medius ; however, it was also substantially more visually brown. Enhancement decreased purge loss of the psoas major . Enhancement increased L * and a * values, hue angles, and chroma than other enhanced muscles. After enhancement the tenderness of the rectus femoris increased by 10%, decreased purge losses from 4.5% to 1.7%, and decreased green color by 18%. It reduced L * and a * values and chroma. Aging increased tenderness. Overall, muscles from the chuck ( infraspinatus and teres major ) appeared to benefit the most from enhancement.     

Probabilistic safety assessment support for the maintenance rule at Duke Power Company

The Nuclear Regulatory Commission (NRC) published the Maintenance Rule on July 10, 1991 with an implementation date of July 10, 1996 [1]. Maintenance rule implementation at the Duke Power Company has used probabilistic safety assessment (PSA) insights to help focus the monitoring of structures, systems and components (SSC) performance and to ensure that maintenance is effectively performed. This paper describes how the probabilistic risk assessment (PRA)¹ group at the Duke Power Company provides support for the maintenance rule by performing the following tasks: (1) providing a member of the expert panel; (2) determining the risk-significant SSCs; (3) establishing SSC performance criteria for availability and reliability; (4) evaluating past performance and its impact on core damage risk as part of the periodic assessment; (5) providing input to the PRA matrix; (6) providing risk analyses of combinations of SSCs out of service; (7) providing support for the SENTINEL program; and (8) providing support for PSA training. These tasks are not simply tied to the initial implementation of the rule. The maintenance rule must be kept consistent with the current design and operation of the plant. This will require that the PRA models and the many PSA calculations performed to support the maintenance rule are kept up-to-date. Therefore, support of the maintenance rule will be one of the primary roles of the PSA group for the remainder of the life of the plant.     

Characterization of striping in fresh, enhanced pork loins

To investigate the striping phenomenon in fresh, enhanced pork, a series of experiments were undertaken to identify possible causes of the problem. No one factor (individual brine components, brine pH, ingredient concentration, enhancement pressure, meat and brine pH, or enhancement level) was specifically identified, which could be used to reduce the severity of the striping problem. Furthermore, tumbling the product for 2h, did not reduce the amount of striping, indicating once striping has occurred, it is permanent. Evaluation of the striping pattern indicates that the stripes are formed not only at the needle injection site, but also follow the muscle fiber orientation. The use of darker pork provided more of a contrast when evaluating striping, thus exacerbating the perceived level of striping.     

Irradiation effects on meat flavor: A review

Irradiating fresh meat, even at low doses, can result in off-odors and flavors which have been described as rotten egg, bloody, fishy, barbecued corn, burnt, sulfur, metallic, alcohol or acetic acid. The odors vary with the type of meat, temperature during irradiation, oxygen exposure during and/or after the irradiation process, packaging and presence of antioxidative substances. Irradiation can induce formation of isooctane-soluble carbonyl compounds in the lipid fraction and low molecular weight, acid-soluble carbonyls in the protein fraction of meat. Increasing irradiation dose increases these compounds however, cooking reduces them. Among the volatile components, 1-heptene and 1-nonene are influenced most by irradiation dose, and aldehydes (propanal, pentanal, hexanal) are influenced most by packaging type (aerobic vs vacuum). Sulfur-containing volatiles formed from sulfur-containing compounds (primarily amino acids) also contribute to irradiation odor. Dimethyltrisulfide is one of the most potent off-odor compounds, contributing fishy, putrid odors, followed by bismethylthiomethane (sulfurous). Reducing the temperature during the irradiation process reduces the effects on odor/flavor because free radical generation and dispersion are reduced. Ultimately, radiolysis of water into free radical species (OH,H, H(3)0(+), e(aq)(-)) may be the initiators of both lipid oxidation breakdown products and sulfur-containing volatiles responsible for irradiation odor. Methods to decrease the detrimental effects of irradiation include oxygen exclusion (vacuum packaging), replacement with inert gases (nitrogen), addition of protective agents (antioxidants), and post-irradiation storage to allow flavor to return to near-normal levels (re-packaging or double packaging in oxygen permeable film).     

Effect of carbon monoxide and high oxygen modified atmosphere packaging and phosphate enhanced, case-ready pork chops

The objective of this study was to evaluate the effects of CO-MAP compared to traditional high oxygen MAP (HiOx-MAP) packaging and enhanced with different phosphate on enhanced pork quality. Pork loins were enhanced to 10.5% over initial weight to contain 0.3% salt and 0.4% phosphate (either sodium tripolyphosphate [STP] or a blend of STP and sodium hexametaphosphate) on a finished weight basis. Chops were cut, packaged in atmospheres containing 0.4% CO/30.0% CO₂/69.6% N₂ (CO-MAP) or 80% O₂/20% CO₂ (HiOx-MAP), aged in the dark, then placed in a lighted retail display case for 48 h. Chops packaged in CO-MAP were redder (higher Minolta a^* values) and darker (lower Minolta b^* values) than chops packaged in HiOx-MAP. Based on sensory scores, the CO-MAP chops were pinker than the HiOx chops after cooking. CO-MAP chops also experienced less purge loss than chops in HiOx-MAP. Results indicate that CO-MAP had no effect on flavor or consumer acceptability and only minimal effects on other characteristics.     

Effects of Shelf-Life Enhancers on E. coli K12 Survival in Solutions Used to Enhance Beef Strip Steaks

ABSTRACT:  The objective of this study was to evaluate the effects of enhancement solutions containing sodium lactate or sodium lactate/sodium diacetate on E. coli K12 transmission to beef strip steaks and in purge. Solutions containing salt, phosphate, and shelf-life enhancers were injected to 10% over initial weight of the steaks. Lactate or lactate/diacetate addition to a solution inoculated with 6 log₁₀ E. coli K12 CFU/mL was equally effective in limiting growth resulting in a 1-2 log₁₀ CFU/g reduction when compared to salt/phosphate in steaks. When inoculation level was 3 log₁₀ CFU/mL in the enhancement solution, microbial growth was detectable only in the purge of steaks enhanced with salt/phosphate only. Lactate increased CIE L* value and b* and decreased a* values when compared to the control. Lactate-/diacetate-containing solutions decreased L* values when compared to lactate alone. Lactate/diacetate also reduced purge loss from steaks compared to lactate and salt/phosphate solutions.     

Characteristics of Low-fat Beef Patties Formulated with Carbohydrate-Lipid Composites

ABSTRACT: Chemical, physical, and sensory characteristics of low-fat beef patties containing carbohydrate-lipid composites (CLCs) were compared with those of all-beef patties. The CLC gels contained high-amylose cornstarch, maltodextrins, and canola oil. CLC patties had higher moisture, cooking yield, and fat retention than 20%-fat control patties. CLCs improved tenderness and juiciness and decreased cohesiveness of low-fat beef patties compared with 10%-fat control patties. Despite differences in CLC gel firmness, patties made with CLC gels containing corn, potato, and tapioca maltodextrins had similar physical and sensory properties. These results suggest that CLC gels perform well as a partial fat replacer in beef patties while providing flexibility in gel firmness selection.     

Effect of Natural Antioxidants,Irradiation, and Cooking on Lipid Oxidation in Refrigerated,Salted Ground Beef Patties

Antioxidant effects of natural antioxidants in 73%‐lean ground beef patties during refrigeration were studied. Samples were subject to an antioxidant treatment (pomegranate extract, grape seed extract, butylated hydroxyanisole, or no treatment) and an irradiation treatment (0 or 1.5 kGy) before being evaluated for both uncooked and cooked indicators of lipid oxidation. Chemical evaluation of antioxidant activity were determined over 9 d through measurement of thiobarbituric reactive substances values. Physical evaluation of antioxidant activity was monitored by changes in physical color and sensory odor analysis on patties before and after cooking. Butylated hydroxyanisole extended the induction period of oxidation in all unirradiated beef patties better than the natural antioxidants. Panelists were able to distinguish a difference (in terms of oxidation attributes) between patty samples of different antioxidant and irradiation treatments while samples were uncooked, but unable to distinguish a difference between patties after cooking.     

Preparation of Aluminum Coatings Containing Homogenous Nanocrystalline Microstructures Using the Cold Spray Process

Nanostructured materials are of widespread interest because of the unique properties they offer. Well-proven techniques, such as ball milling, exist for preparing powders with nanocrystalline microstructures. Nevertheless, consolidation of nanocrystalline powders is challenging and presents an obstacle to the use of nanocrystalline metals. This work demonstrates that nanocrystalline aluminum powders can be consolidated using the cold spray process. Furthermore, transmission electron microscopy (TEM) analysis of the nanocrystalline cold spray coatings reveals that the cold spray process can cause significant grain refinement. Inert gas atomized 6061 and 5083 aluminum powders were ball milled in liquid nitrogen resulting in micron-sized powder containing 250-400 nm grains. Cold spray coatings prepared using these feed stock materials exhibited homogenous microstructures with grain sizes of 30-50 nm. TEM images of the as-received powders, ball-milled powders, and cold spray coatings are shown.