Determining the Effectiveness of Rosemary Essential Oil on the Shelf Life of Ground Beef Under Different Lighting Conditions

This study determined the effectiveness of rosemary extract on the shelf life of ground beef patties under different retail display conditions. Ground beef patties were produced from an 85%:15% blend (lean:fat). Patties were formed from batches of control or amended with rosemary extract. Patties were individually packaged using overwrap. Groups were assigned into one of two lighting groups (3000K and 3500K). Patties were placed in a simulated retail display for 5 d under continuous lighting and rotated once a day. Lipid oxidation and color samples were taken each day. Relating to lipid oxidation, there was no three-way interaction between display day, antioxidant, and light intensity (P \u3e 0.05). There was an interaction observed between antioxidant and day (P \u3c 0.0001). Relating to color spectrometry, L* values presented an interaction between antioxidant and lighting intensity (P = 0.0029). A two-way interaction between day and antioxidant (P = 0.0003) was also shown in a* values and b* values (P = 0.0008). Chroma values displayed an interaction between antioxidant and day (P = 0.0008). The hue data concluded similar results (P = 0.0008); there was an interaction observed between antioxidant × day (P \u3c 0.0001). These results indicate that color instability and degradation can be prevented with the introduction of antioxidants and the reduction of retail display days. These data suggest that antioxidants reduce lipid oxidation regardless of light temperature. Antioxidants can still be used to extend shelf life and improve color stability in ground products

Determining the Effectiveness of Rosemary Essential Oil on the Shelf Life of Ground Beef Under Different Lighting Conditions

This study determined the effectiveness of rosemary extract on the shelf life of ground beef patties under different retail display conditions. Ground beef patties were produced from an 85%:15% blend (lean:fat). Patties were formed from batches of control or amended with rosemary extract. Patties were individually packaged using overwrap. Groups were assigned into one of two lighting groups (3000K and 3500K). Patties were placed in a simulated retail display for 5 d under continuous lighting and rotated once a day. Lipid oxidation and color samples were taken each day. Relating to lipid oxidation, there was no three-way interaction between display day, antioxidant, and light intensity (P \u3e 0.05). There was an interaction observed between antioxidant and day (P \u3c 0.0001). Relating to color spectrometry, L* values presented an interaction between antioxidant and lighting intensity (P = 0.0029). A two-way interaction between day and antioxidant (P = 0.0003) was also shown in a* values and b* values (P = 0.0008). Chroma values displayed an interaction between antioxidant and day (P = 0.0008). The hue data concluded similar results (P = 0.0008); there was an interaction observed between antioxidant × day (P \u3c 0.0001). These results indicate that color instability and degradation can be prevented with the introduction of antioxidants and the reduction of retail display days. These data suggest that antioxidants reduce lipid oxidation regardless of light temperature. Antioxidants can still be used to extend shelf life and improve color stability in ground products

Evaluation of Dry-Heat Cookery Method on Volatile Flavor Compound Development and Consumer Evaluation of Six Beef Muscles

The objective of this study was to determine the influence of dry-heat cookery on beef flavor development of multiple beef muscles. Beef strip loins, top sirloin butts, paired tenderloins, paired shoulder clods, and chuck rolls were collected from USDA Low Choice carcasses (Small00–Small100 marbling; N = 20). Subprimals were wet aged in the absence of light for 21 d at 0°C to 4°C. Subprimals were fabricated into 2.54-cm-thick steaks representative of the following muscles: Gluteus medius, Infraspinatus, Longissimus lumborum, Psoas major, Serratus ventralis, and Triceps brachii and randomly assigned to one of 4 dry-heat cookery methods: charbroiler grill (CHAR), clamshell grill (CLAM), convection oven (OVEN), and salamander broiler (SALA). Steaks were cooked to a medium degree of doneness (71°C) on the randomly assigned cooking method. Untrained consumer panelists (N = 300) evaluated each sample for flavor, tenderness, juiciness, and overall liking. No interactions were observed between cooking method and muscle (P ≥ 0.344) for any palatability traits evaluated. Consumers preferred CHAR steaks (P < 0.05) over CLAM steaks for flavor, tenderness, juiciness, and overall liking. Additionally, CLAM steaks were rated lower (P < 0.05) than all other methods for tenderness and juiciness. OVEN and SALA steaks were rated higher (P < 0.05) than CLAM steaks by consumers for tenderness and juiciness but were similar (P > 0.05) to CLAM steaks for overall liking. CHAR steaks produced a greater concentration of Maillard compounds compared with the other cooking methods. Steaks cooked using OVEN and SALA (P < 0.05) produced more lipid oxidation products. Additionally, CHAR steaks produced the greatest (P < 0.05) total volatile production compared with all other treatments, which may be a result of the combination of Maillard reaction products and the lipid degradation products

Effects of Dry-Heat Cookery Method on Beef Strip Loin Steaks of Two Quality Grades Following Sous Vide Preparation

The objective of this study was to determine the influence of dry-heat cookery method on beef flavor develop- ment in strip loin steaks from 2 USDA quality grades following sous vide preparation. Beef strip loins were selected from 2 USDA quality grades: upper 2/3 Choice (Modest00–Moderate100) and Select (Slight00–Slight100 marbling, n = 20/grade). Following 21 d of wet aging, strip loins were fabricated into 2.54-cm thick-steaks and randomly assigned to one of 4 dry- heat cookery methods: charbroiler grill (CHAR), clamshell grill (CLAM), convection oven (OVEN), and salamander broiler (SALA). Prior to untrained consumer panel and volatile compound analysis via gas chromatography-mass spectrometry, steaks were cooked under sous vide conditions for 1.5 h, then finished on the assigned cookery method. There were no cooking method ×quality grade interactions (P ≥ 0.076) for all consumer traits evaluated. Overall, SALA steaks received higher (P < 0.05) ratings by consumers than CLAM steaks for all palatability traits. OVEN steaks had greater scores (P < 0.05) than CLAM steaks for juiciness, tenderness, and overall liking but were similar to CLAM steaks (P > 0.05) for flavor. CHAR steaks were similar (P > 0.05) to CLAM steaks for flavor but were rated higher (P < 0.05) for tenderness, juiciness, and overall liking. Steaks cooked using the OVEN method produced a greater concentration of lipid-derived volatiles, such as alcohols, aldehydes, and carboxylic acids. In direct contrast, CHAR steaks produced a higher concentration of pyrazines and Strecker aldehydes, which are derived from the Maillard reaction. These data indicate that cookery method, and therefore heat transfer method, has a substantially stronger influence on consumer ratings and flavor development than USDA quality grade in this study when steaks are prepared using sous vide methods

The Impact of Enhancement, Degree of Doneness, and USDA Quality Grade on Beef Flavor Development

The objective of this study was to determine the impact of enhancement, degree of doneness (DOD), and USDA quality grade on beef volatile flavor compounds from cooked strip loin steaks. This study also aimed to evaluate relationships between volatile compounds and consumer sensory responses. Beef strip loins (n = 72; 24/grade) of 3 quality grades (USDA Prime, Low Choice, and Low Select) were enhanced (8% of green weight with brine containing 0.35% salt and 0.4% sodium phosphate) or not enhanced, and cooked to 3 DOD (Rare: 60°C; Medium: 71°C; Very Well Done: 83°C) before volatile analysis. Volatile compounds were evaluated through a split-plot design where enhancement level and quality grade were used as the whole plot factors and DOD served as the subplot factor. Principal component analysis (PCA) was utilized to explore relationships between volatile compounds, consumer response, and treatments. The majority of compounds (n = 32) were impacted (P 0.05). In agreement, PCA indicated volatile compound production was primarily driven by degree of doneness and quality grade. There was no strong link between enhancement and beef volatile flavor compound development, despite the dramatically improved flavor liking scores from consumers

Determination of Package and Muscle-Type Influence on Proteolysis, Beef-Flavor-Contributing Free Amino Acids, Final Beef Flavor, and Tenderness

The objectives of this study were to determine the influence of package and muscle type on postmortem proteolysis and subsequent release of flavor-contributing free amino acids during storage. Beef strip loins and top sirloin butts (n = 20/subprimal) from USDA Low Choice carcasses were fabricated into 2.54-cm steaks (M. longissimus lumborum and M. gluteus medius) at 7 d postmortem. Steaks were randomly assigned to packaging treatments (carbon monoxide mother-bag [CO], high-oxygen modified atmosphere packaging [HIOX], polyvinyl overwrap [OW], or rollstock [ROLL]) and aged for an additional 14 d in dark storage. Steaks intended for OW were initially vacuum packaged during dark storage,then overwrapped just prior to display. Steaks were placed in coffin-style retail cases for 48 h under fluorescent lighting to simulate retail display. HIOX steaks exhibited the highest Warner-Bratzler shear force values (P < 0.05); the lowest desmin degradation rate (P < 0.05); the highest ratings for fishy, bitter, sour, and oxidized flavors; and the lowest overall tenderness scores (P < 0.05) and, in general, produced the lowest amount of free amino acids (P < 0.05) compared with all other treatments. Contrastingly, ROLL packaging produced the highest ratings for beef flavor identity, brown/roasted, bloody/serumy, and umami flavors (P < 0.05). Additionally, ROLL packaging exhibited (P < 0.05) greater desmin degradation in comparison with HIOX steaks. These data indicate that the optimum package for storage and aging is an anaerobic environment to maintain optimum flavor, tenderness, and postmortem proteolysis

Impact of Various Dry-Aging Methods on Meat Quality and Palatability Attributes of Beef Loins (M. longissimus lumborum) from Cull Cow

The objective of this study was to determine the effect of various dry-aging methods on meat quality and palatability attributes of cull cow beef loins. Paired bone-in loins (m. longissimus lumborum) from 13 cull cow carcasses (Holstein, 42þ mo) were obtained at 5 d postmortem, divided into 4 equal sections, and randomly assigned into 4 aging methods (wet-aging [WA], conventional dry-aging [DA], dry-aging in water-permeable bag [DWA], and ultraviolet light dry-aging [UDA]). The beef sections were aged for 28 d at 2°C, 65% relative humidity, and 0.8 m/s airflow. Following aging, surface crusts and bones were removed, and loin samples were collected for the meat quality, microbiological, and sensory analyses. Results indicated that all dry-aged loins had greater moisture and trimming loss compared with WA (P < 0.05), while DWA had lower loss than DA and UDA (P < 0.05). No differences in shear force, cook loss, or both lipid and protein oxidation across all treatments were observed (P > 0.05). Among all treatments, DWA exhibited the least color stability indicated by rapid discoloration observed in the sample, while UDA had color attributes comparable with WA throughout the whole display. Microbial analysis indicated that UDA had lower microbial concentration on the surface than the other samples (P < 0.05). The consumer panel analysis found that all loins were acceptable, and the trained panel analysis indicated that DA loins decreased sourness and animal fat flavor (P < 0.05) and had a trend of decreasing oxidized flavor (P = 0.07). The results indicate that dry-aging can potentially be utilized as an effective natural process by nullifying some of well-known off-flavor attributes associated with cull cow beef while not compromising other meat quality attrib- utes or microbiological shelf life

Thermophysical Properties of Beef Steaks of Varying Thicknesses Cooked With Low and High Grill Surface Temperatures

The objective of this study was to determine the thermodynamic and physical properties of beef strip loin steaks of varying thicknesses and USDA quality grades cooked with high and low grill surface temperatures. Thermal characteristics described by changes in the denaturation temperature (between 55°C – 60°C) and enthalpies of protein denaturation (70°C – 75°C) both differed (P = 0.031 and P = 0.001, respectively) among thick steaks, with thick steaks cooked on a high grill surface temperature having a lower denaturation temperature and enthalpy compared with thick steaks cooked on a low grill surface temperature. No differences (P > 0.05) were observed among thin steaks for denaturation temperature or enthalpy. The elastic behaviors of the surface and center of the steaks were analyzed to determine how the microstructure of the beef responded to applied stress. The elastic behavior of steak centers was influenced in a three-way interaction (P = 0.029) between quality grade, steak thickness, and grill surface temperature. The elastic behavior of the surface of steaks was influenced by the interaction of quality grade and steak thickness (P = 0.031). These interactions, along with the differences in the thermal characteristic of proteins, suggest that the microstructure of steaks was affected by each cooking treatment group. Hardness, resilience, and chewiness were each influenced by a three-way interaction (P = 0.023; 0.014; and 0.030; respectively). Thin steaks possessed greater cohesiveness (P = 0.038) and shear force ( P = 0.007) values. Meanwhile, thin steaks exhibited lower springiness (P = 0.002). The measured alterations in thermal and physical proper- ties in the beef steaks suggest that the composition, thickness, and cooking regiments impact the microstructure of beef, and this was ultimately confirmed through textural measurements. The results of this research can be used in the design of cooking processes that match beef characteristics

Physiological responses to low-force work and psychosocial stress in women with chronic trapezius myalgia

<p>Abstract</p> <p>Background</p> <p>Repetitive and stressful work tasks have been linked to the development of pain in the trapezius muscle, although the underlying mechanisms still remain unclear. In earlier studies, it has been hypothesized that chronic muscle pain conditions are associated with imbalance in the autonomic nervous system, predominantly expressed as an increased sympathetic activity. This study investigates whether women with chronic trapezius myalgia show higher muscle activity and increased sympathetic tone at baseline and during repetitive low-force work and psychosocial stress, compared with pain-free controls.</p> <p>Methods</p> <p>Eighteen women with chronic trapezius myalgia (MYA) and 30 healthy female controls (CON) were studied during baseline rest, 100 min of repetitive low-force work, 20 min of psychosocial stress (Trier Social Stress Test, TSST), and 80 min recovery. The subjects rated their pain intensity, stress and energy level every 20 min throughout the experiment. Muscle activity was measured by surface electromyography in the trapezius muscle (EMGtrap) and deltoid muscle (EMGdelt). Autonomic reactivity was measured through heart rate (HR), skin conductance (SCL), blood pressure (MAP) and respiration rate (Resp).</p> <p>Results</p> <p>At baseline, EMGtrap, stress ratings, and HR were higher in MYA than in CON. Energy ratings, EMGdelt, SCL, MAP and Resp were, however, similar in the two groups. Significant main group effects were found for pain intensity, stress ratings and EMGtrap. Deltoid muscle activity and autonomic responses were almost identical in MYA and CON during work, stress and recovery. In MYA only, pain intensity and stress ratings increased towards the end of the repetitive work.</p> <p>Conclusion</p> <p>We found increased muscle activity during uninstructed rest in the painful muscle of a group of women with trapezius myalgia. The present study could not confirm the hypothesis that chronic trapezius myalgia is associated with increased sympathetic activity. The suggestion of autonomic imbalance in patients with chronic local or regional musculoskeletal pain needs to be further investigated.</p

Evaluating the Safety of Sous-Vide Cooking for Beef Products Inoculated with Single Strains of Salmonella enterica and Escherichia coli O157

Sous-vide cooking is a growing trend among retailers and consumers. Foodborne pathogens may survive the cooking if nonvalidated parameters are used or if pathogens have enhanced thermal resistance. Pathogen inactivation from sous-vide cooking was determined when introduced directly to beef products or via contaminated spices, and with or without a finishing step. Beef products (ground beef, tenderized, and nontenderized steaks) were inoculated with pathogens (Salmonella Montevideo and Escherichia coli O157:NM) in three ways: 1) directly onto the meat 2) ground black pepper incorporated into the recipe 3) ground pepper equilibrated at 30% RH (4 d) prior to incorporation. Beef samples were vacuum-packaged and submerged in a 62.5°C water bath for 120 min. Samples were sampled at 5, 10, 20, and 120 min (recommended from a partner quality study), and a duplicate was grilled to a specific internal temperature (74°C for ground beef, 57°C for steaks) and sampled. Sous-vide cooking reduced pathogen populations by >5 log CFU/g after most treatment times, but less than grilled counterparts (ca. 1–2 log CFU/g difference; p 4 log CFU/g after most 20-min treatments, but 120-min sous-vide treatments or grilling would be needed for >5-log reductions. Contaminated pepper led to less consistent reductions during the cooking process, yet 2-h sous-vide still achieved a 5-log reduction. Sous-vide cooking instructions must be validated as more products and recipes are marketed