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

Relationships between Irritable Bowel Syndrome Pain, Skin Temperature Indices of Autonomic Dysregulation, and Sensitivity to Thermal Cutaneous Stimulation

This study evaluated relationships between irritable bowel syndrome (IBS) pain, sympathetic dysregulation, and thermal pain sensitivity. Eight female patients with diarrhea-predominant IBS and ten healthy female controls were tested for sensitivity to thermal stimulation of the left palm. A new method of response-dependent thermal stimulation was used to maintain pain intensity at a predetermined level (35%) by adjusting thermal stimulus intensity as a function of pain ratings. Clinical pain levels were assessed prior to each testing session. Skin temperatures were recorded before and after pain sensitivity testing. The temperature of palmar skin dropped (1.5°C) when the corresponding location on the opposite hand of control subjects was subjected to prolonged thermal stimulation, but this response was absent for IBS pain patients. The patients also required significantly lower stimulus temperatures than controls to maintain a 35% pain rating. Baseline skin temperatures of patients were significantly correlated with thermode temperatures required to maintain 35% pain ratings. IBS pain intensity was not significantly correlated with skin temperature or pain sensitivity. The method of response-dependent stimulation revealed thermal hyperalgesia and increased sympathetic tone for chronic pain patients, relative to controls. Similarly, a significant correlation between resting skin temperatures and thermal pain sensitivity for IBS but not control subjects indicates that tonic sympathetic activation and a thermal hyperalgesia were generated by the chronic presence of visceral pain. However, lack of a significant relationship between sympathetic tone and ratings of IBS pain casts doubt on propositions that the magnitude of IBS pain is determined by psychological stress

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

Fibromyalgia and neuropathic pain - differences and similarities. A comparison of 3057 patients with diabetic painful neuropathy and fibromyalgia

<p>Abstract</p> <p>Background</p> <p>Patients with diabetic neuropathy (DPN) and fibromyalgia differ substantially in pathogenetic factors and the spatial distribution of the perceived pain. We questioned whether, despite these obvious differences, similar abnormal sensory complaints and pain qualities exist in both entities. We hypothesized that similar sensory symptoms might be associated with similar mechanisms of pain generation. The aims were (1) to compare epidemiological features and co-morbidities and (2) to identify similarities and differences of sensory symptoms in both entities.</p> <p>Methods</p> <p>The present multi-center study compares epidemiological data and sensory symptoms of a large cohort of 1434 fibromyalgia patients and 1623 patients with painful diabetic neuropathy. Data acquisition included standard demographic questions and self-report questionnaires (MOS sleep scale, PHQ-9, Pain<it>DETECT</it>). To identify subgroups of patients with characteristic combinations of symptoms (sensory profiles) a cluster analysis was performed using all patients in both cohorts.</p> <p>Results</p> <p>Significant differences in co-morbidities (depression, sleep disturbance) were found between both disorders. Patients of both aetiologies chose very similar descriptors to characterize their sensory perceptions. Burning pain, prickling and touch-evoked allodynia were present in the same frequency. Five subgroups with distinct symptom profiles could be detected. Two of the subgroups were characteristic for fibromyalgia whereas one profile occurred predominantly in DPN patients. Two profiles were found frequently in patients of both entities (20-35%).</p> <p>Conclusions</p> <p>DPN and fibromyalgia patients experience very similar sensory phenomena. The combination of sensory symptoms - the sensory profile - is in most cases distinct and almost unique for each one of the two entities indicating aetiology-specific mechanisms of symptom generation. Beside the unique aetiology-specific sensory profiles an overlap of sensory profiles can be found in 20-35% of patients of both aetiologies.</p

Creatine-induced activation of antioxidative defence in myotube cultures revealed by explorative NMR-based metabonomics and proteomics

<p>Abstract</p> <p>Background</p> <p>Creatine is a key intermediate in energy metabolism and supplementation of creatine has been used for increasing muscle mass, strength and endurance. Creatine supplementation has also been reported to trigger the skeletal muscle expression of insulin like growth factor I, to increase the fat-free mass and improve cognition in elderly, and more explorative approaches like transcriptomics has revealed additional information. The aim of the present study was to reveal additional insight into the biochemical effects of creatine supplementation at the protein and metabolite level by integrating the explorative techniques, proteomics and NMR metabonomics, in a systems biology approach.</p> <p>Methods</p> <p>Differentiated mouse myotube cultures (C2C12) were exposed to 5 mM creatine monohydrate (CMH) for 24 hours. For proteomics studies, lysed myotubes were analyzed in single 2-DGE gels where the first dimension of protein separation was pI 5-8 and second dimension was a 12.5% Criterion gel. Differentially expressed protein spots of significance were excised from the gel, desalted and identified by peptide mass fingerprinting using MALDI-TOF MS. For NMR metabonomic studies, chloroform/methanol extractions of the myotubes were subjected to one-dimensional ¹H NMR spectroscopy and the intracellular oxidative status of myotubes was assessed by intracellular DCFH₂oxidation after 24 h pre-incubation with CMH.</p> <p>Results</p> <p>The identified differentially expressed proteins included vimentin, malate dehydrogenase, peroxiredoxin, thioredoxin dependent peroxide reductase, and 75 kDa and 78 kDa glucose regulated protein precursors. After CMH exposure, up-regulated proteomic spots correlated positively with the NMR signals from creatine, while down-regulated proteomic spots were negatively correlated with these NMR signals. The identified differentially regulated proteins were related to energy metabolism, glucose regulated stress, cellular structure and the antioxidative defence system. The suggested improvement of the antioxidative defence was confirmed by a reduced intracellular DCFH₂oxidation with increasing concentrations of CMH in the 24 h pre-incubation medium.</p> <p>Conclusions</p> <p>The explorative approach of this study combined with the determination of a decreased intracellular DCFH₂oxidation revealed an additional stimulation of cellular antioxidative mechanisms when myotubes were exposed to CMH. This may contribute to an increased exercise performance mediated by increased ability to cope with training-induced increases in oxidative stress.</p

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

Swimming Exercise Prevents Fibrogenesis in Chronic Kidney Disease by Inhibiting the Myofibroblast Transdifferentiation

BACKGROUND: The renal function of chronic kidney disease (CKD) patients may be improved by a number of rehabilitative mechanisms. Swimming exercise training was supposed to be beneficial to its recovery. METHODOLOGY/PRINCIPAL FINDINGS: Doxorubicin-induced CKD (DRCKD) rat model was performed. Swimming training was programmed three days per week, 30 or 60 min per day for a total period of 11 weeks. Serum biochemical and pathological parameters were examined. In DRCKD, hyperlipidemia was observed. Active mesangial cell activation was evidenced by overexpression of PDGFR, P-PDGFR, MMP-2, MMP-9, α-SMA, and CD34 with a huge amount collagen deposition. Apparent myofibroblast transdifferentiation implicating fibrogenesis in the glomerular mesangium, glomerulonephritis and glomeruloscelorosis was observed with highly elevated proteinuria and urinary BUN excretion. The 60-min swimming exercise but not the 30 min equivalent rescued most of the symptoms. To quantify the effectiveness of exercise training, a physical parameter, i.e. "the strenuosity coefficient" or "the myokine releasing coefficient", was estimated to be 7.154 × 10(-3) pg/mL-J. CONCLUSIONS: The 60-min swimming exercise may ameliorate DRCKD by inhibiting the transdifferentiation of myofibroblasts in the glomerular mesangium. Moreover, rehabilitative exercise training to rescue CKD is a personalized remedy. Benefits depend on the duration and strength of exercise, and more importantly, on the individual physiological condition

Creatine Monohydrate and Conjugated Linoleic Acid Improve Strength and Body Composition Following Resistance Exercise in Older Adults

Aging is associated with lower muscle mass and an increase in body fat. We examined whether creatine monohydrate (CrM) and conjugated linoleic acid (CLA) could enhance strength gains and improve body composition (i.e., increase fat-free mass (FFM); decrease body fat) following resistance exercise training in older adults (>65 y). Men (N = 19) and women (N = 20) completed six months of resistance exercise training with CrM (5g/d)+CLA (6g/d) or placebo with randomized, double blind, allocation. Outcomes included: strength and muscular endurance, functional tasks, body composition (DEXA scan), blood tests (lipids, liver function, CK, glucose, systemic inflammation markers (IL-6, C-reactive protein)), urinary markers of compliance (creatine/creatinine), oxidative stress (8-OH-2dG, 8-isoP) and bone resorption (Ν-telopeptides). Exercise training improved all measurements of functional capacity (P<0.05) and strength (P<0.001), with greater improvement for the CrM+CLA group in most measurements of muscular endurance, isokinetic knee extension strength, FFM, and lower fat mass (P<0.05). Plasma creatinine (P<0.05), but not creatinine clearance, increased for CrM+CLA, with no changes in serum CK activity or liver function tests. Together, this data confirms that supervised resistance exercise training is safe and effective for increasing strength in older adults and that a combination of CrM and CLA can enhance some of the beneficial effects of training over a six-month period. Trial Registration. ClinicalTrials.gov NCT0047390

Neuropathic pain in a rehabilitation setting after spinal cord injury: an interpretative phenomenological analysis of inpatients’ experiences

Study design Qualitative, semi-structured interviews. Objectives Neuropathic pain (NP) can be psychologically and physically debilitating, and is present in approximately half of the spinal cord injured (SCI) population. However, under half of those with NP are adherent to pain medication. Understanding the impact of NP during rehabilitation is required to reduce long-term impact and to promote adherence to medication and psychoeducation recommendations. Setting United Kingdom. Methods Five males and three females with SCI and chronic NP, resident in rehabilitation wards at a specialist SCI center in the United Kingdom, took part. Semi-structured interviews were conducted with participants less than 15 months post-SCI (mean = 8.4 months). Verbatim transcripts were subject to interpretative phenomenological analysis (IPA). Results Three super-ordinate themes were identified, mediating pain and adherence: (1) the dichotomy of safety perceptions; (2) adherence despite adversity; and (3) fighting the future. Analyses suggest that experience of the rehabilitation setting and responsiveness of care shapes early distress. Attitudes to medication and psychosocial adjustment are relevant to developing expectations about pain management. Conclusions Enhancing self-efficacy, feelings of safety in hospital, and encouraging the adoption of adaptive coping strategies may enhance psychosocial and pain-related outcomes, and improve adherence to medication. Encouraging adaptive responses to, and interpretation of, pain, through the use of interventions such as coping effectiveness training, targeted cognitive behavioral pain management, and acceptance-based interventions such as mindfulness, is recommended in order to reduce long-term reliance on medication