Electrical Stimulation Samples Research Articles

Assessing the impact of Bos taurus x Bos indicus crossbreeding and postmortem technologies on the eating quality of loins from pasturefinished young bulls

This experiment aimed to evaluate the effects of Brahman crossbreeding and postmortem technologies (electrical stimulation and vacuum aging) on eating quality of loins from pasture-finished bulls. Fifty yearling bulls representing five Brahman-influenced types (n = 10 each): Brahman (BRAH), F1-Angus (F1ANG), F1-Chianina (F1CHI), F1-Romosinuano (F1ROM), and F1-Simmental (F1SIM) were supplemented on pasture until reaching a desirable conformation at a suitable live weight of ca. 480 kg. All carcasses were classified as “Bullocks” according to U.S. standards. Carcass’s right sides were subjected to high-voltage electrical stimulation (ES) while the left sides were not stimulated (NOES). Longissimus lumborum (LL) steaks from ES and NOES carcasses were allotted either to the vacuum aging control treatment for 2 d (NOAGING) or 10 d (AGING). LL steaks were evaluated for Warner-Bratzler shear force (WBSF) and sensory traits by trained panelists. No differences in WBSF, juiciness, or flavor ratings were detected among breed types (P > 0.05). Sensory ratings for tenderness-related traits varied little with breed type (P < 0.05). Steaks from F1ANG received higher ratings for muscle fiber tenderness, overall tenderness, and amount of connective tissue, and differed (P < 0.05) from those of F1ROM and F1SIM which received the lowest ratings. Bullock loins were more responsive to ES+AGING in WBSF reduction and desirable tenderness ratings than other postmortem treatments (P < 0.05) by reaching a greater proportion (72%) of “tender” (WBSF < 40.1 N) steaks than AGING (48%), ES (36%), and NOES-NOAGING (24%) samples (P < 0.01). Tenderness of bullock loin steaks is marginally improved by crossbreeding; therefore, the application of ES+AGING is necessary to ensure a higher proportion of tenderloin steaks.

Electrical stimulation confers pre-chondrogenic differentiation by modulating TGF-β1 levels in canine adipose-derived mesenchymal stem cells

Background & Aim Background Osteoarthritis (OA) is closely related to the extent of defective articular cartilage, and the targeting of this loss of chondrocytes has emerged as a promising therapeutic strategy. Aim Here, we investigate that electrical stimulation (ES) can drive direct reprogramming of adipose mesenchymal stem cells (MSCs) into hyaline chondrogenic cells. Methods, Results & Conclusion Methods Canine primary adipose-derived mesenchymal stem cells were formed in micromass for 90 min and stimulated under the electrical field for 3 days. Enzymatic digested ES mass and their 3D control were analyzed through western blot and flow cytometry using chondrogenic markers. In addition, secreted TGF-β1 and TGF-β1 inhibition assay were performed in ES samples. Results We found that TGF-beta1, a key requirement for the in vitro chondrogenic differentiation of MSCs, is highly expressed in micromass of MSCs under ES. TGF-beta1 is also an important regulator of specific cartilage genes during chondrogenesis. Notably, Sox9, a key transcriptional regulator of chondrogenesis, distinctively upregulated in ES-micromass in TGF-beta1 dependent manner. Conclusions We demonstrated that ES-micromass showed the features closely resembling those of chondrocytes in articular cartilage. Further understanding of these insights could serve as the basis for broadening the electrotherapeutic scope for cartilage repair using MSCs.

The effect of combining tenderstretching and electrical stimulation on alpaca (Vicugna pacos) meat tenderness and eating quality

The effect of combining tenderstretching (TS; carcase suspension by the pelvic bone) with medium voltage electrical stimulation (ES) during processing on the tenderness of alpaca muscles was investigated. Thirty-six split alpaca carcases were randomly allocated to treatments in a 2 × 2 factorial arrangement (Achilles hung/TS and ES/non-ES). Samples were collected from the m. longissimus thoracis (LT), m. adductor femoris (AF), m. semimembranosus (SM), m. semitendinosus (ST) and m. psoas major (TL) at 24 h post slaughter for shear force, sarcomere length, collagen and myofibre (particle size) measurement. Additional samples were taken from the m. longissimus lumborum (LL) for sensory assessment using an untrained consumer panel. Tenderstretching reduced shear force and variability within the alpaca AF, without negatively affecting the TL, while ES significantly improved TL and LT tenderness. Consumers were able to detect ES treated LL, rating ES samples higher for all sensory traits. Combining ES and TS maximizes alpaca carcase tenderness when considered on a multiple muscle basis.

Effect of electrical stimulation and ageing period on alpaca (Vicugna pacos) meat and eating quality

This study investigated the effects of using medium voltage (~300V) electrical stimulation (ES) and ageing on alpaca meat. A total of 50 huacaya alpacas were distributed across three age groups (18, 24 and 36months) and two genders (females and castrated males). At 24h post mortem the m. longissimus thoracis et lumborum (LL) and m. semimembranosus (SM) muscles were removed and aged for either 5 or 10days. In comparison to non-ES samples, ES significantly reduced: LL purge values by 3.0% and LL shear force (SF) at 5 and 10days (by 21.6N and ageing further reduced tenderness by 6.6N), and SM SF by 5.8N with significant age effects observed in both ES and non-ES SM samples, such that SF increased by 0.53N with each month increase in animal age. Consumers rated ES samples higher on tenderness, juiciness, flavour and overall rating. ES and ageing of alpaca carcasses are recommended.

Tenderness, moisture loss and post-mortem metabolism of broiler Pectoralis muscle from electrically stimulated and air chilled carcases

1. This study was to evaluate the effects of post-mortem electrical stimulation (ES) on carcase moisture loss and on tenderness, R-value and pH of breast fillets following air chilling. 2. In each of 4 replications, 8 birds were electrically stimulated and 12 birds were controls. The ES birds were stimulated at the head in a 1% saline bath (450 V , 0.45 A, 2 s on/1 s off for 7 pulses). After evisceration the carcases were air chilled in a cooler at 1 to 2 C with an average relative humidity of 91% and an air speed of 44 m/min. 3. Breast fillets were harvested at 2 and 4 h postmortem from both ES and control carcases and also at 8 h postmortem from control carcases to determine moisture loss pH and R-value. 4. Although there was no significant effect of ES on shear value at 2 h postmortem, the ES fillets had a lower shear value mean than the control fillets at 4 h postmortem. There was no significant difference between the shear value means of the ES 4 h fillets and the control 8 h fillets. 5. ES accelerated the normal post-mortem decline in pH at both 2 and 4 h postmortem. 6. The R-value means for the control and ES samples were similar 2 h but the R-value mean of the ES samples was greater than the control at 4 h postmortem. 7. The results suggest that, when followed by air chilling, ES accelerates postmortem metabolism, reduces ageing by up to 50%, and has no effect upon evaporative moisture loss.

Effects of electrical stimulation and postmortem storage on changes in titin, nebulin, desmin, troponin-T, and muscle ultrastructure in Bos indicus crossbred cattle.

The effects of electrical stimulation (ES) on degradation of titin, nebulin, desmin, and troponin-T (TN-T) and on structural changes in the longissimus muscle (LM) from Brahman x Simmental (B x S) cattle (Bos indicus cross) were determined. The left side of seven B x S beef carcasses was stimulated (200 V, 20 Hz) within 1 h of death, and the right side was the nonstimulated (NS) control. Myofibrils for SDS-PAGE and samples for transmission electron microscopy were prepared from the LM at 0, 1, 3, 7, 14, and 28 d postmortem (PM). The SDS-PAGE results showed that the T1 band of titin was absent by 7 d in two animals, by 14 d in four animals, and by 28 d in one animal in both NS and ES samples. By SDS-PAGE, intact nebulin was gone by 7 d in two animals and by 14 d in five animals, but in blots, nebulin decreased by 7 d and was absent by 14 d in both NS and ES samples. The desmin band could still be seen as a light band at 28 d in Western blots of both NS and ES samples. A decrease in TN-T and a concomitant increase in the 30-kDa polypeptide were observed in both NS and ES samples. Western blots with a monoclonal antibody to TN-T confirmed that TN-T decreased at similar rates in NS and ES samples but showed that the 30-kDa polypeptide was more heavily labeled in ES samples from 7 to 28 d. Contraction nodes were present in O-d ES samples and were still observed in 28-d ES samples. Narrow, intermediate, and wide I-band fractures were seen earlier and at a greater frequency in ES than in NS samples. Overall, ES had no detectable effect on titin, nebulin, desmin, or TN-T degradation but accelerated the appearance and enhanced the frequency of three types of I-band fractures in the LM from Bos indicus crossbred cattle.

Effect of electrical stimulation on postmortem titin, nebulin, desmin, and troponin-T degradation and ultrastructural changes in bovine longissimus muscle.

Electrical stimulation (ES) of bovine carcasses is usually done to increase tenderness and has been hypothesized to increase the activity of proteolytic enzymes that may degrade structural proteins in muscle cells and cause fractures and breaks in muscle fibers, thus enhancing meat tenderness. Our objective was to compare postmortem (PM) changes in the muscle proteins, titin, nebulin, alpha-actinin, desmin, and troponin-T and in myofibrillar structure in nonstimulated (NS) and ES bovine skeletal muscle. One side of eight beef carcasses was stimulated within 1 h of death, and the other side was the NS control. Myofibrils for SDS-PAGE and samples for transmission electron microscopy were prepared from the longissimus muscle at 0, 1, 3, 7, 14, and 28 d PM. In SDS-PAGE, titin migrated as three bands in both NS and ES 0-d samples. The slowest migrating band, T1 (intact titin), decreased slightly faster in ES samples from five animals. The fastest migrating band, T2 (degraded titin), increased in amount through 3 d and was still present at 28 d. A titin monoclonal antibody (mAb) identified a large family of degradation products that migrated faster than myosin heavy chains and that was more heavily labeled in Western blots of ES samples than in NS samples. In SDS-PAGE of NS samples, intact nebulin disappeared by 3 d in three animals, by 7 d in four animals, and by 14 d in one animal, but in ES samples the nebulin band was absent by 3 d in three animals and by 7 d in five animals. SDS-PAGE showed that the amount of intact desmin decreased slightly sooner in two ES samples and was absent earlier in one ES sample than in the corresponding NS control samples. Blots labeled with a polyclonal antibody to desmin showed that a more heavily labeled 38-kDa desmin degradation product was present in ES than in NS samples. Postmortem degradation of alpha-actinin was not detected. Contraction node (CN) formation, stretching of conjoined sarcomeres adjacent to the nodes, increased frequency of I-band fractures and accelerated appearance of wide I-band fractures adjacent to the Z-line, and, in some animals, slightly accelerated degradation of titin, nebulin, and troponin-T were characteristics of ES muscle.

Improving pork quality by electricalstimulation or pelvic suspension ofcarcasses

This investigation compared the separate and combined effects on meat quality of electrical stimulation (ES) and pelvic suspension of pig carcasses chilled rapidly or conventionally. Sides from 80 pigs, 80–90 kg live weight, were allocated to one of four treatments followed by either conventional chilling (1°C for 24 h) or rapid chilling (-20°C for 2–3 h, before 1°C until 24 h post-slaughter). The four treatments were: Achilles suspended, with and without high voltage ES, and pelvic suspended, with and without ES. The quality attributes: pH, colour and opacity, drip loss, instrumental and sensory texture were measured in M. longissimus thoracis et lumborum, at 10 days post-slaughter. Rapid chilling reduced the evaporative weight loss by 0·5% There were no significant effects of treatment on colour or opacity, although ES samples were slightly paler. Drip loss was also slightly greater with ES, particularly when combined with pelvic suspension, but in no case was the meat classified as PSE. Instrumental measurements of 'texture showed improved tenderness from both ES and pelvic suspension, even after 10 days ageing. The improvement was less pronounced when ES and pelvic suspension were combined Taste panelling confirmed that samples treated by ES or pelvic suspension, separately or combined, were significantly more tender than samples from non-ES, Achilles hung sides. ES and pelvic suspension were equally effective in improving the tenderness of pork loin. Pelvic suspension did not suffer the disadvantage of increased drip loss that occurred with ES in this study.

Influence of Electrical Stimulation, Cooling Rates and Aging on the Shear Force Values of Chilled Lamb

ABSTRACTAn investigation using high voltage (800 VRMS, 1140 V peak at 14.3 Hz) electrical stimulation (ES) showed that lambs should be stimulated within 30 min of slaughter for 60–120 sec for maximum effect on Warner‐Bratzler shear force values. Shear force values of lamb muscles chilled at different rates were significantly (P<0.001) reduced by ES, compared with nonstimulated controls. However, aging at temperatures between 0° and 9°C, for only 2–3 days, educed shear force values of nonstimulated lamb subjected to moderate chilling rates to those of ES samples at 1 day postmortem. Increasing aging temperature significantly (P<0.001) increased aging rate but duration of aging had the greater effect.

The colour and colour stability of beef Longissimus dorsi and Semimembranosus muscles after effective electrical stimulation

The influence of effective low voltage electrical stimulation (ES) of beef on the colour and colour stability of longissimus dorsi (LD) and semimembranosus (SM) muscles, during storage and retail display was studied by tristimulus colorimetry and reflectance spectrophotometry. ES had no significant effect on the colour of the LD muscles, but some significant effects on SM muscles of ultimate pH 5·5-5·7. Three hours after slicing into steaks at 5 days post mortem, stimulated SM muscles had a paler/lighter colour than non-stimulated controls. During a retail display of 3 days, all steaks exhibited a loss of colour quality manifested in loss of redness and decreases in both hue and chroma (saturation). These changes were most marked in the stimulated SM muscles, and analysis indicated that they were due almost exclusively to the formation of metmyoglobin (metMb). Ageing the meat, as primals cuts, for 33 days at 0°C led to no significant differences in the perceived colour three hours after slicing. The colour changes observed during the 3-day retail display of steaks occurred more rapidly in both (ES and non-ES) 33 day-aged samples than in the 5 day-aged ones. The result of this was that the colour stability of non-stimulated steaks prepared at 33 days was similar to that of ES steaks prepared fresh (5 day post mortem). In SM muscles of pH 5·8-6·0 the apparent differences in colour of the ES and non-ES samples were not significant. However, meat of pH > 5·8, although darker than meat of lesser pH, had less tendency to form metmyoglobin during retail display. The present work also confirmed that seemingly small differences in display conditions, especially temperature, have a marked effect on metmyoglobin formation.

Evaluation of Extra Low Voltage Electrical Stimulation Systems for Bovine Carcasses

ABSTRACTTwo extra low voltage electrical stimulation (ES) systems have been evaluated for their effect on the tenderness of beef semimembranosus (SM), longissimus dorsi (LD), gluteus medius, biceps femoris and semitendinosus muscles. Warner‐Bratzler shear force values indicated that both ES systems worked satisfactorily; ES samples had values which (a) were significantly (P < 0.001) lower than obtained for unstimulated (NES) samples where both were held under chilling conditions which should have produced considerable toughening, and (b) were not significantly different from NES samples restrained from shortening. Comparing ES samples with unrestrained and restrained NES samples, held under identical rapid chilling conditions, showed not only that the ES systems worked, but how well they worked. The SM and LD muscles appeared preferable for evaluation purposes.

Electrical Stimulation Effects on Myoglobin Properties of Bovine Longissimus Muscle

ABSTRACTBeef longissimus steaks from 40 bull carcasses were used to study the effects of electrical stimulation (ES) on meat color mechanisms and myoglobin properties. Total pigment concentration and ratios of myoglobin forms for ES and control (C) samples were not different. Color panel and several spectrophotometric measurements indicated ES produced a lighter, brighter‐red color in displayed steaks. Disappearance of reduced myoglobin during blooming was similar in unaged C and ES steaks, but reduced myoglobin decreased faster during blooming of ES steaks aged 6 days. ES decreased anaerobic metmyoglobin reducing activity and induced more metmyoglobin formation when steaks were in a 1% oxygen atmosphere.

Bacteriology of Electrically Stimulated and Unstimulated Rabbit, Pork, Lamb and Beef Carcasses

Electrical stimulation of rabbit muscles caused a reduction in count of Pseudomonas putrefaciens and of a Lactobacillus sp. when inoculated muscles were held for 45 min after electrical stimulation. Little if any change in count was detected on rabbit muscles immediately after electrical stimulation and after 20 min of storage. Electrical stimulation (ES) of pork carcasses did not affect the aerobic plate count (APC) of the skin surface. APC of cutaneous trunci from electrically stimulated sides of beef and lamb carcasses were similar to those of muscles from unstimulated sides or carcasses. APC of ground beef and blade steaks fabricated pre-rigor from electrically stimulated sides were often numerically lower after 3 days of storage than those of corresponding samples from unstimulated sides. Differences in APC between conventional and ES samples of ground beef prepared from vacuum packaged top round were significant (P < 0.05) after 6 days of storage. However, none of the other differences in count were statistically significant (P < 0.05). Electrical stimulation did not cause any consistent substantial changes in microbial types of ground beef, blade steaks, T-bone steaks or rib steaks. When minced, aseptically excised supraspinatus muscle was inoculated with either P. putrefaciens or a Lactobacillus sp., counts of these species in tissues from electrically stimulated beef often were significantly lower than those of corresponding unstimulated samples.