title: Effects of medium-voltage electrical stimulation on postmortem changes in fat-tailed sheep.
abstract: Effects of different medium-voltage electrical stimulation (ES) and ageing on postmortem changes in longissimus dorsi muscle of the fat-tailed sheep were studied. Fifteen male animals were divided into 5 equal groups (n= 3) including: T₁ (control, without ES), T₂ (100 V/30 s), T₃ (100 V/60 s), T₄ (150 V/30 s), and T₅ (150 V/60 s) with fixed frequency of 50 Hz. Five minutes after sticking, the carcasses were stimulated in order of the treatments. After normal processing, they were kept at 6 °C for 14 d. ES accelerated the glycolytic rate resulting in a significant fast fall in pH (P < 0.05) during the 1st 6-h postmortem (PM) with a gradual decline until 24-h PM, and a simultaneous significant reduction in adenosine triphosphate (ATP) content (P < 0.05). There was a significant (P < 0.05) decline in the total calpain activity during the 1st 6-h PM. The muscles from ES carcasses had significantly (P < 0.05) lower water holding capacity (WHC) than those from nonstimulated ones. Ageing revealed a significant (P < 0.05) effect on the reduction of WHC. No significant difference was found for the mean value of the muscle color (L*, a*, and b*) in all treatment groups during ageing (P > 0.05). The results of free amino acid (FAA) content and myofibrillar fragmentation index (MFI) revealed a significant improvement of proteolysis and tenderness by ES and ageing (P < 0.05). In the present study, higher voltage/duration (150 V/60 s) showed greater effects and significantly accelerated glycolysis, pH decline, and ATP depletion and thus decreased the time for rigor completion and improved the tenderness.
authors: Department of Food Hygiene and Public Health, School of Veterinary Medicine, Shiraz University, Shiraz, Iran.
authors: Maryam
authors: M
authors: Abbasvali
authors: Seyed Shahram
authors: SS
authors: Shekarforoush
authors: Mahmoud
authors: M
authors: Aminlari
authors: Hadi
authors: H
authors: Ebrahimnejad
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D002154:Calpain / Q000378:metabolism; D055598:Chemical Phenomena; D055664:Electrochemical Techniques; D005511:Food Handling / Q000379:methods*; D006019:Glycolysis; D006863:Hydrogen-Ion Concentration; D007492:Iran; D007514:Islam; D008297:Male; D008460:Meat / Q000032:analysis*; D055595:Mechanical Phenomena; D018482:Muscle, Skeletal / Q000201:enzymology / Q000378:metabolism*; D059748:Proteolysis; D011786:Quality Control; D034561:Sheep, Domestic; D013997:Time Factors; D014867:Water / Q000032:analysis
chemical_list: D000596:Amino Acids; D014867:Water; D000255:Adenosine Triphosphate; D002154:Calpain