Effects of Medium-Voltage Electrical Stimulation on Postmortem Changes in Fat-Tailed Sheep

• Published in: Journal of food science Vol. 77; no. 1; pp. S47 - S53
• Main Authors: Abbasvali, Maryam, Shahram Shekarforoush, Seyed, Aminlari, Mahmoud, Ebrahimnejad, Hadi
• Format: Journal Article
• Language: English
• Published: Malden, USA Blackwell Publishing Inc 01.01.2012; Wiley; Wiley Subscription Services, Inc
• Subjects: Adenosine triphosphatase; Adenosine Triphosphate - metabolism; Aging; Amino Acids - metabolism; Animal productions; Animals; ATP; Biological and medical sciences; calpain; Calpain - metabolism; Carcasses; Chemical Phenomena; electrical stimulation; Electrochemical Techniques; fat-tailed sheep; Food Handling - methods; Food industries; Food science; Fundamental and applied biological sciences. Psychology; Glucose; Glycolysis; Hydrogen-Ion Concentration; Iran; Islam; Male; Meat - analysis; Meat products; Mechanical Phenomena; Muscle, Skeletal - enzymology; Muscle, Skeletal - metabolism; Muscles; Proteolysis; Quality Control; Reduction; Sheep; Sheep, Domestic; Stimulation; tenderness; Terrestrial animal productions; Time Factors; Vertebrates; Water - analysis; water holding capacity; electrical stimulation; Farming animal; Postmortem; Stimulation; fat-tailed sheep; calpain; Vertebrata; Meat animals; Mammalia; Tenderness; Fat; Sheep; Artiodactyla; Water holding capacity; Ungulata
• ISSN: 0022-1147; 1750-3841
• DOI: 10.1111/j.1750-3841.2011.02463.x

:  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.