The effect of exercise stress, adrenaline injection and electrical stimulation on changes in quality attributes and proteins in Semimembranosus muscle of lamb

In a previous study regarding the effects of Kosher and conventional slaughter techniques on carcass and meat quality of cattle, it was speculated that electrical stimulation may have affected some of the meat qualities. Therefore, the objective of this study was to investigate the effects of electrical stimulation (ES) and non-electrical stimulation (NES) on key carcass and meat quality attributes of cattle slaughtered by Kosher vs. conventional slaughter methods. Carcass pH and temperature profiles over a 24 h post mortem (pm) period, meat shear force and water holding capacity were investigated in feedlot type cattle of comparable weights and breed types. Results showed that the combined effects of slaughter methods did not influence the meat quality attributes, but there were differences within the slaughter groups. The effect of ES on carcass pH lasted longer within the conventionally slaughtered group (12 h), than in the Kosher slaughter group (6 h). Muscle samples from the ES groups for both slaughter methods were more tender. Electrical stimulation also had a significant effect on the cooking loss from Kosher meat, while there was no significant difference in meat from the conventional slaughter methods. The results show that ES influences certain meat and carcass quality attributes of cattle, based on the way cattle were slaughtered.Keywords: Carcass pH, cooking loss, drip loss, electrical stimulation, shear force, slaughter technique

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Acute exercise stress and electrical stimulation influence the consumer perception of sheep meat eating quality and objective quality traits

Australian Journal of Experimental Agriculture ◽

10.1071/ea03270 ◽

2005 ◽

Vol 45 (5) ◽

pp. 553 ◽

Cited By ~ 34

Author(s):

R. D. Warner ◽

D. M. Ferguson ◽

M. B. McDonagh ◽

H. A. Channon ◽

J. J. Cottrell ◽

...

Keyword(s):

Electrical Stimulation ◽

Acute Exercise ◽

Low Voltage ◽

Gluteus Medius ◽

Lower Surface ◽

Exercise Stress ◽

Eating Quality ◽

General Exercise ◽

Initial Ph ◽

Negative Effect

The effects of acute exercise stress and electrical stimulation on lamb eating quality and objective measurements of quality were evaluated on the Longissimus thoracis et lumborum (LTL) and the Gluteus medius (GM) muscles. Meat quality attributes were also assessed on the LTL, Semimembranosus (SM) and the Semispinalis capitis (SC) muscles. Forty-eight Poll Dorset × Border Leicester–Merino ewes of about 6 months old were randomly allocated to treatments in a 2 × 2 factorial design, with the respective factors being exercise (Ex, 0 v. 15 min) and post-slaughter low voltage electrical stimulation (control v. ES). In general, exercise reduced the rate of pH fall and increased the ultimate pH of all 3 muscles (P<0.05). This effect was more pronounced in the SM than in the LTL and SC. Exercised LTL and SM muscles also had lower surface lightness (L*) values and higher muscle total water content, indicating an increased incidence of dark cutting meat. Exercised LTL steaks were rated higher for tenderness and juiciness by the taste panelists and had lower Warner-Bratzler shear force values, as is often observed with high ultimate pH meat. Electrical stimulation reduced initial pH (pH0.5) values, but resulted in a slower rate of pH fall in the LTL and SM thereafter. Electrical stimulation resulted in an elevation of temperature at rigor in the SM by 10°C (15 v. 25°C) and in the LTL by 3.1°C (7.4 v. 10.5°C). While no effect of electrical stimulation was observed with instrumental analysis, electrical stimulation reduced sensory tenderness scores and overall liking for the GM, and tended to reduce flavour and juiciness of both the GM and LTL. In conclusion, acute exercise pre-slaughter improved eating quality, but caused dark cutting meat. The negative effect of low voltage stimulation on the eating quality of the GM was probably due to a high rigor temperature and associated heat toughening.

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