Ohio State University Extension Bulletin

Research and Reviews: Meat 2001

Special Circular 183-02

Viscosity of Semimembranosus And Longissimus Dorsi Bull Muscle Homogenates

Experimental

Investigation was conducted on the Semimembranosus (Sm) and Longissimusdorsi (Ld) muscles taken from six young bulls [age 20 to 21 months, live weight: 1256 ± 28 pounds (571 ± 18.9 kg)] 24 hours after commercial slaughter and a 24 hour chilling period at 2 to 4C. At different periods, the Sm and Ld muscles of pH < 5.8 and pH > 6.2 were excised from the hindquarter and forequarter of earlier selected bulls. The Sm and the Ld muscles were wrapped in polythene bags and transported in a cooler to the laboratory and then stored at 2 to 4C for up to 96 hours p.m. From each muscle two steaks were cut which were ground separately through a 0.12 in. (3 mm) plate. The pH was measured with a pH-meter and electrodes were inserted into the ground meat. A meat homogenate was obtained by homogenisation of 15 g of ground meat with 60 ml of 0.67 M NaCl at pH 6.5 for 1 min at 4000 rpm. This homogenate was used for the determination of viscosity (Pa.'s) under different shear rate Dr ^(s-1) from 0.3333 to 145.8, with a Rotatory viscometer "Rheotest-2" and attachment H. Within each of three replications for each muscle type (Sm, and Ld) and pH muscle group (pH < 5.8, and pH > 6.2) three parallel measurements were determined. Reported rate are means of the three measurements (Table 1). After analysis of variance, the Duncan's method was used to test differences in means (Oktaba, 1980).

Table 1. Means for equation [h = kx( Dr)^n-1] parameters of relationship between viscosity and shear rate for Semimembranosus (SM) and Longissimus dorsi (LD) muscle homogenates during aging time.

Type of muscle Parameter Aging time (hours post-mortem)

24 48 72 96

SM_pH<5.8 k 2276.29^ax 2375.76^ax 2338.27^ax 2150.98^ax

SM_pH>6.2 k 1457.45^ay 1864.34^aby 2501.29^cx 2211.98^bcx

LD_pH<5.8 k 2052.09^ax 2697.54^bx 2799.84^bx 3004.32^by

LD_pH>6.2 k 2105.06^ax 2714.41^bx 2841.38^bx 2605.66^bz

SM_pH<5.8 n 0.2159 0.2155 0.2142 0.2193

SM_pH>6.2 n 0.2232 0.2221 0.2024 0.2109

LD_pH<5.8 n 0.2230 0.2156 0.2155 0.1990

LD_pH>6.2 n 0.2233 0.1970 0.1991 0.2080

*Means with different superscripts (a,b,c) in the same row and letter (x,y,z) in the same column (separately for k and n) are significantly different (P < 0.05).

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Table 1. Means for equation [h = kx( Dr)^n-1] parameters of relationship between viscosity and shear rate for Semimembranosus (SM) and Longissimus dorsi (LD) muscle homogenates during aging time.
Type of muscle	Parameter	Aging time (hours post-mortem)
		24	48	72	96
SM_pH<5.8	k	2276.29^ax	2375.76^ax	2338.27^ax	2150.98^ax
SM_pH>6.2	k	1457.45^ay	1864.34^aby	2501.29^cx	2211.98^bcx
LD_pH<5.8	k	2052.09^ax	2697.54^bx	2799.84^bx	3004.32^by
LD_pH>6.2	k	2105.06^ax	2714.41^bx	2841.38^bx	2605.66^bz
SM_pH<5.8	n	0.2159	0.2155	0.2142	0.2193
SM_pH>6.2	n	0.2232	0.2221	0.2024	0.2109
LD_pH<5.8	n	0.2230	0.2156	0.2155	0.1990
LD_pH>6.2	n	0.2233	0.1970	0.1991	0.2080
*Means with different superscripts (a,b,c) in the same row and letter (x,y,z) in the same column (separately for k and n) are significantly different (P < 0.05).

Research and Reviews: Meat 2001

Special Circular 183-02

Viscosity of Semimembranosus And Longissimus Dorsi Bull Muscle Homogenates

Experimental

Table 1. Means for equation [h = kx( Dr)n-1] parameters of relationship between viscosity and shear rate for Semimembranosus (SM) and Longissimus dorsi (LD) muscle homogenates during aging time.

Table 1. Means for equation [h = kx( Dr)^n-1] parameters of relationship between viscosity and shear rate for Semimembranosus (SM) and Longissimus dorsi (LD) muscle homogenates during aging time.