2.5. Sulfhydryl content
The sulfhydryl content was determined according to the
method of Srinivasan and Hultin (1997). One gramme of meat
was blended in 10 ml of cold 0.9% saline and homogenised. The
protein concentration of the homogenate was determined using a
BCA kit (Bio-Rad Laboratories, Hercules, CA, USA). Approximately
0.5 ml of homogenate was transferred to a tube and dissolved in
8 M urea buffer (1:1). This was incubated with 0.5 ml DTNB
reagent at room temperature for 15 min and then the absorbance
was measured at 405 nm. Sulfhydryl content was calculated using
a molar extinction coefficient of 11,400 M1 cm1 for 5,50-dithiobis2-
nitrobenzoic acid at this wavelength. The results were
expressed as nmol of total free sulfhydryl groups per mg protein.