*2.6. Ca2*<sup>+</sup> *ATPase Activity*

The Ca2<sup>+</sup> ATPase activity was determined by the method described by Benjakul et al. [23]. The content of inorganic phosphate in the supernatant was determined by the method of Thanonkaew et al. [24]. The activity of Ca2<sup>+</sup> ATPase was defined as the milliliter (nmol/mg protein) of inorganic phosphate produced by 1 mg of protein in 1 min.

#### *2.7. Trichloroacetic Acid-Soluble Peptide Content*

According to the method of Sriket et al. [25], a 3 g sample was added to a 27 mL TCA solution (5%), which was homogenized by a high-speed tissue homogenizer for 1 min at 12,000 rpm and then placed in an ice bath for 1 h. Repeated centrifugation was carried out at 4 ◦C and 5000× *g* for 5 min. The result was expressed as umol tyrosine/g muscle.
