*2.5. Microstructure Analysis*

At each storage time point, strips (approximately 5 × 1 × 1 mm) were cut off from three muscles (ST, RH, and IN) and were selected using transmission electron microscopy (TEM). Muscle samples were fixed with 2.5% glutaraldehyde in 0.1 M phosphate buffer (pH 7.2) and 2% osmium tetroxide. Then, the gradually increasing concentrations of ethanol (50–100%, *v*/*v*) were used for dehydration. The solvent was then switched to acetone and the samples were dehydrated with acetone gradient, followed by replacing with propylene oxide and being embedded with resin. The samples were trimmed, sectioned (50–70 nm), and stained with uranyl acetate and lead citrate. The samples were viewed under TEM (Hitachi, H-7500, Japan) at required magnification as per the standard procedures.
