Field emission scanning electron microscopy (FE-SEM)

FE-SEM was carried out at Cheonnam National University, Yeosu Campus to observe the sarcomere structure and muscle fiber size in the extrudates. The extrudates were split into 1×1×0.2 cm dimensions. For analysis, each test extrudate was cut in both the transverse and longitudinal directions. Double-sided carbon tape was used to adhere the test samples to aluminum stubs. Meat cuts from different treatments were pre-fixed with 2.5% glutaraldehyde for 4 h at 4°C. Subsequently, one percent osmium tetroxide was used to post-fix the samples at 4°C for 2 h (dark condition). The samples were soaked thoroughly in PBS and washed in a gradient of ethanol (30% to 99%), air-drying each wash. For 1 min, a platinum coating was applied at 10 mA. Imaging was carried out using a Sigma 500 FE-SEM (Zeiss, Oberkochen, Germany).