*2.5. Light Microscopy (LM)*

Surimi gels were cut into 5 mm cubes and immersed with 10% formalin fixture solution (1:10, *w*/*v*) for more than 24 h. After being dehydrated with gradient alcohol (75%, 85%, 90%, 95%, and 100%), the samples were placed in xylene followed by wax leaching using an embedding machine (JB-P5, Wuhan Junjie Electronics Co., Ltd., Wuhan, China). After cooling at −20 ◦C, the paraffin slice was cut with a thickness of 4 μm carried out by a tissue spreader (KD-P, Zhejiang Kehua Instrument Co., Ltd., Jinhua, China). The dewaxed slices were stained using the periodic acid-Schiff (PAS) method according to the method of Jia et al. [22]. The samples were observed using a light microscope (MS500W, Shanghai Meizs Precision Instrument Co., Ltd., Shanghai, China).
