*2.7. Textural Profile Analysis*

TPA was performed by using a texture analyzer (TMA-Pro, FTC, Washington, DC, USA) according to [11], with some slight modifications. Sausages were cut into 1.0 cm height and 1.5 cm diameter. The detection speed was 60 mm/min and minimum force 0.8 N. The characteristics of sausage were hardness, cohesiveness, springiness, gumminess, and chewiness. All samples were performed in triplicate at room temperature, and the average value was taken.

### *2.8. Free Amino Acids*

The amino acids content was detected by the method according to [21], with slight modifications. The sample (0.2 g) was hydrolyzed by 6 mol/L HCl (10 mL) for 24 h at 110 ◦C. After cooling at room temperature, a hydrolyzed sample was volumed to 50 mL. 10 mL from the 50 mL hydrolysate was taken and dried, the dried sample adding 0.1 mol/L HCl solution to 10 mL. The solution was filtered through a 0.22 μm water membrane. After filtration, the filtrate (500 μL) and internal standard solution (50 μL) were mixed and derived. The derivative solution (2 μL) was injected into Liquid Chromatography (20AT-PDA (Diode Array Detector) Detector, Shimazu, Kyoto, Japan). The measurement conditions were as follows: chromatographic column (C18: Ajs-01 amino acid special analytical column, 3 μm, 4.6 mm × 150 mm), detection wavelength, 338 nm; column temperature, 50 ◦C. Elution gradient and flow rate are as follows: time: 0 s, 6 s, 8 s, 10 s, 23 s, 30 s,31 s, 34 s, 35 s, 35 s, 38 s; mobile phase B%: 5, 10, 10, 16, 40, 50, 100, 100, 55; flow rate (mL/min): 1.6, 1.6, 1.6, 1.3, 1.0, 1.6, 1.6, 1.6, 1.6, 1.6.
