Sausages are loved by people for their unique texture, satisfying chewiness, and pleasant flavor. However, in the production of sausages, red meat and a large amount of fat are mainly used, and long-term consumption will increase the risk of diseases such as obesity, heart disease, hypertension, and cancer. Our previous studies have shown that the intake of red meat and fat can be reduced through the replacement of lean meat and fat in sausages by Lentinula edodes and Pleaurotus eryngii mushrooms, but this will lead to the deterioration of the gel of sausage products and seriously affect the sensory quality of sausages. In this study, the response surface method was used to optimize the amount of balsa fish skin gelatin, soy protein isolate, and starch added to, and the proportion of Lentinula edodes mushrooms replacing lean meat in, the new sausage, with Pleaurotus eryngii mushrooms replacing fat. The results show that Lentinula edodes mushrooms replaced 36.1% of the lean meat, and the addition of 0.96% balsa fish skin gelatin, 10.61% starch, and 9.94% soy protein isolate resulted in the highest sensory score and the sensory quality being the closest to that of traditional sausages. Compared with the control group, this novel sausage exhibits characteristics such as lower fat and saturated fatty acid content, reduced energy levels, and higher levels of amino acids (aspartic acid, glutamic acid, cysteine, methionine, and proline) and polyunsaturated fatty acids. The total phenolic content of the novel sausage is 12.52 times higher than that of the control. In comparison with the control group, the novel sausage demonstrates a 65.58% increase in DPPH radical scavenging activity and a 3.88-fold improvement in ABTS+ radical scavenging activity. These findings highlight the outstanding antioxidant performance of the novel sausage. This study provides new ideas for improving the sensory quality of new sausages, promoting the healthy development of the sausage industry, and promoting the high-value utilization of edible mushrooms.

The differential effects of thermolysin and four commercial proteases on soy protein isolate (SPI) were investigated under enzyme-specific hydrolysis conditions to comparatively assess the structural, functional, and instrumental taste differences among the resulting hydrolysates. Under the enzyme-specific hydrolysis conditions, among the enzymes tested, thermolysin induced substantial fragmentation of SPI, with products mainly distributed below 25 kDa and accompanied by marked conformational rearrangement. Thermolysin-treated SPI exhibited the highest total free amino acid content (14.805 mg/g), especially Tyr and Phe, together with the highest solubility (80.52 ± 4.40%), the highest emulsifying activity index (36.11 m²/g), and the strongest antioxidant capacities in 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay (DPPH), and hydroxyl radical scavenging assays. Electronic tongue analysis further showed that enzymatic hydrolysis generally enhanced umami and richness while reducing astringency relative to native SPI. Notably, SPI-Ther exhibited the most pronounced instrumental taste reconfiguration, characterized by increased umami (9.57) and richness (7.57), but also the highest bitterness (4.75) and aftertaste-B (3.46), indicating a distinct functionality–taste trade-off rather than simple debittering. In contrast, papain generated the highest umami response, whereas trypsin produced the mildest taste profile with the lowest bitterness. Overall, under the enzyme-specific hydrolysis conditions used in this study, thermolysin yielded the most pronounced improvement in the measured functional indices of SPI. However, these findings should be interpreted as a comparative, condition-specific assessment rather than a direct ranking of intrinsic protease specificity, and additional peptide characterization and sensory validation would be needed before taste-oriented applications can be recommended.