PurposeThis study aims to investigate the influence of soy protein isolate hydrolysates (SPIH) obtained using 4 h hydrolysis under 200 MPa on proximate composition, cooking loss, textural properties, color, water distribution, microstructure, thiobarbituric acid reactive substance (TBARS) value and carbonyl and sulfhydryl contents of emulsion sausages.Design/methodology/approachSausages with SPIHs at four concentrations (0, 1.0, 2.0 and 3.0%) were prepared, and the sausage with 0.01% butylated hydroxyanisole (BHA) was used as a positive control. Some sausages were selected for the analyses of quality characteristics and microcosmic properties. Other sausages were stored under 4 °C for 0, 7, 14, 21 and 28 days to investigate the oxidative stability.FindingsThe addition of SPIHs at various levels (0–3.0%) or 0.01% BHA did not affect the proximate composition (protein, fat and ash) of emulsion sausages. The addition of 2.0% SPIH decreased cooking loss and increased moisture content, hardness, springiness, chewiness, resilience and L* value, compared to the sausages without SPIH and with 0.01% BHA (p < 0.05). Furthermore, low-field nuclear magnetic resonance results suggested that sausages with 2.0% SPIH had the shortest T2 relaxation time. In addition, 2.0% SPIH and 0.01% BHA could inhibit the oxidation of emulsion sausages when compared with the sample without SPIH (p < 0.05). Moreover, there were no differences between sausages with 2.0% SPIH and 0.01% BHA (p > 0.05).Originality/valueThese findings confirmed that the 2.0% SPIH obtained under 200 MPa can be used as a natural additive to improve quality properties and antioxidant potential of emulsion sausages during storage.