Stress relaxation has traditionally been employed as one of the principal means for measuring the viscoelastic behavior of foods. In this study, first the quinces slices were dried in an infrared–hot air dryer (375 W, 60°C and 1 m/s flow rate). The effects of quince powder substitution (0, 5, 10, 15 and 20 %) on stress relaxation and textural parameters of sponge cakes were evaluated by the Texture Analyzer. The results showed that mechanical stress relaxation data of quince sponge cakes were fitted well by both the Peleg-Normand and four-element Maxwell models. The F0 (initial force) and %SR (percentage stress relaxation) parameter of quince sponge cakes increased with increasing substitution. Generally, increasing the substitution of flour by quince resulted in less elasticity and higher hardness of sponge cakes. The elasticity of the sponge cakes was the lowest at 20% substitution of quince powder. The consistency and hardness values of baked cakes increased with increasing quince powder levels, whereas the cohesiveness, resilience and chewiness of samples showed a reverse trend.
