Changes in the physicochemical properties of organic acidinducedtofu corresponded with different microstructures (Lee &Kuo, 2011; Wang et al., 2017). Scanning electron micrographs oftofu coagulated with organic acids are presented in Fig. 7. Ahoneycomb-like structure with varying size of pores were observedin tofu prepared with various organic acids at different concentrations.The surface charge of soy protein were screened graduallyby protons, the hydrophobic interactions among proteins werefavored, resulting in the filamentous and porous network (Lee &Kuo, 2011; Liu et al., 2013). Tofu prepared with lower coagulantconcentrations (0.12e0.14 g/100 mL) exhibited with denserhoneycomb-like topography than that prepared with higher acidcoagulant concentrations (0.16e0.18 g/100 mL). In addition, tofuprepared with GDL exhibited a firmer structure with small pores, inaccordance with its higher springiness and hardness (Table 1).Tofu prepared with citric acid formed a higher number of small pores (Fig. 7Aa-Ad) than that prepared with l-(-)-malic (Fig. 7Ba-Bd) or tartaric acid (Fig. 7Ca-Cd), which was in accordance with itshigher storage modulus and gel hardness. This might have resultedfrom differences in acidification rate and pH. Indeed, the smallpores in the former appear to have contributed to higher waterholdingcapacity and hardness. The random and coarse structureof tofu prepared with 0.16 or 0.18 g/100 mL acid indicates the lowerquality of these gels.