# Effects of Organic Acid Coagulants on the Textural and Physical-Chemical Properties of Tofu
## 3 Results and Discussion  
Coagulation Time in the Elaboration and Yield of Tofu and Compositional Analysis in Tofu Elaboration  
The coagulation time for tofu is significantly influenced by the type and concentration of vinegar used as a coagulant. Table 1 shows the coagulation times with concentrations of 1%, 3%, and 5%; the results of each treatment are represented as the mean time in minutes, obtaining intervals from 3.99 to 0.78 min to show the presence of curd. In treatments T1, T4, and T5, it is observed that, at a 5% coagulant concentration, there was a decrease in the time required for curd formation. In contrast, treatments T2, T3, and T6 showed that the lowest coagulation times were obtained with a 3% coagulant concentration. Differences in the coagulation time compared to the experiments conducted by other researchers were related by applying scaling as a pretreatment. Scaling accelerates the coagulation because heating soymilk denatures protein particles, mainly glycinin and \(\beta\)-congylcinin, exposing hydrophobic groups. There is a specific relation between thermal induction and coagulation process changes, as glycinin and \(\beta\)-congylcinin have different denaturation temperatures [18; 19]. Other factors affecting the coagulation time include the temperature and coagulant concentration, which are proportional to the quantity of applied coagulant [20]. The results indicate that the 3% and 5% concentrations significantly accelerated the coagulation time, with the lowest time being 0.78 min, showing that the amount of coagulant is crucial. Table 2 shows the tofu yields, indicating that the yield increases with longer coagulation times. The results indicated that, while there were significant differences in the tofu yield, no significant differences were found for the protein, moisture, and ash contents across the treatments (\(p>0.05\)). The mean values and standard deviations are presented in Table 2, demonstrating that treatment T1C5 had the highest yield (23.73%), followed by T2C3 (23.45%), and T6C3 had the lowest yield (15.73%). Despite the variations in the yield, the compositional analysis showed consistent protein, moisture, and ash contents across all treatments. \begin{table} \begin{tabular}{c c c c c} \hline \hline
**Treatment** & **Yield (\%)** & **Protein (\%)** & **Moisture (\%)** & **Ash (\%)** \\ \hline T1C5 1 & 23.73 \({}^{\mathrm{a}}\)\(\pm\) 0.43 & 3.93 \({}^{\mathrm{a}}\)\(\pm\) 0.13 & 69.74 \({}^{\mathrm{b}}\)\(\pm\) 0.23 & 0.68 \({}^{\mathrm{a}}\)\(\pm\) 0.25 \\ T2C3 2 & 23.45 \({}^{\mathrm{a}}\)\(\pm\) 0.87 & 3.25 \({}^{\mathrm{a}}\)\(\pm\) 0.07 & 73.19 \({}^{\mathrm{a}}\)\(\pm\) 1.40 & 0.65 \({}^{\mathrm{a}}\)\(\pm\) 0.04 \\ T3C3 3 & 22.48 \({}^{\mathrm{a}}\)\(\pm\) 1.28 & 2.7 \({}^{\mathrm{a}}\)\(\pm\) 0.42 & 76.03 \({}^{\mathrm{a}}\)\(\pm\) 1.93 & 0.70 \({}^{\mathrm{a}}\)\(\pm\) 0.10 \\ T4C5 4 & 22.08 \({}^{\mathrm{a}}\)\(\pm\) 1.96 & 1.95 \({}^{\mathrm{a}}\)\(\pm\) 0.78 & 73.29 \({}^{\mathrm{a}}\)\(\pm\) 0.63 & 0.73 \({}^{\mathrm{a}}\)\(\pm\) 0.12 \\ T5C5 5 & 19.18 \({}^{\mathrm{b}}\)\(\pm\) 0.46 & 2.45 \({}^{\mathrm{a}}\)\(\pm\) 0.92 & 74.05 \({}^{\mathrm{a}}\)\(\pm\) 1.21 & 0.58 \({}^{\mathrm{a}}\)\(\pm\) 0.07 \\ T6C3 6 & 15.73 \({}^{\mathrm{c}}\)\(\pm\) 1.11 & 2.85 \({}^{\mathrm{a}}\)\(\pm\) 0.35 & 74.50 \({}^{\mathrm{a}}\)\(\pm\) 1.33 & 0.55 \({}^{\mathrm{a}}\)\(\pm\) 0.03 \\ \hline \hline \end{tabular}  \({}^{\dagger}\)T1C5 = tofu coagulated with apple vinegar at a 5% concentration; \({}^{\mathrm{a}}\) T2C3 = tofu coagulated with rice vinegar at a 3% concentration; \({}^{\mathrm{a}}\) T3C3 = tofu coagulated with white vinegar at a 3% concentration; \({}^{\mathrm{a}}\) T4C5 = tofu coagulated with apple vinegar + white vinegar at a 5% concentration; \({}^{\mathrm{a}}\) T6C3 = tofu coagulated with rice vinegar at a 3% concentration. \({  
Treatment T1C5, which required the most time for curd formation, achieved a 23.73% yield. However, there were no statistical differences among the treatments.