Effect of thermal treatment and pressure on the characteristics of green soybean tofu and the optimization conditions of tofu processing by TOPSIS analysis

Abstract

Effects of selective thermal denaturation (STD) time (0–20 min, 5 min interval, 85 °C) and high pressure homogenization (HPH) pressure (0–100 MPa, 20 MPa interval, 4 cycles) on quality characteristics of green soybean tofu were investigated and its optimal STD and HPH synergism conditions were also achieved by technique for order preference by similarity to an ideal solution (TOPSIS) analysis. The results showed that hardness, water holding capacity, protein contents, fat contents and yields of green soybean tofu increased by 155.70%, 34.48%, 30.31%, 29.11% and 21.42% (p < 0.05), respectively, in comparison with that of untreated tofu. And greenness of green soybean tofu had a negligible loss compared with green soybean milk. Further, synergism of STD and HPH made network structure of green soybean tofu more homogeneous and denser. TOPSIS analysis demonstrated that the optimal synergized treatment was consecutive STD at 85 °C for 10 min and HPH at 80 MPa for 4 cycles.