Use of ultrasound for characterising the gelation process in heat induced CaSO4·2H2OCaSO4·2H2O tofu curd

Mechanical evolution of tofu curd in gelation was investigated using low-power ultrasound and textural analysis. Two independent ultrasonic parameters, velocity and attenuation, were measured at the frequency 1 MHz as a function of time after addition of the calcium sulphate (CaSO4·2H2OCaSO4·2H2O) coagulant to heated soya milk. The responsive ultrasonic velocity has a plateau in the beginning of gelation and tends to a lower steady state after the formation of tofu gels. Ultrasonic attenuation exhibits first-order kinetics that matches the development of firmness revealed by textural analysis. Low-power ultrasound explores the formation of tofu gels in the aspects of pre-gelation processes, protein aggregation in gelation, and mechanical evolution in the gel at the post-gelation stage.