Use of Ultrasound for Measuring Tofu Texture

Abstract

The microstructure of a tofu gel network determines the firmness and hence the taste of the tofu. The structure of a tofu network can be observed with a microscope, and the mechanical properties may be determined through textural analysis. These approaches are destructive and sometimes prohibitively expensive; hence they are unsuitable for on-line measurement of tofu properties in a production line. Therefore, this study uses ultrasound for non-destructive measurement of tofu's structure with scanning electronic microscopy and textural analysis as calibrators. Glucono-delta-lactone (GDL) and CaSO₄·2H₂O tofu curds from the market were examined using microscopic analysis, textural analysis, and ultrasonic measurement. There is a positive correlation between the area percentage of pores in a network and the attenuation coefficient of ultrasound. Hence, ultrasonic power attenuation can be a potential means of exploring the microstructure of tofu gel.