Study of the dynamic states of water and effects of high-pressure homogenization on water distribution in tofu by using low-field nuclear magnetic resonance

摘要

Low-field nuclear magnetic resonance was used to study two traditional types of tofu. The size of diffusive domains was estimated based on diffusive exchange model. T-2 parameters were used to monitor changes in the microstructure and water distribution under different high pressure homogenization (HPH) conditions (50, 100, and 150 MPa). The T-21 relaxation time significantly decreased with increasing pressure, and the tofu prepared using HPH-pretreated soymilk showed a compact protein network structure compared with the control sample. From the perspective of water distribution and water-holding capacity, 50 MPa was the appropriate pressure for pretreatment of soymilk. Significant correlations were further detected among T-21 relaxation time, water-holding capacity, and particle size. Therefore, T-21 relaxation time could be used as the optimal indicator to reflect changes in the microstructure and water distribution in tofu.