Yuan Tao

Bio: Yuan Tao is an academic researcher from Tianjin Agricultural University. The author has contributed to research in topics: Water content & Bound water. The author has an hindex of 1, co-authored 1 publications receiving 35 citations.

Low Field-NMR in Measuring Water Mobility and Distribution in Beef Granules during Drying Process

Abstract: Low field-nuclear magnetic resonance (LF-NMR) was employed in this study to evaluate water mobility and distribution in beef granules during drying process due to its fast and nondestructive detection. Beef granules were dried in a blast drying oven at different temperatures (40, 50 and 60 °C) to a final moisture content around 21% after cooking. Results showed that it took about 150, 90 and 60 min for the samples dried at 40, 50 and 60 °C to get to the drying destination, respectively. The immobilized water was transformed into bound water with lower association degree and free water during drying at different conditions. Drying also resulted in a proportion increase of bound water; what’s more, the proportion of bound water is the largest when drying at 50 °C compared to 40 and 60 °C. After the drying destination was reached, the transverse relaxation time for bound water and immobilized water appeared significant change. It revealed that LF-NMR was an effective tool to assess water mobility and distribution during food drying process.

Suitability of LF-NMR to analysis water state and predict dielectric properties of Chinese yam during microwave vacuum drying

Abstract: The feasibility of low-field nuclear magnetic resonance (LF-NMR) was investigated to predict the dielectric properties of Chinese yam slices. Changes in relaxation behaviors and dielectric properties (at 915 and 2450 MHz) of samples during microwave vacuum drying as well as their relationship were studied. Results showed that the total moisture content decreases gradually over drying time, and the free water was removed first, followed by the immobile water and bound water. Correspondingly, the dielectric constant (e′) gradually decreased till to reach a relative and stable low value; while the loss factor (e″) changed slightly first, then decreased gradually and also reached a low value finally. Univariate linear models showed that the signal intensity of free water peak (A23) and the transverse relaxation time of immobile water (T22) had good correlation with dielectric properties. Furthermore, partial least squares regression (PLSR) models with four NMR parameters as variables gave better results with R2P of 0.946, 0.936, 0.962 and 0.921 for e′ and e″ at 915 MHz and e′ and e″ at 2450 MHz, respectively. The overall results revealed that LF-NMR is suitable for predicting the dielectric properties as a rapid and noninvasive method.