Investigation on water distribution and state in tobacco leaves with stalks during curing by LF-NMR and MRI

Wei, Shuo; Tian, Bin-Qiang; Jia, Hao; Zhang, Hongying; He, Fan; Song, Zhiwei

doi:10.1080/07373937.2017.1415349

Cited by 35 publications

(15 citation statements)

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“…The transverse relaxation times ( T 2 ) distribution characteristics of samples is closely related to the nature of cellular tissue (Wei et al, ), and the relationship of ultrasonic power and water state change and moisture migration during DCU strengthened FIR drying could be investigated by LF‐NMR technology. Figure presents the continuous T 2 distribution curves for kiwifruit samples during DCU‐FIR drying at 36 W. The shortest relaxation time T 21 within 0.01–1 ms is represented as the bound water tightly combined with protein or polysaccharide molecules by hydrogen bonds.…”

Section: Resultsmentioning

confidence: 99%

“…The change of moisture distribution in kiwifruit slices during drying can be visualized by MRI images (Wei et al, ). The proton density images of kiwifruit slices during DCU‐FIR drying at ultrasonic powers of 0, 18, 36, and 54 W are shown in Figure , in which higher redness represents higher proton signal density.…”

Section: Resultsmentioning

confidence: 99%

“…Chemat et al (2011) also found that ultrasound application could improve water mobility and reduce the shrinkage of microcapillary in the material at the same time García-Pérez et al (2009). verified that DCU application in hot air drying on carrot and lemon peel can improve the porosity of material's structure, and then is beneficial for the outward migration of internal moisture.3.3 | Changes of water states in kiwifruit slices during DCU-FIR dryingThe transverse relaxation times (T 2 ) distribution characteristics of samples is closely related to the nature of cellular tissue(Wei et al, 2018), and the relationship of ultrasonic power and water state change and moisture migration during DCU strengthened FIR drying could be investigated by LF-NMR technology.Figure 3presents the continuous T 2 distribution curves for kiwifruit samples during DCU-FIR drying at 36 W. The shortest relaxation time T 21 within 0.01-1 ms is represented as the bound water tightly combined with protein or polysaccharide molecules by hydrogen bonds. The peak of T 22 with a relaxation time of 1-10 ms may represent the immobilized water.…”

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confidence: 88%

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Effect of contact ultrasonic power on moisture migration during far‐infrared radiation drying of kiwifruit

Liu

Zeng

et al. 2019

J Food Process Engineering

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In order to explore the effect of direct contact ultrasound (DCU) on moisture migration during far‐infrared radiation (FIR) drying of kiwifruit, the drying characteristics, microstructure, water status, and moisture change of kiwifruit slices during drying were investigated based on scanning electron microscopy (SEM), low‐field nuclear magnetic resonance (LF‐NMR), and magnetic resonance imaging (MRI). The results showed that the drying time at ultrasonic power of 54 W was 40% shorter than that without DCU application. SEM observation verified that higher ultrasonic power could produce more and larger microcapillaries in the microstructure of kiwifruit slices, which was beneficial for moisture migration. LF‐NMR detection indicated that water mobility and distribution in kiwifruits changed during drying. The relative proportion of free water in kiwifruits decreased from 70 to 0% with the prolongation drying time at different ultrasonic powers, the removal time for free water at ultrasonic power of 54 W was 57% shorter than that without DCU application during FIR drying, and higher ultrasonic power could accelerate the shifting of water in different states. MRI results illustrated that the DCU application at higher ultrasonic power could promote moisture migration and water removal during FIR drying, and then increase drying rate. Practical applications Drying is a commonly utilized process method in food and agricultural industry. Far‐infrared radiation (FIR) drying, as one of the modern drying methods, has desirable advantages including high‐energy efficiency and uniform heating. However, it has unsatisfied promoting effect on internal mass transfer. Ultrasound has significant positive effect on moisture diffusion and water removal. In this study, direct contact ultrasound (DCU) was applied in FIR drying of kiwifruit slices. The study verified that the DCU application in FIR drying could promote drying rate, produce loose microstructure, and shorten drying time significantly. The increase in ultrasonic power could accelerate moisture migration and mass transfer to facilitate water removal. Therefore, DCU application with higher ultrasonic power is beneficial to increasing drying rate and reducing drying time of FIR drying, and FIR drying technology combined with DCU is promising in food industry and can be developed for other food products.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 88%

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Effect of contact ultrasonic power on moisture migration during far‐infrared radiation drying of kiwifruit

Liu

Zeng

et al. 2019

J Food Process Engineering

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“…The longer the transverse relaxation T 2 , the looser water molecules in the sample are bound to other substances, and the freer the proton is. Thereby, the phase and composition of water in the sample can be judged based on the starting position of the peak in T 2 relaxation inversion spectra [22,23] .…”

Section: Theories and Methods Of Moisture Detection Through Nmr Technmentioning

confidence: 99%

Micro-nondestructive detection of the moisture and ion of rice seeds during germination under salt stress

Yang

Wang

et al. 2019

International Journal of Agricultural and Biological Engineering

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Salt stress is one of the major stress factors limiting rice productivity. Its damaging effects include water deficit due to osmotic stress, and ionic toxicity caused by ionic stress. It is very important to study the salt-tolerance mechanism of rice under salt stress, in order to improve the salt-tolerance capacity of rice and thereby increase the yield. In this experiment, the low field nuclear magnetic resonance (LF NMR) technique and the traditional dry-weight weighing method, the non-invasive micro-test technique (NMT) and the inductively coupled plasma emission spectrometry (ICP-AES) were applied to analyze the distribution of water and the flow of K + and Na + of rice seeds during germination under NaCl stress. The results suggested that for all different NaCl concentrations, as germination hours grew, the amplitude of NMR signals of the bound water that of the free water and the total amplitude all increased gradually. And the higher the NaCl concentration is, the weaker the increase trend is. In addition, the moisture content of the seeds and the total amplitude of NMR signals were positively correlated. The regression equation was y =191.53x +1463.6, the correlation coefficient was R=0.9823, and the determination coefficient was R 2 =0.9650. By this regression equation, the moisture content of each state of water during seed germination can be calculated. When without NaCl stress, the rice seeds absorbed K + in the germination process. However, when under NaCl stress at different concentrations, K + efflux was detected. The contents of K + and K + /Na + were lower than that under the control condition. The higher NaCl concentration is, the lower the K + and K + /Na + contents are. These results are in consistence with the K + and Na + contents detected by the inductively coupled technique. These empirical data offer a reference for the study of rice-seeds' response mechanism under salt stress during germination and the screening of germplasm resources, and also put forward a new method of biopsy micro-nondestructive test for plants under stress.

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“…In addition, a prediction model of thermal conductivity of stacked tobacco was established, and the experiment showed that the model had a better prediction accuracy of thermal conductivity. Wei et al (Wei et al, 2018) roasted the Yunyan 87 tobacco in an electric oven and measured the moisture status of tobacco leaves in the process by low-field nuclear magnetic resonance imaging technology. The experiment showed that the drying efficiency of tobacco leaves with stems was lower than that of tobacco without stems.…”

Section: Introductionmentioning

confidence: 99%

Structure Optimization of Outlet Uniformity for a Comas Tower Dryer

et al. 2021

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Tobacco drying is an important part in the whole process of cigarette production, and its quality is directly related to the quality of cigarettes. CTD (Comas Tower Dryer) is a new type of airflow dryer, which is widely used in the tobacco industry because of its high drying efficiency. In actual production, the uneven outlet of the tobacco cutter leads to a stacking phenomenon, which affects the subsequent process of production. In this paper, the distribution of the internal flow field of the drying tower was studied from the aspects of the overlap degree of the orifice plate and deformation of the top structure at the top of the drying tower to explore the way to optimize the inner flow field to lead to the uneven distribution of the outlet. The results show that the structure whose contact position between the wall and the outlet extending outward can improve the uniformity of the outlet, while the overlap degree of the orifice plate had no effect on the uniformity of the outlet.

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Investigation on water distribution and state in tobacco leaves with stalks during curing by LF-NMR and MRI

Cited by 35 publications

References 35 publications

Effect of contact ultrasonic power on moisture migration during far‐infrared radiation drying of kiwifruit

Effect of contact ultrasonic power on moisture migration during far‐infrared radiation drying of kiwifruit

Micro-nondestructive detection of the moisture and ion of rice seeds during germination under salt stress

Structure Optimization of Outlet Uniformity for a Comas Tower Dryer

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