The states of water in Norway spruce (Picea abies (L.) Karst.) studied by low-field nuclear magnetic resonance (LFNMR) relaxometry: assignment of free-water populations based on quantitative wood anatomy

Abstract Low-field nuclear magnetic resonance (LFNMR) relaxometry was applied to determine the spin-spin relaxation time (T2) of water-saturated Norway spruce (Picea abies (L.) Karst.) specimens cut from mature sapwood (sW) and mature and juvenile heartwood (hW), where earlywood (EW) and latewood (LW) were separated. In combination with quantitative wood anatomy data focusing on the void volumes in various morphological regions, the NMR data served for a more reliable assignment of free-water populations found in water-saturated solid wood. Two free-water populations were identified within most sample types. One was assigned to water in the tracheid lumen and the other to water inside bordered pits. Whether water in the ray cell lumina was included in one or the other of these two populations depends on the curve-fit method applied (continuous or discrete). In addition, T2 differences between the different tissue types were studied and, for comparison, sorption isotherms were measured by means of a sorption balance. There was a significant difference between EW and LW as well as between juvenile wood and mature wood in terms of T2 related to the cell wall water. However, no differences were seen between the sorption isotherms, which indicates that the observed T2 differences were not due to differences in cell wall moisture content (MC).

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Characterization of moisture in acetylated and propionylated radiata pine using low-field nuclear magnetic resonance (LFNMR) relaxometry

Holzforschung ◽

10.1515/hf-2017-0072 ◽

2018 ◽

Vol 72 (3) ◽

pp. 225-233 ◽

Cited By ~ 19

Author(s):

Greeley Beck ◽

Emil Engelund Thybring ◽

Lisbeth Garbrecht Thygesen ◽

Callum Hill

Keyword(s):

Nuclear Magnetic Resonance ◽

Cell Wall ◽

Magnetic Resonance ◽

Relaxation Times ◽

Radiata Pine ◽

Saturation Point ◽

Weight Percentage ◽

Low Field ◽

Nuclear Magnetic

AbstractMoisture in radiata pine (Pinus radiataD. Don) earlywood (EW), which was acetylated or propionylated to various degrees, was measured by low-field nuclear magnetic resonance (LFNMR) relaxometry. Spin-spin relaxation times (T2) were determined for fully saturated samples at 22 and −18°C.T2values for EW lumen water increased with increasing acetylation weight percentage gain (WPG), perhaps caused by the less hydrophilic acetylated wood (AcW) surface. Cell wall water (WCW) and the water in pits and small voids also showed increasingT2values as a function of WPG but with a weaker tendency. A possible explanation is the counteracting effects of decreased hydrophilicity and reduced moisture content (MC) of these water populations at higher levels of acetylation. The evaluation of propionylation on WCWT2data was complicated by peak splitting in the relaxation spectrum. ConstantT2values for void water populations at various WPG levels for propionylated samples indicate a modification gradient in the cell wall. Fiber saturation point (FSP) was significantly reduced by both modifications. Slightly higher FSP values for propionylated samples suggest that physical bulking is not the only factor causing moisture exclusion in AcW. But this interpretation is tentative because of the possibility of cell wall damage caused by propionylation.

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Effects of Hydrocolloid Injection on the Eating Quality of Pork Analyzed Based on Low-Field Nuclear Magnetic Resonance (LF-NMR)

Journal of Food Quality ◽

10.1155/2019/3536824 ◽

2019 ◽

Vol 2019 ◽

pp. 1-7 ◽

Cited By ~ 2

Author(s):

Shengmei Gai ◽

Zhonghui Zhang ◽

Yufeng Zou ◽

Dengyong Liu

Keyword(s):

Nuclear Magnetic Resonance ◽

Magnetic Resonance ◽

Water Distribution ◽

Free Water ◽

Color Difference ◽

Eating Quality ◽

Low Field ◽

Lf Nmr ◽

Nuclear Magnetic

This study investigated the effects of hydrocolloid injection on the eating quality of porcine meat based on low-field nuclear magnetic resonance (LF-NMR). The eating quality and water distribution of hydrocolloid-injected pork were compared with control, and the principle component analysis (PCA) was applied for the identification of hydrocolloid-injected pork. Total color difference (ΔE∗), cooking loss, and moisture content of hydrocolloid-injected pork were significantly increased compared with the control (p<0.05). LF-NMR indicated that significant differences in the relaxation time and peak area proportion of immobilized water (T21, P21) and free water (T22, P22) were detected among hydrocolloid-injected samples and the control (p<0.05). The first two principal components (PCs) of PCA accounted for 54.07% and 33.56% of the observed variation, respectively. Based on the two PCs, the hydrocolloid-injected pork could be differentiated from the control. Therefore, LF-NMR combined with PCA offers an effective method for the analysis and detection of hydrocolloid-injected pork.

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Using low-field NMR and MRI to characterize water status and distribution in modified wood during water absorption

Holzforschung ◽

10.1515/hf-2018-0293 ◽

2019 ◽

Vol 73 (11) ◽

pp. 997-1004 ◽

Cited By ~ 2

Author(s):

Wang Wang ◽

Jinyu Chen ◽

Jinzhen Cao

Keyword(s):

Nuclear Magnetic Resonance ◽

Magnetic Resonance ◽

Water Absorption ◽

Loblolly Pine ◽

Combined Treatment ◽

Free Water ◽

Paraffin Wax ◽

Low Field ◽

First Case ◽

Nuclear Magnetic

Abstract In this study, synergism between two wood modification methods was investigated with the aim of providing insights into improving wood hydrophobicity. Loblolly pine (Pinus taeda) was modified using two variants of the same treatment procedure: in the first case, paraffin wax emulsion (PWE) impregnation was followed by thermal modification (TM); in the second case, the order was reversed, and TM was followed by PWE impregnation. The treated samples were then immersed in distilled water for 1, 6, 24, 48 or 96 h. Low-field nuclear magnetic resonance (LF-NMR) and nuclear magnetic resonance imaging (MRI) were employed to evaluate the concentration of different water components, as well as the water distribution. The results indicated that the combined treatment showed much better performance than either treatment individually, particularly when PWE impregnation was followed by TM. Moreover, through the use of MRI, we characterized the role of both methods in the synergistic relationship, which showed that the PWE impregnation increased the wood hydrophobicity through decreasing free water absorption, while the TM performed the same function through bound water absorption. In addition, paraffin wax penetrated the newly formed cracks caused by TM, which also contributed to the synergistic mechanism between PWE impregnation and TM.

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