Low-field Nuclear Magnetic Resonance Method Research Articles

Evolution Characteristics of Coal Microstructure before and after Supercritical CO2 Treatment Based on the L-Weighing-LNMR Method

To accurately and quantitatively characterize the evolution of coal microstructures before and after supercritical CO2 treatment, this paper proposes a microstructural analysis for coal-rock based on low-field nuclear magnetic resonance (LNMR) technology, the L-weighing method. The experimental results of the L-weighing method and the LNMR method were compared and analyzed. The results showed that there were differences between the experimental results of the L-weighing method and the LNMR method, but the overall laws were basically the same. The L-weighing method quantitatively characterizes the water content in coal and determines water consumption and microscopic component extraction in coal with supercritical CO2, while the LNMR method only determines the dissolution of H-containing substances in the coal by supercritical CO2. According to the combined analysis with the L-weighing method and the LNMR method, after the supercritical CO2 entered the coal, it consumed 0.33 g of water from the coal and extracted 0.32 g of microscopic components from the coal, reacted chemically with both water and microscopic components in the coal, and provided effective water consumption and extraction of the coal. The supercritical CO2 increased the saturable water in the coal by 0.71 g, the porosity by 1.57%, and the pore seepage volume by a factor of 1.10, which expanded the volume and increased the permeability of the coal. After the reaction with supercritical CO2, the centrifugal water loss of the coal increased by 0.16 g, the T2 cutoff (T2C) of the coal had shifted to the left by 0.31 ms, and the free water volume of the coal had increased by a factor of 1.15, which enhanced the pore connectivity in the coal. The water consumption, extraction, volume expansion, permeability increase, and pore connectivity increase were primarily responsible for the changes in the coal microstructure effected by supercritical CO2.

What affects the accuracy and applicability of determining wastewater sludge water content via low-field nuclear magnetic resonance?

The accurate determination of waster sludge water content is crucial to sludge dewatering treatment and its disposal management. Though previous studies highlight the great advantages of low-field nuclear magnetic resonance (LF-NMR) in the determination of sludge water content, its accuracy and applicability are not well studied. Herein, this study investigated the settling of operating parameters and the properties of sludge samples on the accuracy and applicability of LF-NMR method in measuring sludge water content. The results showed that the setting of basic parameters such as standard curve, number of scanning times (NS) and sample weight affected the accuracy of sludge water content by LF-NMR. The standard calibration curve constructed by 3 g/L CuSO4, NS = 8 and the sample weight of about 5 g, were suitable for the accurate determination of sludge water content. Furthermore, the existence of magnetic substances in sludge can affect the distribution gradient of main magnetic field, and thus restricted the applicability of LF-NMR. The saturation magnetization of chemical reagents strongly correlated with the measured relative errors of sludge water content (r = 0.995, p < 0.01), the greater the saturation magnetization of the magnetic material, the greater the error of the test results. On the whole, it is necessary to fully consider the influence of process parameters and sludge properties to evaluate the accuracy and applicability of the LF-NMR method, rather than simply copying the parameters in literatures.

Rapid and Simultaneous Measurement of Fat and Moisture Contents in Pork by Low-Field Nuclear Magnetic Resonance.

In order to improve the efficiency of Soxhlet extraction and oven drying, low-field nuclear magnetic resonance (LF-NMR) technology was used to detect fat and moisture contents in pork. The transverse relaxation time (T2) distribution curves were constructed by Carr−Purcell−Meiboom−Gill (CPMG) experiments. In addition, the optimal conditions of adding MnCl2 aqueous solution was explored to separate water and fat signal peaks. Finally, the reliability of this method for the determination of fat and moisture contents in pork was verified. The present study showed that adding 1.5 mL of 20% MnCl2 aqueous solution solution at 50 °C can isolate and obtain a stable peak of fat. The lard and 0.85% MnCl2 aqueous solution were used as the standards for fat and moisture measurements, respectively, and calibration curves with R2 = 0.9999 were obtained. In addition, the repeatability and reproducibility of this method were 1.71~3.10%. There was a significant correlation (p < 0.05) between the LF-NMR method and the conventional methods (Soxhlet extraction and oven drying), and the R2 was 0.9987 and 0.9207 for fat and moisture, respectively. All the results proved that LF-NMR could determine fat and moisture contents in pork rapidly and simultaneously.

LF-NMR intelligent evaluation for lipid oxidation indices of polar compound distribution, fatty acid unsaturation, and dynamic viscosity: Preference and mechanism

The Low Field Nuclear Magnetic Resonance (LF-NMR) intelligent analysis for lipid oxidation indices of polar compound distribution, fatty acid unsaturation, and dynamic viscosity was established and compared. LF-NMR curves obtained from the multivariate approach were more suitable for the establishment of prediction models. Results proved the ability of LF-NMR for the aging evaluation of edible oil, but different prediction performance was found for various indices. The order from the good to bad prediction was: fatty acid unsaturation > polar compound > dynamic viscosity. It demonstrated the preference of LF-NMR for reporting the information of fatty acid than triglyceride in oxidized oil. Two mechanisms for the LF-NMR method were summarized and expressed by equations. Results also supported that the peak 21 in the LF-NMR curve provided unique information about polar and low-molecular-weight products rather than polymer compounds. Data were expected for a better understanding of LF-NMR signals and to accelerate its wide application in the food industry.

Relationship between chloride migration coefficient and pore structures of long-term water curing concrete

The chloride migration coefficient is a useful index for quality control and durability design of reinforced concrete. This paper explored the relationship between chloride migration coefficient and pore structures of long-term water curing concrete. Low-field nuclear magnetic resonance (NMR) and water absorption were used to probe the total porosity and pore sizes distribution. An appropriate dosage of supplementary cementitious materials reduced the total porosity and increased the proportion of capillary pores in the concrete. Fly ash, slag and silica fume effectively increased the capillary pores in the concrete. The capillary pores of 0.35 water to cement ratio concrete with 25% slag was 20% higher than that of the 0.35 water to cement ratio plain concrete at 415 days. The capillary pores of 0.45 water to cement ratio concrete with 25% slag was 32% higher than that of the 0.45 water to cement ratio plain concrete at 415 days. The big pores in the concrete were significantly reduced. According to our analysis, pores were divided into four parts: 0 ∼ R12, R12 ∼ R23, R23 ∼ 50 μm, ≥ 50 μm. R12 and R23 were the sequential minimum distribution frequency pore sizes in the pore size distribution figures tested by the Low-field NMR method. The chloride migration coefficient was dependent on the porosity which included the pore size over R23 and the pore radius R3. R3 was the biggest pore size among several peak frequency pore sizes in the figure of pore size distribution. Their relationship was non-linear. This meant the controlling factors of chloride migration in the concrete were larger capillary pores, voids and the porosity made up of these large capillary pores and voids. The persistent evolution of pores determined the permeability of concrete in late age.

Experimental Insights Into the In Situ Formation and Dissociation of Gas Hydrate in Sediments of Shenhu, South China Sea

Natural gas hydrates as sustainable energy resources are inherently affected by mineral surfaces and confined spaces in reservoirs. However, the habits of hydrates in geological sediments are still an open question. In this work, we systemically studied the process of hydrate formation and dissociation in sediments from the Shenhu area of the South China Sea to examine the evolution of hydrate saturation and permeability in sediments and their relationship. Characterization of samples indicates that sediments of the Shenhu area are mainly composed of clay and fine sand grains and provide a large number of nanopores for hydrate accumulation. For in situ observations enabled by low-field nuclear magnetic resonance methods, the formation of hydrates shows a different kinetic behavior with an induction time compared to hydrate dissociation. Estimated by variations of hydrate saturation (%) over time, the rate of hydrate formation is around 12%/min, while the dissociation rate increases to 3%/min with the higher temperature. With the presence of hydrates, pore space and thus permeability of sediments decreased obviously by one and three orders of magnitude when the hydrate saturation is 20 and 45%, respectively. Compared to models with the assumption of grain-coating and pore-filling hydrates, the tendency of permeability evolution from NMR measurements is between fitted lines from models. It highlights that the existing models considering a single pattern of hydrate growth cannot precisely describe the relationship between permeability and hydrate saturation. Hybrid hydrate habits coexist in sediments resulting from heterogeneous pore structures and thus complex gas–water distributions.

Novel low-field NMR method for characterization content and SARA composition of bitumen in rocks

In the oil industry, there is a need for fast and non-invasive methods for determining the bitumen content and group composition in rock samples. Determination of bitumen saturation of reservoir or source rocks has some difficulties due to existing methods limitations. For this purpose, the novel method is based on a combination of free induction decay (FID) and modified Carr-Purcell-Meilboom-Gill (CPMG) measurements using a low-frequency nuclear magnetic resonance (NMR) relaxation technique was developed. It allows obtaining the content and group composition (SARA fractions) of bitumen directly in the porous media without extraction. FID data fitting based on a combination of Voigt and exponential functions for liquid phase, as well as Abragam and exponential functions for solid phase components respectively was proposed. The developed method was tested on 20 rock samples collected from the productive formation (horizon M) located at the depth of 601–708 m of the wellbore 3001 of the Boca de Jaruco oilfield (Republic of Cuba). The bitumen content in the samples was obtained and compared with data determined by thermogravimetric analysis (TGA) and Rock-Eval pyrolysis. A good agreement of NMR results with TGA and pyrolysis was shown (R2 = 0.99 and 0.97 respectively). The values of liquid HC components (saturates, aromatics and resins) and solid HC components (asphaltenes) were compared with TGA data (R2 = 0.97 and 0.98 respectively). Finally, the proposed NMR method was applied to determine the SARA composition of the bitumen in the samples. To assess the accuracy of determining the SARA composition by the NMR method, SARA analysis (ASTM D4124-09) of extracts from the samples 632, 638, 658, 676, 689, 708 was carried out. NMR and conventional SARA analysis showed close results. To assess the completeness of the bitumen extraction from the mineral matrix, microCT and FIB-SEM were performed before and after extraction. It was found that after extraction the part of the bitumen remains in the pores, which distorts the results of SARA analysis. The proposed NMR method can be used to calculate the bitumen saturation and SARA composition for characterization of bitumen, selecting and modeling the effectiveness of applying the optimal EOR without destroying the samples. Also, the method is promising for the operational control of technological processes of oil production.

Application of a Modified Low-Field NMR Method on Methane Adsorption of Medium-Rank Coals

Methane adsorption capacity is an important parameter for coalbed methane (CBM) exploitation and development. Traditional examination methods are mostly time-consuming and could not detect the dynamic processes of adsorption. In this study, a modified low-field nuclear magnetic resonance (NMR) method that compensates for these shortcomings was used to quantitatively examine the methane adsorption capacity of seven medium-rank coals. Based on the typical T 2 amplitudes obtained from low-field NMR measurement, the volume of adsorbed methane was calculated. The results indicate that the Langmuir volume of seven samples is in a range of 18.9–31.85 m3/t which increases as the coal rank increases. The pore size in range 1-10 nm is the main contributor for gas adsorption in these medium-rank coal samples. Comparing the adsorption isotherms of these coal samples from the modified low-field NMR method and volumetric method, the absolute deviations between these two methods are less than 1.03 m3/t while the relative deviations fall within 4.76%. The absolute deviations and relative deviations decrease as vitrinite reflectance ( R o ) increases from 1.08% to 1.80%. These results show that the modified low-field NMR method is credible to measure the methane adsorption capacity and the precision of this method may be influenced by coal rank.

Evaluation of Methane Dynamic Adsorption–Diffusion Process in Coals by a Low-Field NMR Method

Quantitative characterization of multiphase methane and investigation of the methane dynamic adsorption process of coals were performed by a low-field nuclear magnetic resonance (NMR) method. Meanw...

Determination of fiber saturation point of rattan (Calamus simplicifolius) using the LF-NMR and two conventional methods

Water exists in lignocellulosic materials throughout the whole process from the plant growth to raw materials processing and utilization. The fiber saturation point (FSP) is the inflection point of the physical and mechanical properties of lignocellulosic materials and has an important influence on their physical and mechanical properties. This paper investigates the FSP of Calamus simplicifolius by the low-field nuclear magnetic resonance (LF-NMR) method and two conventional methods including the saturated salt solution method and dynamic vapor sorption (DVS) method. The average FSP values determined by the LF-NMR method, the saturated salt solution method and the DVS method are 38.15%, 32.54% and 28.96%, respectively. The study showed that the FSP values determined by the LF-NMR method were higher than those determined by the two conventional methods. The two conventional methods are simple and cost-effective and are able to directly measure whether the rattan properties are changing with moisture content. From the thermodynamics standpoint, even within the ideal solution limit, free water is present at relative humidity (RH) of less than 100%. Therefore, extrapolation to 100% RH was not strictly correct. The amount of water in rattan in different states could be quantified by the LF-NMR method, and the FSP value was determined by the ratio of the measurements above and below the water melting point. Furthermore, the LF-NMR method is faster and non-destructive compared to the two conventional methods.

Characterization of PLA-P3,4HB active film incorporated with essential oil: Application in peach preservation

This study aimed to develop an active film by using biodegradable materials and antioxidant essential oils to improve gas and water vapor permeability during peach preservation. O2 and CO2 volume fractions and water status were investigated by using an oxygen meter and conducting low-field nuclear magnetic resonance (LF-NMR), respectively. Results revealed that the film added with angelica essential oil (AEO) had a 49.4% increase in 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity and high O2 and CO2 transmission rates and water vapor permeability. The film added with AEO showed the best preservation effect, effectively delaying the oxidation of peach, maintained the combined water, and extended the shelf life of peaches to more than 15 days. This study provided a relatively new LF-NMR method for tracking the internal water status of packaged peaches and served as an effective reference for the development of active food packaging.

Determination of moisture, total lipid, and bound lipid contents in oats using low-field nuclear magnetic resonance

In this study, we aimed to establish a novel method for determining moisture and lipid contents in oats using low-field nuclear magnetic resonance (LF-NMR). The applicabilities of the internal and external standard methods for determining oat moisture were compared. To determine oat lipids, calibration curves were established using the external standard method, and then the LF-NMR method and the conventional method were compared. The independent peaks of T21 (0.01–3.0 ms) and T22 (9.01–410.27 ms) in the T2 spectral curves of oat flour represented water and lipid, respectively. Analysis of moisture content with the internal standard method was more accurate than with the external standard method, which uses 3 % MnCl2•4H2O as a standard. The area of T21 peak and T22 peak has a good linear correlation with the mass of water weight and lipid weight, respectively. The results of the LF-NMR method were consistent with the results of the oven method (for moisture content) and the Bligh method (for total lipid content). Moreover, the endosperm was found to contain 0.58–1.36 % of the bound lipid, which was slightly lower than the value for the oat bran.

An NMR-based investigation of pore water freezing process in sandstone

Understanding the freezing pattern of pore water is the basis for revealing the mechanisms of frost damage in porous rocks. We employed low-field nuclear magnetic resonance method, aided by high-resolution temperature measurements, to investigate the pore water freezing process of in sandstone. Samples were prepared with nine degrees of initial saturation (20% to 100% at 10% intervals). The results indicate the following: 1) pore water in fully-saturated sandstone consists of bound water, capillary water and bulk water. Bound water forms the majority (76%), followed by capillary water (14%) and bulk water (10%). 2) A significant amount of pore water remains unfrozen at −20 °C, which is basically bound water. 3) Supercooling of pore water is distinct in samples with saturation degrees ≧70%. 4) The exotherm of rock temperature declines as the saturation degree decreases, it becomes undetectable in samples with saturation degrees ˂70%. Following further investigation of the variation of each fraction of pore water fully-saturatedduring freezing, we suggest that: 1) The entire freezing process can be broadly divided into four stages: supercooling, repid-freezing stage, stable-freezing and ceasing of freezing. 2) Small pores preferentially freeze before larger ones during the rapid-freezing stage. 3) The initial saturation degree significantly influences the pore water freezing process by determining the fraction of pore water. This study sheds new light on the pore water freezing pattern in sandstone, providing novel ideas for the analysis of frost damage mechanisms in porous rocks.

Real-time dynamic analysis with low-field nuclear magnetic resonance of residual oil and sophorolipids concentrations in the fermentation process of Starmerella bombicola

The yeast Starmerella bombicola is known to produce sophorolipids (SLs) by fermentation method. In the fermentative production of SLs, at least three phases i.e. hydrophilic phase of glucose, ions and acidic-form SLs; hydrophobic phase of oil and lactone-form SLs; solid phase of cell biomass and SLs crystals are present in the broth. Therefore, a rapid and real-time detection of residual oil and SLs can provide valuable information in the regulation and optimization of the process to better produce SLs effectively. Looking into the importance, in this study, a rapid, accurate and precise method to quantify the concentrations of oil and SLs using low-field nuclear magnetic resonance (LF-NMR) was developed. Compared to the traditional weighing method, all the parameters for the evaluation of accuracy, precision and relative recovery presented better performances. Moreover, the proposed LF-NMR method could completely avoid using organic solvents that are commonly employed in the weighing method, besides shortening the pre-treatment and detection times from 24 h to just <20 min. Finally, LF-NMR method has been successfully used to monitor residual oil and SLs during the fermentation of Starmerella bombicola to obtain SLs and it has been observed that the production of SLs would be effectively improved by appropriately controlling the concentration of oil in terms of titer, productivity and yield.

Structuring of a Haplortox by Soil Cover Species

The objective of this work was to evaluate the effect of soil cover species and management systems in improving the physical characteristics of a Haplortox and its effects on grain yield and soybean oil content. The experimental area, consisted of 15 treatments in a completely randomized experimental design. Each plot had size of 20 &amp;times; 25 m. The treatments consisted of: traditional no-tillage system (control), no-tillage system with application of gypsum, no-tillage with scarification and 12 treatments with cover species called soil structure reclaimers. Soil samples were collected in the layers of 0-0.10; 0.10-0.20 and 0.20-0.30 m, with four replicates. The physical attributes evaluated were bulk density, total porosity, microporosity, macroporosity and saturated hydraulic conductivity in the periods of 2014, 2015 and 2016. In the soybean crop the grain yield, oil content, weight of 100 grains, average height of plants and number of plants/m were evaluated in each treatment with four replications. The oil content was performed by the low-field nuclear magnetic resonance method. The averages of the treatments were compared by the Tukey test at 5% of significance. The results showed that five months after soil scarification did not affect bulk density. Eleven months after gypsum application discrete improvements in density, total porosity, microporosity and soil hydraulic conductivity occurred in the 0-0.10 and 0.10-0.20 m layers. It was also concluded that grain yield, oil content, weight of 100 grains and number of plants per meter were not influenced by the soil cover species and soil management systems.

Retained water content after nitrogen driving water on flooding saturated high volatile bituminous coal using low-field nuclear magnetic resonance

Retained water in reservoirs can result in water block damage that can lead to low productivity of coalbed methane wells. To research the water saturation increasing process during water flooding and determine the retained water content variation law after nitrogen driving water, considering that high-pressure nitrogen injection is recently regarded as an effective technology to enhance CBM well production, multiple low-field nuclear magnetic resonance methods, including T2 spectrum testing, multi-slice spin-echo sequence imaging, and spatially-resolved T2 distribution measurements, were applied during water flooding experiment and nitrogen driving water for decreasing retained water content of a high volatile bituminous coal sample. Distributions of fractures, pores and minerals were inversed based on micro-CT technology and the corresponding influences on retained water were discussed. The results showed that water saturation increasing process of total apertures, micro- and transition pores, meso-pores, macro-pores and fractures were increased by logarithmic relation with the increase of water flooding time. Nitrogen driving could basically decrease water saturation in macro-pores and fractures completely, and partly in meso-pores with a 50.11% decrease in water saturation. However, it can lead to increased water saturation by 6.89% in micro- and transition-pores. It is relatively easier to decrease retained water content when inlet pressure is increased during nitrogen driving because effective stress is decreased and connections between apertures are improved. The smaller mineral filling porosity, greater total porosity, and better connection of pores and fractures, the greater water content after water flooding. Retained water content of a sample with connected apertures is discharged effectively under nitrogen driving, while a sample that lacks connected apertures remains high in retained water content.

Application of Low Field Nuclear Magnetic Resonance to evaluate asphalt binder viscosity in recycled mixes

The newly developed method to estimate asphalt viscosity and aging trends using Low Field Nuclear Magnetic Resonance (LF-NMR) was applied to characterize the effect of incorporating recycled materials and recycling agents in asphalt mix samples. The measurements were conducted on asphalt mix samples prepared with different binders: (1) a virgin binder, (2) a recycled binder from Reclaimed Asphalt Pavement (RAP), (3) a blend of virgin and RAP binder (recycled blend) and (4) a rejuvenated blend that consists of the recycled blend with the addition of a recycling agent (tall oil). The LF-NMR measurements were performed at room (25 °C) and magnet (36.4 °C) temperatures. The Relative Hydrogen Index (RHI) obtained from LF-NMR captured the expected binder viscosity trends for the asphalt mix samples prepared with each of the different binders. The viscosity of the binders and blends was estimated from Dynamic Shear Rheometer (DSR) measurements. The relationship between dynamic viscosity and RHI agreed with previous findings. The samples prepared with the rejuvenated blend had lower viscosity and higher RHI than the recycled blend, indicating that the tall oil was effective in lowering its viscosity. Small discrepancies in the trends of the rejuvenated blend as compared to the virgin binder were attributed to their similar detectable hydrogen content, obtained in the rejuvenated blend with the addition of tall oil, but different oxidation state, molecular distribution and steric hindrance. This indicates that the LF-NMR method is more influenced by the chemistry of the asphalt binders rather than their viscosity. The asphalt mix samples with virgin and rejuvenated binders were also subjected to an aging treatment at 70 °C for a month. A significant decrease of the RHI was detected for the samples prepared with rejuvenated binder whereas no significant change was detected for those prepared with virgin binders, which indicates that rejuvenated binders were more susceptible to additional aging that resulted in increased viscosity.

Water Dynamics and Physicochemical Analysis of Two Different Varieties of Apple Jam (Fuji) and (Yinduqing) by LF- NMR and MRI

Abstract Apple jam is one of the favorite foods consumed worldwide. This study investigated the effect of storage time and sugar concentration on water dynamics in Fuji and Yinduqing, using low-field nuclear magnetic resonance (LF-NMR) and magnetic resonance imaging (MRI) techniques. The samples were taken for jam preparation with various concentrations of sugar solution (0, 25, 50 and 75-oBrix) and stored at a room temperature of 20 °C for 16 days. The LF-NMR relaxation time T 2 distribution displayed bound, intermediate and free water, respectively. The lowest T 2 range reflected lowest sugar hydrogen mobility depending on total soluble solids (TSS) and water content. A significant correlation (r &gt; 0.9) existed between LF-NMR analysis and physicochemical parameters (water content, color, pH and TSS). MRI displayed uniform water distributions in samples with low sugar concentration. Fluorescence microscopy was used to evaluate sugar crystals and microstructural changes during processing. The study demonstrated the viability of LF-NMR method in determining water dynamics in the apple jams upon processing and storage that may be implemented for quality analysis in other jam products.

Assessing the moisture migration during microwave drying of coal using low-field nuclear magnetic resonance

ABSTRACTMicrowave drying of coal has the advantage of volumetric and selective heating, which saves energy and time. However, comprehensive assessment of the moisture migration during microwave drying is lacking. In this study, the low-field nuclear magnetic resonance (LF-NMR) was used for moisture characterization during microwave drying. Moisture migration occurs first in larger pores, whereas the smaller pores appear to remain water-saturated. As the microwave power increases, the drying capacity and drying rate both increase because high-power microwave can open the blind pores to promote moisture seepage. Furthermore, moisture migration during microwave drying is usually directional (i.e., along the bedding plane). The LF-NMR method provides a framework for the determination of moisture migration of coals.

A non-invasive method based on low-field NMR to analyze the quality changes in caviar from hybrid sturgeon (Huso dauricus, Acipenser schrenckiid )

A noninvasive LF-NMR method was developed to monitor proton dynamics on caviar stored at −4°C for 11 months. T2 relaxation spectra revealed three peaks at 0.54–0.75, 20.61–30.78, and 147.24–307.37 ms, respectively, whereas T1 showed only one peak around 167.16–217.31 ms. The T21 and T22 components remained unchanged during the storage period, while T23 was irregularly changed. NMR analysis demonstrated the moisture migrated through the extracellular spaces as free water under the action of osmotic pressure gradient during the salting treatment. Moisture and fat contents in caviar remained unchanged during the overall storage time. There was a trend for increased TVB-N values over the 11 months storage. Color measurement was carried out to evaluate the quality change of the caviar. The NMR parameters clearly showed good correlation with moisture. Practical applications Caviar is one of the most expensive fishery products which not only contain protein, but also essential amino acids, trace elements, vitamins and high unsaturated fatty acids. The monitoring and analysis of the quality changes of caviar are essential during the period of caviar processing and storage. Herein, the low-field nuclear magnetic resonance (LF-NMR) and magnetic resonance imaging (MRI) methods were developed and tested to assess the proton changes of caviar during cryopreservation at −4°C for as long as 11 months. The use of LF-NMR and MRI technique is fast, noninvasive, inexpensive, and visualization results are expected. This approach developed in this study is quite general and can be applied to monitor the proton changes of caviar storage in a noninvasive and fast way.