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Magnetic Resonance and Vibrational Spectroscopy and Imaging in Food Analysis

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Photochemistry".

Deadline for manuscript submissions: closed (31 October 2022) | Viewed by 25158

Special Issue Editors


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Guest Editor
Embrapa Instrumentação, Rua XV de Novembro, São Carlos, Brazil
Interests: NMR spectroscopy; NMR relaxometry; analytical chemistry; food NMR; pulse sequences
Special Issues, Collections and Topics in MDPI journals

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Guest Editor
College of Food, Agricultural, and Environmental Sciences, Department of Food Science and Technology, The Ohio State University, Columbus, OH 43210, USA
Interests: NIR; FTIR Raman; miniaturized devices
Special Issues, Collections and Topics in MDPI journals

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Guest Editor
Department of Biotechnology Engineering, Ben Gurion University of the Negev, Beer Sheva, Israel
Interests: food composition; lipids; oxidation; low field NMR relaxation applications; supramolecular chemistry; food quality control; emulsion stability
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Over the past two decades, there have been remarkable changes in the way we analyze the physical, chemical, and sensory properties of fresh and processed food products with the progressive replacement of traditional wet analytical methods (destructive, laborious, time-consuming, requiring the use of hazardous chemicals) with new, fast, non-destructive physical methods where the analysis is performed in a single step, after validation, and without the use of chemical reagents. In this Special Issue, entitled Magnetic Resonance and Vibrational Spectroscopy and Imaging in Foods Analysis, we will be accepting original papers and review articles dealing with the application of magnetic resonance and vibrational spectroscopy methods in food analysis performed in the laboratory, field, factory, warehouse and even supermarket. Applications of high and middle resolution nuclear magnetic resonance spectroscopy (NMR), low field NMR relaxometry and diffusometry, magnet resonance imaging (MRI), and electron spin or electron paramagnetic resonance (EPR), as well as applications of rotational vibrational spectroscopy, such as near (NIR) and mid infrared (MIR) and Raman spectroscopy and imaging applied to food science and technology are welcome. With new magnetic resonance and vibrational methods, food analyses have become faster, more accurate, and better able to determine several parameters per analysis without destroying the sample (non-destructive methods) or in some cases without even having to open their sealed packages (non-invasive methods). Many advances also include the development of new equipment (some even portable), easier access, greater sensitivity, better resolution, lower detection and quantification limits, and the use of computational procedures known as chemometrics or machine learning methods.

Prof. Dr. Luiz Alberto Colnago
Prof. Dr. Luis E Rodriguez-Saona
Prof. Dr. Zeev Wiesman
Guest Editors

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Keywords

  • NMR
  • MRI
  • NIR
  • MIR
  • FTIR
  • Raman
  • spectroscopy and imaging

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Related Special Issue

Published Papers (11 papers)

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Editorial

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2 pages, 179 KiB  
Editorial
Magnetic Resonance and Vibrational Spectroscopy and Imaging in Food Analysis
by Luiz Alberto Colnago, Luis E. Rodriquez-Saona and Zeev Wiesman
Molecules 2022, 27(24), 8831; https://doi.org/10.3390/molecules27248831 - 13 Dec 2022
Viewed by 1338
Abstract
In the past two decades, there have been remarkable changes in the way we analyze the physical, chemical, and sensory properties of fresh and processed food products, with the progressive replacement of traditional wet analytical methods (destructive, laborious, time-consuming, and requiring the use [...] Read more.
In the past two decades, there have been remarkable changes in the way we analyze the physical, chemical, and sensory properties of fresh and processed food products, with the progressive replacement of traditional wet analytical methods (destructive, laborious, time-consuming, and requiring the use of hazardous chemicals) with new, fast, non-destructive physical methods where the analysis is performed in a single step, after validation, and without the use of chemical reagents [...] Full article

Research

Jump to: Editorial

10 pages, 904 KiB  
Article
Using MRI to Study High Pressure Assisted Nutrient Infusion
by Julia D. Kerr, Daniel M. Gruber and Matthew P. Augustine
Molecules 2022, 27(22), 7972; https://doi.org/10.3390/molecules27227972 - 17 Nov 2022
Cited by 2 | Viewed by 1232
Abstract
High pressure assisted infusion of nutrients into food was in situ monitored with magnetic resonance imaging (MRI). Modification of an off-the-shelf pressure reactor with an MRI detection circuit provided a large enough volume to accommodate food. The model food used here was peeled [...] Read more.
High pressure assisted infusion of nutrients into food was in situ monitored with magnetic resonance imaging (MRI). Modification of an off-the-shelf pressure reactor with an MRI detection circuit provided a large enough volume to accommodate food. The model food used here was peeled apple flesh as it is considered as a good mimic for fibrous food. The nuclear spin relaxation properties of the water surrounding the apple flesh were enhanced by adding paramagnetic manganese cations. In this way, MRI relaxation contrast can be used to monitor the location of doped bulk water in and around the apple flesh during pressurization. This work tracked the efficiency of pressure induced nutrient infusion in situ, demonstrating that pressure gating and ramping offer no nutrient mass transport advantage over operation at constant pressure and that the presence of a peel expectedly disrupts solute transport into the fruit. High pressure assisted infusion, with all pressurization strategies shown here, yielded nearly 100-fold faster infusion times than at ambient pressure. Full article
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12 pages, 1289 KiB  
Article
Non-Conventional Time Domain (TD)-NMR Approaches for Food Quality: Case of Gelatin-Based Candies as a Model Food
by Sirvan Sultan Uguz, Baris Ozel, Leonid Grunin, Emin Burcin Ozvural and Mecit H. Oztop
Molecules 2022, 27(19), 6745; https://doi.org/10.3390/molecules27196745 - 10 Oct 2022
Cited by 4 | Viewed by 2199
Abstract
The TD-NMR technique mostly involves the use of T1 (spin-lattice) and T2 (spin-spin) relaxation times to explain the changes occurring in food systems. However, these relaxation times are affected by many factors and might not always be the best indicators to [...] Read more.
The TD-NMR technique mostly involves the use of T1 (spin-lattice) and T2 (spin-spin) relaxation times to explain the changes occurring in food systems. However, these relaxation times are affected by many factors and might not always be the best indicators to work with in food-related TD-NMR studies. In this study, the non-conventional TD-NMR approaches of Solid Echo (SE)/Magic Sandwich Echo (MSE) and Spin Diffusion in food systems were used for the first time. Soft confectionary gelatin gels were formulated and conventional (T1) and non-conventional (SE, MSE and Spin Diffusion) TD-NMR experiments were performed. Corn syrups with different glucose/fructose compositions were used to prepare the soft candies. Hardness, °Brix (°Bx), and water activity (aw) measurements were also conducted complementary to NMR experiments. Relaxation times changed (p < 0.05) with respect to syrup type with no obvious trend. SE/MSE experiments were performed to calculate the crystallinity of the samples. Samples prepared with fructose had the lowest crystallinity values (p < 0.05). Spin Diffusion experiments were performed by using Goldman–Shen pulse sequence and the interface thickness (d) was calculated. Interface thickness values showed a wide range of variation (p < 0.05). Results showed that non-conventional NMR approaches had high potential to be utilized in food systems for quality control purposes. Full article
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14 pages, 2837 KiB  
Article
Maturity Stage Discrimination of Camellia oleifera Fruit Using Visible and Near-Infrared Hyperspectral Imaging
by Hongzhe Jiang, Yilei Hu, Xuesong Jiang and Hongping Zhou
Molecules 2022, 27(19), 6318; https://doi.org/10.3390/molecules27196318 - 25 Sep 2022
Cited by 24 | Viewed by 2514
Abstract
The maturity of Camellia oleifera fruit is one of the most important indicators to optimize the harvest day, which, in turn, results in a high yield and good quality of the produced Camellia oil. A hyperspectral imaging (HSI) system in the range of [...] Read more.
The maturity of Camellia oleifera fruit is one of the most important indicators to optimize the harvest day, which, in turn, results in a high yield and good quality of the produced Camellia oil. A hyperspectral imaging (HSI) system in the range of visible and near-infrared (400–1000 nm) was employed to assess the maturity stages of Camellia oleifera fruit. Hyperspectral images of 1000 samples, which were collected at five different maturity stages, were acquired. The spectrum of each sample was extracted from the identified region of interest (ROI) in each hyperspectral image. Spectral principal component analysis (PCA) revealed that the first three PCs showed potential for discriminating samples at different maturity stages. Two classification models, including partial least-squares discriminant analysis (PLS-DA) and principal component analysis discriminant analysis (PCA-DA), based on the raw or pre-processed full spectra, were developed, and performances were compared. Using a PLS-DA model, based on second-order (2nd) derivative pre-processed spectra, achieved the highest results of correct classification rates (CCRs) of 99.2%, 98.4%, and 97.6% in the calibration, cross-validation, and prediction sets, respectively. Key wavelengths selected by PC loadings, two-dimensional correlation spectroscopy (2D-COS), and the uninformative variable elimination and successive projections algorithm (UVE+SPA) were applied as inputs of the PLS-DA model, while UVE-SPA-PLS-DA built the optimal model with the highest CCR of 81.2% in terms of the prediction set. In a confusion matrix of the optimal simplified model, satisfactory sensitivity, specificity, and precision were acquired. Misclassification was likely to occur between samples at maturity stages two, three, and four. Overall, an HSI with effective selected variables, coupled with PLS-DA, could provide an accurate method and a reference simple system by which to rapidly discriminate the maturity stages of Camellia oleifera fruit samples. Full article
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12 pages, 1065 KiB  
Article
1H LF-NMR Self-Diffusion Measurements for Rapid Monitoring of an Edible Oil’s Food Quality with Respect to Its Oxidation Status
by Tatiana Osheter, Salvatore Campisi-Pinto, Maysa T. Resende, Charles Linder and Zeev Wiesman
Molecules 2022, 27(18), 6064; https://doi.org/10.3390/molecules27186064 - 16 Sep 2022
Cited by 4 | Viewed by 1971
Abstract
The food quality of edible oils is dependent on basic chemical and structural changes that can occur by oxidation during preparation and storage. A rapid and efficient analytical method of the different steps of oil oxidation is described using a time-domain nuclear magnetic [...] Read more.
The food quality of edible oils is dependent on basic chemical and structural changes that can occur by oxidation during preparation and storage. A rapid and efficient analytical method of the different steps of oil oxidation is described using a time-domain nuclear magnetic resonance (TD-NMR) sensor for measuring signals related to the chemical and physical properties of the oil. The degree of thermal oxidation of edible oils at 80 °C was measured by the conventional methodologies of peroxide and aldehyde analysis. Intact non-modified samples of the same oils were more rapidly analyzed for oxidation using a TD-NMR sensor for 2D T1-T2 and self-diffusion (D) measurements. A good linear correlation between the D values and the conventional chemical analysis was achieved, with the highest correlation of R2 = 0.8536 for the D vs. the aldehyde concentrations during the thermal oxidation of poly-unsaturated linseed oils, the oil most susceptible to oxidation. A good correlation between the D and aldehyde levels was also achieved for all the other oils. The possibility to simplify and minimize the time of oxidative analysis using the TD NMR sensors D values is discussed as an indicator of the oil’s oxidation quality, as a rapid and accurate methodology for the oil industry. Full article
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10 pages, 667 KiB  
Article
Non-Invasive Method to Predict the Composition of Requeijão Cremoso Directly in Commercial Packages Using Time Domain NMR Relaxometry and Chemometrics
by G. de Oliveira Machado, Gustavo Galastri Teixeira, Rodrigo Henrique dos Santos Garcia, Tiago Bueno Moraes, Evandro Bona, Poliana M. Santos and Luiz Alberto Colnago
Molecules 2022, 27(14), 4434; https://doi.org/10.3390/molecules27144434 - 11 Jul 2022
Cited by 2 | Viewed by 2038
Abstract
Low Field Time-Domain Nuclear Magnetic Resonance (TD-NMR) relaxometry was used to determine moisture, fat, and defatted dry matter contents in “requeijão cremoso” (RC) processed cheese directly in commercial packaged (plastic cups or tubes with approximately 200 g). Forty-five samples of commercial RC types [...] Read more.
Low Field Time-Domain Nuclear Magnetic Resonance (TD-NMR) relaxometry was used to determine moisture, fat, and defatted dry matter contents in “requeijão cremoso” (RC) processed cheese directly in commercial packaged (plastic cups or tubes with approximately 200 g). Forty-five samples of commercial RC types (traditional, light, lactose-free, vegan, and fiber) were analyzed using longitudinal (T1) and transverse (T2) relaxation measurements in a wide bore Halbach magnet (0.23 T) with a 100 mm probe. The T1 and T2 analyses were performed using CWFP-T1 (Continuous Wave Free Precession) and CPMG (Carr-Purcell-Meiboom-Gill) single shot pulses. The scores of the principal component analysis (PCA) of CWFP-T1 and CPMG signals did not show clustering related to the RC types. Optimization by variable selection was carried out with ordered predictors selection (OPS), providing simpler and predictive partial least squares (PLS) calibration models. The best results were obtained with CWFP-T1 data, with root-mean-square errors of prediction (RMSEP) of 1.38, 4.71, 3.28, and 3.00% for defatted dry mass, fat in the dry and wet matter, and moisture, respectively. Therefore, CWFP-T1 data modeled with chemometrics can be a fast method to monitor the quality of RC directly in commercial packages. Full article
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13 pages, 4282 KiB  
Article
Non-Invasive Rheo-MRI Study of Egg Yolk-Stabilized Emulsions: Yield Stress Decay and Protein Release
by Maria R. Serial, Luben N. Arnaudov, Simeon Stoyanov, Joshua A. Dijksman, Camilla Terenzi and John P. M. van Duynhoven
Molecules 2022, 27(10), 3070; https://doi.org/10.3390/molecules27103070 - 10 May 2022
Cited by 3 | Viewed by 1672
Abstract
A comprehensive understanding of the time-dependent flow behavior of concentrated oil-in-water emulsions is of considerable industrial importance. Along with conventional rheology measurements, localized flow and structural information are key to gaining insight into the underlying mechanisms causing time variations upon constant shear. In [...] Read more.
A comprehensive understanding of the time-dependent flow behavior of concentrated oil-in-water emulsions is of considerable industrial importance. Along with conventional rheology measurements, localized flow and structural information are key to gaining insight into the underlying mechanisms causing time variations upon constant shear. In this work, we study the time-dependent flow behavior of concentrated egg-yolk emulsions with (MEY) or without (EY) enzymatic modification and unravel the effects caused by viscous friction during shear. We observe that prolonged shear leads to irreversible and significant loss of apparent viscosity in both emulsion formulations at a mild shear rate. The latter effect is in fact related to a yield stress decay during constant shearing experiments, as indicated by the local flow curve measurements obtained by rheo-MRI. Concurrently, two-dimensional D-T2 NMR measurements revealed a decrease in the T2 NMR relaxation time of the aqueous phase, indicating the release of surface-active proteins from the droplet interface towards the continuous water phase. The combination of an increase in droplet diameter and the concomitant loss of proteins aggregates from the droplet interface leads to a slow decrease in yield stress. Full article
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10 pages, 1542 KiB  
Article
Monitoring Stimulated Darkening from UV-C Light on Different Bean Genotypes by NMR Spectroscopy
by Marília Vilela Salvador, Flávio Vinícius Crizóstomo Kock, Isabella Laporte Santos, Jean Fausto Carvalho Paulino, Caléo Panhoca de Almeida, Rodrigo Henrique dos Santos Garcia, Luciana Lasry Benchimol-Reis, Luiz Alberto Colnago and Antonio Gilberto Ferreira
Molecules 2022, 27(7), 2060; https://doi.org/10.3390/molecules27072060 - 23 Mar 2022
Cited by 3 | Viewed by 2723
Abstract
The use of UV-C cool white light on bean (Phaseolus vulgaris L.) seeds significantly increases the biochemical seed coat post-harvest darkening process, whilst preserving seed germination. The aim of this work consists in monitoring the effect caused by the incidence of UV-C [...] Read more.
The use of UV-C cool white light on bean (Phaseolus vulgaris L.) seeds significantly increases the biochemical seed coat post-harvest darkening process, whilst preserving seed germination. The aim of this work consists in monitoring the effect caused by the incidence of UV-C light on different bean genotypes using NMR spectroscopy. The genotype samples named IAC Alvorada; TAA Dama; BRS Estilo and BRS Pérola from the Agronomic Institute (IAC; Campinas; SP; Brazil) were evaluated. The following two methodologies were used: a prolonged darkening, in which the grain is placed in a room at a controlled temperature (298 K) and humidity for 90 days, simulating the supermarket shelf; an accelerated darkening, where the grains are exposed to UV-C light (254 nm) for 96 h. The experiments were performed using the following innovative time-domain (TD) NMR approaches: the RK-ROSE pulse sequence; one- and two-dimensional high resolution (HR) NMR experiments (1H; 1H-1H COSY and 1H-13C HSQC); chemometrics tools, such as PLS-DA and heat plots. The results suggest that the observed darkening occurs on the tegument after prolonged (90 days) and accelerated (96 h) conditions. In addition, the results indicate that phenylalanine is the relevant metabolite within this context, being able to participate in the chemical reactions accounted for by the darkening processes. Additionally, it is possible to confirm that a UV-C lamp accelerates oxidative enzymatic reactions and that the NMR methods used were a trustworthy approach to monitor and understand the darkening in bean seeds at metabolite level. Full article
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10 pages, 2837 KiB  
Article
Analyzing the Interaction between Anthocyanins and Native or Heat-Treated Whey Proteins Using Infrared Spectroscopy
by Shuai Ren, Luis Rodriguez-Saona and M. Monica Giusti
Molecules 2022, 27(5), 1538; https://doi.org/10.3390/molecules27051538 - 24 Feb 2022
Cited by 6 | Viewed by 2360
Abstract
The color stability of anthocyanins (ACN) has been shown to be improved by interaction with whey proteins (WP). In this study, we explore the ACN–WP interaction using Fourier transform infrared spectroscopy (IR). ACN from purple corn, grape, and black carrot (50 μM) were [...] Read more.
The color stability of anthocyanins (ACN) has been shown to be improved by interaction with whey proteins (WP). In this study, we explore the ACN–WP interaction using Fourier transform infrared spectroscopy (IR). ACN from purple corn, grape, and black carrot (50 μM) were evaluated. IR spectra (4000–700 cm−1) were collected for native and preheated (40–80 °C) WP (5 mg/mL) and ACN–WP mixtures at pH 7.4. Soft independent modeling of class analogy was used to analyze the IR data. The WP secondary structure changed after heat treatments and after interaction with ACN. As expected, the WP α-helices decreased, and β-sheet increased after heat treatment. The intensities of the WP amide I and II bands decreased after ACN addition, revealing a decrease in the WP α-helix content. Higher preheating temperatures (70–80 °C) resulted in a more disordered WP structure that favored stronger WP–ACN interactions related to amide III changes. Addition of ACN stabilized WP structure due to heat denaturation, but different ACN structures had different binding affinities with WP. WP structure had less change after interaction with ACN with simpler structures. These results increase our understanding of ACN–WP interactions, providing a potential strategy to extend anthocyanin color stability by WP addition. Full article
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12 pages, 1859 KiB  
Article
Screening of Acrylamide of Par-Fried Frozen French Fries Using Portable FT-IR Spectroscopy
by Didem P. Aykas, Alejandra Urtubia, Kevin Wong, Luju Ren, Claudia López-Lira and Luis E. Rodriguez-Saona
Molecules 2022, 27(4), 1161; https://doi.org/10.3390/molecules27041161 - 9 Feb 2022
Cited by 11 | Viewed by 3295
Abstract
Current assays for acrylamide screening rely heavily on LC-MS/MS or GC-MS, techniques that are not suitable to support point of manufacturing verification because it can take several weeks to receive results from a laboratory. A portable sensor that can detect acrylamide levels in [...] Read more.
Current assays for acrylamide screening rely heavily on LC-MS/MS or GC-MS, techniques that are not suitable to support point of manufacturing verification because it can take several weeks to receive results from a laboratory. A portable sensor that can detect acrylamide levels in real-time would enable in-house testing to safeguard both the safety of the consumer and the economic security of the agricultural supplier. Our objective was to develop a rapid, accurate, and real-time screening technique to detect the acrylamide content in par-fried frozen French fries based on a portable infrared device. Par-fried French fries (n = 70) were manufactured at times ranging from 1 to 5.5 min at 180 °C to yield a wide range of acrylamide levels. Spectra of samples were collected using a portable FT-IR device operating from 4000 to 700 cm−1. Acrylamide was extracted using QuEChERS and quantified using uHPLC-MS/MS. Predictive algorithms were generated using partial least squares regression (PLSR). Acrylamide levels in French fries ranged from 52.0 to 812.8 µg/kg. The best performance of the prediction algorithms required transformation of the acrylamide levels using a logarithm function with models giving a coefficient of correlation (Rcv) of 0.93 and RPD as 3.8, which means the mid-IR model can be used for process control applications. Our data corroborate the potential of portable infrared devices for acrylamide screening of high-risk foods. Full article
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10 pages, 1425 KiB  
Article
On-Site Measurement of Fat and Protein Contents in Milk Using Mobile NMR Technology
by Morten K. Sørensen, Nicholas M. Balsgart, Michael Beyer, Ole N. Jensen and Niels Chr. Nielsen
Molecules 2022, 27(3), 583; https://doi.org/10.3390/molecules27030583 - 18 Jan 2022
Cited by 5 | Viewed by 2611
Abstract
Robust and easy-to-use NMR sensor technology is proposed for accurate, on-site determination of fat and protein contents in milk. The two parameters are determined using fast consecutive 1H and 35Cl low-field NMR experiments on milk samples upon the 1:1 addition of [...] Read more.
Robust and easy-to-use NMR sensor technology is proposed for accurate, on-site determination of fat and protein contents in milk. The two parameters are determined using fast consecutive 1H and 35Cl low-field NMR experiments on milk samples upon the 1:1 addition of a low-cost contrast solution. Reliable and accurate measurements are obtained without tedious calibrations and the need for extensive database information and may readily be conducted by non-experts in production site environments. This enables on-site application at farms or dairies, or use in laboratories harvesting significant reductions in costs and time per analysis as compared to wet-chemistry analysis. The performance is demonstrated for calibration samples, various supermarket milk products, and raw milk samples, of which some were analyzed directly in the milking room. To illustrate the wide application range, the supermarket milk products included both conventionally/organically produced, lactose-free milk, cow’s, sheep’s and goat’s milk, homogenized and unhomogenized milk, and a broad nutrient range (0.1–9% fat, 1–6% protein). Excellent agreement between NMR measurements and reference values, without corrections or changes in calibration for various products and during extensive periods of experiment conduction (4 months) demonstrates the robustness of the procedure and instrumentation. For the raw milk samples, correlations between NMR and IR, NMR and wet-chemistry, as well as IR and wet-chemistry results, show that NMR, in terms of accuracy, compares favorably with the other methods. Full article
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