Lutein fortification of wheat bread with marigold powder: impact on rheology, water dynamics, and structure

BACKGROUND

Demands for foods conducive to eye health have been on the increase in the global healthcare sector. Marigold powder as a major source of lutein was utilized to produce lutein-fortified breads for ocular health. The physicochemical characteristics of the doughs and breads were investigated in terms of rheology, water mobility, and protein secondary structures.

RESULTS

The incorporation of marigold powder decreased the water absorption of doughs without significantly altering thermomechanical properties. With a range of fortification levels (1-3%), marigold powder led to decreased storage and loss modulus of doughs by weakening their gluten network, which was supported by their T₂ relaxation times. The resistance of the doughs weakened with increasing levels of marigold powder, while their extensibilities significantly incremented. Fourier transform infrared spectral deconvolution revealed the changes in wheat protein structures upon marigold powder incorporation, in which the proportion of β-turn increased at the expense of β-sheet ratio. The breads with marigold powder displayed increased specific volume from 4.034 to 4.368 mL g^-1 , accompanied by softer textures. The baking process led to heat-induced losses in lutein concentration of less than 10% within the crumb and approximately 30% in the crust.

CONCLUSION

The use of marigold powder induced changes in protein secondary structure and extensional features of doughs, contributing to increased loaf volume and softer texture. Overall, this study provides fundamental information on the rheological and structural effects of marigold powder in a wheat bread system, consequently encouraging the food industry to utilize marigold power as a functional food ingredient. © 2023 Society of Chemical Industry.

Continuous Monitoring of the Hydration Behavior of Hydrophilic Matrix Tablets Using Time-Domain NMR

Time-domain NMR (TD-NMR) was used for continuous monitoring of the hydration behavior of hydrophilic matrix tablets. The model matrix tablets comprised high molecular weight polyethylene oxide (PEO), hydroxypropyl methylcellulose (HPMC), and polyethylene glycol (PEG). The model tablets were immersed in water. Their T₂ relaxation curves were acquired by TD-NMR with solid-echo sequence. A curve-fitting analysis was conducted on the acquired T₂ relaxation curves to identify the NMR signals corresponding to the nongelated core remaining in the samples. The amount of nongelated core was estimated from the NMR signal intensity. The estimated values were consistent with the experiment measurement values. Next, the model tablets immersed in water were monitored continuously using TD-NMR. The difference in hydration behaviors of the HPMC and PEO matrix tablets was then characterized fully. The nongelated core of the HPMC matrix tablets disappeared more slowly than that of the PEO matrix tablets. The behavior of HPMC was significantly affected by the PEG content in the tablets. It is suggested that the TD-NMR method has potential to be utilized to evaluate the gel layer properties, upon replacement of the immersion medium: purified (nondeuterated) water is replaced with heavy (deuterated) water. Finally, drug-containing matrix tablets were tested. Diltiazem hydrochloride (a highly water-soluble drug) was employed for this experiment. Reasonable in vitro drug dissolution profiles, which were in accordance with the results from TD-NMR experiments, were observed. We concluded that TD-NMR is a powerful tool to evaluate the hydration properties of hydrophilic matrix tablets.

Penetration Routes of Oxygen and Moisture into the Insulation of FR-EPDM Cables for Nuclear Power Plants

The polymeric insulation used in nuclear power plants (NPPs) carries the risk of molecular breakage due to oxidation and hydrolysis in the event of an accident. With this in mind, tubular specimens of flame-retardant ethylene-propylene-diene rubber (FR-EPDM) insulation were obtained by taking conductors out of a cable harvested from an NPP. Similar tubular specimens were made from a newly manufactured cable and those aged artificially using a method called the "superposition of time-dependent data." The inner and outer surfaces of each tubular specimen were subjected to various instrumental analyses to examine their oxidation, moisture uptake, and cross-linking. As a result, it has become clear that oxygen penetrates the cable through gaps between the twisted conductor strands. Meanwhile, water vapor diffuses more often through the sheath than through gaps between the conductor strands. Of the two methods used to simulate design-based accidents in NPPs, the one used to simulate the designed loss-of-coolant accident is more severe to FR-EPDM than the one used to simulate the designed severe accident. In addition, the validity of the method called the "superposition of time-dependent data," which is used to give artificial aging treatments to cable samples, was confirmed. Measurements of spin-spin relaxation time and residual dipolar coupling using time-domain nuclear magnetic resonance were found suitable to use to obtain information on the cross-linking of FR-EPDM insulation.

Multi-Tissue Time-Domain NMR Metabolomics Investigation of Time-Restricted Feeding in Male and Female Nile Grass Rats

Metabolic disease resulting from overnutrition is prevalent and rapidly increasing in incidence in modern society. Time restricted feeding (TRF) dietary regimens have recently shown promise in attenuating some of the negative metabolic effects associated with chronic nutrient stress. The purpose of this study is to utilize a multi-tissue metabolomics approach using nuclear magnetic resonance (NMR) spectroscopy to investigate TRF and sex-specific effects of high-fat diet in a diurnal Nile grass rat model. Animals followed a six-week dietary protocol on one of four diets: chow ad libitum, high-fat ad libitum (HF-AD), high-fat early TRF (HF-AM), or high-fat late TRF (HF-PM), and their liver, heart, and white adipose tissues were harvested at the end of the study and were analyzed by NMR. Time-domain complete reduction to amplitude–frequency table (CRAFT) was used to semi-automate and systematically quantify metabolites in liver, heart, and adipose tissues while minimizing operator bias. Metabolite profiling and statistical analysis revealed lipid remodeling in all three tissues and ectopic accumulation of cardiac and hepatic lipids for HF-AD feeding compared to a standard chow diet. Animals on TRF high-fat diet had lower lipid levels in the heart and liver compared to the ad libitum group; however, no significant differences were noted for adipose tissue. Regardless of diet, females exhibited greater amounts of hepatic lipids compared to males, while no consistent differences were shown in adipose and heart. In conclusion, this study demonstrates the feasibility of performing systematic and time-efficient multi-tissue NMR metabolomics to elucidate metabolites involved in the crosstalk between different metabolic tissues and provides a more holistic approach to better understand the etiology of metabolic disease and the effects of TRF on metabolic profiles.

The Physical Stability of Felodipine and Its Recrystallization from an Amorphous Solid Dispersion Studied by NMR Relaxometry

The ¹H nuclear magnetic resonance (NMR) relaxometry method was applied to investigate the physical stability of an active pharmaceutical ingredient (API) and, for the first time, its recrystallization process in an amorphous solid dispersion system (ASD). The ASD of felodipine and polyvinylpyrrolidone (PVP) was prepared using the solvent evaporation method in a mass ratio of 50:50. In the first stage of the study (250 days), the sample was stored at 0% relative humidity (RH). The recovery of magnetization was described by one-exponential function. In the second stage (300 days in 75% relative humidity), the recrystallization process of felodipine was studied, showing in the sample three components of equilibrium magnetization related to (i) crystalline felodipine, (ii) water, and (iii) felodipine and PVP remaining in the ASD. The study shows that the ¹H NMR relaxometry method is a very useful tool for analysing the composition of a three-phase system mixed at the molecular level and for the investigation of recrystallization process of API in amorphous solid dispersion system.

Real-Time Monitoring Polymerization Reactions Using Dipolar Echoes in 1H Time Domain NMR at a Low Magnetic Field

¹H time domain nuclear magnetic resonance (¹H TD-NMR) at a low magnetic field becomes a powerful technique for the structure and dynamics characterization of soft organic materials. This relies mostly on the method sensitivity to the ¹H-¹H magnetic dipolar couplings, which depend on the molecular orientation with respect to the applied magnetic field. On the other hand, the good sensitivity of the ¹H detection makes it possible to monitor real time processes that modify the dipolar coupling as a result of changes in the molecular mobility. In this regard, the so-called dipolar echoes technique can increase the sensitivity and accuracy of the real-time monitoring. In this article we evaluate the performance of commonly used ¹H TD-NMR dipolar echo methods for probing polymerization reactions. As a proof of principle, we monitor the cure of a commercial epoxy resin, using techniques such as mixed-Magic Sandwich Echo (MSE), Rhim Kessemeier-Radiofrequency Optimized Solid Echo (RK-ROSE) and Dipolar Filtered Magic Sandwich Echo (DF-MSE). Applying a reaction kinetic model that supposes simultaneous autocatalytic and noncatalytic reaction pathways, we show the analysis to obtain the rate and activation energy for the epoxy curing reaction using the NMR data. The results obtained using the different NMR methods are in good agreement among them and also results reported in the literature for similar samples. This demonstrates that any of these dipolar echo pulse sequences can be efficiently used for monitoring and characterizing this type of reaction. Nonetheless, the DF-MSE method showed intrinsic advantages, such as easier data handling and processing, and seems to be the method of choice for monitoring this type of reaction. In general, the procedure is suitable for characterizing reactions involving the formation of solid products from liquid reagents, with some adaptations concerning the reaction model.

Solid Fat Replacement with Canola Oil-Carnauba Wax Oleogels for Dairy-Free Imitation Cheese Low in Saturated Fat

Canola oil was structured into oleogels with different amounts of carnauba wax, and their processing performances were assessed as an alternative to solid fat for imitation cheese low in saturated fat. The contents of solid fat in the oleogels were less vulnerable to the change in temperature than the palm oil. The replacement of palm oil with oleogels produced cheese samples with harder and more cohesive/chewy textures. Dynamic and transient viscoelastic measurements demonstrated that the use of oleogels was effective in increasing the elastic nature of the cheeses. Two distinct components with different proton mobilities were observed in the imitation cheeses, and longer T₂ relaxation times were detected in the oleogel samples. The meltability of the cheese with palm oil was not significantly different from those with 3% and 6% oleogels. The saturated fat level of the oleogel cheese was significantly reduced from 45.70 to 5.20%. The application of canola oil-carnauba wax oleogels could successfully produce imitation cheese high in unsaturated fat and low in saturated fat. This study thus demonstrated that the health-functional properties of imitation cheese could be enhanced by using oleogels.

Water and oil signal assignment in low-moisture mozzarella as determined by time-domain NMR T2 relaxometry

A time-domain ¹ H nuclear magnetic resonance relaxometry method was elaborated for the rapid microstructural characterization of mozzarella cheese. For this purpose, there is a strong need to know how the experimentally determined T₂ relaxation time distribution can be related to specific constituents in mozzarella. In this study, a detailed investigation is offered for fresh and aged low-moisture mozzarella cheese, often applied as a pizza cheese, by application of both a conventional Carr-Purcell-Meiboom-Gill (CPMG) sequence and a free-induction decay CPMG (FID-CPMG) sequence. The relaxation behavior was further elucidated by addition of deuterium oxide and by mild heat treatment of samples. The relaxation times of water protons in mozzarella were found to range from a few microseconds to some tens of milliseconds (in aged mozzarella) or to about hundred milliseconds (in fresh mozzarella). The upper limit of the T₂ distribution can even be extended to the seconds range upon releasing water protons from the mozzarella matrix using a mild heat treatment or upon addition of deuterated water. Both stimuli also provided evidence for the absorption of water into the cheese matrix. The potential release and uptake of water demonstrated that mozzarella acts as a very dynamic system during production and storage. The detected differences in the behavior of the water fraction between fresh and aged low-moisture mozzarella might be utilized to study the influence of either production and/or storage conditions on the cheese ripening process.

Application of (19) F time-domain NMR to measure content in fluorine-containing drug products

It is necessary to show that the active content in the dosage form of drugs is within a certain narrow range of the label claim. In case of fluorinated drugs, the active content can be measured by high field solid state NMR because the excipients lack fluorine. To make NMR reachable to any laboratory, simple to use, and at a low cost, measurement of (19)  F nucleus using a 23 MHz (for (1) H) low field benchtop time-domain (TD) NMR was investigated. Three fluorinated drug products, cinacalcet, lansoprazole, and ciprofloxacin, were chosen for this study. The doses for these drug products range from 15 to 500 mg. The average drug content measured using (19)  F TD-NMR compares well with the reported label claims for the three drugs tested. (19)  F TD-NMR is a simple and non-destructive technique to measure drug content in tablets. In addition, the accessibility and simplicity of the technique makes it an excellent process analytical technology tool for development and manufacturing in the pharmaceutical industry. Copyright © 2015 John Wiley & Sons, Ltd.