Non-Destructive Global and Localized 2D T1/T2 NMR Relaxometry to Resolve Microstructure in Apples Affected by Watercore

Nondestructive prediction and visualization of plumpness in live Eriocheir sinensis using low-field 1 H magnetic resonance imaging

BACKGROUND

The plumpness of hepatopancreas and gonad tissues in live Chinese mitten crabs (Eriocheir sinensis) depends on the grading scale and its commercial value. In this work, a low-field T₁ -weighted ¹ H magnetic resonance imaging (LF-¹ H MRI) technique was developed to nondestructively analyze the plumpness of hepatopancreas and gonad tissues in live E. sinensis. Both male and female E. sinensis were characterized by two-dimensional (2D) LF-¹ H MRI. Moreover, a three-dimensional (3D) LF-¹ H MRI model that quantitatively integrated the total volume of lipid tissues in live E. sinensis was used.

RESULTS

The results showed 2D LF-¹ H MRI could accurately discriminate the plumpness of hepatopancreas and gonad tissues in live E. sinensis. The results of the 3D LF-¹ H MRI model displayed that the lipid volume of E. sinensis could be used to quantify lipid accumulation in lipid tissues.

CONCLUSION

LF-¹ H MRI technology was successfully developed to accurately discriminate the development of E. sinensis hepatopancreas and gonad tissues in a nondestructive manner, indicating its application potential in grading commercial live crabs or advising crab farmers on breeding and fattening processes. © 2018 Society of Chemical Industry.

Sweet cherry softening accompanied with moisture migration and loss during low-temperature storage

BACKGROUND

Hardness is one of the important qualities influencing consumer appeal and marketing of fresh sweet cherry (Prunus avium L.). Moisture loss is one of the main causative factors of cherry softening. In this work, moisture loss and softening process of sweet cherry during postharvest storage at 0 and 4 °C were studied. In addition, low-field ¹ H nuclear magnetic resonance (LF-NMR) was used to analyze water distribution and migration in sweet cherry during storage at 4 °C.

RESULTS

Moisture content correlated significantly (p < 0.01) with both skin and flesh hardness of cherry fruit at the two storage temperatures. According to the transverse relaxation curve, relaxation time, as T₂₁ (0.01-10 ms), T₂₂ (10-150 ms), and T₂₃ (150-1000 ms) were ascribed to cell wall protons, cytoplasmic water, and vacuolar water respectively. Contents of cytoplasmic (p < 0.05) and vacuolar water (p < 0.01) changed significantly with storage time. Magnetic resonance imaging results illustrated that water distributes uniformly in fresh tissue. With prolonged storage time, free water content increased gradually, and then internal damage occurred.

CONCLUSION

Sweet cherry softening closely correlated with moisture loss during low-temperature storage. LF-NMR is a useful technique to investigate moisture migration of fruits and vegetables. © 2017 Society of Chemical Industry.

Multi-scale NMR and MRI approaches to characterize starchy products

This review deals with the use of Nuclear Magnetic Resonance techniques to monitor the behavior of starch as well as the migration and distribution of water during the processing or storage of starchy matrices. The aim is to emphasize the potentials of NMR techniques for the quantitative characterization of water transfers in starch-water systems on different length scales. Relaxation and self-diffusion experiments using low-field NMR spectrometry provided important information on the relationship between water dynamics and the microscopic organization of starch granules at various temperatures and water contents. Some works dealt with the botanical origin of starch but also the impact of possible additives. Indeed, the investigation on model starch-based systems was recently expanded to more complex real systems, including dough, bread, cakes, spaghetti and lasagna. Two-dimensional (2D) cross correlation methods have also been developed to elucidate chemical and diffusional proton exchange phenomena, and to improve the interpretation of results obtained in 1D. Finally, magnetic resonance micro-imaging methods were developed to study or to quantify water intake into starch-based matrices.