NMR techniques in studying water in biotechnological systems

Effect of multiple freeze-thaw cycles on water migration, protein conformation and quality attributes of beef longissimus dorsi muscle by real-time low field nuclear magnetic resonance and Raman spectroscopy

Repeated freezing and thawing (F-T) happens during long-term storage and transportation due to the temperature variation, causing quality deterioration of beef products and influencing consumer acceptance. This study was aimed to investigate the relationship between quality attributes, protein structural changes and water real-time migration of beef with different F-T cycles. The results showed that multiply F-T cycles damaged the muscle microstructure and protein structure tended to denature and unfold, led lower population of water reabsorbed, thus triggering the decrease of water capacity, especially a decrease of T₂₁ and A₂₁ of completely thawed beef samples, finally affected the quality, such as tenderness, color and lipid oxidation of beef muscle. Beef should not be abused by F-T cycles >3 times, the quality extremely degraded when subjected to 5 or more F-T cycles, and real-time LF-NMR provided a new aspect to help us control the thawing process of beef.

Dominating roles of protein conformation and water migration in fish muscle quality: The effect of freshness and heating process

The quality characteristics of fish products are a key factor influencing consumer acceptance and preference. This study was aimed to investigate the relationship among quality characteristics, protein structural changes and water migration of mandarin fish with different freshness during heating process. The results showed that the protein structure tended to unfold and more loosen in low freshness fish muscle (4-5 d storage) during heating, leading to an obvious decrease in hydrogen bonds, promoting a reduction of water holding capacity in fish muscle, thus resulting in an increase of T₂₃ and a decrease of A_W, which in turn affected the hardness, stress, and springiness of fish muscle. The protein conformation and water migration could explain the textural differences after heating of different freshness mandarin fish.

Solid State NMR Spectroscopy a Valuable Technique for Structural Insights of Advanced Thin Film Materials: A Review

Solid-state NMR has proven to be a versatile technique for studying the chemical structure, 3D structure and dynamics of all sorts of chemical compounds. In nanotechnology and particularly in thin films, the study of chemical modification, molecular packing, end chain motion, distance determination and solvent-matrix interactions is essential for controlling the final product properties and applications. Despite its atomic-level research capabilities and recent technical advancements, solid-state NMR is still lacking behind other spectroscopic techniques in the field of thin films due to the underestimation of NMR capabilities, availability, great variety of nuclei and pulse sequences, lack of sensitivity for quadrupole nuclei and time-consuming experiments. This article will comprehensively and critically review the work done by solid-state NMR on different types of thin films and the most advanced NMR strategies, which are beyond conventional, and the hardware design used to overcome the technical issues in thin-film research.

Biophysical Reviews-Quantitative analysis of biological phenomenon

This Editorial first describes the articles constituting the current Issue (Volume 12 Issue 3). It then goes on to outline the formal invitation procedure for those interested in submitting a review article to the journal. The Editorial concludes by describing the nomination process for the 2021 Michèle Auger Award for Young Scientists' Independent Research.