## 2 Evolution of NMR Methodologies
### Solid-State NMR for Polysaccharides
#### 2.2.2 Interactions with Water and Small Molecules  
Water interactions play a critical role in polysaccharide functionality, particularly in hydration, gelation, and swelling. NMR spectroscopy, especially ssNMR, has proven to be a valuable tool for studying these interactions. For example, [PERSON] et al. combined time-domain NMR with dynamic vapor adsorption to study how polysaccharides and water interact, revealing the kinetics of hydration at the molecular level [41]. [PERSON] et al. analyzed biofilm polysaccharides and their interactions with quorum-sensing molecules, providing an understanding of biofilm dynamics and bacterial communication [42].  
Ages and Bourg employed NMR spectroscopy alongside MD simulations to investigate the interactions between polysaccharides, such as alginate, and water. The NMR spectra, specifically \({}^{1}\)H and \({}^{13}\)C NMR, were instrumental in identifying how water molecules interact with polysaccharide matrices at the molecular level [43]. These NMR analyses allowed the researchers to map the distribution of water within the polysaccharide network and distinguish between water molecules in close proximity to the polysaccharide (bound water) and those farther away (free water). The shift in chemical shifts and relaxation times observed in the NMR data provided insight into the dynamic behavior of water, particularly how the polysaccharide matrix influences the water's structure and mobility. By integrating these NMR results with MD simulations, [PERSON] and [PERSON] were able to correlate the structural features of polysaccharides with their effect on water dynamics, offering a comprehensive picture of how these biopolymers interact with water at both the molecular and macroscopic levels. This combined approach of NMR and MD simulations not only sheds light on the detailed structural interactions but also enhances the understanding of polysaccharides' roles in water-related biological processes, providing valuable insights into their potential in biomedical applications such as drug delivery and tissue engineering. Similarly, [PERSON] et al. explored the interactions between potato starch and colloids with low-field NMR, showing how to optimize the texture properties of food science [44]. The paper also emphasizes that water binding is important in determining the rheological properties of polysaccharides, which plays a crucial role in food and pharmaceutical preparations.  
Based on these findings, [PERSON] et al. used ssNMR to study the interactions between wheat starch and _Mesona chitensis_ polysaccharides. Their research found out specific ways of hydration that have an impact on gel network formation. It also provided an understanding of how polysaccharides influence the structural properties of complex food matrices [45]. In another study, [PERSON] et al. examined the diffusion of small molecules within composite polysaccharide gels using rheological data combined with ssNMR. This integrated approach allowed the researchers to study the relationship between the gel composition and molecular fluidity. By doing so, they can figure out the characteristics of the microstructure of the polysaccharide aqueous gel [46]. These studies emphasize the versatility of ssNMR in probing polysaccharide-water interactions and its growing role in applications ranging from food science to materials engineering. By combining ssNMR with complementary methods, researchers can achieve a more holistic understanding of hydration and gelation processes in polysaccharides.