(168e) Structural and Rheological Characterization of Gelation of Cranberry Oligosaccharides

The cranberry pomace resulting from juice extraction generates considerable waste. The pomace still contains several components that maintain value in potential products, including proanthocyanidins (PACs), flavanols, and xyloglucan (XG), which is a structural polysaccharide often found in plant cell walls. Cranberry oligosaccharides have shown effects on bacterial adhesion and biofilm formation. These purified oligosaccharides were successfully gelled using a simple experimental protocol, demonstrating the potential to extract useful products from the pomace. The resulting hydrogel is thermoresponsive in nature whose strength increases by 5 orders of magnitude at a transition temperature. Understanding the structure, gelation time and mechanical properties of such hydrogels will enable us to engineer specific applications.

These hydrogels are reversibly thermoresponsive and their mechanical properties can be adjusted by tailoring the synthesis stoichiometry. Observing change in rheological properties during gelation leads to insights into the microstructure of the gel. Studying evolution of autocorrelation function during gelation using dynamic light scattering sheds light in the role of secondary structures and aggregates in the gelation. Thus, DLS and rheological measurements were utilized to study the influence of concentration, temperature and ionic strength on gelation behavior. Oscillatory rheology measurements confirmed the shear thinning behavior of the hydrogel. Evolution and crossover of storage modulus (G’) and loss modulus (G”) with temperature was studied for different concentration of hydrogels to determine gelation temperature for each of these systems. This study provides a novel insight into controlling gelation behavior and mechanical properties of cranberry oligosaccharide hydrogels. The thermoresponsive properties and tunable viscoelastic behavior of oligosaccharides enables their use within the food and agricultural business, cosmetics, and pharmaceutical formulations requiring a non-toxic, water-soluble carrier