## 3. Results and Discussion
### Rheological Characterization of FPs  
The effect of different drying methods on the apparent viscosity of FPs solution are shown in Figure 4. The apparent viscosity of FPs decreases rapidly with increasing shear rate (0.1-100 s\({}^{-1}\)), indicating that the FPs are pseudoplastic fluids with non-Newtonian shear thinning. The order of apparent viscosity of FPs is FPH > FPV > FPF > FPFI. As can be seen from Figure 5 the apparent viscosity of FPs is significantly positively correlated with molecular weight (***) and Ara (**). Previous studies have shown that the apparent viscosity of polysaccharide is closely related to its molecular weight [39]. The maximum apparent viscosity of FPH corresponds to its maximum molecular weight. FPV has a higher apparent viscosity than FPF and FPFI due to the highest Ara molar ratio and higher molecular weight. It is speculated that the apparent viscosity is affected by changing the molecular weight of FPs and molar ratio of Ara. Figure 3: Scanning electron micrographs of the FPs: (**A**) FPF, (**B**) FPFI, (**C**) FPH, (**D**) FPV, 1 \(\upmu\)m*: indicates the scale in this figure, all at magnifications of 10,000\(\times\). Natural polysaccharides are inherently viscoelastic, and their dynamic rheological properties can be determined by frequency scanning [41]. In the linear viscoelastic region with 2% constant strain, the energy storage film volume (G\({}^{\prime}\)) and loss film volume (G\({}^{\prime\prime}\)) of the four FPs are shown in Figure 6. Both G\({}^{\prime}\) and G\({}^{\prime\prime}\) of the four FPs increase with frequency and G\({}^{\prime}\) is always higher than G\({}^{\prime\prime}\). This indicates that in the range of 0.1-100 rad/s, all the four polysaccharides show elastic behavior and exhibit gel nature. With the increase in frequency, the G\({}^{\prime}\) of FPFI(B), FPV(C) and FPH(D) is always much higher than G\({}^{\prime\prime}\), but the G\({}^{\prime}\) of FPF(A) is increasingly close to G\({}^{\prime\prime}\). It is inferred that the increase in temperature intensifies the thermal motion of polysaccharide molecules and enhances the intermolecular force, resulting in the increase in G\({}^{\prime}\) and the enhancement of the gel properties of FPFI, FPV and FPH. The G\({}^{\prime}\) and G\({}^{\prime\prime}\) of FPFI continue to maintain equilibrium and G\({}^{\prime}\) is greater than G\({}^{\prime\prime}\), showing the most stable gel properties. It can be inferred that a higher concentration of FPFI can form a better gel network. As shown in Figure 7, the thermal stability of the heating and cooling processes of different FPs was tested. During heating, the G\({}^{\prime}\) of all FPs was higher than G\({}^{\prime\prime}\) and the polysaccharides showed a typical gel-like system. During the heating process from 20 to 60 \({}^{\circ}\)C, the G\({}^{\prime}\) of the four FPs remained unchanged, the G\({}^{\prime\prime}\) of FPF(A) and FPV(C) remained  
Figure 4: The apparent viscosity of FPs. Figure 5: Pearson correlation analysis of molecular weight, monosaccharide composition, apparent viscosity, uronic acid content and antioxidant and hypolipidemic activity. Note: *: \(p\) < 0.05; **: \(p\) < 0.01; ***: \(p\) < 0.001.  
unchanged and FPFI(B) and FPH(D) showed a decreasing trend. The G\({}^{\prime}\) and G\({}^{\prime\prime}\) of all four polysaccharides increased rapidly during the warming process at 60 to 80 \({}^{\circ}\)C. During the cooling process from 80 to 20 \({}^{\circ}\)C, the G\({}^{\prime}\) and G\({}^{\prime\prime}\) values of all four FPs increased and G\({}^{\prime}\) was greater than G\({}^{\prime\prime}\). The polysaccharides showed a stable gel-like system. Combining the apparent viscosity, dynamic rheological properties and temperature scans of the four FPs, the results show that different drying methods can affect the rheological properties of FPs. All polysaccharides exhibit good gel properties and they can be used as thickeners and stabilizers in the food industry.