Comparative Study of the Characterization and Functional Properties of Oligosaccharides and Nanoparticles Derived from Poria cocos Polysaccharide

The application of Poria cocos polysaccharides (PCP) is largely determined by their unique structural characteristics and functional properties. However, the effect of their derivatives, particularly Poria cocos oligosaccharides (PCO) and Poria cocos polysaccharide nanoparticles (PCNPs) on these properties and their applications is not well understood. In this study, PCO and PCNPs were synthesized and compared with PCP in terms of structure and function to clarify their mechanisms of influence. The molecular weight of PCO, enzymatic digestion by PCP, was determined to range from m/z 504.32 to 992.79, which corresponds to a polymerization degree of 3 to 6. The primary monosaccharide of PCO was glucose, with smaller amounts of arabinose, galactose, and mannose. The PCNPs had an average size of 108.50 ± 2.15 nm and zeta potential of -10.25 ± 0.44 mV, accompanied with notable structural changes observed in Fourier transform infrared (FTIR) spectroscopy. Functionally, the solubility of PCP significantly increased to over 90% after conversion into PCO and PCNPs, leading to improved water and oil holding capacities. Conversely, the apparent viscosity decreased from 161.46 ± 2.77 mPa·s to 76.05 ± 1.25 mPa·s in PCNPs and 36.45 ± 2.33 mPa·s in PCO. Additionally, these derivatives enhanced the antioxidant activity of PCP, notably, PCNPs exhibited the highest DPPH radicals scavenging capacity at 75.27% ± 0.93%, hydroxyl radicals scavenging capacity at 35.45% ± 0.78%, and superoxide anion radicals scavenging capacity at 59.01% ± 0.67%, whereas PCO merely increased the scavenging of superoxide anion radicals in these assays. In general, PCNPs enhanced functionality and a broader range of potential applications in functional foods and pharmaceuticals.