Preparation, stability and digestive properties of tea polysaccharide nanoparticles

This study aimed to investigate the storage stability and functional properties of different sizes of tea polysaccharides, and explore the relationship between sizes and digestive properties, so as to provide reference for the subsequent utilization of tea polysaccharides. In this study, TPS-NPs of about 200 nm and 400 nm were prepared by electrostatic interaction with TPS and EDTA ratios of 6:1 and 100:1, respectively. The structural properties of TPS-NPs were investigated by a series of characterization analyses. The results showed that the major functional groups of TPS-NPs did not change significantly with particle size, but the C--O stretching vibrations in the methylated carboxyl group were more pronounced. However, their DPPH free radical scavenging ability and antioxidant activity of TPS were decreased in vitro because of the destruction of the apparent structure of tea polysaccharides nanoparticles during preparation. Stability measurements revealed that TPS-NPs have high storage, temperature, pH and ionic concentration stability, especially for TPS-NPs with a particle size of 200 nm. The digestibility of 400 nm TPS-NPs was improved to 3.89% compared to TPS. The results showed that the TPS-NPs has excellent stability and digestibility, which contributed to the development of TPS applications in the food industry and related products.