High-internal-phase emulsions stabilized by alkali-extracted green tea polysaccharide conjugates for curcumin delivery

The isolation, characterization and biological activities of the non-glucan polysaccharides from the high-starch-content plant Pueraria mirifica

The dried root of Pueraria mirifica (P. mirifica) is an edible foodstuff widely used in Asian countries. P. mirifica is known for its high starch content. The isolation of polysaccharides from high-starch plant parts is challenging due to the interference of starch. Therefore, this study aimed to develop a technique for isolating and investigating the structure and activity of non-glucan polysaccharides from P. mirifica (PMP). An effective starch removal process was developed using α-amylase hydrolysis and thorough membrane dialysis. Four non-glucan polysaccharides were isolated, and PMP-2 was subjected to structural elucidation. The results indicated that PMP-2 has a molecular weight of 124.4 kDa and that arabinose and galactose are the main components, accounting for 27.8 % and 58.5 %, respectively. Methylation and NMR analysis suggested that PMP-2 is an Arabinogalactan composed of 1,6-linked Galp and 1,4-linked Galp as the main chain, with arabinan and rhamnose as side chains. Furthermore, PMP-C and PMP-2 exhibited concentration-dependent antioxidant activities against DPPH, ABTS, and hydroxyl radicals and certain immunomodulatory activities related to the release of NO, TNF-α and IL-6. These findings suggest that PMP-2 has potential therapeutically active ingredient in functional foods. The developed method successfully removed starch and isolated non-glucan polysaccharides from the high-starch content plant P. mirifica and can be applied to other high-starch plants.

Green tea polysaccharide conjugates and bovine serum albumin have a synergistic effect in improving the emulsification ability

Our previous study revealed that green tea polysaccharide conjugate (gTPC) has emulsion effect, but its emulsifying ability is weak. In order to improve the emulsification ability of gTPC, gTPC and bovine serum albumin (BSA) were combined to form five different mass proportions of the TPC/BSA (TB) complex: TPC/BSA: 5:1, 5:2, 5:3, 5:4, and 5:5 w/w. We observed that the 5:5 w/w TB emulsion was more hydrophobic and surface-active. Furthermore, the emulsions prepared using 50.00 wt% medium-chain triglycerides exhibited the best stability. In addition, the TB emulsion exhibited stability in adverse environments of pH, salt, and heat; in particular, under salt conditions, no significant changes were observed in zeta potential. Subsequently, in vitro simulated digestion experiments were performed to investigate the use of TB emulsions for β-carotene encapsulation. We observed that the encapsulation efficiency for β-carotene was approximately 90.0 %; it was subsequently released in the intestine.