Effect of Yeast Fermentation on the Physicochemical Properties and Bioactivities of Polysaccharides of Dendrobium officinale

Improved the physicochemical properties and bioactivities of oligosaccharides by degrading self-extracting/commercial ginseng polysaccharides

Degradation of polysaccharides is an effective method to improve the physicochemical properties and biological activities. In this study, self-extracting ginseng oligosaccharides (SGOs) and commercial ginseng oligosaccharides (CGOs) were compared with self-extracting ginseng polysaccharides (SGPs) and commercial ginseng polysaccharides (CGPs). The four saccharides were composed of different types and proportions of monosaccharides. And the molecular weight (Mw) size order was SGP > CGP > CGO > SGO. The SGO and CGO had better solubility with smaller particle size, 97.63 ± 0.42 % and 96.23 ± 1.12 %, respectively. Fourier transform infrared, nuclear magnetic resonance, and X-ray diffraction spectroscopy characterized the structures of four saccharides. It was found that the structural features of saccharides did not change after enzymatic hydrolysis. The results of bioactivities showed that SGO and CGO had better antioxidant, hypoglycemic, and hypolipidemic activities. Compared with polysaccharides, oligosaccharides could significantly promote the proliferation and phagocytic ability of RAW 264.7 cells. Oligosaccharides induced RAW 264.7 cells to produce more NO and had better immune activity. Pearson's correlation coefficient analysis confirmed the bioactivities were negatively correlated with the Mw of ginseng saccharides. This study suggests that reducing the Mw of saccharides is an effective strategy to enhance their bioactivities.

Effect of Lactiplantibacillus plantarum fermentation on the physicochemical, antioxidant activity and immunomodulatory ability of polysaccharides from Lvjian okra

Okra polysaccharides exhibits a range of biological activities. To date, its processing using microbial fermentation has not been explored. This study investigated the fermentation of okra juice with various lactic acid bacteria, followed by the extraction and characterization of crude polysaccharides (termed OPS-F), in contrast to their non-fermented counterpart (OPS). Changes in physicochemical properties, antioxidant activity and immunomodulatory ability were noted. The results demonstrated that OPS-F had a 7.42-12.53 % increase in total polysaccharides content compared to OPS. However, high-performance size-exclusion chromatography indicated a reduction in the molecular weight of OPS-F (7.9-9.5 × 105 Da) relative to OPS (1.66 × 106 Da). Compared to OPS, OPS-F had reduced levels of mannose, glucose, glucuronic acid and arabinose, but increased rhamnose, galacturonic acid and galactose, exhibiting enhanced solubility and lower apparent viscosity. Fourier transform infrared spectroscopy and nuclear magnetic resonance analysis showed minimal changes in polysaccharide structure post-fermentation. Moreover, despite a decrease in antioxidant activity post-fermentation, OPS-F exhibited superior immunomodulatory potential. In conclusion, fermenting okra juice with lactic acid bacteria alters the physicochemical properties of crude polysaccharides and enhances their immunomodulatory activity, offering a promising approach for developing new functional food resources.

Recent advances in polysaccharide biomodification by microbial fermentation: production, properties, bioactivities, and mechanisms

Polysaccharides are natural chemical compounds that are extensively employed in the food and pharmaceutical industries. They exhibit a wide range of physical and biological properties. These properties are commonly improved by using chemical and physical methods. However, with the advancement of biotechnology and increased demand for green, clean, and safe products, polysaccharide modification via microbial fermentation has gained importance in improving their physicochemical and biological activities. The physicochemical and structural characteristics, biological activity, and modification mechanisms of microbially fermented polysaccharides were reviewed and summarized in this study. Polysaccharide modifications were categorized and discussed in terms of strains and fermentation techniques. The effects of microbial fermentation on the physicochemical characteristics of polysaccharides were highlighted. The impact of modification of polysaccharides on their antioxidant, immune, hypoglycemic, and other activities, as well as probiotic digestive enhancement, were also discussed. Finally, we investigated a potential enzyme-based process for polysaccharide modification via microbial fermentation. Modification of polysaccharides via microbial fermentation has significant value and application potential.