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Exo-polysaccharides (EPS) isolated from Streptococcus thermophilus ASCC 1275 were sulfated (31%). High-performance liquid chromatography identified that EPS was composed of mannose (30.19%), galactose (20.10%), glucose (18.05%), glucosamine (16.04%), galactosamine (9.06%), glucuronic acid (3.55%), and ribose (3.01%). Pro-/anti-inflammatory cytokine secretion ratios (IL-1β/IL-10, IL-6/IL-10, and TNF-α/IL-10) of lipopolysaccharide stimulated RAW 264.7 macrophages were significantly decreased by EPS and S.EPS treatments in a dose dependent manner. Furthermore, anti-inflammatory activities of S.EPS improved 49.3% and 24.0% than those of EPS before or after LPS treatment. The reactive oxygen species were inhibited by EPS and S.EPS by 49.6% and 55.1% at 50 μg/mL, respectively. Inhibition activities of S.EPS on nitric oxide production were 12.9% and 55.4% higher than those of EPS at 10 and 50 μg/mL. Additionally, S.EPS exhibited stronger antiproliferative activity on Caco-2 and HepG2 cells. Our results indicated that anti-inflammatory and antiproliferative activities of EPS were significantly (P < 0.01) improved by sulfonation.

Pleurotus eryngii is one of the most favored oyster mushrooms and contains various beneficial bioactive compounds. Polysaccharide extracted from P. eryngii (PEPS) was added as a natural-source ingredient to milk before fermentation, and the effects of additional PEPS on fermented milk were investigated in this study. The PEPS were extracted and added to reconstituted skim milk (12%, wt/vol) at 0.5, 0.25, and 0.125% (wt/vol) and fermented by a non-exopolysaccharide-producing strain, Streptococcus thermophilus Australian Starter Culture Collection (ASCC) 1303 (ST 1303), or an exopolysaccharide-producing Strep. thermophilus ASCC 1275 (ST 1275). Bacterial growth, texture properties, microstructure, proteolytic capacity, and angiotensin-I-converting enzyme-inhibitory activities of fermented milk (FM) were determined during refrigerated storage at 4°C for 21d. Viable counts of starter bacteria in FM with 0.5% PEPS added were the highest. Changes in pH were consistent with changes in titratable acidities for all samples. The FM samples with added PEPS showed denser protein aggregates containing larger serum pores in confocal micrographs compared with those without PEPS at d 0 and 21during refrigerated storage. The values for spontaneous whey separation of FM with added PEPS were significantly higher than those of FM fermented by ST 1303 or ST 1275 without PEPS. The proteolytic activities of ST 1303 of FM with added PEPS were higher than those of FM fermented by ST 1303 without PEPS. The FM with added 0.125% PEPS had similar angiotensin-I-converting enzyme-inhibitory activity to that fermented by ST 1303 without PEPS; both were higher than those of other samples during refrigerated storage. Firmness and gumminess values of FM with added PEPS were higher than those of FM fermented by ST 1303 or ST 1275 without PEPS.

Free (FP) and bound phenolics (BP) were extracted from freeze dried (FD), oven dried (OD), as well as boiling treated (BT) Pleurotus eryngii samples. Free, bound, total phenolics were quantified using Folin-Ciocalteau assay. Qualitative and quantitative analysis of phenolic compounds were carried out using high-performance liquid chromatography (HPLC) coupled with diode array detector (DAD), and a total of 8 phenolic compounds were detected. Free phenolic contents followed the order: Freeze-dried free phenolics (FDFP) > Oven-dried free phenolics (ODFP) > Boiling-treated free phenolics (BTFP), and ranged from 95.42 (BTFP) to 442.50 (ODPF) μg gallic acid equivalents (GAE)/g dry weight (DW). Bound and total phenolic contents followed the order: FD > OD > BT, and ranged from 218.33 (BTBP) to 774.17 (FDBP) and 313.75 (BT total phenolics) to 1090.42 (FD total phenolics) μg GAE/g DW. Bound phenolics contributed 49.76% (OD), 69.59% (BT), and 71% (FD) of the total phenolic contents. All free and bound phenolic extracts were investigated for their antioxidant activities by 3 different assays, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, reducing power, and superoxide anion radical scavenging activity. FDFP showed strongest DPPH radical scavenging activity (IC50 at 32.61 μg/mL), ODFP showed strongest reducing power (IC50 at 26.31 μg/mL), and BTBP showed strongest superoxide anion radical scavenging activity (IC50 at 14.07 μg/mL).