Fei Pei

Purification, characterization and antitumor activity of polysaccharides from Pleurotus eryngii residue.

A novel water-soluble polysaccharide from Pleurotus eryngii residue was isolated and further purified by DEAE cellulose-52 chromatography and Sephadex G-100 size-exclusion chromatography to yield PEPE-1, PEPE-2 and PEPE-3. Molecular weights were determined by high-performance size-exclusion chromatography (HPSEC). Gas chromatography (GC) analysis of monosaccharide composition confirmed that PEPE-1, PEPE-2 and PEPE-3 were heteropolysaccharides and mainly composed of glucose. Sulfate and uronic acid content, ultraviolet and infrared spectrum were also evaluated. The antitumor activities of the polysaccharides against HepG-2 cells were studied in vitro. Results showed that the three polysaccharides could suppress the proliferation and enhance lactate dehydrogenase (LDH) release of HepG-2 cells in a dose- and time-dependent manner. The effect increased in the order of PEPE-1<PEPE-2<PEPE-3, respectively. The same order was also observed with uronic acid content. Findings presented in this study suggested that the polysaccharides extracted from P. eryngii residue might be suitable for functional foods and natural antitumor drugs development.

Comparison of Freeze-Drying with Three Different Combinations of Drying Methods and Their Influence on Colour, Texture, Microstructure and Nutrient Retention of Button Mushroom (Agaricus bisporus) Slices

Freeze-drying (FD) and three different combinations of drying methods: freeze-drying combined with hot air drying (FDu2009+u2009AD), freeze-drying combined with vacuum drying (FDu2009+u2009VD) and freeze-drying combined with microwave vacuum drying (FDu2009+u2009MVD) were used to dry button mushroom slices. A comprehensive analysis of dried products was performed on their colour, texture, nutrient retention, microstructure and energy consumption. The results showed that, under conditions of 38xa0% moisture content changing point, most of the parameters including L* values, a* values, average density and hardness of FDu2009+u2009VD and FDu2009+u2009MVD samples had no remarkable changes (pu2009>u20090.05) compared with FD samples. However, only FDu2009+u2009MVD method can reduce drying time by 35.63xa0% in comparison of FD method, although all the combination drying methods can reduce the energy consumption. Moreover, FDu2009+u2009VD and FDu2009+u2009MVD products were better than FDu2009+u2009AD products in nutrient retention except that content of vitamin C was comparatively lower during FDu2009+u2009MVD process. In conclusion, the FDu2009+u2009MVD method has advantages in terms of efficiency and energy saving and could be preferred to produce high-quality products.

Changes in non-volatile taste components of button mushroom (Agaricus bisporus) during different stages of freeze drying and freeze drying combined with microwave vacuum drying

Button mushroom slices were dehydrated using freeze drying (FD) or FD combined with microwave vacuum drying (FMVD), and the non-volatile component profiles were studied. The results showed that the level of non-volatile components in button mushroom firstly increased during sublimation of FD/FMVD process and then fell during desorption in FD process and MVD in FMVD process. Compared to FD products, the contents of soluble sugars and polyols in FMVD products were relatively low, whereas the contents of total free amino acids were significantly higher, close to the level of fresh mushroom. However, there was no significant difference in the contents of 5-nucleotides and organic acids between FD and FMVD products. The equivalent umami concentration (EUC) values for FD and FMVD products did not differ from fresh, indicating that both drying methods could effectively preserve MSG (monosodium glutamate)-like components in button mushroom.

Comparison of Freeze-Drying and Freeze-Drying Combined with Microwave Vacuum Drying Methods on Drying Kinetics and Rehydration Characteristics of Button Mushroom (Agaricus bisporus) Slices

Button mushroom slices were dried using freeze-drying (FD) and freeze-drying combined with microwave vacuum drying (FDu2009+u2009MVD) methods. Drying parameters including drying temperatures (20, 30, and 40xa0°C), chamber pressures (70, 100, and 130xa0Pa) and material layer thicknesses (single, double, and triple) during FD process, and microwave power densities (20, 40, and 60xa0W/g) and material layer thicknesses (single, double and triple) during MVD period of FDu2009+u2009MVD process, were investigated for their drying characteristics. The FD and FDu2009+u2009MVD products were then rehydrated at two temperatures (20 and 70xa0°C). Different mathematical models were tested with the drying and rehydration behaviors of button mushroom slices, and the effective diffusivities (Deff) in the FD and FDu2009+u2009MVD processes were also calculated. The results indicated that based on the statistical tests, the Page model and logarithmic model provided the best fit for FD (in both FD and FDu2009+u2009MVD processes) and MVD (in FDu2009+u2009MVD process) curves, respectively. The regression equations obtained from selected models can accurately predict the relationships between moisture ratio (MR) and time (t). Furthermore, the Deff values of the MVD period in FDu2009+u2009MVD process (2.318–5.565u2009×u200910−5xa0m2/s) were about ten times greater than those in FD process (1.291–3.389u2009×u200910−6xa0m2/s). In addition, the Peleg model gave a better fit for rehydration conditions applied in both FD and FDu2009+u2009MVD products. The values of equilibrium moisture content (We) of FDu2009+u2009MVD products were almost similar to those of FD products, which indicated that the rehydration capacities of the two dehydrated products were comparable.

Antiproliferative and immunostimulatory activity of a protein from Pleurotus eryngii.

BACKGROUNDnCurrently, the use of mushrooms as functional foods, nutraceuticals or phytopharmaceuticals source has risen. In contrast, the possible cellular cytotoxicity and immunostimulatory activity of Pleurotus eryngii (DC. ex Fr.) Quel protein (PEQP) is unknown. Here we report extraction, anti-tumorigenic and immunostimulatory activity of PEQP in vitro.nnnRESULTSnPEQP was extracted from the dried fruiting bodies of P. eryngii, purified and characterised. Its in vitro antiproliferative activity was then evaluated in human non-small cell lung cancer A549 (NSCLC), stomach adenocarcinoma BGC-823, hepatocellular carcinoma HepG2 and gastric carcinoma HGC-27 cell lines using conventional cancer drugs (paclitaxel, doxorubicin and mitomycin C) as positive controls. The protein fractions (PEQP 1, 2, 3 and 4) obtained inhibited tumour cell proliferation dose-dependently with fraction PEQP 2 having significant (P < 0.05) toxicity in all tumour cells. PEQP had no significant toxicity on normal liver Chang cells but their proliferation was significantly inhibited by mitomycin C. Moreover, PEQP stimulated the proliferation, lysosomal enzyme activity, pinocytosis, nitric oxide and hydrogen peroxide production of RAW 264.7 cell lines dose-dependently.nnnCONCLUSIONnBased on these results, P. eryngii protein has a potential application in functional foods as a natural anti-tumour agent with immunostimulatory activity.

Immunopotentiation of Pleurotus eryngii (DC. ex Fr.) Quel

ETHNOPHARMACOLOGICAL RELEVANCEnPleurotus eryngii (DC. ex Fr.) Quel has been collected from the wild, cultivated and used in traditional medicines to treat various disorders and diseases since antiquity. In traditional Chinese medicine, the powdered fruiting bodies of Pleurotus eryngii were used for immunostimulation, skin-care, wound-healing, cancer and lumbago treatment. In the current study, we investigated the antiproliferative activity of Pleurotus eryngii powder on A549, BGC-823, HepG2 and HGC-27 cancer cells and its immunomodulating activity on macrophage, RAW 264.7 cells based on its active compound.nnnMATERIALS AND METHODSnA novel bioactive protein (PEP) was extracted from Pleurotus eryngii fruiting bodies powder and purified on DEAE-52, CM-52 and Superdex 75 column chromatographies using an ÄKTA purifier. Its cytotoxicity on A549, BGC-823, HepG2, HGC-27 and RAW 267.4 cell lines was then evaluated using MTT, alamar blue (AB), trypan blue (TB), neutral red (NR), lactate dehydrogenase (LDH), Annexin V FITC/PI and morphological change assays. Moreover, lysosomal enzyme activity, pinocytosis, nitric oxide (NO) and hydrogen peroxide (H₂O₂) production assays were used to examine immunomostimulatory activity of PEP on RAW 267.4 cells.nnnRESULTSnBased on high performance gel permeation chromatography (HPGPC), Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) analyses, the isolated protein (PEP) had a molecular weight of 63 kDa, a secondary (α-helical) structure and was mainly composed of arginine, serine and glycine. PEP significantly (P<0.05) inhibited A549, BGC-823, HepG2 and HGC-27 tumor cells proliferation dose-dependently with an IC₅₀ range of 36.5 ± 0.84 to 229.0 ± 1.24 µg/ml. Contrarily, PEP stimulated the proliferation of macrophages.nnnCONCLUSIONnPleurotus eryngii fruiting bodies powder has a potential application as a natural antitumor agent with immunomodulatory activity, proposedly, by targeting the lysosomes of cancerous cells and stimulating macrophage-mediated immune responses.

The influence of four drying methods on nonvolatile taste components of White Hypsizygus marmoreus

AbstractnThe influence of four drying methods on nonvolatile taste components of White Hypsizygus marmoreus (WHM) was studied. The soluble sugar, free amino acids, organic acids, and flavor nucleotides of WHM were determined and compared by HPLC after hot air drying, vacuum drying (VD), microwave-vacuum drying (MVD), and vacuum freeze-drying (FD). Equivalent umami concentration (EUC) was used to evaluate the umami taste of WHM. The results showed that the four drying methods had different influence on the soluble sugar, free amino acids, organic acids, and flavor nucleotides. Soluble sugar retention after MVD was the highest (192.61xa0mg/g), but the EUC (147.6xa0g/100xa0g) was lower. The content of essential amino acids (22.83xa0mg/g), flavor amino acids (22.05xa0mg/g), and total amino acids (48.95xa0mg/g) after VD was the highest, but the EUC was the lowest; FD can reduce the loss of the total flavor nucleotides to the minimum, compared with the other three drying methods. FD got the highest retention rate of the total organic acids especially succinic acid, and the influence on amino acids was almost the same with VD. Considering the maximum retention of nonvolatile taste components, FD is the most optimal drying method. Different drying methods have their respective advantages, and this study provided reference for the processing of the WHM.

Separation and speciation analysis of zinc from Flammulina velutipes

Orthogonal experiment was applied to optimize the water extraction parameters of zinc from Flammulina velutipes, and then the extracts were separated by membrane filter (0.45xa0μm) and D101 macroporous resin. Six different species of Zn were obtained and the Zn content of various species were determined by flame atomic absorption spectrometry. The optimized conditions for the extraction of Zn were: ratio of dried material to water, 1:30; extraction temperature, 75°C; extraction time, 120 minutes. About 34.43xa0μg Zn was extracted from 1xa0g dried F. velutipes powder under the optimal conditions. The recovery value for Zn was 96.5% with a low relative standard deviation. In addition, the content of the organic state of Zn was more than that of the inorganic state, and most of the organic state Zn was found in the polysaccharide and protein fractions.