Feasibility of using Hericium erinaceus as the substrate for vinegar fermentation

In this study we investigated the production of vinegar using a Hericium erinaceus fermentation. After 9 days of alcoholic fermentation, the alcohol contents reached 16% with all concentrations (1.25%, 2.5% and 5.0%) of H. erinaceus powder investigated, whereas the sugar content decreased from 25 °Brix to 14 °Brix. Also, the broth pH decreased from 4 to 3.7 and the acidity increased from 0% to 0.3%. According to the sensory evaluation, the mushroom wine produced with 5.0% H. erinaceus powder was preferred by the panel, which was then chosen for subsequent acetic acid fermentation. During the acetic acid fermentation, there was little change in pH, even though the acidity increased from 2% to 4.09%. Besides the abundant acetic acid present in the H. erinaceus vinegar, malic acid and succinic acid were also detected after 9-day of fermentation. Moreover, the H. erinaceus vinegar showed antioxidant activity comparable to other vinegar products when assayed by DPPH and ABTS.     

Structural investigation of a novel water-soluble heteropolysaccharide from the fruiting bodies of Phellinus baumii Pilát

A novel water-soluble heteropolysaccharide termed PBF2 was isolated from the fruiting bodies of Phellinus baumii Pilát using hot water extraction and purified on Sephacryl S-1000. PBF2 was shown to be composed of l-fucose, d-mannose and d-glucose. Its structural characteristics were further investigated by FT-IR spectroscopy, sugar analysis, methylation analysis and NMR spectroscopy. Based on the data obtained, PBF2 was found to be a heteropolysaccharide containing a β-(1 → 6)-d-glucopyranose backbone with a fucosyl unit on O-3 of the 3,6-di-O-substituted-d-glucosyl units and it also contained a minor (1 → 3, 6)-β-d-mannose residue and terminal glucose residues.     

Structure characterization of a novel neutral polysaccharide isolated from Ganoderma lucidum fruiting bodies

Ganoderma lucidum (G. lucidum) is a mushroom which has been used for health promotion for a long time in China. In the present work a neutral hetero-polysaccharide, named FYGL-1, was isolated from FYGL which was reported previously capable of antihyperglycemia in vivo for further detailed chemical structure investigation. The results of monosaccharide composition and GPC analysis indicated that FYGL-1 consisted of galactose, rhamnose and glucose in mole ratio of 1.00:1.15:3.22 with a molecular weight of 78kDa. The detailed structure of FYGL-1 was characterized by periodate oxidation, Smith degradation, methylation analysis, along with FT-IR, GC, GC-MS, 1D (1)H and (13)C NMR and 2D NMR (HSQC, COSY, NOESY and TOCSY). Based on the analysis of the results, the structure of the repeating unit of FYGL-1 was established as:     

Structural characterisation and antioxidant properties of polysaccharides from the fruiting bodies of Russula virescens

Water-soluble crude polysaccharide named as RVP was obtained from the fresh fruiting bodies of Russula virescens by boiling-water extraction. DEAE-Sepharose CL-6B column chromatography was used for the fractionation of polysaccharide RVP. Two fractions were obtained, namely RVP-1 and RVP-2. RVP-1 and RVP-2 were composed mainly of glucose, with the estimated equivalent dextran molecular weights of 3.1 × 10⁵ and 4.2 × 10⁵ Da, respectively. Analysis by Periodate oxidation–Smith degradation indicated that RVP-1 was composed of 68.3% (1 →)- or ((1 → 6)-glycosidic linkages and 31.7% (1 → 3)-glycosidic linkages, and RVP-2 7.9% (1 →)- or (1 → 6)-glycosidic linkages, 9.6% (1 → 2)-glycosidic linkages, 35.7% (1 → 4)-glycosidic linkages, and 46.8% (1 → 3)-glycosidic linkages. RVP-1 exhibited equivalent inhibiting power for self-oxidation of 1,2,3-phentriol to vitamin C (Vc), a little higher scavenging activity of superoxide radical and hydroxyl radical than Vc. The reducing power of RVP-1 at 20.0 mg/ml was 0.77, and RVP-1 was a good chelating agent for ferrous ions. Overall, RVP-1 possessed good antioxidant properties and should be developed as a novel potential antioxidant.     

Structural characterisation and antimutagenic activity of a novel polysaccharide isolated from Sepiella maindroni ink

A new heteropolysaccharide, named as SIP, was isolated from the ink of cuttlefish, Sepiella maindroni, by enzymolysis, anion-exchange and gel-permeation chromatography and tested for its antimutagenic activity. It was homogeneous with a molecular weight of 1.13 × 10⁴ Da by HPSEC–MALLS analysis. SIP contained glucuronic acid, mannose, N-acetylgalactosamine, and fucose in a molar ratio of 1:1:2:2. Its structural characteristics were investigated and elucidated by methylation analysis, GLC–MS, and NMR (¹H, ¹³C, H–H COSY, HMQC, HMBC, TOCSY and NOESY). The hexasaccharide repeating unit of SIP was found to be a backbone composed of fucose, N-acetylgalactosamine and mannose in a molar ratio of 2:2:1, and with a single branch of glucuronic acid at the C-3 position of mannose. According to the micronucleus test, SIP could significantly reduce the frequency of micronucleated cells in polychromatic erythrocytes and reticulocytes induced by cyclophosphamide in tumor-bearing mice, which revealed that SIP presented strong antimutagenic activity.     

Structural characterization and antioxidant activity of an extracellular polysaccharide isolated from Brevibacterium otitidis BTS 44

A water-soluble acidic extracellular polysaccharide reaching a maximum concentration of 23.4 g/l growth medium, coded as BSMA, was isolated from the non-pathogenic soil bacteria Brevibacterium otitidis BTS44, by precipitating with two volumes of ethanol. BSMA consisted of arabinose, mannose, glucose and mannouronic acid in ratios of 2.7:3.6:2.1:1.0. No protein was detected in the BSMA fraction, and its molecular weight was about 127 kDa. It has a backbone composed of (1 → 5)-linked arabinose, (1 → 6)-linked mannose with three branches attached to O-3 of (1 → 6)-linked mannose and terminated with either mannose, or mannose and glucose; all the glucose and most of the mannouronic acid are distributed in branches. Partial acid hydrolysis of BSMA gave four sub-fractions termed BSMA-1, BSMA-2, BSMA-3 and BSMA-4. BSMA-1 was composed of arabinose, mannose and trace amounts of mannouronic acid; BSMA-2 was only composed of arabinose and mannose; BSMA-3 was composed of mannose, mannouronic acid and glucose, and BSMA-4 was only composed of mannose and glucose. In the in vitro antioxidant assay, BSMA was found to possess DPPH radical-scavenging activity, with an IC₅₀ value of 120 μg/ml.     

Structural features of a xylogalactan isolated from Hymenaea courbaril gum

The gum from Hymenaea courbaril (Caesalpiniaceae) produced gum at seed level. The gum is soluble in water, dextrorotatory and less viscous than the gum from Cyamopsis tetragonolobus (guar gum). The polysaccharide, isolated from this gum, contains galactose, glucose, xylose and arabinose. The preparation of degraded products by acid hydrolysis and Smith-degradation process led to obtain degraded gums A and B, and the polysaccharides I and II. Chemical methods in combination with 1D NMR (¹H, ¹³C, DEPT-135) and 2D NMR (COSY, HMQC and HMBC) were applied. The backbone is a xylogalactan; β-d-galactose and β-d-xylose residues are 4-O- and 2-O-linked, respectively. The branches are constituted by xylose, arabinose and galactose. It was also observed 4,6-di-O-substituted galactose residues. This work shows interesting structural features of the polysaccharide isolated from H. courbaril gum.     

Structural characterisation of acid- and alkali-soluble polysaccharides in the fruiting body of Dictyophora indusiata and their immunomodulatory activities

The acid- and alkali-soluble polysaccharides (DIPs I and II) were extracted from the fruiting body of Dictyophora indusiata in this work. DIP I comprised of Glc (glucose), Fru (fructose) and Man (mannose), whereas DIP II was of Glc and Fru. Glc was the dominant monosaccharide in both DIPs with relatively molar percentage of >60%, which constructed the backbone of polysaccharide chain. The analysis of the glycosidic linkages indicated that Glc occurred as Glc 1 → 6 in DIP II. The immunological assays showed that both DIPs I and II had a noticeable effect on the hemolysis antibody level in the tested dosage range. However, DIP I could improve the weight of thymus organ and phagocytosis of monocyte. DIP II could restore delayed-type hypersensitivity reaction to dinitrofluorobenzene (DNFB), improving the activity of natural killer cells and the proliferation of splenocytes at high dose.     

Indole compounds in fruiting bodies of some edible Basidiomycota species

The contents of nonhallucinogenic indole compounds were determined in methanol extracts from fruiting bodies of four common edible European species of higher fungi representing the most popular taxon Basidiomycota: Agaricus bisporus (J.E. Lange), Cantharellus cibarius Fr., Lactarius deliciosus (L. Fr.) S.F. Gray and Leccinum rufum (Schaef.) Kreisel. Amongst eleven compounds under analysis, 6–7 metabolites, distinct in different species, were identified in the extracts of fruiting bodies. Serotonin and melatonin were the only common compounds to all species. The contents of the analyzed compounds were diverse, ranging from 0.01 to almost 40 mg/100 g d.w. The contents of tryptophan, 5-hydroxytryptophan, tryptamine and melatonin were low (below 1.40 mg/100 g d.w.). Noteworthy, the serotonin contents were very high in all species under study and amounted to 5.21, 29.61, 18.42 and 31.71 mg/100 g d.w., respectively. Moreover, the fruiting bodies of these species contained indoleacetic acid (max. 2.04 mg/100 g d.w.) and tryptophan degradation products: kynureine sulfate (max. 39.20 mg/100 g d.w.) and kynurenic acid (6.21 mg/100 g d.w.).     

Purification,composition analysis and antioxidant activity of a polysaccharide from the fruiting bodies of Ganoderma atrum

A water-soluble protein-bound polysaccharide was extracted from the fruiting bodies of Ganoderma atrum and isolated by gel-filtration chromatography. Its primary structural features and molecular weight were characterized by infrared spectrometry, gas chromatography, size exclusion chromatography, amino acid analyzer and high-performance liquid chromatography (HPLC). The data obtained indicated that the glycoprotein contains 10.1% of protein and 17 general amino acids and it is rich in glutamic acid, asparagic acid, alanine, glycine, threonine, and serine. It was mainly composed of mannose, galactose and glucose in a molar ratio of 1:1.28:4.91, with an average molecular weight of about 1013 kDa. The existence of an O-glycosidic linkage in PSG-1 (polysaccharide1) was demonstrated by a β-elimination reaction. The antioxidant activity of the purified polysaccharides was evaluated in vitro by 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging assay, self-oxidation of 1,2,3-phentriol assay. Those various antioxidant activities were compared to standard antioxidants vitamin C and BHT. It was found that the scavenging effects of the purified polysaccharides increased with measuring concentration. The results indicated that the purified polysaccharides showed strong DPPH free radical and superoxide anion radical scavenging activities. This study suggested that the purified polysaccharides could potentially be used as natural antioxidants.     

Biochemical characterization of a proteoglycan complex from an edible mushroom Ganoderma lucidum fruiting bodies and its immunoregulatory activity

A fraction, LZ-D-7, was isolated from the fruiting body of the edible mushroom Ganoderma lucidum using a series of chromatographic steps. Biochemical experiments showed that the complex is a proteoglycan and has a carbohydrate percentage of 95.3%, along with a protein percentage of 3.3%. Methylation analysis showed the polysaccharide moiety of LZ-D-7 had a backbone of 1,4-disubsituted-glucopyranosyl and 1,2,6-trisubstituted-glucopyranosyl residues. The branches were mainly composed of 1-substituted-glucopyranosyl residue, which was attached to 1,2,6-trisubstituted-glucopyranosyl residue via 2 or 6 position. Investigation of modulation of LZ-D-7 on BALB/c mouse spleen lymphocytes cells resulted in a three to four-fold increase of MSLs percentage. Analysis of activation and proliferation of MSLs indicated that LZ-D-7 activating most of the activated cells were B cells. The B cells were enlarged, expressed CD⁷¹⁺ and CD²⁵⁺ on the cell surface.     

Structural characterisation of a heteropolysaccharide by NMR spectra

An undocumented water-soluble polysaccharide, LZ-C-1, was isolated from the fruiting bodies of the fungus, Ganoderma lucidum. The polysaccharide had a molecular weight of 7 × 10³ Da, and was mainly composed of l-Fuc, d-Glc and d-Gal. LZ-C-1 had a sugar content of ∼96.4% as measured using the phenol–sulphuric acid method. As a precondition to understand the bioactivity, structural features of LZ-C-1 were investigated by a combination of total hydrolysis, methylation analysis, FT-IR and NMR studies. The results indicated that LZ-C-1 had a backbone of 1,6-disubstituted-α-galactopyranosyl, 1,2,6-trisubstituted-α-galactopyranosyl, 1,3-disubstituted-β-glucopyranosyl and 1,4,6-trisubstituted-β-glucopyranosyl residues. The branches were mainly composed of 1-substituted-β-glucopyranosyl and 1-substituted-α-fucopyranosyl residues.     

Structural characteristics of water-soluble polysaccharides from Rabdosia serra (MAXIM.) HARA leaf and stem and their antioxidant capacities

Water-soluble polysaccharides of Rabdosia serra leaf and stem were fractionated by ultrafiltration and DEAE-Sepharose fast flow chromatogram to obtain water (RSLP-I and RSSP-I), 0.1M NaCl (RSLP-II and RSSP-II) and 0.2M NaCl (RSLP-III and RSSP-III) eluates. Their molecular weights were determined by high performance gel permeation chromatography. Monosaccharide composition analysis indicated that the water eluates comprised of rhamnose, arabinose, xylose, mannose, glucose and galactose. The ascending percentage of galactose and descending percentage of glucose in the eluates were observed with the increase of NaCl concentration. The branched RSLP-I and RSSP-I were composed mainly of →6)-Glcp-(1→, →6)-Galp-(1→, and →5)-Araf-(1→ residues with the ratio of 15.0:4.2:3.8 and 5.5:6.4:3.5, respectively. However, a low level of 1,6-linked glucosyl was observed in RSLP-II, RSSP-II, RSLP-III and RSSP-III. The structural characteristics were further analysed by infrared spectrophotometry. The purified leaf and stem polysaccharides possessed moderate antioxidant capacities.     

Comparison of sterol composition between Tuber fermentation mycelia and natural fruiting bodies

Truffle, belonging to Tuber genera, is a nutritious and sterol-rich edible fungus, and sterol is a potential health beneficial compound. A comparison of Tuber sterol composition indicates that the total sterol contents in the fermentation mycelia (i.e., 10.5 mg g⁻¹) (n = 3) were approximately 3.2-5.6 times higher than that of the fruiting bodies (p < 0.05) with the addition of soybean flour into the basal fermentation media. Moreover, the phytosterol profile of fermentation mycelia could be significantly improved by adding soybean flour into the fermentation media. After the addition of soybean flour, stigmasterol and β-sitosterol appeared in the fermentation mycelia and the contents of total phytosterols (2279 μg g⁻¹) (n = 3), brassicasterol (943 μg g⁻¹) (n = 3), and campesterol (418 μg g⁻¹) (n = 3) were all increased significantly (p < 0.05). Moreover, the total contents of sterols and phytosterols in the fermentation mycelia cultured in the soybean media were much higher than those in the fruiting bodies (i.e., 1883-3240 and 479-1832 μg g⁻¹, respectively) (n = 3, p < 0.05). This work confirms the potentiality of Tuber fermentation mycelia as the alternative resource for its fruiting bodies from the viewpoint of sterols production.     

Properties and safety aspects of Enterococcus faecium strains isolated from Chungkukjang, a fermented soy product

Enterococcus faecium isolated from Chungkukjang, a Korean traditional fermented soybean food was studied for their functional characteristics as potential new starter culture and safety. Microbiological analysis of ripened Chungkukjang revealed the presence of an enterococcal population in numbers of up to 6 log CFU per g. Seven isolates with higher activity were selected for further study and the strains were identified as E. faecium. The E. faecium strains showed resistance against simulated gastrointestinal conditions such as acidic environment and the presence of bile salts. These strains also showed bile salt hydrolase activity but neither hemolytic activity nor virulence determinant such as gelE and efaAfm. All strains were susceptible to glycopeptides and lacked potential as vancomycin-resistant enterococci (VRE). Two strains, S2C10 and S2C11, showed inhibited the viability of Listeria monocytogenes in vitro. The ability was probably due to the production of bacteriocin. The lipase activity influenced the stability, while either acidic condition or high temperature did not play a significant role in the activity of the antimicrobial substances. The strains also produced thermostable listericidal antimicrobial substance. For this reason, the strains could be used as selected starters or protective cultures in soybean fermented food production.     

Short communication: Biofilm production characterization of mecA and mecC methicillin-resistant Staphylococcus aureus isolated from bovine milk in Great Britain

Staphylococcus aureus is an important cause of contagious intramammary infection in dairy cattle, and the ability to produce biofilm is considered to be an important virulence property in the pathogenesis of mastitis. The aim of this study was to characterize the biofilm formation capacity of methicillin-resistant Staph. aureus (MRSA), encoding mecA or mecC, isolated from bulk tank milk in Great Britain. For this purpose, 20 MRSA isolates were grown on microtiter plates to determine the biofilm production. Moreover, the spa-typing and the presence of the intercellular adhesion genes icaA and icaD were analyzed by PCR. All MRSA isolates tested belonged to 9 spa-types and were PCR-positive for the ica genes; 10 of them (50%) produced biofilm in the microtiter plate assay. This is also the first demonstration of biofilm production by mecC MRSA.     

Purification and identification of polysaccharide derived from Chlorella pyrenoidosa

The conditions for extracting and purifying polysaccharides from Chlorella pyrenoidosa, including intensity and duration of ultrasound, the temperature and incubation time, and ethanol concentration, were investigated through an orthogonal design of L₁₆(4⁵) in this work. High performance liquid chromatography (HPLC) and gas chromatography (GC) were used to characterize the compounds in C. pyrenoidosa. The highest yield of 44.8 g kg⁻¹ was achieved at 400 W of ultrasound for 800 s and then followed by incubation in water bath at 100 °C for 4 h in 80% ethanol. Two polysaccharide fractions (S1 and S2) were separated from the extracts of C. pyrenoidosa using Sepharose 4B column chromatography. The average molecular weights (M_w) of S1 and S2 were 81,877 Da and 1749 Da, respectively. Gas chromatographic (GC) traces of the hydrolyzed polysaccharides showed that most of the majority of monosaccharide in both fractions was mannose (78.0% and 76.5% of relative mass from S1 and S2, respectively) with low levels of glucose (13.2% and 8.4% of relative mass from S1 and S2, respectively). The Fourier-transform infrared spectra (FT-IR) of S1 and S2 revealed typical characteristics of polysaccharides. Both samples had the characteristics of hydroxyl groups, weak C–H band and α-pyranoses; however, only S2 had a carboxyl group.     

Antioxidation and antiglycation of polysaccharides from Misgurnus anguillicaudatus

Misgurnus anguillicaudatus is a fish widely inhabiting rivers, lakes, ponds, swamps and rice fields in China, Japan, Korea and other Asian countries. It is edible and can be used to treat xiao ke (namely diabetic) in traditional Chinese medicine. Polysaccharides from M. anguillicaudatus (MAPs) were extracted and separated into four parts which were named MAP I, MAP II MAP III and MAP IV, respectively. The percentage of polysaccharide in dry weight is about 3.06%. Hydroxyl radical and superoxide radical anion scavenging activities together with glycation inhibition of these polysaccharides were investigated. The results showed that all the MAPs had an inhibitory effect on oxidation and glycation and exhibited a dose-dependent response. Especially MAP IV displayed a stronger antioxidation effect than glucosamine and better antiglycation activities than aminoguanidine. As oxidation and glycation are relevant to diabetic complications, the result of this work suggests that MAPs may be effective in preventing and treating diabetic complications.     

Effects of simulated digestion in vitro on cell wall polysaccharides from kiwifruit (Actinidia spp.)

Cell wall polysaccharides are resistant to digestion and absorption in the human small intestine and are considered to be delivered to the colon in a chemically unaltered state. In this paper, pulp from green and gold kiwifruit was subjected to in vitro upper-intestinal tract digestion and the chemical and physical changes to cell wall polysaccharides (dietary fibre) were investigated. Yields of insoluble fibre decreased slightly with simulated digestion while soluble fibre yields increased. Constituent sugar and glycosyl linkage analysis of the soluble and insoluble fibre fractions revealed that the chemical composition and structure of the non-starch polysaccharides remained largely unchanged. However, the degree of methylesterification of galacturonic acid residues present in the pectin-rich soluble fibre fractions of both fruit decreased with treatment; size-exclusion chromatography detected changes in the molecular weight profiles of these fractions. These changes may affect the physicochemical properties and fermentability of kiwifruit dietary fibre in the large intestine.