Short communication: Cultivation of Lentinus edodes mycelia using whey permeate as an alternative growth substrate

The major objective of this research was to use whey permeate as an alternative growth medium for the cultivation of mycelia of the edible mushroom Lentinus edodes and to find an optimum condition for solid-state cultivation. Response surface analysis was applied to determine the combination of substrate concentration (40 to 60 g of lactose/L), temperature (20 to 30°C), and pH (4 to 6) resulting in a maximal mycelial growth rate. The radial extension rates, estimated by measuring the diameters of growing colonies on the Petri dishes, were used as the growth rate of the mycelia at different conditions. The conditions predicted to maximize the mycelial growth of 6.41 ± 0.47 mm/d were determined to be 40 g of lactose/L, temperature 23.6°C, and pH 5.0. It was concluded that a partial cubic equation could accurately model the response surface of, and predict optimal growth conditions for, L. edodes mycelia using whey permeate because the model prediction agreed with the experimental growth rate, 6.39 ± 0.22 mm/d. The results suggest that whey permeate could be utilized as a growth substrate for the cultivation of mycelia from the edible mushroom L. edodes, enhancing the use of this by-product by the cheese manufacturing industry.     

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:     

Recovery of lactose from simulated delactosed whey permeate by a low-temperature crystallization process

Delactosed whey permeate is the mother liquor/by-product of lactose manufacture, but it still contains around 20 wt% lactose. The high mineral content, stickiness, and hygroscopic behavior prevent further recovery of lactose in the manufacturing process. Therefore, its use is currently limited to low-value applications such as cattle feed, and more often it is seen as waste. This study investigates a new separation technique operating at sub-zero conditions. At low temperature, precipitation of calcium phosphate is expected to be reduced and the lower solubility at sub-zero temperature makes it possible to recover a large portion of the lactose. We found that lactose could be crystallized at sub-zero conditions. The crystals had a tomahawk morphology and an average size of 23 and 31 µm. In the first 24 h, the amount of calcium phosphate precipitated was limited, whereas the lactose concentration was already close to saturation. The overall rate of crystallization was increased compared with the crystals recovered from a pure lactose solution. Mutarotation was rate limiting in the pure system but it did not limit the crystallization of lactose from delactosed whey permeate. This resulted in faster crystallization; after 24 h the yield was 85%.     

The effect of delactosed whey permeate on phytochemical content of canned tomatoes

The effect of delactosed whey permeate (DWP) treatment on antioxidant and phyto-chemical components of canned Irish plum tomatoes were investigated. Tomatoes were sterilised for 5 min (F₀) at 120 °C and stored for 6 months. The DWP treatment retained significantly (p < 0.05) higher levels of ascorbic acid and lycopene of tomatoes. The antioxidant activity of DWP treated tomatoes was higher (7%) than the control at the end of storage. The firmness in DWP-treated fruits was around 40% higher than that in control. All the parameters decreased significantly (p < 0.05) during storage except lycopene and total phenols. Lycopene content showed no significant change and total phenols increased during storage. The changes in ascorbic acid, antioxidant activity and texture were fitted well to Weibull kinetic models with high coefficients of determination (R²) and low RMSE (root mean sum of squared error). The results clearly indicate that DWP enhanced the retention of antioxidant compounds in tomatoes during storage.     

Use of chitosan for selective removal of beta-lactoglobulin from whey

A method is described for selective removal of undenatured β-lactoglobulin from cheese whey based on interactions between whey proteins and chitosan. Whey was previously clarified at pH 4.5 with addition of chitosan (25 mg/100 mL), and selective removal of β-lactoglobulin was studied in the pH interval 4.6 to 6.5. Addition of chitosan caused selective precipitation of β-lactoglobulin that increased with pH. The content of β-lactoglobulin in whey decreased as the amount of chitosan added was increased. At pH 6.2, addition of 1.9 to 3.0 mg/mL of chitosan led to complete removal of β-lactoglobulin, whereas at least 80% of the rest of whey proteins remained in solution. The production of cheese whey without β-lactoglobulin could help to expand the applications of dairy by-products in food processing, and to isolate hypoallergenic whey protein concentrates.     

Short communication: Composition of coproduct streams from dairy processing: Acid whey and milk permeate

This article provides composition information for 3 abundantly available but little characterized dairy coproduct streams: acid whey from Greek yogurt (GAW), acid whey from cottage cheese (CAW), and milk permeate (MP). Three replicate samples obtained on different dates from several dairy processors were analyzed. The main component in all streams was lactose, with up to 3.5, 2.1, and 11.9% in GAW, CAW, and MP, respectively. Crude protein content ranged from 1.71 to 3.71 mg/g in GAW, 1.65 to 5.05 mg/g in CAW, and 3.2 to 4.35 mg/g in MP, and pH ranged from 4.21 to 4.48, 4.35 to 4.51, and 5.4 to 6.37, respectively. Chemical oxygen demand varied from 52,400 to 62,400 mg/L for GAW, 31,900 to 40,000 mg/L for CAW, and 127000 to 142,000 mg/L for MP; biochemical oxygen demand ranged from 45,800 to 50,500 mg/L (GAW), 32,700 to 40,000 mg/L (CAW), and 110,000 to 182,000 mg/L (MP). The GAW had the lowest pH (4.21–4.48) and highest mineral content of all streams. These data will assist processors and researchers in developing value-added uses of these dairy coproducts.     

Bistage control of pH for improving exopolysaccharide production from mycelia of Ganoderma lucidum in an air-lift fermentor

It was found that pH control definitely affects mycelial cell growth and exopolysaccharide (EPS) production of the mycelial cultivation of Ganoderma lucidum. Compared to the case of uncontrolled pH cultivation, a culture system whose pH was kept constant at 3 and 6 exhibited improved mycelial cell growth and EPS production, respectively. The bistage pH control technique, that is, shifting the pH from 3 to 6 at the initial phase of the exponential growth, is introduced to improve cell growth and EPS production. This technique can greatly increase EPS production to 20.1 g/l from 4.1 g/l in the case of uncontrolled pH cultivation, without adverse effects on cell growth as in the case of constant maintenance of a high pH. It was also proved that bistage pH control retained the desirable morphologies of the mycelia during cultivation and resulted in low viscosity and yield stress of the culture broth. It will be useful for the application of the culture process to mycelial growth in a large-scale fermentor.     

富硒灵芝功能性奶粉的研制

采用灵芝深层发酵对无机元素硒进行富集和转化，获得了硒合量2936μg／g的灵芝菌丝体。富硒灵芝菌丝体不但强化了硒营养，将无机硒转化为吸收和利用率较高的有机硒。而且，各种氨基酸含量大幅度提高，强化了营养价值。以富硒灵芝菌丝体作基料配制的功能性奶粉，除含有普通奶粉的营养成分外，还含有丰富的灵芝多糖和有机硒，具有特殊的保健功能，是一种理想的功能性食品。     

The impact of delactosed whey permeate treatment on shelf‐life and antioxidant contents of strawberries

The aim of this study was to investigate the effect of delactosed whey permeate (DWP) treatment on antioxidant and physicochemical properties of strawberries. Fresh strawberries treated with 3% DWP were analysed for different quality, nutritional and microbiological markers during 10 days of storage at 5 °C. The results showed that DWP treatment significantly reduced incidences of decay (70%) and numbers of total aerobic counts (～1.4 Log₁₀ CFU g^?1) and yeast and moulds (～1.8 Log₁₀ CFU g^?1). DWP treatment also inhibited the loss of firmness (15%) and maintained significantly (P ≤ 0.05) higher levels of vitamin C, total phenols and antioxidant activity of strawberries. Sensory scores confirmed that the DWP‐treated strawberries retained a good appearance and overall quality. The aroma and colour attributes were not reduced during storage. These results suggest that DWP treatment has potential to extend the shelf‐life and maintain the quality of strawberries during storage.     

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.     

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.     

Purification and identification of bovine cheese whey fatty acids exhibiting in vitro antifungal activity

Milk lipids contain several bioactive factors exhibiting antimicrobial activity against bacteria, viruses, and fungi. In the present study, we demonstrate that free fatty acids (FFA) derived from the saponification of bovine whey cream lipids are active in vitro at inhibiting the germination of Candida albicans, a morphological transition associated with pathogenicity. This activity was found to be significantly increased when bovine FFA were enriched in non-straight-chain FFA. At low cell density, this non-straight-chain FFA-enriched fraction was also found to inhibit in a dose-dependant manner the growth of both developmental forms of C. albicans as well as the growth of Aspergillus fumigatus. Using an assay-guided fractionation, the main components responsible for these activities were isolated. On the basis of mass spectroscopic and gas chromatographic analysis, antifungal compounds were identified as capric acid (C10:0), lauroleic acid (C12:1), 11-methyldodecanoic acid (iso-C13:0), myristoleic acid (C14:1n-5), and γ-linolenic acid (C18:3n-6). The most potent compound was γ-linolenic acid, with minimal inhibitory concentration values of 5.4 mg/L for C. albicans and 1.3 mg/L for A. fumigatus, in standardized conditions. The results of this study indicate that bovine whey contains bioactive fatty acids exhibiting antifungal activity in vitro against 2 important human fungal pathogens.     

Quantification of total polysaccharides and triterpenoids in Ganoderma lucidum and Ganoderma atrum by near infrared spectroscopy and chemometrics

Two chemometrics, the partial least-squares (PLS) and radial basis function (RBF) network were performed to develop a quantification method for total polysaccharides and triterpenoids in Ganoderma lucidum and Ganoderma atrum from different origins based on near infrared reflectance spectroscopy (NIR). The influences of spectral window and spectral pre-treatments were initially studied in the construction of PLS model. The best result was obtained when the standard normal transformation (SNV) +1st derivative spectrum over 4100–7750 cm⁻¹ was used for the modelling. Then based on each principle, both of the two models were optimised respectively. The final results with high determination coefficient (R²) (higher than 0.973, 0.989 for PLS and RBF, respectively) and low root mean square errors of prediction (RMSEP) (low to 0.1109 and 0.01298 for polysaccharides and triterpenoids, respectively) confirm the good predictability of the two models. The overall results show that NIR spectroscopy combined with chemometrics can be efficiently utilised for accurate analysis of routine chemical compositions in G. lucidum and G. atrum.     

Changes in some components of soymilk during fermentation with the basidiomycete Ganoderma lucidum

Soymilk was fermented with the basidiomycete Ganoderma lucidum WZ02 and the changes in the contents of polysaccharide, sugars, crude protein, B-vitamins, free amino acids and isoflavones were analyzed. Polysaccharide and crude protein were increased by the fermentation of G. lucidum while most free amino acids were reduced. The flatulence factor (e.g. stachyose and raffinose) was significantly decreased and stachyose was not detected after 72 h of fermentation. The contents of thiamin, riboflavin, and niacin were increased during the fermentation. Most of isoflavone glycosides were converted to aglycones and the contents of daidzein and genistein were increased by the fermentation of G. lucidum. The results suggested that fermentation by G. lucidum could improve the acceptability and health properties of soymilk.     

Biotransformation of ginsenoside Rd in the ginseng extraction residue by fermentation with lingzhi (Ganoderma lucidum)

Ginseng and lingzhi (Ganoderma lucidum) both are valuable traditional Chinese medicines and have been extensively utilised in functional foods and traditional medicines in many Asian countries. However, massive quantity of ginseng residue is produced after extraction of ginseng which still contains a lot of bioactive compounds such as ginsenosides. The goal of this study was to reuse the American ginseng extraction residue as the fermentation medium of G. lucidum to produce bioactive ginsenoside enriched biotransformation products. The changes of ginsenosides in the fermentation products were analysed during fermentation. Our results showed that after 30 days of fermentation, ginsenoside Rg1, Rd, and compound K (CK) significantly increased, especially Rd, while other ginsenosides (Re, Rb1 and Rc) decreased during fermentation. Ginsenoside Rd is the major ginsenoside in the final fermentation product. Furthermore, the biotransformation of ginsenosides was the major reaction in this fermentation process.     

New fungal biomasses for cyanide biodegradation

Cyanide, a hazardous substance, is released into the environment as a result of natural processes of various industrial activities which is a toxic pollutant according to Environmental Protection Agency. In nature, some microorganisms are responsible for the degradation of cyanide, but there is only limited information about the degradation characteristics of Basidiomycetes for cyanide. The aim of the present study is to determine cyanide degradation characteristics in some Basidiomycetes strains including Polyporus arcularius (T 438), Schizophyllum commune (T 701), Clavariadelphus truncatus (T 192), Pleurotus eryngii (M 102), Ganoderma applanatum (M 105), Trametes versicolor (D 22), Cerrena unicolor (D 30), Schizophyllum commune (D 35) and Ganoderma lucidum (D 33). The cyanide degradation activities of P. arcularius S. commune and G. lucidum were found to be more than that of the other fungi examined. The parameters including incubation time, amount of biomass, initial cyanide concentration, temperature, pH and agitation rate were optimized for the selected three potential fungal strains. The maximum cyanide degradation was obtained after 48 h of incubation at 30 °C by P. arcularius (T 438). The optimum pH and agitation rate were measured as 10.5 and 150 rev/min, respectively. The amount of biomass was found as 3.0 g for the maximum cyanide biodegradation with an initial cyanide concentration of 100 mg/L. In this study, agar was chosen entrapment agent for the immobilization of effective biomass. We suggested that P. arcularius (T 438) could be effective in the treatment of contaminated sites with cyanide due to capability of degrading cyanide.     

Enhancement of repair of radiation induced DNA strand breaks in human cells by Ganoderma mushroom polysaccharides

The DNA repair ability of a cell is vital to the integrity of its genome and thus to its normal functioning and that of the organism. The repair-enhancing property of polysaccharides isolated from Ganoderma lucidum which belongs to the polyporaceae family was determined by comet assay in human peripheral blood leukocytes. Comet parameters were studied at 2 Gy gamma irradiation with 15 min intervals. The comet parameters after 2 Gy exposures to γ-radiation were reduced to nearly normal levels after 120 min of exposure. The polysaccharides from G. lucidum enhance the repair process, which is a promising approach for protection from radiation exposure, but a detailed study of the molecular mechanism is needed for further application.