Anita Klaus

Antioxidants of Edible Mushrooms

Oxidative stress caused by an imbalanced metabolism and an excess of reactive oxygen species (ROS) lead to a range of health disorders in humans. Our endogenous antioxidant defense mechanisms and our dietary intake of antioxidants potentially regulate our oxidative homeostasis. Numerous synthetic antioxidants can effectively improve defense mechanisms, but because of their adverse toxic effects under certain conditions, preference is given to natural compounds. Consequently, the requirements for natural, alternative sources of antioxidant foods identified in edible mushrooms, as well as the mechanistic action involved in their antioxidant properties, have increased rapidly. Chemical composition and antioxidant potential of mushrooms have been intensively studied. Edible mushrooms might be used directly in enhancement of antioxidant defenses through dietary supplementation to reduce the level of oxidative stress. Wild or cultivated, they have been related to significant antioxidant properties due to their bioactive compounds, such as polyphenols, polysaccharides, vitamins, carotenoids and minerals. Antioxidant and health benefits, observed in edible mushrooms, seem an additional reason for their traditional use as a popular delicacy food. This review discusses the consumption of edible mushrooms as a powerful instrument in maintaining health, longevity and life quality.

Polysaccharides of higher fungi: biological role, structure and antioxidative activity

The fungal polysaccharides attract a lot of attention due to their multiple challenging biological properties, such as: anti-tumor, anti-viral, anticomplementary, anticoagulant, hypolipidemic, immunomodulatory and immune-stimulatory activities, which all together make them suitable for application in many quite distinctive areas, such as food industry, biomedicine, cosmetology, agriculture, environmental protection and waste water management. This article presents results with respect to biological properties, structure and procedures related to the isolation and activation of polysaccharides of higher fungi. It is considered and presented along with a review of the critical antioxidative activity and possible influence of the structural composition of polysaccharide extracts (isolated from these higher fungi) upon their antioxidative properties.

The edible mushroom Laetiporus sulphureus as potential source of natural antioxidants

Hot water extract (LN), partially purified polysaccharides (LP) and hot alkali extracted polysaccharides (LNa) obtained from fruiting bodies of the wild basidiomycete Laetiporus sulphureus were examined for their antioxidant activities. LNa was the most active antioxidant, as shown by the median effective concentrations (EC50 values) of 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity (0.5 ± 0.2 mg/ml), reducing power (4.0 ± 0.3 mg/ml) and ferrous ion-chelating ability (1.5 ± 0.1 mg/ml). LNa contained the highest level of α-glucan (17.3 ± 1.2 g/100 g dw), whereas LP contained mostly β-glucans (66.8 ± 1.3 g/100 g dw). The prevalent monosaccharide in all extracts was glucose. The EC50 values of all three antioxidant activity assays were well-correlated with the α-glucan content. Strong and significant correlation was found between total phenolic compounds and DPPH scavenging ability and also reducing power. The three investigated extracts (at concentrations of 0.1–10 mg/ml) were not toxic to HTR-8/SVneo trophoblast cell line.

Antibacterial activity of aromatic plants essential oils from Serbia against the Listeria monocytogenes

The purpose of this study was to examine the effectiveness of selected essential oils for the control of the growth and survival of pathogenic bacteria Listeria monocytogenes ATCC 19112 and Listeria monocytogenes ATCC 19115, which are of significant importance in food hygiene. Essential oils extracted from Salvia officinalis L., Rosmarinus officinalis L., Majorana hortensis Moench., Thymus vulgaris L., Carum carvi L., Pimpinella anisum L. and Coriandrum sativum L. were evaluated. Antibacterial activity was done by the disk diffusion method in the presence of pure essential oils and four suspensions in alcohol. The best results obtained with Thymus vulgaris and Majorana hortensis essential oils, which were acting microbicidaly on both observed strains of Listeria monocytogenes, even in the small concentration. Because some of the essential oils were highly inhibitory even in small quantities to selected pathogenic bacteria, they may provide alternatives to conventional antimicrobial additives in foods. .

Antimicrobial activity of chitosan coatings and films against Listeria monocytogenes on black radish

The antibacterial activity of chitosan coatings prepared with acetic or lactic acid, as well as of composite chitosan-gelatin films prepared with essential oils, was evaluated in fresh shredded black radish samples inoculated with Listeria monocytogenes ATCC 19115 and L. monocytogenes ATCC 19112 during seven days of storage at 4°C. The chitosan coating prepared with acetic acid showed the most effective antibacterial activity. All tested formulations of chitosan films exhibited strong antimicrobial activity on the growth of L. monocytogenes on black radish, although a higher inhibition of pathogens was achieved at higher concentrations of chitosan. The antimicrobial effect of chitosan films was even more pronounced with the addition of essential oils. Chitosan-gelatin films with thyme essential oils showed the most effective antimicrobial activity. A reduction of 2.4log10CFU/g for L. monocytogenes ATCC 19115 and 2.1log10CFU/g for L. monocytogenes ATCC 19112 was achieved in the presence of 1% chitosan film containing 0.2% of thyme essential oil after 24h of storage.

ANTIOXIDANT ACTIVITIES OF HERBS, FRUIT AND MEDICINAL MUSHROOM Ganoderma lucidum EXTRACTS PRODUCED BY MICROFILTRATION PROCESS

This paper presents kinds of extraction and cross-flow filtration of composition of 46 healthful and aromatic herbs, 8 fruits and fungi Ganoderma lucidum. Those extracts are part of Bitter 55, which have significant antioxidant capacity. Antioxidative activities of plant extracts have been determined by DPPH test using method of Blois. Bitter 55 which was kept at the green bottle in the dark has EC50 = 141.07 μl/ml and it was stable during 150 days. Synthetic anti-oxidants BHT (ditertbutilhydroxytoluen, EC50 = 6.2 μgml-1), trolox (vitamin E analog soluble in water, EC50 = 6.8 μgml-1) were used for comparison. EC50 values were calculated as concentration of the extract necessary to decrease DPPH radical concentration for 50 %. Bitter 55 contents 35% vol of alcohol (wheat origin), 88.22 g/l total extract and slice of medicinal mushroom Ganoderma lucidum (1 % w/v) which was extracted 30 days before analyses. The main problem in practical applications of MF is the reduction of permeate flux with time, caused by the accumulation of feed components in the pores. During microfiltration bitter herbal liquor, the function of filtrate flux is decreased with VCR. Dependence of decreasing flux with VCR can be separated in three periods. For the first, starting period, rapid decrease of filtrate flux is characteristic. Second period is defined with much smaller decrease of the flux than in the first phase. Third period has as characteristic minor decrease of flux and can be defined as steady state. Steady state emerges after τs = 80 min.

Safety of Foods Based on Mushrooms

Abstract Throughout the long period of human history, mushrooms played a very important role in some societies, where they were used as a highly appreciated food and medicine and as a psychoactive substances in some religious rites. As extremely healthy and nutritious foodstuffs, low in calories, fats, and essential fatty acids, and on the other hand high in vegetable proteins, vitamins, and minerals, mushrooms are recommended and desirable in our daily diet. Most people prefer to eat them fresh due to much more attractive flavor and texture, which rarely can be compared to that of processed mushrooms. However, mushrooms are highly perishable foods, subject to extremely rapid microbiologic and biochemical changes. In an effort to extend their shelf life and thus make them available to more people, over a longer period, several preserving methods have been developed.

Total quality index of Agaricus bisporus mushrooms packed in modified atmosphere

BACKGROUND The aim of this study was to develop a total quality index and examine the effects of modified atmosphere packaging (MAP) on the quality of Agaricus bisporus mushrooms stored for 22 days at 4 °C. Mushrooms were packaged under three MAPs: high nitrogen packaging (HNP), low carbon dioxide packaging (LCP) and low oxygen packaging (LOP). Passive MAP with air inside initially was used as the atmosphere treatment (AIR). RESULTS This research revealed two phases in quality deterioration of A. bisporus mushrooms. During the first week, most of the quality parameters were not statistically different. Thereafter, odor intensities were stronger for all four types of packaging. Color difference and browning index values showed significantly lower color changes for AIR and LOP compared with HNP and LCP mushrooms. CONCLUSION The best total quality index was calculated for LOP, followed by LCP and AIR. The findings of this study are useful with respect to examining two-component MAPs, separating the limiting factors (O2 and CO2 ) and evaluating quality deterioration effects and the total quality index of A. bisporus mushrooms.

Influence of structural features on immunostimulating activity of glucans extracted from Agaricus blazei mushroom.

High molecular weight b-D-glucans derived from Basidiomycetes cell walls are able to specifically activate cellular and humoral components of the host immune system. The aim of this paper was to examine immunomodulating activity of native, chemically and enzimatically modified glucans from Agaricus blazei mushroom and to determine which structural features are of primary importance for their stimulation referring to humane immune cells. The immunomodulating activities were tested in vitro, by stimulation of peripheral blood mononuclear cells (PBMCs) and measuring of interferon-gamma (IFN-g) production by enzyme linked immunosorbent assay (ELISA). Measurements of immunomodulatory capacity of Agaricus blazei native glucans showed their expressive immunostimulating effect on activated PBMCs and synthesis of IFN-g. The results obtained after the stimulation of cells with 1M H2SO4 and 1M NaOH, the treated glucans showed that primary structure is of more importance than the tertiary structure of the triple helix for their immunostimulating activity and synthesis of IFN-g. Glucans of lower molecular weight obtained after acid hydrolysis appeared as effective immunostimulators of PBMCs. The results obtained after the incubation of cells with 1,6 b-glucanase modified glucans suggest that b-(1,6) binding of glucose monomers probably has no importance for the production of imunostimulating effects, in vitro. This confirmed that b-(1,3) bonds are the primary determinants of immunomodulatory activities and stimulation of IFN-g synthesis.

Antifungal-demelanizing properties and RAW264.7 macrophages stimulation of glucan sulfate from the mycelium of the mushroom Ganoderma lucidum

Underutilized mycelium of Ganoderma lucidum BCCM 31549 has been a significant source of a glucan sulfate (GS) possessing therapeutic activities. GS have been evaluated for their antifungaldemelanizing properties and nitrite oxide production from stimulated RAW264.7 macrophages. GS exhibited antifungal activity against Aspergillus niger A60 with a minimum inhibitory concentration of 60 mg/mL and a minimum fungicidal concentration of 100 mg/mL. At 60mg/mL (sublethal) and 30mg/mL (subinhibitory) doses of GS, the mycelium of A. niger A60 was successfully demelanized with a conidiophore head and black pigment reduction. Additionally, GS successfully stimulated RAW264.7 macrophage cells at a concentration of 500 μg/mL to produce 0.45 μM of nitric oxide. The GS-stimulated RAW264.7 macrophages were morphologically similar to those treated with lipopolysaccharide. The results highlight a novel bifunctional property of mycelial GS from G. lucidum.