Jovana Vunduk

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.

Raspberry wine fermentation with suspended and immobilized yeast cells of two strains of Saccharomyces cerevisiae

The objectives of this study were to assess the differences in fermentative behaviour of two different strains of Saccharomyces cerevisiae (EC1118 and RC212) and to determine the differences in composition and sensory properties of raspberry wines fermented with immobilized and suspended yeast cells of both strains at 15 °C. Analyses of aroma compounds, glycerol, acetic acid and ethanol, as well as the kinetics of fermentation and a sensory evaluation of the wines, were performed. All fermentations with immobilized yeast cells had a shorter lag phase and faster utilization of sugars and ethanol production than those fermented with suspended cells. Slower fermentation kinetics were observed in all the samples that were fermented with strain RC212 (suspended and immobilized) than in samples fermented with strain EC1118. Significantly higher amounts of acetic acid were detected in all samples fermented with strain RC212 than in those fermented with strain EC1118 (0.282 and 0.602 g/l, respectively). Slightly higher amounts of glycerol were observed in samples fermented with strain EC1118 than in those fermented with strain RC212. Copyright

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.

Achieving high antimicrobial activity: Composite alginate hydrogel beads releasing activated charcoal with an immobilized active agent

New composites based on Ca-alginate hydrogels were produced that release activated charcoal (AC) particles with adsorbed povidone iodine (PVP-I) as a model antimicrobial substance in a physiological-like environment. Composite beads with different alginate (0.5-1.5%w/w) and AC (1-20%w/w) concentrations were analyzed by FE-SEM and characterized regarding textural parameters, swelling, and AC release kinetics. PVP-I was easily adsorbed onto AC particles within the optimized beads (0.5%w/w alginate, 20%w/w AC) as indicated by UV-vis spectroscopy, EDX and FT-IR analyses. The obtained beads have shown strong bactericidal effects against two standard bacterial strains (Staphylococcus aureus and Pseudomonas aeruginosa) and clinical multi-resistant wound isolates (MRSA, Escherichia coli, Pseudomonas aeruginosa, Еnterococcus faecalis and Proteus mirabilis) and, at the same time, exhibited negligible PVP-I desorption in physiological saline solution. Thus, the obtained composites could provide utilization of potent antiseptics such as iodine, in wound dressings, without the concern of systemic absorption.

Challenging the difference between white and brown Agaricus bisporus mushrooms: Science behind consumers choice

Purpose The purpose of this paper is to examine compositional differences between brown and white varieties of Agaricus bisporus during shelf life and to determine if the growing demand for the brown variety is scientifically justified. Design/methodology/approach Field research enabled analyzing consumers’ perceptions on intrinsic, extrinsic and quality characteristics of mushrooms. A total of 275 consumers participated in the survey. Obtained results were used for comparing white and brown varieties of A. bisporus over a period of 22 days. Mushrooms were packed in air and in modified atmosphere packaging (MAP) at 4°C. Samples were analyzed for their nutritional, antioxidative and microbiological characteristics. Findings Two weeks from harvest, white variety showed higher amount of essential nutrients, while during the third week, brown mushrooms were more nutritionally valuable. Brown variety had better antioxidative ability for all 22 days of storage. Aerobic plate count (APC) was as expected for the mushrooms. MAPs significantly lowered APC in both varieties. The number of Enterobacteriaceae was equal for both varieties at the beginning, but later on they developed much faster in the case of brown variety. Field research combined with specific analyses clarified that there are no nutritive or microbiological reasons for the precedence of brown variety over white. Research limitations/implications Sensory aspect of the quality of mushrooms was not analyzed. Originality/value Market trend toward brown variety was scientifically challenged.