No abstract

β-Glucan is a polysaccharide with anticancer properties, and it is present in the mushroom Agaricus subrufescens. The aim of this study was to compare two analytical methods to quantify β-glucan in mushrooms and analyze the nutritional characteristics, the concentration of phenolic compounds and the mineral composition, for A. subrufescens strains. An enzymatic extraction was performed, and βglucan was quantified by spectrophotometry and high performance liquid chromatography (HPLC). No significant differences were found between the two methods of quantification of β-glucan. The CS7 and CS10 strains were found to have greater amounts of β-glucan, similar to the levels found in Pleurotus eryngii and Pleurotus-sajor-caju. Pleurotus ostreatus and Lentinula edodes samples contained even higher amounts of β-glucan. Significant differences were found in the nutritional characteristics for all parameters assessed, except for fat content. There was no difference between the strains with regard to phenolic compounds or certain mineral components. Fresh A. subrufescens mushrooms are not considered to be a high-protein food. However, they are a good source of fiber and minerals, in addition to being low in fat. Spectrophotometry presents the advantages of being quicker and lower in cost; this technique may be suggested as the standard for measurement of the β-glucan.

Agaricus brasiliensis cultures quickly lose viability when stored at cool temperatures, even for a short period of time. We evaluated several low-cost preservation methods using varied substrates, preservation solutions, and storage temperatures. Agaricus brasiliensis was intolerant to freezing temperatures, making liquid nitrogen use and deep-freezing methods impossible for its preservation. The best preservation conditions for the A. brasiliensis CS1 strain tested in this study were obtained by using rice as substrate and water as preservation solution, with storage at room temperature or when using soil, mushroom cultivation compost, or rice and stored at 10 °C without preservation solution. Those cultures that were reactivated showed the same productivity attributes as the control. In addition, no effect on productivity or biological efficiency was observed through successive subculturing of the strain (CS1). Parboiled rice was successfully used for other A. brasiliensis strains (CS2, CS5, CS7, CS9, and CS10), and also for Pleurotus ostreatus, P. sajor-caju, and Lentinula edodes.

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