Ganoderma lucidum beta-glucan extract, preparation method and detection method therefor

A method for detecting a Ganoderma lucidum β-glucan extract, consisting of:

• crushing fruiting bodies of Ganoderma lucidum, mixing the crushed fruiting bodies with an ethanol solution, adding trypsin for enzymatic hydrolysis for 0.5-2 h, and separating to obtain a Ganoderma lucidum fruiting body filter residue;
• mixing the Ganoderma lucidum fruiting body filter residue with a 0.1 mol/L sodium hydroxide (NaOH) solution, carrying out ultrasonic extraction at 70° C., adjusting the pH value of the obtained filtrate to be neutral, and concentrating to obtain a crude Ganoderma lucidum polysaccharide;
• adding the crude Ganoderma lucidum polysaccharide to 2-5 times volume of 90% ethanol solution, letting a resulted mixture stand at room temperature for 8-12 h for alcohol precipitation, collecting a precipitate, and freeze-drying the precipitate to obtain a crude Ganoderma lucidum β-glucan extract;
• purifying the crude Ganoderma lucidum β-glucan extract by an ion exchange chromatography column using 0.1 mol/L NaOH solution as a mobile phase to obtain the Ganoderma lucidum β-glucan extract,
• preparing standard solutions with different concentrations using glucose or a compound containing glucose or a glucose moiety, carrying out high performance liquid chromatography on the standard solutions with the different concentrations to obtain chromatographic peak areas, and plotting a standard concentration-peak area curve according to the concentrations of the standard solutions and the chromatographic peak areas;
• dissolving the Ganoderma lucidum β-glucan extract in hydrochloric acid, adding water and hydrolyzing at a pressure over standard-pressure, cooling the obtained hydrolysate, and adding a potassium hydroxide (KOH) solution to adjust the pH value to 6-7;
• adding an exo-1,3-beta-glucanase and β-glucosidase solution diluted with a 0.2 mol/L pH 5.2 sodium acetate buffer, mixing evenly, carrying out enzymatic hydrolysis reaction for 1-2 h, and using the obtained hydrolysate as a test solution;
• and
• carrying out high performance liquid chromatography on the test solution to obtain a chromatographic peak area, and calculating the content of β-glucan in the Ganoderma lucidum β-glucan extract according to the chromatographic peak area and the standard concentration-peak area curve.