A comparative study of analytical methods for alkali-soluble beta-glucan in medicinal mushroom, Chaga (Inonotus obliquus)

Abstract

Crude beta-glucan content in the medicinal Mushroom Chaga (Inonotus obliquus) was measured by different extraction and analytical methods, and the results were compared. The alkali extraction (AE) method or enzymatic digestion (ED) method followed by a gravimetric analysis was employed to determine the crude beta-glucan content. The amount of crude beta-glucan in Chaga obtained by either AE or ED was 13.7g/100g or 15.3g/100g of the sample, respectively. Crude beta-glucan content of Chaga obtained by the above preparation methods were corrected by chemical composition analysis and HPLC analysis. After composition analysis, the amounts of beta-glucan measured in the 100g Chaga samples were corrected to 10.1g for ED and 10.7g for AE method. beta-glucan contents calculated by the amount of glucose in the HPLC analysis were 8.3g/100g and 8.1g/100g for ED and AE preparation methods, respectively. Although extraction method did not affect beta-glucan content in Chaga as indicated by no significant difference (P > 0.05) between extraction method, significant differences (P < 0.05) were noted between the correction methods. The discrepancies of the result indicate a need for standardization of analytical method for beta-glucan measurement in Chaga (C) 2007 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.