Fractionating Chitin-Glucan Complex and Coproducts from Pleurotus Ostreatus Mushrooms

Purpose: A large amount of wasted mushroom stems are accumulated yearly by the mushroom industry. To reduce this waste, we have proposed a fractionation method to isolate several useful coproducts using reusable solvents. Methods: Coproducts were extracted by sequential solvent extraction before producing chitin-glucan complex from Pleurotus ostreatus (oyster) mushrooms. The extracted β-glucans, polyphenols, and proteins were confirmed by 3,5-dinitrosalicylic acid (DNS), Folin-Ciocalteau, and bicinchoninic acid (BCA) assays respectively. Extracted lipids were analyzed by gas chromatography-mass spectrometry (GC–MS). The chitin-glucan complex was characterized by Fourier-transform infrared spectroscopy (FT-IR), high performance liquid chromatography (HPLC), and powder X-ray diffraction (XRD). Results: The extract yield of chitin-glucan complex was 8.3%. The crystallinity index of the extracted chitin-glucan complex was 71.2% when compared to 85% for crustacean chitin. The reduced crystallinity in mushroom chitin was due to the presence of the residual β-glucans. Conclusion: The reported fractionation method uses less solvent and provides a greener alternative to producing chitin-glucan complex when compared to the conventional methods of using a large volume of harsh chemicals harmful to the environment. Further, fractionating several coproducts while producing the chitin-glucan complex will reduce the total processing cost.