Green simple microwave-assisted extraction (MAE) of cellulose from Theobroma cacao L. (TCL) husk

Abstract

This work had successfully produced Theobroma cacao L. (TCL) husk-based cellulose used efficiently and friendly environmentally simple microwave-assisted extraction (MAE) method. The microwave-assisted heating time optimization of alkaline-treatment was carried out for 10, 20, 30 and 40 minutes. Microwave-assisted bleaching process was also conducted using green bleaching agent H2O2, and also utilizing microwave heating for 60 minutes. The followed treatment was filtered, neutralized, washed and overnight freeze-dried. Fourier transform infrared (FTIR) analysis confirmed common cellulose functional groups of TLC, are β-(1,4)-glycosidic bonds at ∼897 cm-1, O-H (hydrogen bond) at 3412 cm-1, C-H vibration at 2902 cm-1, C-O-C asymmetric at 1161 cm-1, and C-OH out-of-plane bending at 665 cm-1. FTIR analysis, in addition, also studied crystallinity ratio (CrR), hydrogen bond energy (E H) and hydrogen bond distances (R H), while particle size analyzer (PSA), X-ray diffraction (XRD) and thermogravimetry analysis (TGA) were carried out to confirm particles sizes, crystallinities and thermal stability properties of TCL husk, cellulose of TCL husk and commercial-microcrystalline cellulose (MCC), respectively.