Investigation of the physicochemical properties of microcrystalline cellulose from agricultural wastes I: orange mesocarp

Orange mesocarp was obtained after removal of the epicarp and the endocarp from oranges. It was dried, pulverized and digested with 2% w/v sodium hydroxide at 80°C for 3 h. Alpha- and micro-crystalline celluloses were extracted from the pulp using 17.5% w/v and 2.5 N hydrochloric acid, respectively. The physicochemical and powder properties of the extracted material were evaluated. Results obtained showed that the yield of α-cellulose from the orange mesocarp was 62.5% and that of microcrystalline cellulose 25.3%. The total water-soluble substances were 0.0018 g/g, ash 0.00035 g/g and the true density 1.760 g cm⁻¹, while the pH and hydration capacity are 6.61 and 2.916, respectively. Elemental analysis of the cellulose ash shows the absence of Pb and Mn and the preponderance of K, Na and Fe. The water sorption profile of the microcrystalline cellulose was also studied.