| The steam explosion method of fractionation of lignocellulosic materials was applied to coffee (Coffea arabica) hull as a pretreatment for the production of microcrystalline cellulose. A factorial design was used to quantify the influence of two variables in the process, temperature (T): 160, 180, 200°C; retention time (t): 8, 12, 16, and 20 minutes. These variables are related to the severity parameter R0 = t*exp [(T-100)/14.75]. The delignification was achieved by transforming the hull using steam explosion as pretreatment which was then followed by an alkaline extraction. The remaining fiber was bleached and analyzed by X-ray diffraction and its degree depolymerization (DP) was determined. The maximum depolymerization was 710 (DP) at 4.25 of severity. Crystallization of the cellulose was promoted by steam explosion pretreatment. It is demonstrated that the texture of yogurt increased with the depolymeration of the fiber. |
