Phytosterol from cocoa shell can be reused in food industries in order to add value of the agricultural waste. Its extraction from the cocoa shell using ethanol can be assisted by using microwave for effective heating. This study was carried out to delineate the effect of temperature, power and radiation time of the microwave onto the extraction of β-sitosterol, as the key phytosterol, from the cocoa shell of Theobroma cacao L. species using absolute ethanol. Salkowski test, IR spectra and GC-MS analyses confirmed the presence of β-sitosterol and a flame-ionization-detector gas chromatography was employed to measure its concentration. Based on the one-factor-at-a-time (OFAT) approach, the maximum yield was obtained 13% higher than the yield of conventional maceration, i.e. 3546.1 mg/100g, at the optimum values of 70°C, 500 W and 10 min. Solubility and boiling point of ethanol onto extraction at various extraction temperatures probably caused the differences.

Xylose production has become one of the most studied process over the year due to the significant application as a raw material for the production of a variety of specialty chemicals, mainly xylitol. The most promising raw material is lignocellulosic biomass because of its widely available and cheap. There are several type of pretreatment process has been studied to depolymerized the lignocellulosic compounds into fermentable sugars. Among all, dilute acid hydrolysis is the most promising process to produce high xylose. However, disadvantage of this pretreatment process is production of byproduct that can slowdown the fermentation step. Understanding the effect of pretreatment processing parameters on lignocellulosic depolymerization could possibly result in minimization of degradation compounds. Therefore, the aim of this work is to carry out the sensitivity analysis of the acid hydrolysis process used for the production of fermentable sugars with the aid of Aspen Plus by considering the concentration of xylose, glucose, furfural and acetic acid obtained at the outlet of reactor as the output variable. Sensitivity analysis were apply at temperature (160 °C, 170 °C and 180 °C) and residence time (0-160 min). The results indicate that the developed process model is possible to improve lignocellulosic conversion efficiency while minimizing degradation product generation with the highest xylose produce is 18.26 g/L at 180 °C during 20 min reaction time.

Dilute acid hydrolysis is one of the most effective pretreatment methods for lignocellulosic biomass. The aim of this study is to develop and simulate process model for xylose production using Aspen Plus simulator. Based on experimental study for xylose production, a flowsheet has been proposed for a possible commercial production. Sawdust was used as a feedstock for the simulation as it has above 29% of xylan content. The hydrolysis of hemicellulose and cellulose to its monomeric constituents were modeled by a series of first-order reactions. A kinetic and stoichiometric based reactor was used for dilute acid hydrolysis and neutralization process. The results from the simulation were compared with experimental study from literature. Results from the developed process model show a good agreement with experimental study with 2.4% overall mean error for xylose and 4.5% overall mean error for glucose production.