Jurnal Reaktor

201-210

Authors: Hadiyanto Hadiyanto, AJB van Boxtel

Bread product quality is highly dependent to the baking process. A model for the development of product quality, which was obtained by using quantitative and qualitative relationships, was calibrated by experiments at a fixed baking temperature of 200°C alone and in combination with 100 W microwave powers. The model parameters were estimated in a stepwise procedure i.e. first, heat and mass transfer related parameters, then the parameters related to product transformations and finally product quality parameters. There was a fair agreement between the calibrated model results and the experimental data. The results showed that the applied simple qualitative relationships for quality performed above expectation. Furthermore, it was confirmed that the microwave input is most meaningful for the internal product properties and not for the surface properties as crispness and color. The model with adjusted parameters was applied in a quality driven food process design procedure to derive a dynamic operation pattern, which was subsequently tested experimentally to calibrate the model. Despite the limited calibration with fixed operation settings, the model predicted well on the behavior under dynamic convective operation and on combined convective and microwave operation. It was expected that the suitability between model and baking system could be improved further by performing calibration experiments at higher temperature and various microwave power levels.

220-224

Authors: Nazriati Nazriati, Heru Setyawan, Sugeng Winardi, Reza Arizanova, Enggar Eka V

Synthesis of silica aerogel from bagasse ash was done by alkaline extraction followed by sol-gel. Bagasse ash was extracted with NaOH at its boiling temperature for one hour with continue stirring, to produce sodium silicate. Subsequently, sodium silicate was pass through ionic exchanger resin, to produces silicic acid (SA). Silicic acid solution was then added with TMCS and HMDS as surface modifier agent. In order to form gel pH must be adjusted to final pH of 8-9 by addition of NH4OH solution. The resulting gel then was aged and dried at ambient pressure and at a certain time and temperature. Characterization of products was done by measuring its pore volume, surface area, and hydrophobisity (contact angle). TMCS serves as water expeller from the pores and subsequently surface was modified by HMDS and TMCS. HMDS content will linearly increase surface area, pore volume, and the contact angle of the resulting silica aerogel. Characteristics of silica aerogel was generated by varying the composition of the SA:TMCS:HMDS resulting has a surface area of 50-488 m2/g, pore volume from 0.2 to 0.9 m3 /g, the contact angle of 48-119 and pore diameter ranging from 5.7-22.56 nm. Based on the resulting pore diameter, the synthesized of silica aerogel categorized as mesoporous.

231-236

Authors: Bakti Jos, Bambang Pramudono, Aprianto Aprianto

Cinnamon oleoresin is a complex mixture of resin and essential oil extracted from cinnamon burmanii by using organic solvent, and is primarily used as a coloring and flavoring in food products. Major component in essential oil is cinnamic aldehyde. Extraction was usually performed by percolation or soxhlet with various solvents. Several studies on the extraction of oleoresin have been completed by using polar organic solvents. Generally Recognized as Safe (GRAS) solvents, which are safe to use in food, were considered as alternative extraction solvents. Hildebrand solubility parameter concept was also used to choose the solvent. In this research, oleoresin from cinnamon was extracted by using ultrasound assisted extraction. Methanol, ethanol and isopropyl alcohol were used as the solvent to determine the extraction time, extraction rate and the kinetic model correspond to the yield of oleoresin. The result showed that the optimal time and extraction intensity are 66 minutes and 20% respectively, oleoresin yield by using solvent extraction of methanol, ethanol, and isopropyl alcohol were 22.86%, 17.87%, and 14.64% respectively. The results were similar compared to conventional extraction. Kinetic study confirmed that the second-order kinetic model is suitable for this research and the extraction rate constant for the second-order kinetic model of these solvents were 0.098, 0.057, and 0.089 respectively.

242-247

Authors: Yuli Ristianingsih, Sutijan Sutijan, Arief Budiman

The removal of phospholipids (‘degumming’) is the first step in the process of refining crude vegetable oil. The purpose of this research was to study degumming process and its effects to the oil’s quality. CPO used in this research was reacted with phosphoric acid using stirred tank reactor. The batch process was operated for 2 hours in various temperature, phosphoric acid concentration, and agitation speed. The sample was taken every 15 minutes which then analyzed by spectrophotometer at the wave length of 650 nm to measure the gum concentration in the oil. By minimizing sum of squares of errors between experimental and simulation data, the mass transfer coefficient (Kca), reaction rate constant (k1) and phase equilibrium constants (K) were be calculate. The result showed that the temperature, phosphoric acid concentration and agitation speed were highly affecting in the degumming process. At the range of temperature of 323≤T≤353 K, the higher temperature, the larger reaction rate constant and its relationship can be express as . At the range of Reynolds number of 121.4438 ≤ Re ≤ 630.2521, the effect of agitation speed to mass transfer coefficient (Kca) can be express as Sh=0.09986.Re0.5998.Sc0.3995. From these two equations obtained, one can say that the temperature has effect on the reaction rate and mass transfer.

254-261

Authors: Husni Husin, Mahidin Mahidin, Marwan Marwan

Study on the use of coconut fiber ash, palm bunch ash and K2CO3 as the catalysts for conversion of jatropha oil into biodiesel using methanol solvent has been done. The biodiesel is produced by converting unpurified jatropha oil over catalyst through transesterification reaction. The catalysts are burned at temperature of 500, 600, 800 and 900oC for 10 hours. Transesterification reaction is conducted in three-neck flask at constant temperature of 60oC for 3 hours. The results showed that the unburned and burned coconut fiber ashes at 800oC catalysts give the highest biodiesel yield (87.05 and 87.97%) with low soap content (0.23-0.26%).The characteristic of biodiesel produced over those catalysts met the Indonesian and international quality standards, therefore those catalysts can be used as substitute for K2CO3 commercial catalyst.