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.

131-139

Authors: Istadi Istadi, Luqman Buchori, Suherman Suherman

The plastic waste utilization can be addressed toward different valuable products. A promising technology for the utilization is by converting it to fuels. Simultaneous modeling and optimization representing effect of reactor temperature, catalyst calcinations temperature, and plastic/catalyst weight ratio toward performance of liquid fuel production was studied over modified catalyst waste. The optimization was performed to find optimal operating conditions (reactor temperature, catalyst calcination temperature, and plastic/catalyst weight ratio) that maximize the liquid fuel product. A Hybrid Artificial Neural Network-Genetic Algorithm (ANN-GA) method was used for the modeling and optimization, respectively. The variable interaction between the reactor temperature, catalyst calcination temperature, as well as plastic/catalyst ratio is presented in surface plots. From the GC-MS characterization, the liquid fuels product was mainly composed of C4 to C13 hydrocarbons.

148-154

Authors: Praswasti Pembangun Dyah Kencana Wulan, Widodo Wahyu Purwanto, Yuswan Muharam

The main focus of this research was to obtain micro kinetics decomposition of methane producing carbon nanotube on the surface of the Ni-Cu-Al catalyst. Experimental kinetics data collected at a temperature range of 650-750oC and pressure of one atmosphere. The preliminary test was conducted to obtain the kinetics are not influenced by external and internal diffusion limitations as well as inter-phase transfer. Kinetics data were tested by micro kinetic model derived from the catalyst surface reaction mechanism. The most appropriate kinetic model becomes the rate-limiting step of methane decomposition reaction. Results of preliminary experiment showed that the kinetics of the external diffusion effect is negligible at flow rates above 150 mL/min. Internal diffusion can be ignored with a catalyst under 0.25 mm in diameter with a weight of 0.04 grams of catalyst and contact time 2.5x10-4. Rate equation analysis shows that the rate-limiting step is the adsorption which indicates that intermediate consumption (CH4I + I Û CH3I + HI) is faster than the formation of intermediate (adsorption of methane, CH4 + I Û CH4I). The activation energy obtained for 34.628 kJ/mol and pre-exponential factor of 6.583x106.

165-171

Authors: Bambang Cahyono, Muhammad Diah Khoirul Huda, Leenawaty Limantara

Curcuminoid a yellow coloring agent of turmeric is known to have many benefits in food and medicinal industries. This compound can be isolated by simple extraction from fresh rhizome or symplicia. The research of comparing qualitative and quantitative of curcuminoid in different drying process has not yet been published. Drying methods used in this research were done in an oven at 60°C and under 30-watt electrical lamp at ±30°C. Each method was carried out in time variation of 1, 3, and 5 days. Extraction of curcuminoid was done using ethanol 95% followed by fat reduction process using petroleum ether. Curcuminoid analysis was done by TLC, UV-Visible spectrophotometer and HPLC. The result showed that the water content of all samples was approximately 4.06%-7.76%. TLC analysis identified the presence of two dominant components in the curcuminoid with the Rf values of 0.37 and 0.15. The UV-Visible spectra indicated that simplicia would give more result in curcuminoid than fresh rhizome. There were 4 substances detected in HPLC analysis, they were curcumin 61-67%, demetoxycurcumin 22-26%, bisdemetoxycurcumin 1-3%, and curcuminoid derivative 10-11%. In addition, drying on oven resulted brighter and crispier simplicia than drying under lamp.

178-184

Authors: Laeli Kurniasari, Mohammad Djaeni, Aprilina Purbasari

Drying is one process which is used in many industries, especially in food product. The process usually still has low energy efficiency and can make food deterioration because of the usage of high temperature. One alternative in drying technology is the use of zeolite as a water vapor adsorbent. This kind of drying method make it possible to operate in lower temperature, hence it will be suitable for heat sensitive product. Natural zeolit can be one promising adsorbent since it is spreadly abundant in Indonesia. Natural zeolite must be activated first before used, in order to get zeolite with high adsorption capacity. Activation process in natural zeolite will change the Si/Al ratio, polarity, and affinity of zeolite toward water vapor and also increase the porosity. Activation of natural zeolite can be done with two methods, chemical activation use NaOH and physical activation use heat. In the activation using NaOH, natural zeolite is immersed with NaOH solution 0.5-2N in 2 hour with temperature range 60-900C. The process is continued with the drying of zeolite in oven with 1100C for 4 hours. While in heat treatment, zeolit is heated into 200-5000C in furnace for 2-5 hours. SEM analysis is used to compare the change in zeolite morphology before and after each treatment, while to know the adsorption capacity of zeolite, the analyses were done in many temperature and relative humidity. Result gives the best condition in NaOH activation is NaOH 1N and temperature 700C, with water vapor loading is 0.171 gr/gr adsorbent. In heat treatment, the best condition is 3000C and 3 hours with loading 0.137 gr water vapor/gr adsorbent.

194-200

Authors: Kristinah Haryani, Widayat Widayat

Citric acid is an important organic acid that has many advantages used in foods, drinks, pharmaceuticals industries. Waste of pine apple (covers and core of the fruit) still have high contents of glucose and sucrose components, that these are potentially used as basic material for making citric acid by means of fermentation using Aspergillus niger. The reactor to do so is a reactor air-lift external loop with 88 cm in height, 45.41 cm2 in riser area, and 2.01 cm2 in downcomer area. This research is intended to study the influence of volumetric flow and viscosity upon mass transfer in the fermentation process of citric. The variable factors are concentration of total sugar (5 to 25%) and of volumetric flow of gas 9.4 to 23.3 cc/second. A dynamic method used to measure of the constants transfer of gas-fluid mass where oxygen concentration soluted is measured every 30 second using DO meter device. Result of this research shows that the increase of viscosity causes the decrease of hold up gas and fluid circulation speed of the fluid, and the decrease of the constants of mass transfer. The increase of air speed flow will cause the increase of hold up gas and fluid circulation speed, and constants of mass transfer. Relation of the constraints of mass transfer to volumetric flow and viscosity is formulated as follow