Journal Information
ISSN / EISSN : 08520798 / 24075973
Current Publisher: Diponegoro University (10.14710)
Total articles ≅ 388
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DOAJ
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Latest articles in this journal

Nita Aryanti, Richard Andrew Williams, Qinchung Yuan
Published: 13 March 2020
REAKTOR, Volume 20, pp 47-56; doi:10.14710/reaktor.20.1.47-56

Abstract:
Rotating membrane emulsification (RMR) has been intensively developed and applied for producing emulsion as well as particulate products such as microcapsules. Polyurea microcapsules were generally prepared by interfacial polycondensation polymerisation with addition of modifier to produce more stable microcapsules. In this research, development of the RMR was applied for producing polymer particles stabilised by nanoparticle without any addition of surfactant or modifier. Two types of membrane pores, the square (Type-A) with hydraulic diameter (Dh) of 84 mm and oblong pores with an aspect ratio of 0.33 (Type-B) having Dh of 69 mm was investigated. For the membranes designed in this research, pore shape A membrane could produce good uniformity in both polyurea microcapsule and polymer particle. In the polymer stabilised particle, this membrane type obtained a narrower size distribution than the usage for o/w emulsification. Reasonable uniform particles at high membrane rotation speed could also be achieved with the use of Type-A membrane. The uniformity confirmed that there was only minor breakup of products during operation at high membrane rotation. This attractive feature was significant in the production of fragile or shear-sensitive particulate products since the delicate structure of these products is possibly easy to destroy at high membrane rotation speed. Keywords: polyurea microcapsules; particles stabilised nanoparticles; slotted pore
Intan Cidarbulan Matita, Titri Siratantri Mastuti, Smita Maitri
Published: 13 March 2020
REAKTOR, Volume 20, pp 18-25; doi:10.14710/reaktor.20.1.18-25

Abstract:
In this study, Torbangun leaves are processed into three different types varying in their oxidation degree, namely unoxidized, semioxidized and oxidized Torbangun leaves. Each type is then brewed into herbal tea and analyzed in terms of its total phenolic, total flavonoid and antioxidant activity. Unoxidized Torbangun herbal tea shows higher content of total phenolic (44.22 mg GAE/g) and total flavonoid (17.02 mg QE/g) compared to oxidized (24.66 mg GAE/g total phenolic content and 8.61 mg QE/g total flavonoid content) and semioxidized (33.83 mg GAE/g total phenolic content and 10.68 mg QE/g total flavonoid content) Torbangun herbal tea. In terms of the antioxidant activity, processing the Torbangun leaves into herbal tea tremendously decreased the antioxidant activity based on the IC50 value of 1400.89 ɥg/mL for unoxidized Torbangun herbal tea, 3211.71 ɥg/mL for semioxidized Torbangun herbal tea and 4504.78 ɥg/mL for oxidized Torbangun herbal tea. However, steam blanching used in the preparation of unoxidized Torbangun leaves is proven to increase the total phenolic and flavonoid content of raw or unprocessed Torbangun leaves from 39.02 to 44.22 mg GAE/g and an increase of total flavonoid from 10.32 to 17.02 mg QE/g.Keywords: antioxidant; flavonoid; herbal tea; phenolic; torbangun
Kam Natania, Giovani Fransisca Setiawan
Published: 13 March 2020
REAKTOR, Volume 20, pp 38-46; doi:10.14710/reaktor.20.1.38-46

Abstract:
Clove oil as a potent antimicrobial agent was added to enhance the properties of edible films. Clove oil was converted to single and double emulsion emulsions for homogenous dispersion in a starch based edible film suspension. Double emulsion was made with two steps emulsification with CaCl2 as inner water phase and guar gum as outer water phase. Single emulsion was prepared similarly without inner water phase. The physico-chemical characteristics and the antimicrobial activity of the of starch-based edible film added with the emulsion were observed. MBC/MFC of clove oil was determined against E. coli, S. aureus, R. stolonifer, and A. niger which gives value of 1.95, 1.46, 0.52, and 0.35 mg/ml respectively. Incorporation of different emulsions on starch-based edible films affect the properties of resulting edible films by increasing thickness, opacity, elongation at break, water vapor transmission rate, and swelling index. Both emulsions showed comparable physicochemical characteristics such as thickness, WVTR, and swelling index value. However, double emulsion produced more superior edible films in terms of tensile strength and antimicrobial activity. 15% addition of double emulsion were able to show strong antimicrobial activity with inhibition zone of more than 8.0 mm for E. coli and 24.0 mm for R. stolonifer.Keywords: clove oil; edible film; single and double emulsion
Tutuk Djoko Kusworo, Bayu Aji Pratama, Dhea Putri Safira
Published: 13 March 2020
REAKTOR, Volume 20, pp 1-9; doi:10.14710/reaktor.20.1.1-9

Abstract:
The need for fuel oil continues to increase in line with the increasing number of human populations and the growth rate of dependence on fuel oil. Bio-oil is a condensed-liquid mixture that results from the thermal derivation of biomass containing hemicellulose, lignin, and cellulose. This research developed an optimization of the operation condition of bio-oil from empty palm fruit bunches (OPEFB) using a modified pyrolysis reactor. The temperature and mass of empty palm fruit bunches were the two parameters considered in this study. Optimization was carried out on process parameters using the surface response methodology (RSM) and variance analysis (ANOVA). The significance of the different parameters and the effect of the relationship between parameters on the bio-oil yield is determined using a full factorial central composite design. The optimal operation condition of pyrolysis was found to be 570.71 oC, and the mass of empty palm fruit bunch 420.71 gr. Predictions from the optimum variable of operating conditions produce a bio-oil yield of 5.58%. The actual bio-oil yield on the optimum condition that was be validated is 5.6 %. The chemical composition of bio-oil obtained was evaluated by GCMS to ensure its characterization as a fuel.Keywords: Empty palm fruit bunches, Bio-oil, Pyrolysis, Response Surface Methodology, Optimization
Megawati Megawati, Astrilia Damayanti, Radenrara Putri, Angga Pratama, Tsani Muftidar
Published: 13 March 2020
REAKTOR, Volume 20, pp 10-17; doi:10.14710/reaktor.20.1.10-17

Abstract:
This research aims to study the hydrolysis of passion fruit peel using cellulase and its evaluation for ethanol production. Passion fruit peel is a fruit processing waste that has not been utilized properly. Passion fruit peel contains holo-cellulose (64% w/w), which can be converted into ethanol through hydrolysis followed by fermentation. Hydrolysis using cellulase is more efficient and its fermentation using yeast to produce ethanol is common. The hydrolysis is carried out at various enzyme ratios (3, 5, 7, and 9% v/v) and at temperature 30 oC, material concentration 5 g/100 mL, pH 4-5, and shaking speed 160 rpm. The kinetics chosen were heterogeneous models; they were the fractal model by Valjamae and Kopelman. Before being hydrolyzed, the essential oil and pectin in passion fruit peel were extracted, because the compositions were quite high; the results were around 16.23 and 11.36% w/w, respectively. The effect of the enzyme ratio to the sugar concentration by hydrolysis is very significant. At 9 h, the glucose concentration reached 45.38, 51.86, 60.50, 66.00 g/L at various enzyme ratios of 3, 5, 7, 9% v/v. During the hydrolysis, the glucose concentration continues to increase and starts to decrease after 9 h. Hydrolyzate solution fermentation obtained from hydrolysis in various enzyme ratios showed consistent results; the higher the enzyme ratio and glucose, and the higher the ethanol will be (5.6, 6.8, 7.6, and 8.9% v/v). The kinetics model by Valjamae is more appropriate to describe the enzymatic hydrolysis mechanism of passion fruit peel than Kopelman. The fractal exponent values obtained from Valjamae and Kopelman models were 0.28 and 0.27. In Valjamae model, the enzyme ratio rises, from 3 to 9% v/v, the rate constant rises from 0.22 to 0.53 1/h. In Kopelman model, the rate constant rises too, from 0.21 to 0.51 1/h.Keywords: bio-ethanol; cellulase; enzymatic hydrolysis; fractal kinetic; passion fruit peel
Diah Meilany, Dewinka Anugeraheni, Abdul Aziz, Made Tri Ari Penia Kresnowati, Tjandra Setiadi
Published: 13 March 2020
REAKTOR, Volume 20, pp 32-37; doi:10.14710/reaktor.20.1.32-37

Abstract:
The biological route to produce xylitol from Oil Palm Empty Fruit Bunches (EFBs) comprises of EFBs pretreatment, enzymatic hydrolysis, fermentation, and downstream separation of the produced xylitol. Due to the specificity in the hemicellulose composition of EFBs, a xylanase enzyme that has a high affinity to EFBs is required to hydrolyze the EFBs into xylose. In this research, the influences of aeration, humidity, and mixing in xylanase production were mapped. The xylanase production was performed by Aspergillus fumigatus ITBCCL170 in a solid-state fermentation using a tray fermenter with EFBs as the substrate. The optimal configuration was further scaled up into xylanase production using 1000 g of EFBs as the substrate. The results showed that the highest enzyme activity was 236.3 U/g EFB, obtained from the use of humid air airflow of 0.1 LPM, and mixing was performed once a day. The scaling up resulted in a lower xylanase activity and call for a better design of the fermenter.Keywords: aeration, humidity, mixing, OPEFBs, tray fermenter, xylanase, xylitol
Yuana Elly Agustin, Lieke - Riadi, Titie Prapti Utami
Published: 13 March 2020
REAKTOR, Volume 20, pp 26-31; doi:10.14710/reaktor.20.1.26-31

Abstract:
The conditions for protein hydrolysis were optimized to prepare Reutealis trisperma cake for potential animal feedstock. The cake’s content was 34.03 % protein, 6.32 % moisture, 18.56 % total sugar, 15.58 % lipid and 25.51% others. Other components in cake could be fibre and lignin. The cake is a byproduct of mechanical pressing process of the seeds and contains high protein content (34.03%). It was ground prior the hydrolysis process. A central composite design including concentration of NaOH, ratio of cake to NaOH, time and temperature were used to develop second order model to predict protein content under various experimental conditions. Protein yield was primarily affected by ratio pressed cake to NaOH and concentration of NaOH. Based on the Response Surface Methodology (RSM) model, maximum yield of protein was 11.33% which was obtained at cake/solvent ratio 1: 50; 1.5 % w/v NaOH; 15 minutes of hydrolysis at 40oC. The actual maximum protein yield from the experiment was obtained at cake/solvent ratio 1: 40; 1.5 % w/v NaOH; 20 minutes of hydrolysis at 45oC which was 21.28 %.Keywords: animal feedstock; protein hydrolysis; response surface; Reutealis trisperma
Umi Laila, Rifa Nurhayati, Tyas Utami, Endang Sutriswati Rahayu
Published: 31 December 2019
Reaktor, Volume 19, pp 152-161; doi:10.14710/reaktor.19.4.152-161

Abstract:
The mathematical models can be used as a tool in predicting microbial population in sorghum fermentation, either spontaneous fermentation or fermentation with the addition of lactic acid bacteria (LAB) inoculum. Gompertz model modified by Gibson, Gompertz model modified by Zwietering, Baranyi-Robert model, Fujikawa model, Richards model, Schnute model were used in predicting the growth of lactic acid bacteria (LAB) and coliform bacteria during spontaneous fermentation, and also the growth of LAB during fermentation with the addition of inoculum. Meanwhile, there was death (inactivation) of coliform bacteria during sorghum fermentation with the addition of LAB inoculum. The Geeraerd model and the Gompertz model modified by Gil et al. were used to predict the inactivation. The accuracy and precision of models were evaluated based on the Root Mean of Sum Square Error (RMSE), coefficient of determination (R2), and curve fitting. Gompertz model modified by Gibson had the highest accuracy and precision, which was followed by the accuracy of the Fujikawa model and Baranyi-Robert model in predicting the growth of LAB and the growth of coliform bacteria during spontaneous fermentation. Meanwhile, in predicting LAB growth during fermentation with the addition of inoculum, high accuracy and precision was obtained from Richards and Schnute models. In predicting the inactivation of coliform bacteria, Geeraerd model provided higher accuracy and precision compared to Gompertz model modified by Gil et al. Keywords: fermentation; inoculum; mathematical; model; sorghum; spontaneous
Anggara Diaz Ramadhan, Nindya Carolina C.S, Nuryoto Nuryoto, Teguh Kurniawan
Published: 31 December 2019
Reaktor, Volume 19, pp 172-179; doi:10.14710/reaktor.19.4.172-179

Abstract:
Natural zeolite in Indonesia generally divided into 2 types, which are mordernite and clinoptilolite. As far the use of zeolites is very limited. This experiment tries to use both types of natural zeolites to find out its work. The purpose of this experiment is testing the performance of mordenite natural zeolite from Bayah-Indonesia and clinoptilolite from Lampung- Indonesia in the esterification reaction between glycerol and oleic acid integrated by several variable that affect the reaction. The experiment will be done by using three-neck rounded flask batch reactor. The result showed that modernite zeolite has a better performance compared to clinoptilolite zeolite. To get the oleic acid conversion of 70%, clinoptilolite zeolite needs 4% catalyst of glycerol weight and reactant ratio of 6:1 mole of glycerol/mole of oleic acid, Meanwhile the mordernite zeolite only needs 2% catalyst of glycerol weight with reactant ratio of 4:1 mole of glycerol/mole of oleic acid.Keywords: natural zeolite; glycerol; reaction; diffusion
Agus Hadiyarto, Dyah Ayu Pratiwi, Aldila Ayu Prida Septiyani
Published: 31 December 2019
Reaktor, Volume 19, pp 137-144; doi:10.14710/reaktor.19.4.137-144

Abstract:
The anaerobic decomposition process of human feces substrate with a C/N ratio of 14.6 has failed to produce biogas optimally. In order to produce biogas maximally, the C/N ratio in the substrate should be in the range of 20-30. In this study, a combination of human feces substrate (C / N = 14.6) with corn stalk waste (C / N = 66.5) was carried out. Corn stalks were soaked first in a NaOH solution to separate lignin before being mixed with human feces. In this study the effect of the C/N ratio from the combination of feces and corn stalks as well as the effect of the type of activated sludge on the rate of biogas production were evaluated. The C/N ratios were varied at 20, 25, and 30 with F/M of 0.5. As the source of microbes is the activated sludge of human feces. A further experiment was carried out by varying the types of microbes where sludge from cow's rumen, activated sludge from feces, and activated sludge from rotten corn stalk was employed at a C/N ratio of 30 and F/M of 0.5. The results of this study showed that the optimal biogas production was obtained at a C/N ratio of 30 with a cumulative gas volume of 13.185 ml for 60 days. The type of microbes that produce maximum biogas production was the activated sludge from the rumen. The optimum biogas yield was obtained at 4.184 liters/kg COD, which was achieved in the stationary phase with a C/N ratio of 30.Keywords: anaerobic co-digestion; biogas; corn stalk; human feces
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