31665 research outputs found
Sort by
Development of mathematical model for robusta coffee decaffeination process in a single column reactor
No full textConsumers drink coffee not as nutrition source, but as refreshment drink. For coffee consumers who have high tolerance for caffeine, coffee may warm up and refresh their bodies. However high caffeine content in coffee beans may cause health problems to consumers who are susceptible to caffeine. One of the efforts for coffee market expantion is product diversification to decaffeinated coffee. The general objective of this research was to optimize decaffeination process of robusta coffee in single column reactor with leaching method. The specific objectives of this research were to study process characteristic of Robusta coffee decaffeination in single column reactor using acetic acid as solvent, to develop mathematical model for predicting decaffeination time with leaching method, and to optimize process decaffeination of robusta coffee using developed model. Temperature (T) and concentration (c) of solvents were both variables analysed in decaffeination process. Mathematical model validation was checked by comparing prediction time (t-predict) versus observation time (t-obsr). Mathematical model was valid if the result showed that determination coefficient value (R2) > 0.75. Coffee decaffeination was processed using vertical single column reactor. A simple mathematic model for caffeine kinetic description during the extraction process (leaching) of coffee bean was developed. A non-steady diffusion equation coupled with a macroscopic mass transfer equation for solvent was developed and then solved analytically. The kinetic of caffeine extraction from coffee bean was expressed by: - =- - - + - - 0.3 0.3 ).(4.4106. exp )( 3.3319 10.302)) ln 2 (det) (( 0 0.01282 ( 1041.82 / ) 1 2 A T AS c c c d d t p where d was coffee beans diameter (m), c was solvent concentration (%), T was solvent temperature (K), and cAS was caffeine content at-t (%). In the first step of decaffeination process, coffee beans was steamed during 1.5 hours using water vapour, and continued with leaching process using acetic acid, effluent of fermented cocoa beans, and tertiary solution of fermented cocoa pulp as solvents. Linier regression analysis showed that t-obsr = 0.8914. t-predict + 0.5045 with R2 0.9326 for acetic acid, t-obsr = 0.771.t-predict + 2.8137 with R2 0.9556 for effluent of fermented cocoa beans, and t-obsr = 0.8825.t-predict + 2.8354 with R2 0.7727 tertiary solution of fermented cocoa pulp as solvents. Response Surface Methodology (RSM) showed that optimum condition for coffee beans decaffeination was 0.4976%/hours decaffeination rate and 4.99 hours decaffeination time with 100oC solvent temperature and 69% solvent concentration using acetic acid as solvent; 0.3426%/hours decaffeination rate and 5.68 hours decaffeination time with 100oC solvent temperature and 55% solvent concentration using effluent of fermented cocoa beans as solvents; and 0.3016%/hours decaffeination rate and 6.57 hours decaffeination time with 100oC solvent temperature and 70% solvent concentration using tertiary solution of fermented cocoa pulp as solvent. The developed mathematical model can be used in designing single column reactor for coffee decaffeination process, to predict decaffeination time and rate, and decaffeination process in optimum condition using acetic acid, effluent of fermented cocoa beans, and tertiary solution of fermented cocoa pulp.Kopi diminum oleh konsumen bukan sebagai sumber nutrisi melainkan sebagai minuman penyegar. Untuk penikmat kopi yang memiliki toleransi tinggi, kafein akan membuat tubuh menjadi lebih segar dan hangat. Tingginya kadar kafein di dalam biji kopi diduga dapat menyebabkan keluhan terutama bagi penikmat kopi yang memiliki toleransi rendah terhadap kafein. Tujuan umum dari penelitian ini adalah melakukan optimasi proses dekafeinasi biji kopi robusta dalam reaktor kolom tunggal dengan metode pengurasan (leaching). Tujuan khusus penelitian adalah karakterisasi proses dekafeinasi biji kopi robusta dengan pelarut asam asetat dalam reaktor kolom tunggal, pengembangan model matematik pendugaan waktu proses dekafeinasi biji kopi robusta dengan metode pengurasan (leaching), optimasi laju pelarutan kafein biji kopi robusta dengan menggunakan model matematik yang dikembangkan. Suhu (T) dan konsentrasi pelarut (c) adalah variabel yang diteliti dalam proses dekafeinasi. Validasi dilakukan dengan membandingkan data waktu proses prediksi (t-prediksi) yang diperoleh dari hasil model matematik yang dibangun dengan data waktu proses observasi (t-observasi) yang diperoleh dari hasil percobaan. Model simulasi dikatakan valid apabila diperoleh nilai koefisien determinasi (R2)>0.75. Proses dekafeinasi biji kopi dilakukan dalam reaktor kolom tunggal berbentuk silinder tegak. Model matematik untuk menggambarkan kinetika kafein selama proses ekstraksi (pengurasan) dalam biji kopi telah dikembangkan. Persamaan difusi pada kondisi tak mantap (non steady) yang berkaitan dengan persamaan perpindahan massa makroskopik untuk pelarut telah dikembangkan dan diselesaikan secara analitis. Kinetika ekstraksi kafein dari dalam biji kopi dapat diekspresikan dengan persamaan berikut : - =- - - + - - 0.3 0.3 ).(4.4106. exp )( 3.3319 10.302)) ln 2 (det) (( 0 0.01282 ( 1041.82 / ) 1 2 A T AS c c c d d t p Dalam hal ini d adalah diameter biji kopi (m), c adalah konsentrasi pelarut (%), T adalah suhu pelarut (K), dan cAS adalah kadar kafein yang pada kondisi-t (%)
Model pengelolaan lahan gambut berbasis sumberdaya lokal pada agroekologi perkebunan kelapa sawit : studi kasus agroekologi perkebunan kelapa sawit rakyat di Kabupaten Bengkalis-Meranti Provinsi Riau
Full text linkOil palm plantations on peatlands are faced with problems of land degradation, emission of greenhouse gases (GHG) and biodiversity loss. This study was aimed to (1) identify changes in biophysical characteristics of peatlands, (2) assess the sustainability of peatland management, (3) examine important factors that affect peatland management, and (4) formulate a local resource-based model of peatland management on the agroecology of smallholder oil palm plantations. Research sites were in the Regency of Bengkalis-Meranti, Riau Province on marine and brackish peat. The data was collected using a survey method, field observations and measurements, in-depth interviews and documentation. The biophysical characteristics of peatland were analyzed descriptively. The sustainability of peatland management was assessed in dimensions of ecology, economy, socio-cultural aspects, technology and infrastructure, legal and institutional aspects, and analyzed by using the Multi Dimensional Scaling (MDS) with the technique of Rap-Insus Landmag (Rapid Appraisal-Sustainability Index of Land Management). The important factors in the peatland management were determined through a prospective analysis. The formulation of the local resourcebased model of peatland management in oil palm plantations was done by integrating MDS, leverage and prospective analysis. The research results showed that the biophysical characteristics of peatland experienced changes in the horizon profile, peat thickness, decomposition level, moisture content, ash content, pH, C-organic and biomass. The sustainability index of peatland management is at the level of less-to-moderate category. The dominant factors affecting the sustainability of peatland management (G) on oil palm plantations are the management system of water and land (a),community empowerment (p), cooperation among stakeholders (s), management of oil palm production (t), processing industry (i), structure and access to capital (m). The model of peatland management is an interaction between the dominant factors in the relationship of function G = f (a, p, s, t, i, m).Lahan gambut merupakan salah satu tipe ekosistem yang terbentuk pada kondisi anaerob (drainase buruk) di rawa pasang surut atau lebak dan mengandung bahan organik (> 50%) dari hasil akumulasi sisa tanaman dengan ketebalan lebih dari 50 cm. Lahan gambut memberikan beberapa pelayanan (services) ekologi, ekonomi dan sosial yang potensial untuk dikembangkan sebagai sistem pendukung kehidupan (life supporting system). Pengembangan kelapa sawit pada lahan gambut dihadapkan pada permasalahan degradasi lingkungan seperti potensi emisi CO2 sebagai gas rumah kaca (GRK), penyebab utama bencana kebakaran lahan dan konflik sosial antara masyarakat dan perusahaan. Pemanfaatan lahan gambut untuk perkebunan kelapa sawit diharapkan mampu menjaga keberlanjutan fungsi ekologi, ekonomi dan sosial pada ekosistem tersebut. Untuk itu perlu dilakukan kajian yang integratif agar diperoleh informasi tentang hal-hal yang mendasari fungsi lingkungan dan produksi pada agroekologi perkebunan kelapa sawit pada lahan gambut
Pengelolaan Penangkaran Rusa Timor (Rusa timorensis de Blainville 1822) di Kabupaten Kudus dan Kontribusi Sosial Ekonominya
No full textRusa timor (Rusa timorensis de Blainville 1822) merupakan salah satu jenis
satwa dilindungi di Indonesia yang memiliki potensi dan prospek ekonomi. Salah
satu upaya pelestarian sekaligus bentuk pemanfaatan rusa timor yang diperbolehkan
adalah penangkaran. Penelitian ini bertujuan untuk mengidentifikasi pengelolaan
penangkaran rusa timor milik individu serta menilai kontribusinya terhadap aspek
sosial ekonomi masyarakat sekitar. Penelitian ini dilaksanakan pada bulan Maret
2016 di penangkaran rusa timor yang berlokasi di Desa Gondosari Kecamatan
Gebog dan Desa Margorejo Kecamatan Dawe Kabupaten Kudus. Hasilnya
menunjukkan bahwa pengelolaan penangkaran rusa timor dilakukan secara semi
intensif. Upaya perkembangbiakkan rusa timor tergolong cukup berhasil,
ditunjukkan dengan angka kelahiran (0.26) yang lebih besar daripada angka
kematiannya (0.09). Penangkaran telah memberikan kontribusi ekonomi dalam
memenuhi kebutuhan rumah tangga masyarakat sekitar melalui penyerapan tenaga
kerja dan penyediaan lapangan kerja. Kontribusi sosial juga ditunjukkan melalui
peran penangkaran sebagai penyedia tempat wisata serta sarana pendidikan bagi
masyarakat Kudus dan sekitarnya