Judul: Development of mathematical model for robusta coffee decaffeination process in a single column reactor
Abstrak: Consumers 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.
Keyword: robusta coffee, mathematical model, decaffeination process, single column reactor

Judul: Optimasi Konsentrasi Ragi Komersial dan Lama Waktu Fermentasi Terhadap Kadar Lemak Kopi Robusta (Coffea canephora)
Abstrak: Proses pembuatan kopi luwak memiliki permasalahan dalam kode etik. Kopi yang difermentasi secara in vitro merupakan salah satu solusi untuk menghasilkan kopi fermentasi. Proses fermentasi berpengaruh terhadap lipid serta kualitas dan cita rasa kopi yang dihasilkan. Penelitian ini bertujuan untuk menentukan kondisi optimum konsentrasi ragi komersial dan lama fermentasi pada kopi robusta terhadap kadar lemak menggunakan Response Surface Methodology (RSM). Rancangan percobaan RSM yang digunakan adalah Central Composite Design (CCD). Kadar lemak yang diperoleh berkisar 9,23-10,91%. Model mean merupakan model yang disarankan software Design Expert. Nilai p-value yang didapat sebesar 0,5042. Tidak terdapat titik optimum dimana tidak adanya gradasi warna pada contour plot dan grafik 3D yang menunjukkan warna solid, yaitu warna hijau. Model solusi yang dipilih software adalah konsentrasi 2,556% dan waktu fermentasi 27,257 jam dengan nilai desirability 0,522. Hasil verifikasi didapatkan kadar lemak 10,258 gram dan %RSE sebesar 1,48%. Kesimpulan dari penelitian ini konsentrasi ragi komersial dan waktu fermentasi tidak berpengaruh secara signifikan terhadap kadar lemak.
Keyword: coffee, fat, fermentation, RSM

Judul: Trichomonas Gallinae Penyebab Trichomonosis Pada Unggas
Abstrak: Trichomonas gallinae adalah protozoa yang bergerak aktof dengan keempat flagella yang mempunyai layar dan pada salah satu sisinya terdapat membran seperti sirip ikan yang berombak. Spesies dari genus Trichomonas ini mempunyai arti penting pada unggas, karena dapat menyebabkan infeksi pada alat pencernaan bagian atas.
Keyword: