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: Acetic Acid Production from Robusta Coffee Pulp using Saccharomyces cerevisiae and Acetobacter aceti
Abstrak: Kopi merupakan salah satu komoditas perkebunan yang banyak dibudidayakan di Indonesia. Jenis kopi yang umum dibudidayakan oleh petani Indonesia yaitu jenis kopi robusta (Coffea robusta). Pengolahan kopi robusta sampai saat ini hanya berfokus untuk menghasilkan biji kopi dengan cita rasa yang baik namun menyisakan limbah berupa pulp kopi yang tidak dimanfaatkan. Penelitian ini bertujuan memanfaatkan limbah pulp kopi menjadi produk berupa cuka melalui proses fermentasi menggunakan khamir Saccharomyces cerevisiae dan bakteri asam asetat Acetobacter aceti. Pembuatan cuka dimulai dengan meremajakan A. aceti pada media YPG dan membuat kurva pertumbuhannya. Fermentasi pulp kopi menjadi cuka melalui dua tahapan fermentasi yaitu fermentasi alkohol dan fermentasi asam cuka. Pengamatan kultur pada akhir fermentasi adalah nilai pH, kadar asam asetat, kadar gula, dan efisiensi penggunaan substrat dalam pembentukan produk. Pertumbuhan A. aceti mencapai fase log pada jam ke-6 sampai jam ke-8 dengan ???????? sebesar 0,45 jam-1. Cuka dari pulp kopi memiliki kadar asam asetat tertinggi dari fermentasi alkohol 10 hari dan fermentasi asam asetat 7 hari, yaitu sebesar 2,37%, dengan nilai pH sebesar 3,02, nilai Yp/s 0,995, dan nilai ???/?? sebesar 0,69. Kadar asam asetat yang diperoleh belum memenuhi ketetapan SNI 01-4371-1996., Coffee is one of the plantation commodities widely cultivated in Indonesia. The type of coffee commonly grown by Indonesian farmers is robusta coffee (Coffea robusta). The processing of robusta coffee has so far only focused on producing coffee beans with good flavor, leaving behind coffee pulp waste that needs to be utilized. This study aims to utilize coffee pulp waste to produce vinegar through a fermentation process using the yeast Saccharomyces cerevisiae and the acetic acid bacteria Acetobacter aceti. Vinegar production begins by rejuvenating A. aceti in YPG media and creating a growth curve. The fermentation of coffee pulp into vinegar involves two fermentation stages: alcoholic fermentation and acetic acid fermentation. Observation of the culture at the end of fermentation includes pH value, total acetic acid content, sugar content, and substrate utilization efficiency in product formation. The growth curve of A. aceti reaches the log phase at the 6th to 8th hour with a ???????? of 0,45 hours-1. Vinegar from coffee pulp has the highest total acetic acid in 10 days of alcoholic fermentation and 7 days of acetic acid fermentation, which is 2,37%, with a pH value of 3,02, a Yp/s value of 0,995, and a ???/?? value of 0,69. The amount of acetic acid obtained does not fulfill the requirements of SNI 01-4371-1996.
Keyword: acetic acid bacteria, vinegar, growth curve, coffee pulp waste, saccharomyces cerevisiae

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.
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