Judul: Produksi Kopi Secara Enzimatis Menggunakan Bakteri Proteolitik dan Kombinasi Bakteri Selulolitik dan Xilanolitik Dari Luwak
Abstrak: Civet coffee is a commercial coffee produced from in vivo by civet. The production of civet coffee is rely on the availability and sustainability of civet life cycles. The purpose of this research was to produces civet like coffee by solid substrate fermentation. Coffee pulp (60 mesh) used as a media growth of bacteria and produced enzyme which used by coffee beans. The substrate of fermentation added inoculum at 10% (wet basis) and fermented for 4 days at 30oC and 37oC. Inoculum using a single bacteria (proteolytic), a mix between cellulolytic and xylanolytic bacteria, and a mix between proteolytic, cellulolytic, and xylanolytic bacteria. Data measured were reducing sugar, total sugar, protein content and enzyme activity daily. Coffee beans from the best fermentation for each treatment analyzed by HPLC. Fermentation using proteolytic bacteria shown best performance at 37oC for one day incubation, fermentation using a mix cellulolytic and xylanolytic bacteria at 30oC after three days incubation and the combination of three bacteria similar to using combination of two bacteria. Quality of fermented coffee based on organic acids and caffeine content equivalent to the original civet coffee. For all treatments was lower caffeine contents than civet coffee. Organic acids in fermented coffee shown higher lactate, butyrate, and ascorbate acids and lower oxalate acids. Fermented coffee has a better nutrition contents than original civet coffee.
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Judul: Produksi Kopi Luwak Sintesis Secara Enzimatis menggunakan Bakteri Xilanolitik dan Kombinasi dengan Bakteri Proteolitik dan Selulolitik
Abstrak: Civet coffee is a coffee having a high selling price and produced by civet. The purpose of this research was to produce civet like coffee by solid state fermentation using bacteria that isolated from civet’s feces. The research initially was characterized proteolytic bacteria .The fermentation of coffee was held at 30o and 37o C for 4 days. The inoculum (10%, wet base) using xylanolytic bacteria, combination xylanolytic and proteoliyic bacteria, and combination xylanolytic, proteolytic, and cellulolytik bacteria.The best fermentation condition performed by enzyme activity, total sugar, reduction sugar, weight decrease, and degree of polymerization.The fermentation using xylanolytic and combination of two bacteria shown best performance at 37o C and 72 hours incubation time. However, for the fermentation using combination of three bacteria performed best result at 37o C and 72 hours incubation time. In general, the fermentation of coffee result a lower caffeine and oxalic acid content than original civet coffee. However, the ascorbic acid, butyric acid, and lactic acid shown a higher value.
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Judul: Simulasi persamaan keadaan bintang dengan pendekatan klasik dan relativistik
Abstrak: Komposisi bintang yang selalu berubah akanmempengaruhi massa dan radius bintang itu sendiri. Dimana semakin tua sebuah bintang, maka bintang akan didominasi oleh unsur-unsur berat. Dengan persamaan politrop dan metode Runge-Kutta orde 4 didapatkan radius dan massa bintang semakin berkurang seiring berkurangnya nilai Ye, sedangkan kerapatan semakin meningkat. Pendekatan terbaik terdapat pada nilai Ye sebesar 0.5 dimana didapatkan bahwa massa bintang katai putih sebesar 1.4Mo sesuai dengan massa Chandrasekhar dengan radius bintang 5000 km dan nilai kerapatan bintang sebesar 5.31x 106 g cm-3. Untuk massa bintang neutron diperoleh nilai 0.05Modan radius bintang sebesar 2300 km, sedangkan kerapatannya bintang neutron diperoleh sebesar 1.84 x 107 g cm-3 dengan menggunakan pendekatan relativistic. Pendekatan relativistic terbukti lebih baik untuk menentukan radius dan massa bintang, dengan pendekatan terbaik pada nilai Ye sebesar 0.5 yaitu pada bintang katai putih
Keyword: Composition of the stars, density of the stars, mass of the stars, radii of the stars