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: Transisi Fasa Materi Hadronik ke Materi Kuark pada Inti Bintang Neutron.
Abstrak: Bintang neutron terdiri dari beberapa lapisan yang disusun oleh materi nuklir yang berbeda dengan kerapatan yang semakin tinggi ketika mendekati pusat bintang. Inti luar bintang neutron disusun oleh materi hadronik (nukleon, lepton, dan hyperon), sedangkan inti dalam bintang neutron disusun oleh kuark-kuark bebas (up, down, strange) yang saling berinteraksi. Tujuan penelitian ini adalah mempelajari bagaimana transisi dari inti luar ke inti dalam bintang neutron dengan menggunakan pendekatan RMF (Relativistic Mean Field) untuk materi hadronik dan CIDDM (Confined Isospin Density Dependent Mass) untuk materi kuark. Tekanan transisi diperoleh ketika potensial kimia barion materi hadronik dan materi kuark bernilai sama. Nilai tekanan transisi dengan parameter SU6-TM1 sekitar 87 MeV/fm3 dan diperoleh massa maksimum bintang neutron yaitu 1.92M dengan jari-jari sekitar 8.62 km. Nilai tekanan transisi dengan parameter SU6-G2 sekitar 53 MeV/fm3 dan massa maksimum bintang neutron yaitu 1.88M dengan jari-jari sekitar 8.16 km. Jenis transisi fasa adalah orde satu ditandai dengan diskontinuitas dalam kerapatan energi (adanya mixed phase). Parameter-parameter pada model nuklir yang digunakan menyebabkan perbedaan kekakuan persamaan keadaan (EOS) dari materi hadronik dan materi kuark sehingga nilai tekanan transisi dari fasa hadronik ke fasa kuark juga berbeda.
Keyword: bintang neutron, persamaan keadaan, transisi fasa