Judul: Ekstraksi dan Karakterisasi Kolagen dari Kulit Ikan Tongkol (Euthynnus affinis)
Abstrak: Collagen is the most abundant protein in the living body and comprising approximately 30% of the total protein content. Utilization of waste from the skin of eastern little tuna to produce collagen is one alternative to increase the economic value of its waste. Pretreatment process in extracting collagen affects the quality of collagen that obtained. The different concentration of NaOH (0.05; 0.1; and 0.2 M) and soaking time (2, 4, 6, 8, 10, and 12 hours) were used as the pretreatment step. The best result of pretreatment was obtained from soaking the skin in a solution of 0.05 M NaOH for 12 hours with the lowest of soluble non-collagen protein concentration was 0.140 mg/mL. The yield and pH of the best collagen were 7.459% and 5.29, respectively. The highest solubility of collagen was 90.80% at pH 3. Amino acid analysis showed that the collagen has a glycine, proline, arginine, and alanine were dominant. FTIR analysis showed the major absorption bands of amide A, B, I, II, and III were at wavenumber 3395 cm-1, 2929 cm-1, 1652 cm-1, 1543 cm-1, and 1237 cm-1, respectively.
Keyword: amino acid, collagen, eastern little tuna, FTIR, yield

Judul: Ekstraksi dan Karakterisasi Kolagen Larut Papain dari Kulit Ikan Tuna Sirip Kuning.
Abstrak: Kolagen merupakan protein jaringan ikat yang banyak dihasilkan dari tubuh mamalia hingga mencapai 30%. Pemanfaatan limbah kulit ikan tuna sirip kuning menjadi kolagen adalah salah satu alternatif untuk meningkatkan nilai jual limbah. Tujuan penelitian ini adalah untuk ekstraksi dan karakterisasi kolagen larut papain dari kulit ikan tuna sirip kuning. Kolagen larut papain dilakukan dengan pretratment perendaman kulit ikan dalam 0,1 M NaOH dan asam asetat 0,5 M. Ekstraksi kolagen dilakukan dengan papain pada konsentrasi 3.000; 5.000 dan 7.000 U/mg/g kulit. Hasil ekstraksi pada konsentrasi tersebut menunjukkan rendemen kolagen larut papain sebesar 7,55±0,18%, 12,12±0,53%, dan 22,79±1,29%. Analisis SDS-PAGE kolagen pada ketiga perlakuan diperoleh pita β, α1 dan α2. Analisis FTIR menunjukkan adanya amida A, amida B, amida I, amida II, dan amida III. Nilai pH kolagen larut papain yaitu 5,96±0,09; 5,95±0,04; dan 5,90±0,22. Kelarutan kolagen sebesar 88,67±4,04%; 78,67±9,45%; dan 95,27±2,95%. Asam amino tertinggi glisina, prolina dan arginina.
Keyword: asam amino, enzim papain, kolagen, SDS-PAGE, tuna sirip kuning

Judul: Analysis of M/G/1 Queue Model with Two Phases of Service and Bernoulli Feedback System
Abstrak: Model antrean M/G/1 dengan sistem feedback Bernoulli adalah model antrean dengan proses kedatangan mengikuti proses Poisson. Pada karya ilmiah ini dibahas sistem antrean M/G/1 dengan dua fase layanan. Setelah layanan pertama selesai, pelanggan dapat memilih untuk meninggalkan sistem dengan peluang ... dst, The M/G/1 queueing model with the Bernoulli feedback system is a queueing model with the arrival process following the Poisson process. In this manuscript M/G/1 queueing system with two phases of service is discussed. After the first service is completed, the customer can choose to leave the system with probability ... dst
Keyword: queue, Bernoulli, probability generating function, expected value