Judul: Ekstraksi dan Karakterisasi Gelatin dari Tulang Ikan Cobia (Rachycentron canadum)
Abstrak: emanfaatan tulang ikan cobia (Rachycentron canadum) belum dilakukan secara optimal. Konversi tulang menjadi gelatin dapat meningkatkan nilai tambah produk. Isolasi gelatin dari tulang ikan cobia dilakukan melalui empat tahap, yaitu degreasing, deproteinisasi dengan NaOH 0,05M dengan rasio sampel/larutan, yaitu 1:10 (b/v) selama 5 hari, demineralisasi menggunakan HCl 5% dengan rasio sampel/larutan adalah 1:6 (b/v) selama 4 hari, dan ekstraksi menggunakan akuades selama 3 jam pada suhu 70oC dengan rasio sampel/larutan 1:2 (b/v). Rendemen yang diperoleh berdasarkan perhitungan basis basah adalah 5,76%. Gelatin yang dihasilkan memiliki kandungan protein yang tinggi yaitu 86,65%, kadar air (10,35%), abu (0,75%), dan lemak(1,25%) yang rendah. Nilai pH yang diperoleh yaitu 6,56. Analisis asam amino menunjukkan bahwa gelatin memiliki komposisi glisin dan prolina yang tinggi. Analisis FTIR menunjukkan wilayah penyerapan amida A, B, I, II, III pada 3335, 2923, 1657, 1543, dan 1235 cm-1
Keyword: Rachycentron canadum, degreasing, deproteinitation, demineralitation, extraction, gelatin

Judul: Ekstraksi dan Karakterisasi Kolagen dari Kulit Ikan Cobia (Rachycentron canadum)
Abstrak: Cobia fish (Ranchycentron canadum) was used for a culinary purpose, but their skin was waste part. Convert in a value added product like collagen was a good practice of post harvest management. Isolation of collagen from the skin of cobia fish (Rachycentron canadum) has been successfully conducted with three stages: first soaked in 0,05 M NaOH with a sample/solution ratio of 1:10 (w/v) for 6 hour, second soaked in 0,1 M acetic acid with a sample/solution ratio of 1:6 (w/v) for 2 hour, and third extraction with destilated water at temperature 40 ºC for 3 hour. The yield of collagen was 10,508%. The pH of collagen was 7,08; protein content 86,46%; moisture 11,08%; fat 0,26%; and ash contents 0,19%. Amino acid analysis of collagen revealed the high proline and glycine. FTIR spectra analysis revealed that collagen molecules had the compact triple helical structure stabilized mainly by the hydrogen bond. Fourier transform infrared (FTIR) spectroscopic study showed major absorption bands of amide A, B, I, II and III at 3310, 2932, 1651, 1543 and 1242 cm-1 respectively.
Keyword: FTIR, water ekstraction, cobia (Rachycentron canadum), collagen

Judul: A Continuous Vaccination Strategy in the SVIR Epidemic Model
Abstrak: Vaccination is conducted to minimize the spread of a disease. The vaccination is usually done several times within a fixed time interval. In the SVIR model, it is assumed that individuals do not get immediate immunity following a vaccination program. So according to process of vaccination on SVIR model, there are two strategies, i.e. the continuous vaccination strategy (CVS) and the pulse vaccination strategy (PVS). In this study, only the CVS strategy in epidemic model SVIR is considered. Results of the study indicate that dynamics of the CVS system depends on the basic reproductive number. If the basic reproductive number is less than one, then the disease-free fixed point is asymptotically stable. It means that the disease will eventually disappear from the population. Conversely, if the basic reproductive number is greater than one, then the endemic fixed point is asymptotically stable, which means that the disease will remain exist in the population. Simulation result shows that the vaccination would minimize the spread of disease by reducing the basic reproductive number. If the time for the vaccinated recipients to obtain the immunity, as well as a possibility of vaccinated recipients to be infected are neglected, then the disease will be eradicated. This condition is called an over-evaluating effect of vaccination.
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