Judul: Characterization of Tilapia Fish Scale Gelatin (Oreochromis niloticus) Extraction Process Optimization Results Using Response Surface Methodology
Abstrak: Sisik ikan nila menjadi salah satu sumber bahan baku halal yang dapat dimanfaatkan untuk produksi gelatin ikan. Penelitian ini bertujuan menentukan kondisi pretreatment yang optimum melalui penggunaan konsentrasi NaOH dan HCl yang tepat berdasarkan metode Response Surface Methodology (RSM) serta menentukan karakteristik gelatin hasil optimasi. Variabel bebas yang digunakan, yaitu konsentrasi NaOH dan konsentrasi HCl dengan variabel respon penelitian meliputi, rendemen, kadar air, kadar abu, kekuatan gel, viskositas, pH, dan setting point. Hasil optimasi diperoleh respon optimum pada konsentrasi NaOH 0,05 M dan konsentrasi HCl 0,257 M. Hasil verifikasi keadaan optimum memperoleh gelatin dengan rendemen 17,20±0,36%, kadar air 2,42±0,19%, kadar abu 0,47±0,02%, kekuatan gel 223,448±5,55 Bloom, viskositas 15,37±0,29 mPas, pH 6,87±0,08, dan setting point 19,63±0,06℃. Gelatin hasil optimasi memiliki gugus fungsi amida A, B, I, II, III dan bobot molekul menunjukkan rantai β 241,048 kDa; α_1 161,318 kDa dan α_2 100,646 kDa., Tilapia scales are one of halal raw sources that can be utilized for fish gelatin production. This study aims to determine the optimum pretreatment conditions through the use of the right NaOH and HCl concentrations based on the Response Surface Methodology (RSM) and determine the characteristics of the optimized gelatin. The independent variables were used, such as NaOH concentration and HCl concentration with response variables including yield, moisture content, ash content, gel strength, viscosity, pH and setting point. Based on this study, it showed the optimum response at NaOH concentration of 0,05 M and 0,257 M for HCl concentration. The verification results of the optimum conditions obtained gelatin with a yield of 17,20±0,36%, moisture content of 2,42±0,19%, ash content of 0,47±0,02%, gel strength of 223,448±5,55 Bloom, viscosity of 15,37±0,29 mPas, pH 6,87±0,08, and setting point of 19,63±0,06℃. The optimized gelatin has amide functional groups A, B, I, II, III and the molecular weight shows β chain 241,048 kDa; α_1 161,318 kDa dan α_2 100,646 kDa.
Keyword: gelatin, halal, optimization, RSM, scales

Judul: Characteristics of Gelatin from Tilapia Fish Scales (Oreochromis niloticus) and Gourami Fish (Osphronemus goramy)
Abstrak: Sisik merupakan salah satu limbah hasil samping perikanan yang dapat digunakan sebagai bahan baku alternatif pembuatan gelatin. Gelatin adalah produk turunan protein yang dihasilkan melalui degradasi kolagen. Perlakuan yang digunakan dalam penelitian ini adalah pengunaan sisik ikan yang berbeda, yaitu sisik ikan nila (Oreochromis niloticus), sisik ikan gurami (Osphronemus goramy), serta sisik campuran ikan nila dan gurami. Analisis statistik yang digunakan adalah analisis ANOVA dan uji lanjut Duncan. Kualitas gelatin terbaik diperoleh dari jenis sisik campuran ikan gurami dan ikan nila. Rendemen yang dihasilkan dari gelatin sisik ikan tersebut yaitu 14,45±0,28%; kadar air 11,04±0,18%; kadar abu 0,49±0,25%; kekuatan gel 208,29±2,6 bloom; viskositas 7,26±0,02 mPas; setting point 18,60±1,90ºC; dan pH 7,11±0,06. Gelatin sisik ikan gurami, sisik ikan nila serta sisik campuran ikan gurami dan ikan nila menunjukkan rantai ß, a1, a2 dan hasil FTIR menunjukkan gugus fungsi khas gelatin yaitu amida A, amida I, amida II dan amida III., Scales are a by-product of fisheries that can be used as an alternative raw material for making gelatin. Gelatin is a protein derivative product produced through collagen degradation. This research aims to determine the influence of different types of fish scale raw materials. The treatments used in this study were the use of different fish scales, namely tilapia fish scales (Oreochromis niloticus), gourami fish scales (Osphronemus goramy) and mixed scales of tilapia fish and gourami fish. The statistical analysis used was ANOVA analysis and Duncan's post-hoc test. The best quality gelatin is obtained from mixed types of gourami and tilapia fish scales. The yield produced from fish scale gelatin was 14.45±0.28%; water content 11.04±0.18%; ash content 0.49±0.25%; gel strength 208.29±2.6 bloom; viscosity 7,26±0,02 mPas; setting point 18.60±1.90ºC; and pH 7.11±0.06. The gelatin of gourami fish scales, tilapia fish scales and mixed scales of gourami fish and tilapia fish shows ß, a1, a2 chains and FTIR results show the typical functional groups of gelatin, namely amide A, amide I, amide II and amide III.
Keyword: gelatin, sisik, halal, nila, gurami, gelatin, scales, halal, tilapia, gourami

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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