Judul: Optimization Gelatin Extraction Process for Catfish (Pangasius sp.) Skin with Response Surface Methodology Application
Abstrak: Ikan patin merupakan bahan baku gelatin alternatif yang aman dan halal. Kulit ikan memiliki karakteristik yang berbeda dengan hewan terestrial sehingga memerlukan optimasi pada proses ekstraksi sebelum masuk ke skala industri. Penelitian ini bertujuan melakukan optimasi kondisi pretreatment pada proses ekstraksi gelatin menggunakan Response Surface Methodology (RSM) serta menentukan karakteristik gelatin terpilih. Rancangan eksperimen yang digunakan yaitu Central Composit Design (CCD) dengan dua variabel bebas (konsentrasi NaOH dan konsentrasi asam asetat) dan 7 variabel respon (rendemen, kadar air, kadar abu, kekuatan gel, viskositas, pH, dan setting point). Hasil optimasi diperoleh respon optimum pada konsentrasi NaOH 0,3 M dan konsentrasi asam asetat 0,067 M. Hasil validasi keadaan optimal memperoleh gelatin terpilih dengan rendemen 22,44±0,68%, kadar air 8,53±3,4%, kadar abu 0,325±0,22%, derajat keasaman (pH) 6,65±0,13, kekuatan gel 241,58±9,5 Bloom, viskositas 6,65±0,5 mPas, dan setting point 19,75±1,06 ℃. Karakteristik gelatin terpilih telah memenuhi standar gelatin SNI 8622:2018 dan GMIA 2019., Catfish is an alternative raw material for gelatin that is halal and safe. Pangasius skin has different characteristics from terrestrial animals, so it requires to optimize the extraction process before industrial scale production. This study aims to optimize the pretreatment conditions in the gelatin extraction process using the Response Surface Methodology (RSM) and determine the characteristics of the selected gelatin based on the pretreatment conditions. Central Composite Design (CCD) with two independent variables (NaOH concentration and acetic acid concentration) and 7 response variables (yield, moisture content, ash content, gel strength, viscosity, pH, and setting point) was performed. The results showed the optimum response at 0.3 M NaOH and 0.067 M acetic acid. The validation obtained selected gelatin with a yield 22.44 ± 0.68%, water content 8.53 ± 3.4%, ash content 00.325 ± 0.22%, degree of acidity (pH) 6.65 ± 0.13, gel strength 241.58 ± 9.5 Bloom, viscosity 6.65 ± 0.45 mPas, and setting point 19.75 ± 1.06 ℃. The characteristics of the selected gelatin have met the SNI 8622: 2018 and GMIA 2019 gelatin standards.
Keyword: catfish, gelatin, halal, process optimization, RSM

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: 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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