Judul: Effect of Sodium Hydroxide Concentration on Catfish Skin Gelatin Characteristics and Application as Hard Capsules.
Abstrak: Gelatin merupakan protein turunan dari jaringan kolagen dan dapat dimanfaatkan dalam bidang pangan dan non pangan. Pembuatan gelatin perlu dilakukan optimasi untuk memperoleh hasil yang optimal. Optimasi proses pembuatan gelatin kulit ikan patin dilakukan dengan Response Surface Metodhology (RSM). Faktor yang digunakan yaitu konsentrasi NaOH dan waktu perendaman larutan NaOH. NaOH berfungsi mengikis protein non kolagen dan pengotor seperti lemak dan mineral. Variabel respon yang digunakan yaitu rendemen, pH, kadar air, kadar abu, viskositas, setting point, melting point, dan kekuatan gel. Hasil optimasi pada perlakuan konsentrasi NaOH 0,08 M dengan waktu perendaman 1,5 jam. Nilai validasi yang diperoleh rendemen 22,83±1,25 %; pH 5,56±0,09; kadar air 6,94±1,1 %; kadar abu 0,22±0,07 %; viskositas 59,66±1,15 mps; setting point 20,5±0,7 °C; melting point 27,34±2,08 °C; dan kekuatan gel 242,28±10,99 bloom. Hasil gelatin optimasi dimanfaatkan sebagai bahan baku pembuatan kapsul keras. Karakteristik kapsul yang dihasilkan telah sesuai dengan standar Departemen Kesehatan RI (1995)., Gelatin is a protein derived from collagen tissue and can be used in food and non-food fields. The production of gelatin needs to be optimized to obtain optimal results. Optimization of the process of making catfish skin gelatin was carried out using the Response Surface Methodology (RSM). The factors used are the concentration of NaOH and the immersion time of the NaOH solution. NaOH functions to erode non-collagen proteins and impurities such as fats and minerals. Variable responses used are yield, pH, water content, ash content, viscosity, setting point, melting point, and gel strength. The optimization results were treated with 0,08 M NaOH concentration with an immersion time of 1,5 hours. The validation value obtained was 22,83±1,25 %; pH 5,56±0,09; water content 6,94±1,1%; ash content 0,22±0,07%; viscosity 59,66±1,15 mps; setting point 20,5±0,7 °C; melting point 27,34±2,08 °C; and gel strength 242,28±10,99 bloom. The results of optimization gelatin are used as raw material for making hard capsules. The characteristics of the capsules produced are in accordance with the Indonesian Ministry of Health (1995) standards.
Keyword: Gelatin, Hard capsule, NaOH, optimization, RSM

Judul: Effect of Citrict Acid Soaking Volume and Time on Catfish Skin for Optimazion of Gelatin Extraction
Abstrak: Gelatin berasal dari protein kolagen yang diperoleh melalui hidrolisis kolagen kulit dan tulang hewan yang dapat dimanfaatkan sebagai bahan baku pembuatan kapsul keras. Penelitian dilakukan untuk mendapatkan formula proses pembuatan gelatin optimal dari kulit ikan patin dengan Response Surface Methodology (RSM) serta dilakukan analisis fisik dan kimia kapsul keras gelatin. Rancangan eksperimen yang digunakan yaitu Central Composite Design (CCD) yang terdiri dari dua variabel yaitu volume asam sitrat (300 mL, 400 mL dan 500 mL) dan waktu perendaman asam sitrat (6 jam, 12 jam dan 18 jam) pada suhu ekstraksi 65°C selama 8 jam dengan delapan respon yaitu rendemen, kadar air, kadar abu, pH, kekuatan gel, viskositas, setting point dan melting point. Ekstraksi gelatin optimal pada perlakuan volume 500 mL dan waktu perendaman 18 jam menghasilkan gelatin dengan kualitas yang telah sesuai standar GMIA 2019 dan SNI 86222018. Nilai validasi keadaan optimal yang diperoleh yaitu rendemen 22,41±0,20% kadar air 6,72±0,40%; kadar abu 0,30±0,05%; pH 5,26±0,02; kekuatan gel 266,08±14,68 bloom; viskositas 59±0,16 mps; setting point 20,33±1,5°C; dan melting point 24,67±1,52°C. Karakteristik kapsul keras yang dihasilkan telah sesuai dengan standar Depkes RI 1995., Gelatin is derived from collagen protein obtained through hydrolysis of animal skin and bone collagen which can be used as raw material for making hard capsules. The research was conducted to obtain the optimal formula for the process of making gelatin from catfish skin with Response Surface Methodology (RSM) and physical and chemical analysis of hard gelatin capsules were carried out. The experimental design was the Central Composite Design (CCD) which consisted of two variables, namely the volume of citric acid (300 mL, 400 mL and 500 mL) and the immersion time of citric acid (6 hours, 12 hours and 18 hours) at an extraction temperature of 65°C for 8 hours with eight responses, namely yield, water content, ash content, pH, gel strength, viscosity, setting point and melting point. Optimal gelatin extraction at treatment volume of 500 mL and soaking time of 18 hours produced gelatin with quality that complies with GMIA 2019 and SNI 8622-2018 standards. The optimal validation value obtained was yield of 22,41±0,20% water content 6,72±0,40%; ash content 0,30±0,05%; pH 5,26±0,02; gel strength 266,08±14,68 bloom; viscosity 59±0,16 mps; setting point 20,33±1,5°C; and a melting point of 24,67±1,52°C. The characteristics of the hard capsules produced are in accordance with the 1995 Ministry of Health standards.
Keyword: Catfish, Gelatin, Hard capsule, Optimal, Response Surface Methodology

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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