Judul: Effect of NaOH Comparison on Patin Skin Pretreatment (Pangasius hypophthalamus) on Gelatin and Its Application on Hard Capsule Shells
Abstrak: Kulit ikan patin sangat potensial menjadi sumber gelatin, namun proses pretreatment yang dilakukan belum maksimal. Penelitian ini bertujuan menentukan perbandingan NaOH dan sampel dalam proses preatreatment, serta karakteristik fisik-kimia gelatin kulit ikan patin. Metode yang dilakukan yaitu Rancangan Acak Lengkap dan uji lanjut Duncan. Karakteristik gelatin yang telah sesuai dengan standar GMIA 2019 dan SNI 8622-2018. Perlakuan terbaik didapatkan pada perlakuan perbandingan 1:8 (b/v). Perlakuan tersebut menghasilkan rendemen 22,66 ± 1,07%; pH 6,43 ± 0,14; viskositas 67,5 ± 1,50 mps; dan kekuatan gel 244,143 ± 1,69 bloom. Perlakuan tersebut diaplikasikan dalam pembuatan cangkang kapsul keras. Karakteristik cangkang kapsul keras yang dihasilkan telah sesuai dengan standar Departemen Kesehatan RI (2020). Analisis histologi menunjukkan bahwa perlakuan yang digunakan belum mampu menghancurkan lapisan stratum compactum, sehingga perlu dilakukan treatment dengan cara lain agar rendemen gelatin yang dihasilkan maksimal., Pangasius skin has the potential to be a source of gelatin, but the process of pretreatment is not optimal. The purpose of this research was to determine the ratio of NaOH and samples in the process of the pre-treatment, as well as physicochemical characteristics of gelatin from catfish skin. The method used was Completely Randomized Design and Duncan's further test. Gelatin characteristics that are in accordance with the GMIA 2019 standard and SNI 8622-2018. The best treatment was obtained at a 1:8 (w/v) comparison treatment. This treatment resulted in a yield of 22.66 ± 1.07%; pH 6.43 ± 0.14; viscosity 67.5 ± 1.50 mps; and gel strength 244.143 ± 1.69 bloom. This treatment was applied in the manufacture of hard capsule shells. The characteristics of the hard capsule shell produced meet the standards of the Indonesian Ministry of Health (2020). Histological analysis showed that the treatment used had not been able to destroy the layer stratum compactum, so it was necessary to do other treatments in order to maximize the yield of gelatin.
Keyword: catfish, gelatin, hard capsule, NaOH, pretreatment

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: 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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