Judul: The Use of Alkaline Agents and Soaking Fillet on Making of Catfish Surimi (Pangasius pangasius) on Pempek Formulation
Abstrak: Palembang sebagai sentra produksi pempek, mengandalkan bahan baku pembuatan pempek gabus dari hasil tangkapan. Pada beberapa tahun terakhir muncul kecenderungan hasil tangkapan yang semakin kecil ukurannya. Ikan gabus belum dapat dibudidayakan dan harganya mahal. Penggunaan bahan baku alternatif perlu dilakukan dengan memanfaatkan ikan budidaya dengan tingkat produksi tinggi dan bernilai jual rendah misalnya ikan patin. Patin banyak digunakan oleh masyarakat setempat sebagai bahan baku masakan tradisional, seperti pindang dan brengkes. Kadar lemak yang tinggi menyebabkan warna daging agak kekuningan dan kemampuan membentuk gel menjadi rendah., Catfish (Pangasius pangasius) was initially washed with NaHCO3 and Na2HPO4 solution (0%, 3%, 5% and 7% w/v), followed by 1, 2, 3 and 4-washing cycles to obtain surimi with lower fat content and better gel strength. At alkaline solution of 0% (water) and one-washing cycle produced best gel strength of surimi (230,42 g.cm) and had fat content lower in compared to minced flesh. Soaking of fillet before mincing were carried out for 0, 10, 20 and 30 minutes and followed by either with or without washing. The treatments were performed to determine the effectiveness of washing with water to reduce fat content. The gel strength of the surimi was prepared by 30-minutes soaking and one-washing cycle in cold water was highest. This surimi was subsequently used in pempek formulation. Commercial pempek was used as comparing control. Based on the different assessment of panelists gained formulation of 400 g surimi, tapioca 200 g, 150 ml water and 24 g of salt produced the best pempek. The level of similarity between this pempek with comparing control is 65%.
Keyword: 

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: 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.
Keyword: