Judul: Pengaruh Iradiasi Sinar Gamma terhadap Sifat Gelatin Kulit Ikan Patin
Abstrak: Gelatin merupakan jenis protein yang diperoleh dari proses hidrolisis kolagen. Salah satu bahan baku gelatin adalah kulit ikan patin. Iradiasi sinar gamma Cobalt 60 mampu mengurangi jumlah populasi mikroba indegenus dengan cara merusak rantai DNA sehingga terjadi kematian sel, mutasi sel, atau transformasi sel. Penelitian ini bertujuan menentukan karakteristik fisik-kimia dan mikrobiologi gelatin kulit ikan patin dengan dosis iradiasi sinar gamma 0 kGy, 2 kGy, 4 kGy dan 8 kGy. Produksi gelatin dilakukan dengan pretreatment di dalam NaOH 0,2 M, asam asetat 0,05 M dan jeruk nipis 0,5%. Rancangan percobaan yang digunakan yaitu Rancangan Acak Lengkap (RAL) dan uji lanjut Duncan. Perbedaan dosis iradiasi sinar gamma tidak berpengaruh secara nyata terhadap kenampakan, kadar air, kadar abu, pH, dan setting point. Perlakuan dosis sinar gamma berpengaruh nyata terhadap kekuatan gel, viskositas dan jumlah mikroba. Gelatin kulit ikan patin dapat digunakan dalam produk pangan karena telah memenuhi standar GMIA 2019 dan SNI 8622-2018. Kata kunci : dosis, gelatin, mikroba, sinar gamma., Gelatin was a type of protein which has obtained from the hydrolisis of collagen process. One of the raw material for gelatin was Pangasius skin. Gamma irradation Cobalt-60 was able to reduce the number of indigenous microbial populations by damaging the DNA chain so that resulting cell death, cell mutation or cell transformation. This study aimed to determine the physico-chemical and microbiological characteristics of Pangasius skin gelatin at a dose of gamma ray irradiation 0 kGy, 2 kGy, 4 kGy and 8 kGy. Gelatin production was beginned by pretreatment in 0,2 M NaOH, 0,05 M asetic acid, and 0,5% lime. The experimental design used was Completely Randomized Design (CRD) and Duncan’s follow-up test. The difference of gamma irradiation dose had no effect on appearance, moisture content, ash content, pH, and setting point. The treatment of gamma irradiation had effect on gel strength, viscosity and number of microbial. The gelatin of Pangasius skin can be used in food product because it has met the standards of GMIA 2019 and SNI 8622-2018. Keyword : dose, gamma radiation, gelatin, microbial
Keyword: dose, gamma radiation, gelatin, microbial

Judul: Effect of Multistage Extraction on the Gelatin Properties of Pangasius Fish Skin (Pangasius hypopthalmus)
Abstrak: Gelatin merupakan produk hidrolisis kolagen yang dapat membentuk gel reversibel. Salah satu bahan baku gelatin adalah kulit ikan patin. Ekstraksi tunggal gelatin menyisakan kolagen di dalam struktur kulit ikan patin sehingga perlu dilakukan ekstraksi bertingkat. Ekstraksi bertingkat bertujuan meningkatkan rendemen sekaligus mempertahankan kualitas gelatin. Produksi gelatin diawali dengan pretreatment di dalam NaOH 0,2 M dan asam asetat 0,05 M. Ekstraksi bertingkat menggunakan kombinasi suhu 55-75, 55-80, dan 65-75 oC selama 10 jam pada setiap tahap dengan pelarut akuades. Rancangan percobaan yang digunakan yaitu Rancangan Acak Lengkap (RAL) dan uji lanjut Duncan. Penggunaan metode ekstraksi bertingkat meningkatkan rendemen dibanding ekstraksi tunggal. Perbedaan perlakuan berpengaruh terhadap viskositas, kekuatan gel, dan distribusi bobot molekul gelatin. Perlakuan tidak berpengaruh terhadap pH, kadar air, kadar abu, serta setting point. Hasil terbaik diperoleh pada perlakuan ekstraksi 65-75oC yang menghasilkan rendemen (25.05±0.35%), viskositas (63.67±2.08 mps), serta kekuatan gel (255.69±2.94 bloom). Perbedaan perlakuan menyebabkan perbedaan tingkat kerusakan pada struktur stratum compactum kulit ikan patin., Gelatin is hydrolyzed collagen that can form a reversible gel. One source of gelatin is Pangasius skin. Gelatin single extraction left some collagen in Pangasius skin so that a multistage extraction is needed. Multistage extraction aims to increase yield and maintain gelatin quality. Gelatin production began with pretreatment in 0,2 M NaOH and 0,05 M acetic acid. This extraction used some combination of 55-75, 55-80, and 65-75 oC for 10 hours at each stage in distilled water. The experimental designs in this study were completely randomized design (CRD) and Duncan's advanced test. Multistage extraction improved gelatin yield from a single extraction. Different treatments affected viscosity, gel strength, and molecular weight distribution. Treatments did not affect pH values, water contents, ash levels, and setting points. The best results were obtained at 65-75 oC treatment which resulted in a yield (25.05±0.35%), viscosity (63.67±2.08 mps), and gel strength (255.69±2.94 bloom). Different treatments caused different damage to the stratum compactum of Pangasius skin.
Keyword: gel, histologi, kolagen, reversibel, suhu

Judul: Penggunaan Teorema Homeomorphy 2-Manifold dan Teorema Euler Poincare pada Torus 𝑇�� dan Simplicial Complex 𝐾��
Abstrak: Two dimensional topological spaces are said to be homeomorphic if they have the same topological invariant, where one of topological invariant used is an Euler characteristic. Homeomorphy 2-Manifold’s Theorem and Euler Poincare’s Theorem are used to distinguish two topological spaces. Homeomorphy 2-Manifold’s Theorem uses Euler characteristic to identify two dimensional topological spaces. Euler Poincare’s Theorem is an alternative way to find Euler characteristic with Betti number, which is topological invariant as well. The objective of this paper is to investigate the homeomorphism of torus 𝑇����� and simplicial complex 𝐾�����. Topological space torus and simplicial complex 𝐾����� have the same Euler characteristic, which is two. Based on Homeomorphy 2-Manifold’s Theorem topological space torus 𝑇����� and simplicial complex 𝐾����� is homeomorphic.
Keyword: simplicial, torus, Euler, homeomorphism, topology