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: Effect of Extraction Time on The Characteristics of Starch Fish Skin Gelatin
Abstrak: Gelatin merupakan produk hidrolisis protein kolagen kulit dan tulang hewan yang dapat dimanfaatkan dalam berbagai industri pangan maupun nonpangan. Penelitian ini bertujuan untuk menentukan perbandingan waktu ekstraksi terbaik untuk membuat gelatin, serta karakteristik fisik-kimia gelatin kulit ikan patin. Waktu yang digunakan untuk proses ekstraksi yaitu 6, 8 dan 10 jam. Waktu terbaik ditentukan berdasarkan karakteristik gelatin yang dihasilkan menggunakan analisis ANOVA dengan uji lanjut Duncan. Perlakuan terbaik didapatkan pada perlakuan waktu ekstraksi 8 jam. Perlakuan tersebut menghasilkan rendemen 17,64±0,18%; kadar air 10,22±0,18%; kadar abu 0,26±0,02%; pH 5,50±0,49; setting point 20,83±0,83ºC; viskositas 63,0±2,0 mps; dan kekuatan gel 204,688±4,52 bloom. Karakteristik gelatin yang dihasilkan telah sesuai dengan standar GMIA 2019 dan SNI 8622-2018. Analisis logam berat gelatin menunjukkan bahwa gelatin yang dibuat tidak terdeteksi logam berat arsen (As), merkuri (Hg), cadmium (Cd) dan timbal (Pb)., Gelatin is a product of hydrolysis of animal skin and bone collagen protein that can be used in various food and non-food industries. This study aims to determine the ratio of the best extraction time to make gelatin, as well as the physico-chemical characteristics of catfish skin gelatin. The time used for the extraction process is 6, 8 and 10 hours. The best time was determined based on the characteristics of the gelatin produced using ANOVA analysis with Duncan’s further test. The best treatment was obtained at the extraction time of 8 hours. This treatment resulted in a yield 17.64±0.18%; water content 10.22±0.18%; ash content 0.26±0.02%; pH 5.50±0.49; setting point 20.83 ± 0.83ºC; viscosity 63.0±2.0 mps; and gel strenght 204.688±4.52 bloom. The characteristics of the gelatin produced are in accordance with the GMIA 2019 standard and SNI 8622-2018. Heavy metal analysis of gelatin showed that the gelatin made did not detect heavy metals arsenic (As), mercury (Hg), cadmium (Cd) and lead (Pb).
Keyword: catfish, exctraction time, gelatin, heavy metal

Judul: Utilization of terra/MODIS L1B data for analysis of horizontal wind profile in the troposphere
Abstrak: This study was concerned with horizontal wind derived from data collected with the Moderate-resolution Imaging Spectroradiometer (MODIS) on board the NASA’s Earth Observation System (EOS)-Terra satellite. The aim of this study is to develop a method for the estimation of horizontal wind movement in the troposphere based on Navier-Stokes equation. The method was applied to a calibrated and geolocated Terra/MODIS L1B 1 km data set. The data inputs to estimate surface temperature are retrieved from TIR (Thermal Infrared) bands 31 (10.780 μm to 11.280 μm) and 32 (11.770 μm to 12.270 μm). The obtained surface temperatures were later used to approximate geopotential height on a constant-pressure surface by using the modified Poisson equation. The main assumptions used are the hydrostatic equilibrium, ideal gas law, constant lapse rate and constant acceleration of gravity. Based on the distribution of geopotential height, the pressure gradient force is measured by the gradient of geopotential on an isobaric coordinate to present the horizontal wind profile. For certain topographic areas especially in the mountain ranges, there was a disadvantage of using pressure as a vertical coordinate which lead to inaccuracy. In spite of that, Terra/MODIS L1B data with 1 km spatial resolution can be used to estimate the horizontal wind movement in the troposphere.
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