Judul: Characteristics of Catfish (Pangasius sp.) Skin  Collagen from Ultrasonic Extraction
Abstrak: Kolagen umumnya bersumber dari hewan mamalia yang dikhawatirkan terkait kehalalan dan wabah penyakit yang ditimbulkan. Kulit ikan patin dapat menjadi salah satu solusi sumber bahan baku alternatif kolagen. Metode ekstraksi secara fisik dapat dilakukan dengan bantuan ultrasonik. Penelitian terkait ekstraksi kolagen dari kulit ikan patin dengan bantuan ultrasonik belum dilakukan. Penelitian ini bertujuan mengkarakterisasi kolagen kulit ikan patin yang dihasilkan menggunakan metode ultrasonikasi dengan variasi waktu berbeda (0 menit, 60 menit, 90 menit, dan 120 menit). Waktu terbaik ultrasonikasi yaitu selama 120 menit menghasilkan rendemen sebanyak 12,3%. Karakteristik fisik kolagen meliputi suhu pelelehan 97,01℃. Karakteristik kimia kolagen meliputi kadar air 9,85%, nilai pH 6,7, hasil FTIR menunjukkan terdeteksinya gugus amida A, amida B, amida I, amida II, dan amida III yang merupakan gugus khas kolagen, dan bobot molekul kolagen dengan lama ultrasonik 120 menit yaitu 155,234 kDa (α1), 97,517 kDa (α2), dan 237,548 kDa (β).
Keyword: collagen, fish skin, thermal stability, tissue structure, ultrasonic time

Judul: Karakteristik Hidrolisat Kolagen dari Kulit Ikan Patin (Pangasius hypophthalmus) dengan Perbedaan Konsentrasi Enzim Papain
Abstrak: Kolagen merupakan struktur protein kompleks yang diperoleh dari jaringan ikat. Pembuatan kolagen secara enzimatis menggunakan enzim papain akan memperoleh produk berupa hidrolisat kolagen. Penelitian ini bertujuan untuk menganalisis perubahan struktur jaringan pada kulit ikan patin sebelum dan setelah dilakukan pretreatment dan ekstraksi, serta menentukan karakteristik hidrolisat kolagen dengan perbedaan konsentrasi enzim papain (1%, 3%, dan 5%). Struktur jaringan kulit ikan patin sebelum pretreatment terlihat benang stratum compactum tebal, sedangkan setelah pretreatment dan ekstraksi terlihat benang stratum compactum terurai dan rusak. Hidrolisat kolagen memperoleh nilai derajat hidrolisis (72,37±1,86)-(97,22±3,93)%, nilai pH (6,23±0,12)-(7,22±0,08), dan nilai bobot molekul 12,016-23,877 kDa. Potensi aktivitas antioksidan yang diperoleh tergolong sangat kuat pada metode FRAP dan ABTS. Aktivitas antioksidan pada metode FRAP memperoleh nilai sebesar (536,31±2,61)(641,43±4,08) μmol Fe(II)/g, sedangkan pada metode ABTS memperoleh nilai sebesar (38,02±1,72)-(54,17±0,98) ppm., Collagen is a complex protein structure obtained from connective tissue. Enzymatic production of collagen using the papain enzyme will obtain a product in the form of collagen hydrolyzate. This study aims to analyze changes in the tissue structure of catfish skin before and after pretreatment and extraction, and to determine the characteristics of collagen hydrolyzate with different concentrations of papain enzymes (1%, 3%, and 5%). The structure of the catfish skin tissue before pretreatment showed thick stratum compactum threads, whereas after pretreatment and extraction, the stratum compactum threads were seen to be decomposed and damaged. Collagen hydrolyzate obtained a hydrolysis degree of (72.37±1.86)-(97.22±3.93)%, a pH value of (6.23±0.12)-(7.22±0.08), and a molecular weight value of 12.016-23.877 kDa. The potential antioxidant activity obtained is classified as very strong in the FRAP and ABTS methods. The antioxidant activity in the FRAP method obtained a value of (536.31±2.61)(641.43±4.08) mol Fe(II)/g, while the ABTS method obtained a value of (38.02±1.72)-(54.17± 0.98) ppm.
Keyword: antioxidant, collagen hydrolyzate, papain enzyme, structural change

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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