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 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: Thermal Characteristics and Dynamics of Tropical Cyclone over Western North Pacific Ocean: A Case Study of Typhoon Songda (Chedeng) 2011
Abstrak: The frequent occasion of Tropical Cyclone (TC) over Western North Pacific (WNP) Ocean lies from 10˚N to 26˚N and 121˚E to 170˚E. Sources of TC development come from warm ocean temperature where latent heat is released during condensation processes and subsequently concentrated in the boundary layer. Relative humidity at 850-700 hPa is responsible to produce the most intense storm. Meanwhile, weak vertical wind shear between 850-200 hPa is one of the dynamical factors that lead to the development of TC. Pressure level of 850-200 hPa is chosen to minimize the thermodynamic effect in the lower troposphere. Typhoon Songda (Chedeng in the Philippines) or TSC lasted from May 18th to 30th, 2011 and strengthened into powerful Super Typhoon stage between May 24th and 27th. Long curving track and the exhibition of all sequences of TC life cycle, TSC is then considered as an ideal case of TC. The objective of the study with case of TSC is to investigate the role of thermal characteristics and dynamics on TC intensity. The research is carried out by using Advanced Research of Weather Research and Forecasting model (WRF ARW model) version 3.3. Two domains are employed in the model. The first domain situate from 02˚N to 40˚N and 118˚E to 149˚E and cover spatial resolution () of 33.1 km. The second domain situate from 09˚N to 27˚N and 119˚E to 132˚E with of 11 km. Timestep of the model () is 120 seconds. The model is supported by the following physical parameterization, i.e., Yonsei University Scheme (YSU) in the boundary layer, Kain-Fritsch scheme (KF) in the cumulus, and WRF Single-Moment 3-class scheme in the microphysics. Initial meteorological condition prior to the formation of the cyclone is generated using WRF ARW standard-release model. Sensitivity of the model output is obtained from a selected single-parameter change scenarios, namely, 10 % to 20 % decrease and increase of wind shear initial data at 850-200 hPa, and by 10 % to 20 % decrease of relative humidity initial data at 850-700 hPa. The result showed that the negative correlations between wind shear and intensity are found in wind shear scenarios. Wind shears of 10 ms-1 which lead to strengthening of the wind intensity in the early period of Typhoon development are found in wind shear scenarios. The effect of wind shear changes on wind intensity is statistically significant in the 20 % wind shear scenarios. During mature stage, weak wind intensity occurred when wind shear increase as given in the WRF standard-release and the 20 % decreasing scenario. Different situation is found in the 20 % increasing scenario where wind shear tend to weak and lead to strong wind intensity at this stage. Meanwhile, the reduction of moisture supply at 850-700 hPa resulting from 20 % decreasing relative humidity play a major role in the weakening of wind intensity and reduces mechanical energy of the cycle process as much as 300 J kg-1.
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