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: 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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