Judul: Aktivitas antioksidan hidrolisat protein ikan lencam (Lethrinus lentjan).
Abstrak: Ikan lencam (Lethrinus lentjan) merupakan salah satu jenis ikan laut yang bernilai ekonomis dengan kandungan protein sebesar 14-24%, sehingga berpotensi untuk menjadi hidrolisat protein ikan dengan nilai tambah antioksidan. Penelitian ini bertujuan untuk menentukan enzim (alkalase dan papain) dan bagian fillet (skin on dan skinless) sebagai sumber hidrolisat protein ikan lencam (Lethrinus lentjan) dengan antioksidan terbaik. Hidrolisat protein ikan dengan perlakuan enzim alkalase 3% dan papain 5% pada bagian skinless fillet dan skin on fillet. Hidrolisis dilakukan pada suhu 55 °C selama 180 menit dengan waterbath shaker. Derajat hidrolisis tertinggi yaitu pada bagian skinless fillet dengan alkalase 3% sebesar 57.52% dan terendah pada bagian skin on fillet dengan papain 5% sebesar 31.05%. Pengujian antioksidan yang digunakan yaitu DPPH, ABTS, FRAP, dan CUPRAC. Aktivitas dan kapasitas antioksidan tertinggi yaitu pada bagian skinless fillet dengan alkalase 3% dan terendah pada bagian skin on fillet dengan papain 5%.
Keyword: antioksidan, enzim, hidrolisat, Lethrinus lentjan

Judul: Aktivitas Antioksidan dan Profil Peptida Hidrolisat Protein Ikan Nila (Oreochromis niloticus).
Abstrak: Hidrolisat protein ikan merupakan produk yang dihasilkan dari pengurairan protein pada ikan menjadi peptida sederhana dan asam amino. Tujuan penelitian ini adalah menentukan aktivitas antioksidan dan profil peptida dari hidrolisat protein ikan nila (Oreochromis niloticus). Penelitian ini dilakukan dengan beberapa tahap yaitu preparasi sampel, analisis morfometrik, proporsi bagian tubuh ikan, analisis proksimat, analisis mineral (Fe, Zn, dan Mg), hidrolisis protein ikan nila menggunakan enzim alkalase dan enzim papain, analisis aktivitas antioksidan (DPPH, ABTS, FRAP dan CUPRAC), analisis asam amino dan analisis profil protein menggunakan metode SDS-PAGE. Aktivitas antioksidan tertinggi terdapat pada sampel skinless fillet dengan enzim alkalase sebesar 91.31±6.60 ppm pada metode DPPH, 74.64±0.41 ppm pada metode ABTS, 249.61±5.14 μmol/g pada metode CUPRAC dan 348.92±1.67 μmol/g pada metode FRAP. Asam amino esensial tertinggi terdapat pada leusin sebesar 5.02% dan non esensial pada asam glutamat sebesar 9.94%. Bobot molekul hidrolisat protein ikan nila sebesar 3.486-16.950 kDa.
Keyword: antioksidan, hidrolisat protein ikan nila, ikan nila

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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