Judul: Reaktivitas Lisin dalam Bentuk Asam Amino Bebas dan Protein dalam Reaksi Maillard
Abstrak: Tujuan penelitian ini adalah untuk mempelajari reaktivitas lisin dalam bentuk asam amino bebas dan protein dalam reaksi Maillard berdasarkan perbandingan komponen volatil yang dihasilkan. Penelitian ini dilakukan dengan mengambil pemodelan reaksi Maillard dari kondisi yang terjadi pada bahan pangan. N-a-acetyl-L-lysine digunakan untuk mewakili lisin dalam bentuk protein. Dari struktrur kimianya, senyawa ini memiliki guguS a-amino yang diblok oleh guguS asetil serta memiliki guguS £-amino bebas sehingga dianggap dapat mewakili lisin yang terikat dalam ikatan peptida. Untuk mewakili lisin dalam bentuk asam amino, dipilih L-Iysine monohydrochloride, sedangkan D-xylose dipilih sebagai gula pereduksi. Penelitian perbandingan reaktivitas lis in ini dilakukan pada dua kondisi. yaitu berdasarkan jumlah mol bahan lisin yang sama dan berdasarkan jumlah mol amino yang sama.
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Judul: Mempelajari Beberapa Sifat Protein Dendeng Sapi
Abstrak: Tujuan penelitian ini adalah untuk mempelajari beberapa sifat protein dendeng sapi, baik mentah maupun setelah digo- reng, akibat reaksi Maillard, dibandingkan dengan daging mentah dan daging rebus. Penelitian ini dilakukan di Laboratorium Pusbangtepa- IPB, Jurusan Teknologi Pangan dan Gizi-IPB dan Balai Peneli- tian Ternak, Ciawi, dengan menganalisa komposisi proksimat, komposisi asam amino, kandungan lisin tersedia, kadar nitro- gen protein terlarut, pengaruh pH terhadap kelarutan protein, reaksi hidrolisa enzimatis in vitro, pengukuran kecerahan warna dan penentuan total kapang. Dari hasil analisa ternyata tidak dijumpai perbedaan yang besar pada kandungan asam amino daging rebus dan daging - mentah. Tetapi kandungan lisin tersedia (available lysine) menunjukkan perbedaan, yaitu pada daging mentah 8.62 mg/g protein, sedangkan pada daging rebus sebesar 14.78 mg/g pro- tein, dimana kandungan lisin total masing-masing adalah 29.28 dan 27.77 mg/g protein. Dibandingkan dengan daging mentah, maka pada dendeng mentah terjadi peningkatan kadar lisin dan arginin, yaitu menjadi 125.14 dan 165.86 mg/g pro- tein, dengan kadar lisin tersedia sebesar 113.06 mg/g protein. ...
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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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