Judul: Peningkatan kadar vanillin homogenat vanila dengan penambahan ekstrak enzim dari kapang Aspergillus niger
Abstrak: Ekstrak vanila alami berharga sampai dengan USD 4000 per kilogram. Industri sudah menggunakan vanillinsintetik sebagai pengganti flavor vanila alami. Hargavanillin sintetis jauh lebih murah(USD 12 per kilogram), akan tetapi penggunaannya sangat berpengaruh terhadap flavor produk secara keseluruhan. Ekstrak vanila alami terdiri lebih dari 100 komponen yang semuanya memiliki kontribusi terhadap flavor akhir, sementara produk penggantinya hanya mengandung vanillin (Dignum, 2002). Rendahnya kualitas flavor vanila Indonesia diduga terjadi karena tidak semua senyawa glikosida terhidrolisis menjadi aglikon, disebabkan rendahnya aktivitas enzimatik ẞ-glukosidase yang terdapat dalam buah vanila. Penelitian ini bertujuan untuk meningkatkan kadar vanillin homogenat vanila melalui peningkatan aktivitas enzim ẞ-glukosidase dengan cara menambahkan ekstrak enzim ẞ-glukosidase dari kapang Aspergillus niger. Penelitian pendahuluan dilakukan untuk mengetahui jenis kapang dan waktu inkubasi yang optimum untuk memproduksi enzim ẞ-glukosidase. Kapang yang digunakan adalah Aspergillus niger dan Aspergillus oryzae. Hasil yang diperoleh kemudian dikarakterisasi untuk mengetahui kondisi optimum enzim untuk diaplikasikan kedalam homogenat vanili. ...
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Judul: Pengaruh Aktivator Butanol dan Sistein Terhadap Kadar Vanillin Pada Pengolahan Panili (Vanilla planifolia Andrews)
Abstrak: Panili (Vanilla planifolia Andrews) merupakan salah satu komoditi perkebunan andalan Indonesia sebagai negara produsen panili terbesar kedua setelah Madagaskar. Walaupun demikian Indonesia masih memiliki masalah dalam pengolahan panili yaitu mutu panili hasil olahan berkadar vanillin rendah. Untuk mengatasi mutu panili yang rendah diperlukan pengolahan panili yang dapat menghidrolisis semua senyawa prekursor flavor secara sempurna. Proses pengolahan panili terdiri dari empat tahap utama yaitu pelayuan (killing), pemeraman (sweating), pengeringan (drying), dan penuaan (conditioning) (Purseglove et al., 1981). Pada proses pengolahan tersebut terjadi hidrolisis senyawa prekursor flavor oleh enzim. Prekursor flavor utama panili adalah glukovanillin dan enzim yang menghidrolisis glukovanillin menjadi vanillin dan glukosa adalah β-glukosidase. Aktivitas enzim β-glukosidase dapat ditingkatkan dengan menggunakan gabungan aktivator enzim butanol dan sistein (Hasmilda, 2004).
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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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