Judul: Hidrolisis Limbah Agroindustri Glukomanan secara Asam dan Enzimatis.
Abstrak: Pengolahan umbi iles-iles (Amorphophallus oncophyllus) menjadi tepung glukomanan menyisakan limbah berupa serbuk padat yang merupakan hasil samping proses pemisahan glukomanan. Limbah tersebut memiliki kandungan pati, serat, serta sisa glukomanan yang masih dapat dimanfaatkan menjadi gula sederhana melalui hidrolisis. Tujuan penelitian ini adalah mengkaji proses hidrolisis limbah agroindustri glukomanan menggunakan metode asam dan enzimatis sebagai pembanding serta untuk mengetahui pengaruhnya terhadap produk dan hasil samping yang terbentuk. Hidrolisis asam menggunakan pemanasan konvensional (otoklaf) dan gelombang mikro dengan asam encer yaitu HCl dan H2SO4 pada konsentrasi 0.5 M dan 1 M. Hidrolisis enzimatis menggunakan konsorsium α-amilase (1.75 dan 3.5 U/g), amiloglukosidase (0.3 dan 0.6 U/g), serta selulase (1 dan 2 U/g). Hasil penelitian memperlihatkan potensi limbah dengan komponen utama terdiri atas pati (47.26 ± 0.29 %), serat (15.79 ± 0.62 %), sisa glukomanan (12.64 ± 0.26 %). Hidrolisis asam menggunakan HCl memberikan hasil yang sedikit lebih tinggi dibandingkan H2SO4. Hidrolisis otoklaf menghasilkan gula dengan DE yang tinggi namun dengan rendemen yang lebih rendah, sedangkan hidrolisis gelombang mikro menghasilkan gula dengan DP dan rendemen yang lebih tinggi. Semakin tinggi konsentrasi asam, nilai gula pereduksi, DE, dan HMF semakin tinggi, namun DP semakin rendah. Pada hidrolisis enzimatis peningkatan dosis enzim memberikan hasil yang tidak berbeda nyata. Perlakuan terbaik diperoleh dari hidrolisis enzimatis dengan dosis normal karena memiliki gula pereduksi dan total gula yang tinggi serta HMF yang rendah.
Keyword: asam, enzimatis, hidrolisis, limbah agroindustri glukomanan

Judul: Pemurnian Glukomanan secara Enzimatis dari Tepung Iles-iles
Abstrak: Glucomannan is typical polysaccharide derived from konjac tuber. Conventional fractionation of glucomannan in konjac flour is by mechanical separation method, but it produces low purity glucomannan flour and needs further purification methods. This research is explored the glucomannan purification by enzymatic hydrolysis directly from konjac flour. Since konjac flour mainly consisted of starch, glucomannan and fiber, in this research sole thermophilic α-amylase enzyme and consortium of enzymes (amylase, xylanase and cellulose) were applied on 50 and 65 oC of incubation temperature for 2 hours. The results showed that consortium of enzymes can not be used for glucomannan purification; because glucomannan component is hydrolyzed by xylanase and cellulose. Glucomannan flour produced from sole α-amylase with incubation temperature of 50ᵒC has the highest yield (42.7%) compared to incubation temperature of 65ᵒC (31.6%). Duration of incubation also influenced to the glucomannan yield, and two hours of incubation time gave the best glucomannan flour with highest yield (37.0%), purity (46.1%), viscosity (42.3 cPs) and good whiteness (12.7%). Enzymatic hydrolysis of konjac flour also produced starch syrup (DE 55.6 – 77.9) as by- products.
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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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