Judul: Isolasi Senyawa Lutein dari Ekstrak Bunga Brokoli sebagai Antioksidan
Abstrak: Antioxidant activity is important to protect our body from free radicals. Green vegetables such as broccoli has high content of lutein which can act as an antioxidant. The objective of this study was to isolate and characterize lutein extract of broccoli flowers, and then further evaluated its antioxidant activity by using α,α-diphenyl-β-picrylhydrazyl (DPPH). The extraction used n-hexane as solvent and KOH/ethanol for saponification process. Extracted lutein was characterized with preparative thin layer chromatography (TLC). Four fractions were obtained from preparative TLC and fraction 3 had the same Rf compared with lutein standard. This fraction was further analyzed with Fourier transform infrared (FTIR) spectrophotometer and had similar functional groups with lutein standard. Based on this result, it can be concluded that broccoli flower extract has lutein compound and potential as an antioxidant with 99.321 μg/mL IC50 value.
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Judul: Pengaruh Waktu Pemasakan dan Konsentrasi Terhadap Aktivitas Antioksidan dan Kadar Fenolik Total Brokoli (Brassica oleracea L. var. italica)
Abstrak: There are many plants that can be used as alternative medicine. One of them is broccoli which is known as vegetable that contain antioxidant, such as phenolic compounds. Antioxidant is capable to inhibit free radicals in human tuJy. This research was aimed to measure the effect of cooking time and concentration of broccoli on antioxidants activity tested by DPPH (1,I-diphenyl-2-pycrilhydrazil) method and total phenolic content. Butylated hydroxytoluene (BHT) was used as positive control with various concentrations, 2, 4, 6, and 8 ppm. Some samples were cooked by conventional boiling treatment for 10, 20, and 30 minutes, and then were extracted with methanol. The extracts were separated by flash chromatography with toluene:ethyl acetate (11:9) as mobile phase. The number of fractions were determined with bioautography thin layer chromatography that were sprayed with DPPH 0.004% to get the active fraction. The methanol extracts and the active fractions were diluted to various concentrations, 10, 30, 50, and 70 ppm and then were determined for their antioxidant activity and the total phenolic content. The results showed that cooking time of broccoli from 10 to 30 minutes were significantly decreased antioxidant activity of extracts while increasing concentration of extract and active fraction from 10 to 70 ppm increase antioxidant activity of both of them. The ICso value of methanol extracts and active fraction were 226.94 and 221.78 ~g/mL, respectively. The ICso value of BHT was 6.46 ~g/mL. The total phenolic content active fraction for raw vegetable, 10, 20, and 30 minutes cooking time were 764.91, 495.96, 441.19, dan 304.66 mg/lOOg, respectively. Total phenolic content of broccoli were significantly decreased during the cooking.
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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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