Judul: Ketahanan dan Viabilitas Lactobacillus plantarum yang Dienkapsulasi dengan Susu Skim dan Gum Arab Setelah Pengeringan dan Penyimpanan
Abstrak: Probiotik adalah suplemen berupa mikroba hidup yang memberi keuntungan bagi kesehatan pencernaan manusia dalam jumlah yang cukup (107-109 cfu/g). (Fuller 1999). Dalam sistem pencernaan, probiotik menghadapi beberapa hambatan diantaranya keberadaan pH yang rendah dan adanya garam empedu. Untuk mengatasi kendala diatas dan untuk meningkatkan viabilitas probiotik maka perlu perlindungan dengan cara enkapsulasi. Tujuan penelitian ini adalah untuk memperoleh bahan enkapsulasi probiotik L. plantarum yang mampu melindungi probiotik selama pengeringan (spray drying), dalam kondisi pH rendah (pH 2,0) dan garam empedu (3%) serta selama penyimpanan satu bulan pada suhu rendah (4 oC) dan suhu kamar. Penelitian meliputi empat tahap, yaitu seleksi probiotik tahan panas, produksi kultur dan biomasa sel probiotik, enkapsulasi dengan metode spray drying, serta penyimpanan mikrokapsul probiotik. Pada pengujian ketahanan panas diperoleh dua isolat yang mempunyai ketahanan panas tertinggi, yaitu L. plantarum sa28k dan L. plantarum mar8. Kultur probiotik baik L. plantarum sa28k dan L. plantarum mar8 yang dienkapsulasi dalam bentuk biomasa menghasilkan ketahanan setelah spray drying dan viabilitas setelah disimpan satu bulan pada suhu rendah dan suhu kamar yang lebih baik dari pada dalam bentuk suspensi, tetapi pada ketahanan pH rendah (pH 2,0) dan garam empedu (3%) tidak berbeda nyata. Bahan enkapsulasi susu skim, gum arab dan kombinasi susu skim gum arab menghasilkan ketahanan setelah spray drying , viabilitas setelah penyimpanan selama satu bulan pada suhu rendah (4 oC) dan suhu kamar, serta ketahanan pada pH rendah (pH 2,0) dan garam empedu (3%) yang tidak berbeda nyata secara statistik. Penggunaan galur L. plantarum sa28k dan L. plantarum mar8, tidak berbeda nyata secara statistik untuk semua perlakuan. Pada perlakuan spray drying, L. plantarum mengalami penurunan sel berkisar 0,7-1,2 log cfu/g, dengan populasi akhir sekitar 107-109 cfu/g berat kering. Penurunan sel setelah penyimpanan satu bulan pada suhu rendah (4 oC) sebesar 2,4 log cfu/g, dengan populasi akhir sekitar 104-107 cfu/g berat kering, sedangkan pada suhu kamar terjadi penurunan sebesar 4,8 log cfu/g, dengan populasi akhir sekitar 102-105 cfu/g berat kering. Pada pengujian ketahanan terhadap pH rendah (pH 2,0) penurunan sel sebesar 2,4 log cfu/g, dengan populasi akhir sekitar 104-106 cfu/g berat kering, dan pada sel bebas penurunannya sebesar 4,3 log cfu/g. Sedangkan pada garam empedu penurunan sel sebesar 1,6 log cfu/g, dengan populasi akhir sekitar 105-107 cfu/g berat kering, dan pada sel bebas penurunannya sebesar 2,7 log cfu/g. Total kapang khamir pada mikrokapsul sekitar 1,2-1,9 log cfu/g. Hasil pemeriksaan dengan SEM menunjukkan mikrokapsul secara umum berbentuk bulat dengan permukaan yang retak-retak, tidak rata atau terdapat lipatan yang dalam pada permukaannya. Ukuran dari mikrokapsul bervariasi, yaitu berkisar antara 5-12 μm.
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Judul: Campuran Enkapsulan dan Pemanasan Sub-Letal Meningkatkan Kualitas Mikrokapsul Lactobacillus plantarum dalam Serbuk Jambu Biji Kering Semprot.
Abstrak: The demand for nondairy probiotic foods in the global market has increased recently. Innovation today is to develop probiotic foods such as fruit based probiotics. One problem pose is that the number of probiotics generally decreased during food processing and storage conditions and when consumed through the digestive tract. Microencapsulation technique by spray drying method has been reported can increase the survival of probiotic when exposed to these environment. Factors that influence the effectivity of this method are the type of microencapsulating material and sub-lethal temperature performed on the probiotic culture before spray drying. The objectives of this study were to select the suitable encapsulating material for microencapsulation of two probiotic strains L. plantarum (2C12 and BSL) in guava juice by spray drying and to obtain the optimum sublethal pre-heating temperature exposed to probiotic culture before spray drying. The temperatures of the spray dryer were set at 1200C (inlet) and 700C (outlet). Encapsulating materials used in this study were maltodextrin (MD) and mixture of MD-Arabic gum, MD-Inulin, and MD-GOS (galactoorigosaccaride). In separate experiment, optimization of the sublethal pre-heating temperature (500C, 52.50C, and 550C) were studied. The quality of microcapsules of both L. plantarum obtained was evaluated including probiotic survival after spray drying and resistance to heat (500C, 600C, and 700C), low pH (2.0), and bile salt (0.5%). The results showed that all encapsulating materials produced good quality microcapsules of both L. plantarum strains based on the probiotic survival after spray drying and improved the resistance of probiotic after heat, low pH, and bile salts. Mixture of maltodextrin and arabic gum was considered as the best encapsulating materials in producing spray dried microcapsules with the highest cell number of both L. plantarum strains. The resistance of encapsulated probiotics to heat, low pH and bile salt was varied by the type of encapsulating materials and L. plantarum strain. Microencapsulating using maltodextrin could be able to protect the probiotic strain toward heating at 500C by 2-3 log cfu g-1 guava powder compared to free cells. While mixture of maltodextrin and GOS showed the highest protection toward low pH and bile salt, except for L. plantarum BSL, maltodextrin alone demonstrated the best protection toward bile salt. Antimicrobial activity of the probiotics after microncapsulation againts Eschericia coli did not change significantly. The optimum sublethal temperature before spray drying was at 550C which was effective in increasing the survival of probiotic about 1.0 log cfu g-1 in guava powder. The spray dried guava powder probiotic had water activity (0.4), good water solubility (90-95%), and the color measured by chromameter (L, a, b) were 84.11, 2.35, 7.85, respectively.
Keyword: guava powder, Lactobacillus plantarum, microencapsulation, spray drying

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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