Judul: Mikroenkapsulasi Lactobacillus plantarum MB427 dalam alginat-kitosan meningkatkan sintasan dan umur simpan selai salak probiotik
Abstrak: Selai salak dapat digunakan sebagai makanan pembawa probiotik (Lactobacillus plantarum MB427). Tujuan penelitian adalah meningkatkan sintasan dan umur simpan selai salak probiotik dengan mengenkapsulasi L. plantarum MB427 dalam alginat 3% dilanjutkan dengan penyalutan menggunakan kitosan. Konsentrasi kitosan terbaik ditentukan menggunakan berbagai konsentrasi (0.4, 0.6, 0.8, 1.0, 1.2, 1.5, dan 2.0%) setelah dipapar pada suhu 50oC, 20 menit. Pemaparan menghasilkan sintasan probiotik pada konsentrasi 0.4, 0.6, 0.8% menurun sebesar 1 log, sedangkan konsentrasi 1.0, 1.2, 1.5, 2.0% tidak mengalami penurunan nyata (p>0.05). Tahap kedua adalah menentukan umur simpan selai salak probiotik pada suhu 15oC yang dikemas dalam plastik HDPE steril. Sebanyak 10% b/b probiotik bebas/mikrokapsul alginat/ alginat-kitosan dimasukkan dalam selai salak. Teknik mikroenkapsulasi dapat meningkatkan sintasan probiotik. Viabilitas probiotik bebas sebesar 6.73 log cfu/g hanya bertahan sampai minggu ke 3. Pada minggu ke-5 viabilitas probiotik alginat sebesar 6.71 log cfu/g, sedangkan viabilitas probiotik alginat-kitosan sebesar 6.29 log cfu/g dapat dipertahankan sampai mingggu ke 6. Interpolasi waktu penyimpanan selai salak saat viabilitas probiotik mencapai 6 log cfu/g untuk probiotik bebas, mikrokapsul alginat, dan alginat-kitosan masing-masing adalah 27, 42, dan 47 hari. Total kapang khamir hingga minggu ke 6 sebesar 1.90 log cfu/g. Hasil uji statistik untuk pH, aw, kadar air, dan total padatan terlarut (TPT) tidak signifikan terhadap kontrol (selai tanpa probiotik). Selama penyimpanan terjadi penurunan pH serta peningkatan TPT, aw, dan kadar air. Selama penyimpanan juga terjadi perubahan nyata pada evaluasi sensori selai probiotik bebas (rasa) dan selai mikrokapsul alginat-kitosan (tekstur). Nilai kapasitas antioksidan selai salak (51.76%) berbeda nyata lebih rendah 27% dari buah salak segar (70.82%). Kata kunci: mikroenkapsulasi, kitosan, Lactobacillus plantarum MB427
Keyword: Microencapsulation, Lactobacillus plantarum mb427, Konsentrasi kitosan probiotic, Mikro kapsul probiotik

Judul: Karakteristik Mikrokapsul Lactobacillus plantarum dan : Stabilitas dalam Selai Salak Selama Penyimpanan
Abstrak: Modern consumers expect their food to be healthy and to prevent illness. Therefore the demand of functional food including probiotic products growing significantly. Functional foods containing probiotic bacteria generally are dominated by milk-based foods. Recently, the incorporation of probiotic bacteria in various food products especially fruit-based products have been studied. Probiotic strains in this research had been isolated from saurkraut (Lb. plantarum BSL) and beef (Lb.plantarum 2C12). Many reports indicated that there were poor survival of probiotic bacteria in food products containing free probiotic cells. Providing probiotic living cells with a physical barrier such as microencapsulation to resist adversed effect of environmental conditions is therefore an approach currently receiving considerable interest. The objectives of the study were 1) to evaluate the effect of Lb. plantarum microencapsulation by emulsion technique toward the resistancy to heat, injured cell, low pH (2.0) and bile salt (0.5%) and its antimicrobial activity. 2) to determine the most suitable temperature for incorporation probiotic into snake fruit jam. 3) to study the viability of free and encapsulated Lb. plantarum in snake fruit jam, total yeast mold, pH changes and water activity during room storage. The first stage of this study was microencapsulation of probiotics by emulsion method with sodium alginate as encapsulanting material. Characterization of the encapsulated probiotic were conducted including resistance to heat, injured cell, low pH and bile salt resistance, antimicrobial activity againts E. coli ATCC 25922, Salmonella typhii ATCC 14038, S. aureus ATCC 25923, S. cereviseae ATCC 9763 and Aspergillus niger. The second stage was incorporating the encapsulated probiotic into snake fruit jam. The most suitable temperature for incorporate based on the result of heat resistance.The last stage was evaluation of the probiotic viability in snake fruit jam during storage in room temperature for 4 weeks. The results showed that high survival number (11 log cfu g-1) of both Lb. plantarum strains were achieved after encapsulation. Heat resistance of the encapsulated strains at 50oC was better than their free cells, but the higher the temperature applied the lower the number of survivors would be. Heating at 70oC was more detrimental to all encapsulated probiotics with a decrease of more than 5 log cell numbers. Heating at 50o-70oC caused injury to all probiotics cells. Encapsulation probiotics also showed significantly higher survival (P<0.05) in bile salt (0.5%) and low pH (pH 2) treatments compared to their free cells. All encapsulated Lactobacillus strains could inhibit the growth of E. coli, Salmonella typhii and S. aureus as well as their free cells, but none of them could inhibit S. cereviseae and Aspergillus niger. Encapsulated probiotic bacteria in snake fruit jam showed good viability throughout the four weeks of storage, whereas the free probiotic lost their viability within two weeks. No changes of pH and water activity of the products were observed between free and encapsulated probiotic. The overall results suggested that microencapsulated probiotic prepared by emulsion method is suitable to be incorporated in snake fruit jam and provided good stability during 4 weeks of storage at room temperature.
Keyword: probiotics, Lb. plantarum, snake fruit jam, microencapsulation

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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