Judul: Improvement Resistant Starch Type 3 Content of Daluga Starch (Cyrtosperma merkusii) by Physical and Chemical Modification, and Evaluation of Prebiotic Properties by In Vitro
Abstrak: Umbi daluga yang digunakan diperoleh dari Kepulauan Siau, Provinsi Sulawesi Utara, Indonesia. Umbi daluga memiliki kandungan karbohidrat tinggi. Pati merupakan salah satu komponen karbohidrat yang penting dan sangat berpotensi dikembangkan sebagai sumber RS. Namun, secara alami pati daluga memiliki kadar RS yang rendah. Oleh karena itu, diperlukan suatu metode modifikasi pati untuk meningkatkan kadar RS dalam umbi daluga tersebut. Metode modifikasi yang dapat digunakan berupa modifikasi secara kimia maupun fisik yang terdiri dari hidrolisis asam, debranching, autoclaving-cooling, dan heat moisture treatment (HMT)., The giant swamp taro starch or daluga corm starch in this study was extracted from corms collected from Siau Island of North Sulawesi Province in Indonesia. Daluga corm has higher carbohydrate. Its starch potential used as source of resistant starch, but daluga native starch lowest resistant starch content, so some starch modified method were needed to increased its resistant starch content. Modification starch by physical and chemical method such as acid hydrolisis, debranching, autoclaving-cooling, and heat moisture treatment. Modification of daluga native starch for increase resistant starch type 3 (RS3) content.
Keyword: RS3 and daluga starch modified, physical and chemical modification, chemical properties, prebiotics properties

Judul: Karakteristik Fisikokimia dan Prebiotik Tepung Daluga (Cyrtosperma Merkusii (Hassk.) Schott) Hasil Modifikasi Fermentasi Bakteri Asam Laktat (BAL) dan Heat Moisture Treatment (HMT).
Abstrak: Daluga (Cyrtosperma merkusii. (Hassk.) Schott) adalah salah satu umbi yang berasal dari Kepulauan Siau, Manado, Sulawesi Utara. Kandungan pati dan amilosa daluga yang cukup tinggi berpotensi sebagai bahan baku pembentukan pati resisten (Resistant starch/RS). Tujuan penelitian yaitu meningkatkan kadar RS pada tepung daluga dengan modifikasi metode HMT menggunakan oven (100° C, 16 jam), otoklaf (121° C, 60 menit), dan kombinasi fermentasi BAL menggunakan Lactobacillus plantarum BSL (37° C, 18 jam) dan HMT. Dari ketiga modifikasi diperoleh metode terbaik berdasarkan parameter kadar serat pangan, pati resisten, dan amilosa yaitu TD-HMT otoklaf masing-masing sebesar 18.55%, 8.81%, 20.21%. Hasil evaluasi sifat prebiotik dari TD dan TD-HMT otoklaf menunjukkan bahwa TD-HMT otoklaf berpotensi sebagai prebiotik. Nilai sifat prebiotik TD-HMT otoklaf yang diperoleh untuk aktivitas prebiotik, indek dan efek prebiotik, ketahanan terhadap cairan asam lambung artifisial masing-masing sebesar 0.17%, 3.74%, 0.97%, 92,3%.
Keyword: HMT, pati resisten, tepung daluga modifikasi, sifat prebiotik

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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