Judul: Produksi Pati Ganyong (Canna edulis Kerr) Resisten Tipe IV melalui Modifikasi Asetilasi
Abstrak: Edible canna is a potential forest product that can be used as food diversification. The objective of this research was to obtain resistant starch which has been proven for its physiological effect. The production of resistant starch was done by chemically modified which used different concentration of acetic anhydride, namely 3, 4, and 5% in 300 g of edible canna. Two types of edible canna used in this research are red edible canna and white edible canna. The degree of substitution which gained through acetylation is 0.082, 0.168, 0.257 for red edible canna and 0.082, 0.168, 0.257 for white edible canna. Through proximate analysis, modification of edible canna starch resulted in increase of water content and decrease of ash content, while protein content, lipid and carbohydrate content showed no relatively difference. Total starch content, amylose, amylopectin, dietary fiber, resistant starch and digestibility of starch were measured for edible canna and the selected modified edible canna (4%). The results showed that modification through acetylation can increase resistant starch content. It increased 3.54% in red edible canna while for white edible canna is 3.80%. These results influenced the increasing of total dietary fiber with value 2.45% for red edible canna and 1.95% for white edible canna. The increasing of dietary fiber will result in the decreasing of digestibility of starch with value 1.58% for red edible canna and 1.98% for white edible canna.
Keyword: starch modification, resistant starch type IV, digestibility, Canna edulis

Judul: Optimasi Pembuatan Pati Resisten Tipe III dari Pati Singkong Gen (Manihot esculenta Crantz)
Abstrak: One of products of cassava starch modification is resistant starch. Resistant starch has several benefits which of play a role in the metabolism of fat and cholesterol, binding toxins, bile acids, preventing colon cancer, coronary heart disease and diabetes type II. The purpose of this research is to optimization of making starch cassava (Manhot esculenta Crantz) with autoclaving-cooling method and debranching with pululanase enzyme method to produce resistant starch type III. Extract cassava starch has a moisture content of 9.58% with yield of 17.44%. The yield of starch modification by using a drying oven. Based on this study, modification of cassava starch with autoclaving-cooling method obtained the highest resistant starch content by debranching method was 87.64% at a concentration 1.04 U/g. In this study showed that the best resistnt starch content, modification of starch was using debrancing with pululanase enzyme method.
Keyword: Bogor Agricultural University (IPB), resistant starch, debrancing, cassava starch, Autoclaving-cooling

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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