Judul: Analisis sifat fisikokimia dan sifat fungsional beras (Oryza sativa) Varietas Beras Hitam dan Beras Merah asal Cianjur, Solok, dan Tangerang
Abstrak: Black rice and red rice are claimed to be safely consumed by the diabetic patients and known to have high antioxidant content. Rice which is grown in different area may have different physical and chemical properties, thus it may also affect the rice functional properties. The purposes of this study were to determine the physical properties (hardness, color and gelatinization profile), chemical properties (proximate composition, total phenolic content, total flavonoid content and digestibility of starch) and the functional properties (antioxidant activity) of the black rice and red rice from Cianjur, Solok and Tangerang and also to observe the effect of cooking on the reduction of total phenolic content, flavonoids and antioxidant activity. In vitro analysis of starch digestibility with α-amylase showed that the starch digestibility of rice which had anthocyanin pigments (black and red varieties) ranged from 56.10-83.43%, smaller than white rice which was 87.35%. In addition, the result also showed that the total phenolic content, flavonoid and antioxidant activity in black, red and white rice were decreasing after cooking process. Black rice and red rice from Solok and Cianjur had the better chemical content and functional properties than the Tangerang one.
Keyword: Bogor Agricultural University (IPB), total flavonoid content, total phenolic content, red rice, black rice, Antioxidant activity

Judul: Evaluasi nilai biologis beras coklat (Oryza sativa L.) coklat Ciherang dan Cianjur
Abstrak: Unpolished or brown rice is rice which is only processed through dehulling, while polished rice is rice which is dehulled and polished and already lost its bran. Polishing causes the decrease of nutrient for polished rice, compared to brown rice. The theory is proven through this study where brown rice is higher in almost all biological value. The highest content for ash, fat, protein, total phenolic, antioxidant capacity, total dieatary fiber, and the lowest for glycemic index, which are as followed 1,57% (Cianjur brown rice); 2,35% (Ciherang brown rice); 10,18% (Cianjur brown rice); 33,69 mg galic acid/ 100 g sample (Ciherang brown rice); 11,25 mg AEAC/ 100 gram sample (Ciherang brown rice); 1,43% (Ciherang brown rice); and GI score is 37,03 (Ciherang brown rice). Though the higher content in polished rice are water and carbohydrate, which are 14,43% (Ciherang polished rice) and 76,39% (Cianjur polished rice). So it is concluded that brown rice is safe to be consumed by prediabetic and diabetic patients because it has low rate of glucose adsorption, moreover it won’t interfere the insulin secretion system and beta cells in pancreas won’t be burdened.
Keyword: Bogor Agricultural University (IPB), insulin, diabetic patients, glycemic index, AEAC, unpolished rice

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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