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: Rekayasa Proses Pengolahan Beras Pratanak Untuk Memperbaiki Kualitas dan Menurunkan Indeks Glikemik pada Gabah cv. Ciherang
Abstrak: Rice milling process causes the nutrients contained in the aleuron and perikarp layer wasted and resulting high glycemic index. Foods having high glycemic index raise blood glucose level quickly, they are not recommended for consumption by people with diabetes mellitus. To provide an alternative staple food, parboiled rice could be selected. Parboiled rice processing method that has been developed in Indonesia takes a long time process, so it is necessary to find an alternative process faster and able to reduce the value of glycemic index. Parboiled process can be accelerated by soaked a few moments or even just washed, steamed with high pressure, then dried until it reaches 14% moisture content and milled. The research was aimed: (1) to study the effect of steaming pressure on physical quality, chemical composition and organoleptic properties; (2) to study the glycemic index of parboiled rice at various steaming pressure. The study was conducted using a completely randomized design with 4 treatments and 2 controls as much as 4 replications. The treatments used steaming pressure i.e 0.8 kg/cm2 (110oC), 1.5kg/cm2 (122oC), 2.0kg/cm2 (127oC) and 2.5 kg/cm2 (132oC) and controls used polished and brown rice. Parboiled rice, polished and brown rice then analyzed on physical quality, chemical composition, functional and organoleptic properties. Analysis of physical quality parameters include whole grains, heads grain, broken grains, water content and yield. Chemical composition of the analyzed parameters include moisture content, ash content, fat content, protein content, carbohydrates content, amylose and resistant starch content. Analyzed for functional properties is the glycemic index. Organoleptic test was conducted to test hedonic scale really like to strongly dislike (1-7), including color, flavour, texture and taste, of 30 untrained panelists. Data from a variety of parameters, then analyzed using the methods of data analysis of variance at level α = 5%. If there is a real difference, then followed by Duncan's multiple comparison test. The results showed that engineering of pressure parboiled rice processing, could increase physical quality i.e increased the whole grain from 63.84% to 84.55%, reduced broken from 22.65% to 7.54%, reduced small broken from 0.44% to 0.28% and increased yield from 66.01% to 72.44%. Pressure parboiled rice processing was also able to change chemical compositions i.e increased fat from 0.89% to 1.27%, increased ash from 0.57% to 0.76%, increased amylose from 30.29% to 34.5%, increased amylose resistant starch from 33.64% to 34.59%, reduced carbohydrate from 88.78% to 88.77% and reduced protein from 9.76% to 9.21%. The use of a higher steaming pressure on parboiled rice processing, could reduce the level of preferring for parameters color, arome, texture and flavor. The panelist relatively preferred of arome and texture, but rather preferred of color and flavor. Pressure parboiled rice processing with 2.0 kg/cm2 steaming pressure (127oC) could reduce the glycemic index from 48.18 to 35.52, while the steaming pressure of 0.8 kg/cm2 (110oC) could reduce the glycemic index from 48.18 to 44.88.
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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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