Judul: Pengaruh jenis Kapang terhadap mutu kimia dan aktivitas antimikroba Tempe Kacang Merah (phaseolus vulgaris L.)
Abstrak: Tempe merupakan salah satu pangan yang banyak digemari di Indonesia. Selain kedelai, bahan baku dalam pembuatan tempe bermacam-macam, salah satunya ialah kacang merah. Kandungan gizi tempe kacang merah dengan kedelai memiliki sedikit perbedaan, namun masih tergolong tinggi. Selain kandungan gizinya yang tinggi, tempe juga menghasilkan senyawa antimikroba yang dapat bermanfaat bagi penderita diare. Dalam pembuatan tempe, peranan laru tempe mempengaruhi hasil dari produk jadi tempe. Laru yang paling banyak digunakan ialah R. oligosporus dan R. oryzae. Karakteristik kedua kapang ini berbeda sehingga akan berpengaruh pada tempe yang dihasilkan. Dalam penelitian ini, akan dilihat pengaruh jenis kapang terhadap mutu kimia tempe dan aktivitas antimikrobanya. Pengujian antimikroba dilakukan dengan metode sumur dengan menggunakan bakteri S.aureus sebagai bakteri gram positif dan E.coli sebagai bakteri gram negatif. Hasil penelitian menunjukkan bahwa tempe kacang merah dengan kapang R. oligosporus menghasilkan mutu terbaik dari segi kandungan asam amino dan antitripsin. Kadar asam amino tertinggi ialah tempe dengan penambahan kapang campuran dalam satu laru, yaitu sebesar 314396 mg/kg. Namun tempe dengan laru Rhizopus oligosporus dan tempe dengan penambahan kapang campuran dalam satu laru memiliki kadar asam amino yang tidak berbeda nyata pada taraf signifikansi 0.05. Selain itu, tempe kacang merah dengan kapang R. oligosporus mempunyai kandungan antitripsin paling rendah, yaitu 8360.4 TUI, bila dibandingkan dengan tempe kacang merah yang lainnya. Keempat tempe kacang merah yang dihasilkan tidak mengandung oligosakarida dan tidak memiliki aktivitas antimikroba terhadap bakteri S. aureus dan E. coli., Tempeh is one of favourite food in Indonesia. In addition to soybean, raw materials for the manufacture of tempeh are various, one of them is red bean. Nutrient content of red bean tempeh with soybean have a slight difference, but still relatively high. In addition to its high content of nutrition value, tempeh also produces antimicrobial compounds that can be beneficial for patients with diarrhea. In the making of tempeh, mold is the one who will affect the product. The most commonly used of mold are R. oligosporus and R. oryzae. The characteristics of each molds are different, and it affects the result of tempeh. This research shows the influence of mold types in the chemical qualities of tempeh and antimicrobial activity. The testing of antimicroba was conducted using wells method with S. aureus as gram positive bacteria and E.coli as gram negative bacteria. The result shows that red bean tempeh with R. oligosporus produces the best quality in terms of amino acids and antitrypsin. The highest levels of amino acid is in tempeh C, i.e., 314396 mg/kg. However, tempeh B and tempeh C have no significantly different in level of amino acid (α<0.05). In addition, red bean tempeh with R. oligosporus have the lowest level of antitrypsin, i.e., 8360.4 TUI, if it compares to others. Four red bean tempeh do not contains oligosaccharide in all treatments, and they do not have antimicrobial activity against S. aureus and E. coli.
Keyword: Kacang merah, tempe, mutu kimia, aktivitas antimikroba

Judul: Pengaruh Jenis Inokulum dan Waktu Inkubasi Terhadap Sifat Fisiko-Kimia Tempe Kacang Merah (Phaseolus vulgaris L.)
Abstrak: Tempeh is one of Indonesian’s favourite food and it is known as source of protein. Red bean or red kidney bean contains protein in high amount so that it has big potency to be utilized as raw material of tempeh. Mold mycellium that growth covering the beans will form the compact texture and also being the source of protein. This research uses factorial experiment design with two factors: inoculum type and incubation time. The production of red bean tempeh in this reasearch is using four types of inoculum which are Laru A (R.oligosporus), Laru B (R.oryzae), Laru C (R.oligosporus+R.oryzae 1:1), and Laru D (Laru A+Laru B 1:1) On the other hand, the incubation times used for this research are 24, 36, and 48 hours. Parameter which are measured to determine the optimum inoculum type and incubation time for red bean tempeh is protein content, especially soluble protein content. The other parameters are yield, the slicing force, and color. The red bean tempeh production steps are similar with soybean tempeh. Every type of inoculum and incubation time produced red bean tempeh with different physicochemical characteristics. Samples which have similar high protein content with 5% significancy are A48 (40.12%db), C48 (41.15%db), A36 (43.81%db), and B36 (46.05%db). Samples whose similar high soluble protein content are C36 (2.63%db), A36 (2.67%db), A48 (2.94%db), dan C48 (3.00%db) with 5% significancy. Samples with the highest yield are A36 (95.10%), D36 (95.15%), and C36 (97.21%), similiar with yield of 24 hours tempeh. The highest slicing force 198.1 N.mm (A48) while slicing force of soybean temoeh as control is 140.1 N.mm. Samples with similar brightness value with control (78.833%) are A24 (80.575%), A36 (76.740%), B48 (74.110%), and C36 (79.425%). The whole red bean tempeh samples show yellow as their dominant chromatic colour (a value = +0.230 to +6.150 and b value = +5.840 to +19.025).
Keyword: Bogor Agricultural University (IPB), R.oryzae, R.oligosporus, red bean tempeh, protein, incubation time

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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