Judul: The Effect of Anaerobic Fermentation Time on GABA Content in Pigeon Pea Tempe and Soybean Tempe
Abstrak: Based on BPS output data, in 2021 soybean production in Indonesia only reach 613 thousand tons per year, while soybean consumption in Indonesia in the same year reached 3.2 million tons of soybeans. The high demand for soybeans and the small value of local production means that our country has to import 2.48 million tonnes of soybeans or 1.48 billion US Dollars per year 2021. Pigeon pea beans (Cajanus cajan [L.] Millsp.) are a type of legume plant. Pea beans are widely planted by people as garden plants. Pigeon pea beans are very easy to grow and require little water because their roots are very deep. Pigeon pea plants are very suitable for the Indonesian climate so they are easy to cultivate. γ-aminobutyric acid, or commonly known as GABA, is a non-protein amino acid with four carbon atom groups. This research aims to determine the effect of fermentation time on the GABA content in pigeon pea tempe which is fermented aerobically at room temperature (28-32oC) and followed by anaerobic fermentation. Physicochemical analysis shows that pigeon pea tempe has lower nutritional and physical characteristics than soybean tempe. The combination treatment of pigeon peas and soybeans as much as 40:60% in making combination tempeh resulted in an increase in the physicochemical characteristics of pigeon pea tempe. The results of the GABA analysis showed that pigeon pea tempe had optimal GABA content at an anaerobic fermentation time of 10 hours, while the combination of pigeon pea-soy tempe (40:60%) and soybean tempe had optimal GABA content at an anaerobic fermentation time of 20 hours.
Keyword: GABA, Pigeon Pea, Tempe

Judul: Nutritional Contents and Protein Nutritional Value of Local and Imported Soybean Tempe Flours and Their Antioxidant Activities
Abstrak: The rate of population growth in Indonesia has increased rapidly, but the ability of farmers to produce foodstuffs has declined, including soybean production. Central Agency on Statistics (2013) noted that national soybean production in 2012, only amounted to 843.15 thousand tons, while the national total requirement was 2.3 million tons. To fulfill this shortage, the government should import soybean from other countries. There are many kinds of soybean products, such as tempe, tofu, tauco, soy sauce, soy milk, yuba, etc. Tempe is Indonesian traditional fermented soybean. The main problem of tempe product is its short shelf life. An alternative way to solve this problem is making tempe into flour. The objectives of this research were (1) to compare the nutritional and nonnutritional contents of local (grobogan) and imported (GMO and non-GMO) soybean tempe flours, (2) to evaluate the protein nutritional value of local (grobogan) and imported (GMO and non-GMO) soybean tempe flours, and (3) to measure antioxidant activities to DPPH radical and malonaldehyde (MDA) content in rat liver. Experimental material : local grobogan, imported GMO (Roundup Ready) and non-GMO soybean tempe flours. The research was conducted in two stages, in vitro and in vivo analysis. In vitro analysis was consists of proximate, amino acid, fatty acid, dietary fiber, total isoflavones, and vitamin E analysis. The biological assay was conducted on 25 male albino rats Sprague-Dawley as an animal model, divided into five groups, fed with imported GMO and non-GMO soybean tempe flours, local grobogan soybean tempe flours and casein as control. Parameters that used in the evaluation of protein nutritional value were protein efficiency ratio (PER), feed conversion efficiency (FCE), net protein ratio (NPR), true protein digestibility (TPD), biological value (BV), net protein utilization (NPU) and protein digestibility corrected amino acid score (PDCAAS) value. The measurement of antioxidant activity consist of DPPH antioxidant analysis and measure the MDA content in rat liver. The results showed that the nutritionals (proximate, amino acid, fatty acid, and vitamin E) and non nutritionals (dietary fiber and total isoflavones) compound of local grobogan soybean tempe flour were not much different from imported GMO and non-GMO soybean tempe flours. The evaluations of protein nutritional value showed that there were no significantly different of FCE (average 20.45%), PER (average 2.04) and NPR (average 2.80) values from all of tempe flours but lower than casein. TPD value of grobogan soybean tempe flour and non-GMO were not statistically different (average 82.62%), significantly higher than GMO soybean tempe flour (80.27%), but lower than casein (87.33%). There were no significantly different of BV (average 89.59%) and NPU (average 74.55%) values from all of samples. The PDCAAS value from local grobogan soybean tempe flour (61.82) was higher than imported GMO (52.1) and non-GMO (56.2) soybean tempe flours, but lower than casein (75.1). The scavenging activity (IC50) for DPPH radical of local grobogan soybean tempe flour was 2524.7 ppm, imported GMO was 3349.3 ppm, imported non GMO was 4049.6 ppm, while vitamin C was 5.03 ppm. MDA forming in liver showed that there was not difference (p>0.05) between grobogan (0.290 μg/g sampel), GMO (0.268 μg/g
Keyword: Antioxidant activity, local soybean, imported soybean, nutritional value, tempe flour.

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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