Judul: Stabilisasi Bekatul dan Penerapannya pada Beras Analog
Abstrak: Indonesian rice consumption is one of the largest one in the world. This condition has raised concern to from the government. They issued Presidential Decree No. 22 in 2009 aims accelerate food diversification progam based on local resources. The development of analog rice can be one alternative to support food diversification program. Extrusion technology is used in manufacturing process of analog rice. This technology enables to formulate rice with various compositions and also makes product preparation and development easier. Corn flour, sago, soy flour, and rice bran are local resources used for analog rice. Corn flour, soy flour, and sago were used because these raw materials have been very common for Indonesian society, therefore analog rice resulted in this study was expected to be easily accepted in Indonesia. Corn flour was used because it has higher dietary fiber than wheat. Soy flour was used as a source of protein. The presence of protein increases the nutritional value and improves the texture of the analog rice. Other raw material of analog rice is sago. Sago is one of the primary food in East Indonesia. Rice bran contains high dietary fiber and has good antioxidant activity. Rice bran contains tocopherol (vitamin E), tocotrienols and oryzanol that have antioxidant capacity. Rice bran also has low glycemic index. Rice bran is a by-product of rice mill. It is a thin layer covering the rice seeds after husk removal. Rice bran must be stabilized immediately upon production to protect it from lipase activity, which can reduce quality of the rice bran by stimulating off flavor formation. Many methods have been developed to deactivate the lipase in rice bran. However, those methods are difficult to operate and they require a lot of energy so that less suitable for small rice milling unit. Therefore in this study, we developed another stabilization method by using single screw conveyor. The initial study was undertaken to determine the effects of stabilization treatment by using a single screw conveyor to the content of free fatty acids and bioactive components (α-tocopherol and ϒ-oryzanol) of rice bran. The treatments used were A100 (screw speed of 15 Hz, 100 °C), A120 (screw speed of 15 Hz, 120 °C), A140 (screw speed of 15 Hz, 140 °C), B100 (screw speed of 25 Hz, 100 °C), B120 (screw speed of 25 Hz, 120 °C), and B140 (screw speed of 25 Hz, 140 °C). It was shown that rice bran stabilization by using screw conveyor was able to significantly suppress an increase of FFA content of stabilized rice bran as compared to control (unstabilized one). Particularly, A120 was the best treatment for preventing rancidity (FFA content <10%) with a minimum decrease in α-tocopherol and γ-oryzanol content. It can be concluded that single screw conveyor is potential to be used in small-medium scale rice milling unit to produce rice bran with better self-life, while the nutrition content can be preserved. 6 The stabilized rice bran obtained from the most optimum condition was used in analog rice formulation using Mixture Design in Design Expert program (DX7). Mixture Design in the Design
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Judul: Stabilisasi Tepung Bekatul dengan Metode Pemanasan Bertekanan dan Pengeringan Rak serta Pendugaan Umur Simpannya.
Abstrak: The national production of the unhulled rice on 2007 reported about 60,3 million tons (BPS,2008). The by product is about 12,1 million tons hull, 1,8 million tons broken rice, and 6 million tons bran. For this time bran is used as feed for breed animals and as medium to grow fungi, even though the bran is a potential source of phytochemical materials. The bran contain some of vitamin, minerals, and other nutrition that is necessary to keep human health. The problem is the bran contain many enzymes, especially lipase that can trigger rancidity process in the bran if they don’t be handled well. One of the tech to solve this problem is using pressed steaming. The purpose of this research is to obtain characteristic of the fresh bran, the time of stabilization with pressed steaming and predict storage time of stabilized bran. The fresh bran characteristics include the water level 11,30 %, protein 14,41 %db, fat 18,99 %db, crude fibre 7,25 %db, carbohydrate 46,06 %db, ash 7,8%db, and TBA 1,36 mg malanoldehid/kg of sample. The fresh bran then stabilized by using pressure of heating method (autoclave). Time of process that is used are 5, 10, 15 minutes and dried during 4 hours. Stabilized bran with heating process at 5 minutes was decided as material for predicting of storage time with characteristic of water level 4.94 % and TBA value 0.11 mg malanoldehid/kg of sample. The low of water level can inhibit destruction of the bran and the low of TBA value showed the little action of destruction of the bran. During the storage, the water level and the brightness of the bran has been decreased, mean while TBA value has increased as same as the storage time. The bran is packed by using metallized material and be storaged in the incubator at 35oC, 45oC, and 50oC during 8 weeks. The critical point of this analysis is based on the TBA value. TBA value is opted as the critical point because of can be used as indicator of the succeed factor of stabilization, that showed rancidity indicator. Critical point of TBA value is based on odor test, the value is 0,36 malanoldehid/kg of sample. The Arrhenius equation for the storage is k = 25,1033 e-2092/T. The storage time of the bran at temperature storage 15°C is 9 weeks, 25°C is 7 weeks, and 30°C is 6 weeks 2 days.
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Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf