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 Melalui Metode Pengukusan Dan Pengeringan Rak Serta Pendugaan Umur Simpannya
Abstrak: Bran is side product from rice milling. According to BPS (2008), bran production reach at 4,8 million tons. Bran can be processed to be various product, one of them is bran powder. Bran powder can be used as brade substitution agent, cookies, and dietary drink. The decreasing of quality of bran can occure through hydroliytic and oxidation processes. The problem can be solved trough bran stabilization. It can be processed by steaming of the material in certain time. The purposes of this research are to get condition of stabilization and bran drying, bran characterization and stabilized bran, also to predict the packaging time. Constant condition of drying of the fresh bran reached in 4 hours with the drying rate about 1 x 10-4 g/second untill the water level at 5 %. Steaming of the bran was carried out in 3 level of time; 5, 10, and 15 minutes. The next step was characterizing the bran and stabilized bran. The characterization of fresh bran include water level 6,86 %, fat 16,84 % (db), ash 7,43 % (db), protein 13,72 % (db), crude fiber 7,25 % (db), carbohydrate by different 47,9 % (db), and TBA 0,68 mg malonaldehid/kg sample, solubility 11,95 %, swelling power 5,96 %, cyneresis 95,50 %, total colony number 1,65 x 106, and was not found E. Coli colony. Based on tested parameter water level, fat, and TBA were choosen bran with steaming at 5 minutes. The stabilized bran characterization include water level 5,61 %, fat 14,23 % (db), and TBA 0,23 mg malonaldehid/kg sample. The bran that was stabilized at 5 minutes was used as the material to predict the storage and shelf life. The product packed in metalizzed and was storaged at tempeature 35, 45, and 50oC during 8 weeks. The quality parameter that was used in were water level, TBA, and brightness level. During the storage, it occured decreasing of water level and brightness level, also the increasing of TBA value. The critical value of the quality parameter that was used in packaging time of stabilized bran was TBA. Based on organoleptic test at the 4th week at storage 50oC, the critical point was 0,51 mg malonaldehid/kg sample. Arrhenius equation of stabilized bran during the packaging was k = 0,074 e -176 (1/T). Packaging time of stabilized bran at 30oC was predicted in 39 days, at temperature 25oC was in 40 days, and at temprature at 15oC was in 50 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