Judul: Production of Dried Lactobacillus plantarum NHC6 Starter by Using Rice Bran Matrix
Abstrak: Starter Bakteri Asam Laktat (BAL) merupakan kultur BAL instan yang telah dipreparasi untuk menginisiasi produksi asam laktat dalam proses fermentasi. Pembuatan starter BAL membutuhkan media alternatif sebagai pengganti media MRS yang memakan banyak biaya bila digunakan untuk produksi skala industri. Starter kering memiliki keunggulan dibandingkan dengan starter cair. Untuk melindungi sel, diperlukan matriks enkapsulan yang berfungsi memberi pelindung bagi sel bakteri terhadap proses pengeringan yang dapat merusak sel. Diperlukan media yang baik dan mampu menjadi matriks enkapsulasi dalam pembuatan starter BAL kering. Bekatul dalam bentuk fraksi larut air panas terbukti mampu menjadi media pertumbuhan dan matriks enkapsulasi bagi Lactobacillus plantarum NHC6 dengan konsentrasi 10% menggunakan metode spray drying. Starter kering yang dihasilkan mengandung populasi Lactobacillus plantarum NHC6 sebanyak 1 x 107 CFU/g dan mampu mempertahankan viabilitas yang lebih baik pada penyimpanan suhu 4°C selama 28 hari masa penyimpanan. Berdasarkan keunggulan dan kemampuan mempertahankan viabilitasnya, starter Lactobacillus plantarum NHC6 kering dengan matriks bekatul berpotensi menjadi produk pangan probiotik nonsusu.
Keyword: LAB, rice bran, dried starter, encapsulation, probiotic

Judul: Seleksi Bakteri Asam Laktat dan Pemanfaatannya sebagai Starter Kering Menggunakan Matriks Tapioka Asam
Abstrak: Starter is a microbial preparation that will be added to the raw materials in production of fermented food products. It is used to accelerate the fermentation process and reduce the risk of failure during the fermentation. Although starter cultures could be in the liquid or dry forms, the dried culture is more advantageous due to its long stability without regenerated. The most widely used bacteria for starter cultures production is lactic acid bacteria (LAB). LAB as a starter should be safe for other natural microorganisms in human body and has a high fermentation productivity. Therefore, the strains selection of LAB which would be used as a starter is important to do. The important criterias for LAB selection are the ability of producing lactic acid and antibiotic sensitivity. LAB should also have a high cell viability after the drying process and during storage, meaning that drying techniques and proper matrix are also pivotal factors to produce a desirable starter cultures. Sour cassava starch is a modified starch which is produced from fermented tapioca. This material has promising properties for LAB encapsulation matrix because it is prepared using LAB-induced fermentation, and does not contain food chemical additives as well as contain fermented monosaccharides which can act as a protective agent (protectant) during drying and storage. Raw materials of sour cassava starch are widely available, economical and renewable. The aims this study were to produce LAB dried starter using sour cassava starch matrix and to study its viability after storage. Eleven local LAB isolates obtained from spontaneous fermentation of carbohydrate commodity were selected based on their acid production ability and antibiotic sensitivity. The initial selection of the acid production ability was conducted by measuring the total acid and pH level of culture media. The isolate sensitivity to antibiotics tetracycline, erythromycin and chloramphenicol were tested by disc diffusion method. The isolate that produce high level of acid and is vulnerable to antiobiotics was selected and subsequently evaluated its lactic acid production using high performance liquid chromatography (HPLC). The isolate that have a higher production of lactic acid was choosen for this study. Furthermore, its morphological character and growth curve were observed. Morphological characters have been observed using a light microscope including Gram staining and cell shape observation. Growth curve was observed by calculation of cell numbers (log CFU/mL) while the optical density (OD) using a spectrophotometer at a wavelength (λ) 620 nm. Cell numbers was calculated using total plate count (TPC) on de Man Rogosa Sharpe agar (MRSA) medium were incubated at 37°C for 48 hours. Observation was conducted every hour until the cells reached a maximum specific growth rate (μm,h-1). Dried starter of selected isolate was produced using freeze dryer (-50oC) and spray dryer (inlet 170°C, outlet 70°C). The matrix used was sour cassava starch and sour cassava starch enriched with 10 % skim milk were used as the positive control. Starter has been stored in an airtight aluminum foil for water content analysis (%), cell viability (log CFU/g) and survival rate (%) after drying. Storage stability of the best starter was evaluated in four
Keyword: dried starter, lactic acid bacteria, sour cassava starch, freeze drying, spray drying

Judul: Sudoku Tereduksi dan Grup Simetri Sudoku
Abstrak: Sudoku is a logic game in form of square games consisting rows, columns and mini grids. In this game, the square is filled by numbers from 1 to . At this game, the player plays the game precisely because each cell in a row or column should have a unique number. The mini grid should have no repeated numbers. This research proves that to determine the number of the isomorphic Sudoku solutions from given Sudoku solutions can be calculated using reduced Sudoku. Sudoku symmetry group is a collection of Sudoku solutions that is experienced symmetry group operations. Symmetry group operation is an operation permutation consisting permutation values, stack permutations, permutations band, column permutations on the stack, or row permutations of the band. The isomorphic Sudoku solutions from reduced Sudoku can be obtained from symmetry group operation imposed on Sudoku reduced. The total possible Sudoku solutions calculated from the number of given reduced Sudoku.
Keyword: sudoku symmetry group, reduced sudoku, isomorphic