Judul: Study of Antioxidant Potential of Red Rice and Their Utilization in “Beras Kencur” Drink
Abstrak: The objective of this research is to evaluate potential antioxidant of indigenous red rice and its application as ingredient of “beras kencur” drink. Eleven local varieties of red rice obtained from various places in Indonesia have been elaborated for their antioxidant activities by using established in vitro systems, including 2,2’-diphenyl-1-picahydrazyl free radical-scavenging (DPPH) and ferric reducing antioxidant power (FRAP). Their total phenolic and flavonoid contents were determined by colorimetric assay. The methanolic red rice extract showed various DPPH free radical scavenging activities ranging between IC50 108.9 to 320 μg/ml and the FRAP ranging between 477.9 to 1371.1 μmol Fe(II)/g. Total phenolic and flavonoid contents were in range of 27.6 – 82.1 TEA/g and 119.8 – 215.6 QE/g. Red rice from Jatiluwih exhibited the best quality among 11 samples being analyzed in term of total phenolic and flavonoid content as well as its antioxidant activity. Therefore, it was selected for further research as the main ingredient in “beras kencur” drink formulation. Formulation of “beras merah kencur” drink has been optimized by using mixture design experiment software. The optimization results indicated that the composition of 60% red rice, 20% galingale and 20% ginger had the higest desirability value. The comparative test on the “beras merah kencur“ drink, obtained from optimal formula drink (BMKOFD), with three commercial “beras kencur” drinks showed that the BMKOFD showed higher antioxidant activity (significanly different at =0.05). Morover, BMKOFD also had higher consumer acceptences in sensory aspect, e.g colour, aroma, taste and after taste (5.5, 7.4, 4.5 and 4.4 at 1-7 scale). In conclusion, the use of red rice could increase antioxidant activity of “beras kencur’ drink without lowering consumer acceptences
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Judul: Development of Potentially Functional Drink from Skimmed Milk Enriched with Red or Black Variety Rice Bran
Abstrak: Rice bran is a good source of antioxidants such as polyphenol compounds that are potentially formulated in skimmed milk drink. The objectives of this research were to develop potentially functional drink from skimmed milk enriched with red or black variety rice bran and to evaluate their physical, chemical and sensory qualities. The milk drinks were formulated with skimmed milk (95%) and sucrose (5%) as fixed formula. Considering the result of preliminary research, the addition of red or black variety rice bran at amount of 4, 6, 8% (w/w) and carboxy methyl cellulose (CMC) at amount of 0, 0.05, 0.1% (w/w) were based on fixed formula and water addition in ratio 4:1 (w/w) of water weight and total weight of skimmed milk powder, sucrose, rice bran, and CMC. The milk drink formula was selected based on total phenolic content (TPC), total anthocyanin content (TAC) and its antioxidant activities using DPPH and FRAP assay. Two selected formulas were characterized in terms of physical properties (viscosity and colour), chemical properties (pH, total soluble solid, and proximate), and sensory evaluation by rating hedonic. Red and black variety rice bran had high TPC with amount 512.19±43.91 and 1247.56±196.34 mg GAE/100 g, TAC with amount 1.94±0.19 and 40.69±4.21 mg C-3-G/100 g, respectively. Red and black variety rice bran also showed antioxidant activity based on DPPH assay (106.68±13.49 and 209.93±19.75 mmol Trolox/100 g, respectively) and FRAP assay (8.04±0.39 and 14.66±0.56 mmol FeSO4/100 g, respectively). The milk drink enriched with red variety rice bran, the highest content of TPC (33.83±1.00 mg GAE/100 mL), TAC (1.86±0.32 mg C-3-G/L), and antioxidant activities of DPPH (83.38±1.37 mmol Trolox/100 mL) and FRAP (0.43±0.01 mmol FeSO4/100 mL) by addition of 8% red variety rice bran and 0.05% CMC. The milk drink enriched with 8% black variety rice bran and 0.1% CMC showed the highest values in TPC (39.61±0.11 mg GAE/100 mL), DPPH (196.22±3.77 mmol Trolox/100 mL), FRAP (0.63±0.07 mmol FeSO4/ 100 mL) and TAC (5.53±0.03 mg C-3-G/L). Furthermore, the proximate analysis showed that the selected drinks had low fat content and high fiber content. Both milk drinks also were moderately liked on overall liking attribute. Based on its TPC, TAC and antioxidant activities, these milk drinks enriched with black and red variety rice bran are potentially developed as functional drinks.
Keyword: antioxidant activity, black and red variety rice bran, functional milk drink, skimmed milk

Judul: Estimating Parameter and the Convergence of Parameter Estimator of Poisson Hidden Markov Model
Abstrak: Model hidden Markov terdiri dari sepasang proses stokastik yaitu proses observasi dan proses yang memengaruhi observasi. Proses stokastik yang memengaruhi observasi ini diasumsikan membentuk rantai Markov dan tidak diamati. Model Poisson hidden Markov (MPHM) adalah salah satu model hidden Markov diskret dan proses observasinya jika diketahui proses yang memengaruhinya diasumsikan menyebar Poisson., A hidden Markov model (HMM) consists of a pair of stochastic processes, that is the observation process and process that affected observation. The stochastic process which causes this observation is assumed to form a Markov chain and is not observed. Poisson hidden Markov models (PHMM) is one of the discrete HMM and the observation process given the cause is assumed having a Poisson distribution.
Keyword: Poisson hidden Markov model, Forward-Backward algorithm, Expectation Maximization algorithm