Judul: Pengembangan Minuman Fungsional Berbasis Daun Pegagan (Centella asiatica) dengan Aktivitas Anti-Hiperurisemia : Optimasi Proses Ekstraksi Bahan Baku Minuman Fungsional
Abstrak: The aim of this research is to optimize the extraction process of the ingredients pegagan functional beverage.The plant extract of Centella asiatica (pegagan), Orthosiphon aristatus (kumis kucing), Zingiber oficinale (ginger) and Cinnamomum sp. (cinnamon)are dried using spray dryer. Response surface methodology (RSM) is used for the experimental design and optimization with Design Expert 7 software.The optimization results of the four samples are as follow: pegagan is using A oC temperature of extraction in B hours extraction process inside the waterbathshaker, C% amounts of maltodextrin and DoC inlet temperature on spray dryer; cinnamon needs E minutes extraction time on boiling water (approx. 95oC), F% amounts of maltodextrin and GoC inlet temperature on spray dryer; kumis kucing and ginger are best mixed with the lowest amounts of maltodextrin, which is H% and the inlet temperature for spray dryer is IoC. The response results show the antioxidant activity for pegagan is 36867 ppm AEAC, the phenolic compound is 10028 ppm GAE; kumis kucing has antioxidant activity 81450 ppm AEAC andphenolic compounds 22272 ppm GAE; cinnamon hasantioxidant activity 65200 ppm AEAC and the phenolic compound is 22941 ppm GAE; and ginger has 42572 ppm AEAC antioxidant activity and phenolic compounds 9808 ppm GAE. The xanthine oxidase enzyme inhibition for optimized samples are: pegagan 30%, kumis kucing 60%, cinnamon 45%, and ginger 26%.
Keyword: Optimization, Xanthine oxidase, Response surface methodology, Anti-hyperuricemia, Centella asiatica, Functional beverage

Judul: Formulasi Minuman Fungsional Instan Berbasis Pegagan (Centella asiatica) dengan Potensi sebagai Antihiperurisemia
Abstrak: Hyperuricemia is one of metabolic diseases characterized by high level of uric acid in blood. The objective this research was formulating of functional drink which is potential as antihyperuricemia based on gotu kola (Centella asiatica) with java tea (Orthosiphon arustatus), ginger (Zingiber officinale), and cinnamon (Cinnamomum burmanii) as adjunct ingredients. Formulas were made based on maximum and minimum acceptance level by Focus Group Discussion (FGD). F2 and F3 were preferred flavor (neutral to slightly like), and they had 63.63 % and 81.82 % ability of xanthine oxidase inhibition on a dilution factor five times. The optimum formula, which formulated by Mixture Experiment method with Historical Data design, using Design Expert 7.0 software, was the mixture of a % of gotu kola, b % of java tea, c % of ginger, and d % of cinnamon, had 2 240.68 ppm GAE of total phenol, 39 611.7 ppm AEAC of antioxidant, with 100% desirability. Inhibitory activity for optimum formula was calculated by extrapolation method from total phenol comparison, resulted 100 % of xanthine oxidase inhibition activity. This proves that instant drink based on gotu kola has the potential to be developed into an antihyperuricemia functional drink
Keyword: xanthine oxidase, Centella asiatica, gotu kola, hyperuricemia, functional beverage

Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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