Judul: Hidrolisis Pati Umbi Tacca Menggunakan Ekstrak Kasar α-Amilase dari Brevibacterium sp. untuk Menghasilkan Oligosakarida
Abstrak: Oligosaccharides have an important function in various sectors such as healthcare, industrial, food and feed, including as functional food ingredients (prebiotics). Oligosaccharides were produced from Tacca tubers (Tacca leontopetaloides) which containing 66.65 % of starch. Tacca tubers were used from Hutan Jati, and enzymes were used α-amylase from Brevibacterium sp. which has enzyme activity of 1.78 U mL-1 . The purposes of this research are to determine the optimum conditions Tacca tuber starch hydrolysis reaction and determine the type of oligosaccharides using Thin Layer Chromatography (TLC) and High Performance Liquid Chromatography (HPLC). Optimal production was achieved at 3 % substrate concentration, enzyme and substrate ratio of 1:5 and hydrolysis time of 6-8 hours. Oligosaccharides profile analysis both using TLC and HPLC showed that the enzimatically hydrolyzed samples contained maltose, maltotriose and maltotetraose.
Keyword: High Performance Liquid Chromatography (HPLC), Thin Layer Chromatography (TLC), maltooligossacharides, Brevibacterium sp., Tacca tubers

Judul: Analisis oligosakarida hasil hidrolisis pati kentang hitam (Culeus tuberosus) oleh Enzim amilase dari Brevibacterium sp.
Abstrak: Oligosaccharide is an important group of carbohydrate macromolecul composed of 2 to 20 saccharide units. Oligosaccharide has many benefits in the field of food and health. Starch is one of the source origin material for oligosaccharide production by enzimatic process. Black potatoes contain high carbohydrates especially starch of about 83%. To obtain oligosaccharide from black potato starch can be hidrolyzed using amylase enzymes which are produced by Brevibacterium sp. Crude extracts amylase enzyme production from Brevibacterium sp. producing enzyme activity of 3.25 U/mL. Black potato starch hydrolysis results a value of reducing sugar of 7482.500 ppm, after freeze drying a value of reducing sugar was 9647.500 ppm, and after concentrated by vacuum evaporator the value of reducing sugar was 14908.300 ppm. The results of HPLC analysis of black potato starch hydrolysis showed that there are oligosaccharide compound such as maltose, maltotriose, and maltopentose. The samples were given preferential treatment freeze dry and evaporation produce reducing sugar value and concentration of the oligosaccharide better than the fresh samples without treatment. The identification result of oligosaccharide obtained by HPLC shows that freeze drying and evaporating samples has a higher concentration and better peak and sharp.
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Judul: Approximation of the Median of Poisson Distribution Using the Relation of Poisson-Gamma Distribution
Abstrak: A major drawback of median is that median cannot usually be defined in closed form, even in the cases where their distribution functions are known. This study gives an approximation of the closed form for the median of the Poisson distribution by using the relation of Poisson-Gamma distribution. The approximation uses elementary techniques based on the monotonicity of certain sequences involving tail probabilities of the Poisson distribution and the Central Limit Theorem. Furthermore, a closed form expression for the mean absolute deviation 􀜧|􀜰􀰒 􀵆 􀜯􀝁􀝀􁈺􀜰􀰒􁈻| is also studied. The median is relevant because of the fact that it minimizes the mean absolute deviation of a Poisson random variable (􀜰􀰒􁈻 by considering median as central tendency.
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