Judul: Produksi Oligosakarida dari Umbi Kentang Hitam melalui Hidrolisis Ekstrak Kasar α-Amilase asal Brevibacterium sp.
Abstrak: Oligosaccharides is a carbohydrate macromolecule composed of 2-10 monosaccharide residues that have benefits in the field of food and health. One way to produce oligosaccharides with enzymatic hydrolisis of starch. Black potatoes have high carbohydrate content, especially starch by 83%. Activity of amylase enzyme from raw extraction have 1.708 U/ml. Degree of polymerization of black potatoe’s starch is 10. Hydrolysis reaction of black potatoe’s starch with that enzyme gave 3 spots on TLC analysis with mobile phase n-buthanol:acetic acid:water purified (2:1:1). In HPLC analysis showed 3 main peaks that means consist of 3 compound with mobile phase acetonitrile:water (75:25). Fresh sample consist of glucose as many as 1,60% (b/v), maltose 0,36% (b/v), and maltotriose 0,46% (b/v). Freeze dried sample consist of glucose as many as 4,20% (b/v), maltose 0,21% (b/v), and maltotriose 0,30 % (b/v).
Keyword: Brevibacterium sp., α-amylase enzyme, HPLC, oligosaccharides, black potatoes

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: Desain Sistem Transfer Energi Nirkabel Berbasiskan Tesla Coil
Abstrak: Tesla coil merupakan alat yang ditemukan oleh Nikola Tesla yang dapat mentransmisikan daya tanpa kabel dengan memanfaatkan prinsip induksi elektromagnetik. Pada penelitian ini dibuat sebuah prototype Tesla Coil dengan menggunakan transistor C1970 dan receiver menggunakan rangkaian LC. Identifikasi alat meliputi pengaruh daya input transmitter terhadap receiver, bentuk signal yang dipancarkan transmitter, pengaruh jarak transmitter dan receiver, nilai efisiensi serta efek alat terhadap perangkat lain. Hasil pengamatan menunjukkan bahwa semakin besar daya input maka semakin besar daya yang dipancarkan oleh transmitter. Bentuk sinyal yang dipancarkan oleh transmitter berupa gelombang listrik AC sinusoidal dengan frekuensi ~2.9 MHz. Semakin jauh jarak receiver terhadap transmitter maka semakin kecil amplitudo gelombang AC yang diterima oleh receiver, menyebabkan semakin kecil daya yang diterima oleh receiver. Adapun nilai efisiensi terbesar penangkapan daya oleh receiver yaitu sebesar 0.00516 % serta terdapat gangguan pada alat-alat tertentu seperti monitor komputer dan radio.
Keyword: rangkaian LC, receiver, tesla coil, transistor C1970, transmitter