Judul: Review on Purification Method of Glucomannan from Porang Corm (Amorphophallus muelleri Blume) and Its Potential Application in Food Products
Abstrak: Umbi porang (Amarphophallus muelleri Blume syn Amarphophallus oncophyllus Prain) merupakan salah satu umbi lokal yang mempunyai nilai ekonomi tinggi karena mengandung glukomanan sehingga berpotensi untuk dikembangkan di Indonesia. Kandungan glukomanan yang tinggi (20 – 60%) dalam umbi porang membuat glukomanan dalam umbi porang dapat diekstrak dan diaplikasikan pada produk pangan, baik sebagai bahan tambahan pangan maupun pangan dengan manfaat untuk kesehatan. Telaah ini bertujuan memberikan gambaran mengenai beberapa metode purifikasi glukomanan dari umbi porang dan potensi aplikasi pada produk pangan. Metode telaah meliputi pendeskripsian topik, penelusuran pustaka, seleksi pustaka, serta analisis dan interpretasi pustaka. Hasil telaah menunjukkan metode purifikasi glukomanan dari umbi porang dapat dilakukan dengan metode mekanis, kimiawi, serta dengan bantuan enzim, asam, dan ultrasonik. Perbedaan metode dan kondisi purifikasi menghasilkan karakteristik fisikokimia glukomanan yang berbeda. Metode purifikasi tersebut menghasilkan glukomanan dengan kadar kemurnian yang memenuhi standar, yaitu 60 – 92,69%. Metode purifikasi yang menghasilkan glukomanan dengan karakteristik fisikokimia paling baik adalah metode mekanis menggunakan stamp mill, kombinasi ball mill dan maserasi etanol, ultrasound-assisted extraction, serta maserasi etanol konsentrasi bertingkat. Beberapa penelitian telah membuktikan bahwa glukomanan dari umbi porang berpotensi diaplikasikan pada produk pangan, baik sebagai bahan tambahan pangan maupun sebagai pangan dengan manfaat untuk kesehatan., Porang tuber (Amarphophallus muelleri Blume syn Amarphophallus oncophyllus Prain) is one of the local corms that has high economic value because it contains glucomannan so it has the potential to be developed in Indonesia. The content of glucomannan in porang corm is high (20 – 60%) so that it can be extracted and applied in the food products, both as a food additive and as a food with health benefit. This literature review aimed to provide an overview of several methods on purifying glucomannan from porang corms and their potential applications in food products. The method of review included topic descriptions, literature searches, literature selection, and literature analysis and interpretation. The results of review showed that the method of purifying glucomannan from porang corms could be carried out by mechanical and chemical methods, as well as method which involve the enzymes, acid, and ultrasonics. The different purification methods and conditions resulted in different physicochemical characteristics of glucomannan. The purification methods in this review produced glucomannan with a purity level that meets the standards, i.e: 60 – 92.69%. The purification method producing glucomannan with the best physicochemical characteristics was a mechanical method using a stamp mill, combination of ball mill and ethanol maceration, ultrasound-assisted extraction and multilevel ethanol maceration. Several studies had proven that glucomannan from porang corms had the potential to be applied to food products, both as a food additive and as food with health benefit.
Keyword: glukomanan, glukomanan porang, umbi porang, purifikasi, glucomannan, porang glucomannan, porang corms, purification

Judul: Kajian Proses Pemurnian Tepung Glukomanan dari Umbi Iles- Iles Kuning (Amorphophallus Oncophyllus) dengan Menggunakan Enzim α-Amilase
Abstrak: Elephant foot yam (Amorphophallus oncophyllus) as tuber crops which grows wildly at subtropical and tropical forest in Indonesia, apparently is one of the potential exports commodity. The export of this yam tubers to Japan is usually in the form of chips or flour, which then processed to be a kind of traditional food, “shirataki” noodle and “konyakku” tofu. Elephant foot yam tubers can be purified into a glucomannan flour that has special characteristics. The special characteristics of glucomannan flour among other hydrocolloid is its capability to form thick solution in water, swell by a high swelling power, form gel, form thin film in sodium hydroxide solution or form impermeable thin layer with glycerin. It also has a melting characteristics like agar-agar, so it can be used for microbial growth media. In industry, glucomannan is used as raw material of paper, textile and glue, celluloid material, blasting material, foodstuff, cosmetics and cleaner. The conventional method for preparation of glucomannan flour is by mechanical, like sieving, blowing, and polishing. High purified glucomannan flour is produced by separating starch from yam flour. This study has done in other approach that the utilization of α-amylase as starch digesting enzyme will release the starch from cell glucomannan so it resulted to the high purified glucomanna. This research will examine the effects of t temperature (65 oC, 80 oC, and 95 oC) and enzyme dose (1 Unit/g flour, 2 Unit/ g flour dan 3 Unit/ g flour) to the characteristics of glucomannan flours. The result from preliminary research showed that carbohydrate is the main components in fresh tuber and flour. The α-amylase shows the highest activity in pH 5 and has activity on 1.764,71 U/ml, 3.363,29 U/ml and 13.545,75 U/ml for temperature 65 oC, 80 oC, and 95 oC, respectively Starch content in glucomannan flour after α–amylolysis declined from 10.63 % to 4.76 - 0.40 %, while glucomannan content increased from 28.75 % to 42.35 - 80.53 %. The value of whiteness degree changed from 21.26 % of glucomannan flour before hydrolysis into 19.48 % until 28.37 %. The viscosity of glucomannan declined from 16,833.33 cPs to 1500 - 3925 cPs. The water absorption capability of glucomannan flour changed from 1464.75 % to 1288.78 – 1696.29 %. Bulk density of glucomannan flour before hydrolysis is 741.65 kg/m3 then changed to 641.48 - 776.01 kg/m3 after hydrolysis. Value of pH flour glucomannan before and after hydrolysis had changed from pH 6.58 to around pH 4.90 - 5.21. Hydrolysis temperature, enzyme dose treatment and interaction both of them obviously influenced to the starch content, glucomannan content, and whiteness degree of flour, while the yield and viscosity are only influenced by temperature (p<0,05). Glucomannan flour after hydrolysis and extracted by using ethanol 95 % gives high glucomannan content but has lower value of viscosity. The best treatment for preparing the glucomannan flour by α–amylolysis can be obtained from 65 oC of hydrolysis temperature, 3 U/g flour of enzyme dose for 30 minutes
Keyword: 

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