Judul: Kandungan 2-Asetil-1-Pirolina dan Heksanal pada Beberapa Varietas Beras (Oryza Sativa L.) Aromatik Selama Penyimpanan dengan Beragam Derajat Sosoh dan Jenis Pengemas
Abstrak: Scented rice or aromatic rice varieties is popular because of their flavor and texture. 2-Acetyl-1-pyrroline (2AP) contribute to pandan-leaves-like aroma, and hexanal is used as indicator of rancidity. Three aromatic cultivars (Mentik Wangi, Pandan Wangi, and Sintanur) with 100, 90, and 0% (brown rice) milling degree were stored in two types of packaging, i.e., plastic bag and hermetic bag for 4 months in room temperature. 2-Acetyl- 1-pyrroline and hexanal were determinded every 2 month during storage using gas chromatography mass spectrophotometer. Prescribed nutrient content with proximate analysis including moisture, ash, fat, protein, and amylose content, were done at the begining and at the end of storage time. Preference of rices was done by hedonic test. 2- Acetyl-1-pyrroline concentration decreasing during storage and as increasing with the milling degree. Brown rice have a highest hexanal than 90% and 100% of milling degree. Hexanal increased during 2 month storage, and decreased in 4 month storage. During storage, moisture, ash content, protein, and fat were still in standard range according to several references. Based on the amylose content, the texture all of rice before storage was sticky category and after four months of storage fell into smooth until hard texture. however ash and fat content were increasing. From preference test, Mentik Wangi 100% milling degree before storage is the most prefered rice than others. Both of hermetic bag and plastic bag gives no different influence in this case.
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Judul: Identifikasi Character Impact Compounds Flavor Beras Aromatik (Oryza myristica L.) Asli Indonesia
Abstrak: Consumers prefer aromatic rice because of its pleasant aroma when it is eaten. Study on the aroma components of Indonesian aromatic rice is still limited. The objective of this study was to evaluate the composition of aroma components in aromatic rice (varieties of Pandan Wangi Garut, Pandan Wangi Cianjur, and Rojolele) and non-aromatic rice (IR-64) and to identify the character impact compounds of aromatic rice in the variety Pandan Wangi Garut by Aroma Extract Dilution Analysis (AEDA) method. The aroma components of non aromatic rice (IR-64) were also analyzed to compare the composition results. The aroma component of aromatic and non aromatic rice were extracted using Simultaneously Distillation Extraction (SDE) Likens Nickerson method and were analyzed by Gas Chromatography-Mass Spectrometry (GC-MS) and Gas Chromatography-Olfactometry (GC-O). The number of aroma components identified in aromatic rice was vary between 17 to 48 compounds, whereas non aromatic rices had 17 compounds. Their chemical classes are aldehides, alcohols, heterocyclic compounds, esters, hydrocarbons, ketones and carboxylic acids. The difference between aromatic and non aromatic rice was the occurence of 2-acetyl-1-pyrroline and the concentration of hexanal, 1-pentanol, acetophenone, 1-octen-3-ol, (E,E)-2,4-decadienal and 2-penthylfuran. Their similarity was the concentration of ethyl acetate. The character impact compounds of aromatic rice Pandan Wangi Garut were 2-acetyl-1-pyrroline, which has sweet, pleasant, pandan aroma, and ethyl acetate which has a caramel and fruity aroma.
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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