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Currently, 80% of conventional energy is used to fulfill general public's needs andindustries. The depletion of oil and gas reserves and rapid growth in conventional energyconsumption have continuously forced us to discover renewable energy sources, like solar, wind,biomass, and hydropower, to support economic development in the future. Solar energy travels at aspeed of 186,000 miles per second. Only a small part of the radiant energy that the sun emits intospace ever reaches the Earth, but that is more than enough to supply all our energy demand.Indonesia is a tropical country and located in the equator line, so it has an abundant potential ofsolar energy. Most of Indonesian area get enough intensity of solar radiation with the average dailyradiation around 4 kWh/m2. Basically, the solar systems use solar collectors and concentrators forcollecting, storing, and using solar radiation to be applied for the benefit of domestics, commercials,and industrials. Common applications for solar thermal energy used in industry are the SWHs, solardryers, space heating, cooling systems and water desalination.

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Beras analog merupakan beras tiruan yang terbuat dari bahan-bahan seperti umbi-umbian dan serealia. Ubi ungu (Ipomea batatas) adalah salah satu potensi lokal pangan yang layak dikembangkan sebagai bahan baku beras analog. Penelitian ini bertujuan untuk mengkaji pengaruh perbandingan komposisi tepung pati ubi ungu terhadap nilai gizi, sifat fisikokimia, sifat hedonik beras analog dibandingkan dengan beras padi, serta menentukan komposisi bahan baku terbaik dari beras analog ubi ungu. Penelitian ini terdiri dari 3 tahapan utama, yaitu tahap pembuatan tepung dan pati ubi ungu, tahap fortifikasi yang dilakukan bersamaan dengan proses pembuatan beras analog, serta tahap analisis hasil. Penelitian ini menggunakan variasi komposisi tepung dan pati ubi ungu sebesar 100:0 (A); 90:10 (B); 80:20 (C); 70:30 (D); 60:40 (E) dengan basis 100 gram. Beras Delangu digunakan sebagai variabel kontrol dalam penelitian ini. Hasil penelitian menunjukkan bahwa semakin tinggi komposisi pati dalam beras analog ubi ungu, maka kandungan amilosa meningkat, tekstur beras semakin keras dan tidak mudah rapuh, daya rehidrasi tinggi, dan densitas kamba rendah. Beras analog dengan komposisi 80% tepung dan 20% pati (kode C) merupakan produk yang paling disukai oleh panelis. Produk ini memiliki rasa, tekstur, dan kenampakan yang menyerupai beras pada umumnya. Beras analog kode C kaya akan kandungan protein 6,7337%, kadar amilosa 15,56%, nilai densitas kamba 0,638 g/ml dan daya rehidrasi sebesar 1,5 ml/g. Nilai gizi, sifat fisikokimia dan sifat hedonik beras analog memiliki karakteristik yang menyerupai beras Delangu. Berdasarkan beberapa parameter, beras analog memiliki keunggulan dibandingkan beras Delangu. Kata kunci: beras analog, ubi ungu, tepung ubi ungu, pati ubi ungu, sifat fisikokimia

A proper understanding of the properties of iron could increase the effectiveness of programmes for alleviating iron deficiency. Recently, encapsulation has been considered an appropriate method for protecting iron from injurious reactions. However, several events may occur during encapsulation processes, including changes in the iron’s oxidation state. Oxidation of ferrous iron is not desirable since the intestines can only absorb iron in the ferrous form. In this study, a cyclic voltammetry method was applied to investigate the likelihood of ferrous gluconate oxidation for the preparation of chitosan-tripolyphosphate microparticles. Then, the electrochemical properties of ferrous gluconate were confirmed experimentally. The oxidation rate of ferrous gluconate is also discussed in this paper. All the experimental solutions were formulated in detail to produce conditions similar to those of microparticle production. Cyclic voltammetry analysis was conducted using a configuration of three electrodes connected to an electrochemical analyser. Graphite, platinum wire, and Ag/AgCl were employed as the auxiliary, working, and reference electrodes, respectively. The cyclic voltammetry results show that the observed potential for each anodic peak shifted negatively in the presence of chitosan and sodium tripolyphosphate. Moreover, the rate of ferrous oxidation tended to increase during 75 min of experiments due to the presence of chitosan and sodium tripolyphosphate. These behaviours indicate the transformation of ferrous iron to ferric iron during iron microparticle preparation. Furthermore, these findings suggest that spray drying is a preferable method to minimise the oxidation reaction.