Pengeringan Lidah Buaya (Aloe Vera) Menggunakan Oven Gelombang Mikro (Microwave Oven)

. Aloe vera (Aloe vera) is known as a useful plant, both as food, cosmetics or pharmaceuticals. Due its high water content, Aloe vera should be processed immediately after harvest. This paper will discuss the drying of aloe vera using microwave oven. The drying process of 50 gr Aloe vera gel and rind using 80 Watts microwave power completed in 140 minutes to reach the final moisture content of 7% wet basis. The drying process in microwave drying shows similar process to that of conventional drying. Dipolar rotation mechanism of water molecules at microwave drying does not affect the drying stage. It shows however shorter process time. The water removal of the drying material occurred in the early minutes until the 50th minute. This because of the high free water surface on the material, while from minute 50 to minute 140 slowed the drying process. Highest temperature of the material during the process is achieved at 57.6 oC in drying of gel and 70.7 oC in drying of Aloe vera rind. It is expected that there is no damage of nutritional content during drying in the this temperature range. Quality analysis of flour and tea of Aloe vera after drying by microwave showed that Aloe vera powder produced within the range of the standard, both visually and microbiologically, but indicated as low quality when viewed from acid content levels. Whether microwave heating mechanism affects the acidity, this needs further study

Aplikasi Microwave untuk Disinfestasi Tribolium Castaneum (Herbst.) Serta Pengaruhnya terhadap Warna dan Karakteristik Amilografi Terigu

Aplikasi microwave telah dipelajari untuk disinfestasi Tribolium castaneum (Herbst.) dan pengaruhnya terhadap karakteristik warna dan amilografi tepung terigu. Kerusakan karena serangan T. castaneum selama penyimpanan menyebabkan terjadinya Perubahan fisik dan kimiawi tepung. Kerusakan fisik berupa terjadinya Perubahan warna tepung, sedangkan kerusakan kimiawi karena adanya aktifitas enzim lipase dan benzokuinon yang berasal dari hasil sekresi T. castaneum. Penelitian dilakukan dengan menggunakan tepung yang tidak di fumigasi pada tahap milling. Kontaminasi pun dilakukan dengan memberikan biakan T. castaneum masing-masing 10 jantan dan 10 betina ke dalam 50 g dan 100 g sampel tepung. Hasil penelitian menunjukkan bahwa tingkat mortalitas pada sampel yang tidak diberi aplikasi microwave setelah penyimpanan 42 hari adalah 0 % baik untuk sampel 50 g dan 100 g. Kadar air meningkat, sedangkan tingkat kecerahan warna, puncak viskositas menurun. Sampel yang diberi perlakuan energi microwave 23,76 kJ, 24,00 kJ, 31,68 kJ dan 36,00 kJ menunjukkan mortalitas 100 % dari T. castaneum, sedangkan kecerahan warna, puncak viskositas, kadar air, menurun setelah penyimpanan 42 hari baik pada berat sampel 50 g dan 100 g

Pengaruh Kadar Air terhadap Beberapa Sifat Fisik Biji Lada Putih

Sifat fisik biji-bijian diperlukan dalam merancang suatu peralatan untuk penanganan, pemisahan, pengeringan, penyimpanan dan pengolahannya. Sifat fisik biji lada putih ditentukan sebagai fungsi kadar air pada rentang 15,40 - 64,80 % basis kering (b.k.). Tinggi, panjang dan lebar rata-rata pada kondisi kadar air 15,40 % (b.k.) adalah 4,11 ± 0,27 mm; 4,35 ± 0,34 mm dan 4,35 ± 0,35 mm berturut-turut. Pada rentang kadar air 15,40 - 64,80 % b.k., hasil penelitian ini menunjukkan peningkatan secara linear pada ketiga dimensi aksial, diameter rata-rata, kebulatan dari 0,969 hingga 0,977, volume dari 39,50 hingga 67,34 mm3, luas permukaan dari 55,87 hingga 79,92 mm2 dan massa seribu biji dari 52,47 hingga 75,63 g. Bulk density dan true density memiliki hubungan polinomial dengan Perubahan kadar air biji. Porositas menurun dari 45,01 % hingga 44,88 % dengan peningkatan kadar air pada rentang 15,40 - 64,80 % (b.k.)

Slow pyrolysis of Ulva lactuca (Chlorophyta) for sustainable production of bio-oil and biochar

Ulva Lactuca is a fast-growing algae that can be utilized as a bioenergy source. However, the direct utilization of U. lactuca for energy applications still remains challenging due to its high moisture and inorganics content. Therefore, thermochemical processing such as slow pyrolysis to produce valuable added products, namely bio-oil and biochar, is needed. This study aims to conduct a thorough investigation of bio-oil and biochar production from U. lactuca to provide valuable data for its further valorization. A slow pyrolysis of U. lactuca was conducted in a batch-type reactor at a temperature range of 400–600 °C and times of 10–50 min. The results showed that significant compounds obtained in U. lactuca’s bio-oil are carboxylic acids (22.63–35.28%), phenolics (9.73–31.89%), amines/amides (15.33–23.31%), and N-aromatic compounds (14.04–15.68%). The ultimate analysis revealed that biochar’s H/C and O/C atomic ratios were lower than feedstock, confirming that dehydration and decarboxylation reactions occurred throughout the pyrolysis. Additionally, biochar exhibited calorific values in the range of 19.94–21.61 MJ kg−1, which is potential to be used as a solid renewable fuel. The surface morphological analysis by scanning electron microscope (SEM) showed a larger surface area in U. lactuca’s biochar than in the algal feedstock. Overall, this finding provides insight on the valorization of U. lactuca for value-added chemicals, i.e., biofuels and biochar, which can be further utilized for other applications

Aplikasi Energi Gelombang Mikro untuk Pengendalian Hama Gudang Araecerus Fasciculatus (De Geer) pada Biji Kakao

Kualitas biji kakao Indonesia masih tergolong rendah akibat adanya interferensi serangga hama. Fumigasi merupakan upaya yang selama ini dilakukan untuk menekan interferensi serangga hama. Namun, kekhawatiran akan kesehatan dan polusi lingkungan telah menyebabkan cara tersebut kurang baik. Tujuan penelitian ini adalah menganalisis pengaruh pemanasan dengan oven gelombang mikro dengan berbagaitingkat daya dan waktu terhadap mortalitas hama gudang Araecerus fasciculatus pada biji kakao dan penurunan kadar airnya serta penggunaan energi oven gelombang mikro selama proses pemanasan. Daya masukan oven gelombang mikro yang digunakan adalah 264, 400, dan 600 watt, sedangkan waktu pemanasan adalah 60, 120, dan 180 detik dengan tiga kali ulangan. Mortalitas hama gudang Araecerus fasciculatus mengalami peningkatan dengan meningkatnya tingkat daya dan waktu pemanasan. Hama Araecerus fasciculatus mencapai mortalitas 100% pada tingkat daya 600 watt selama 180 detik dengan penggunaan energi sebesar 99.72 kJ. Persentase penurunan kadar air basis basah pada tingkat daya dan waktu tersebut sebesar 28.7%

Instrument Design and Measurement of Dielectric Properties Within Radio Frequency Range

Dielectric properties indicated the ability of a system to store, transmit anf reflect electromagnetic wave energy. Recently, the utilization of the properties in agriculture field tends tio increase. For example, dielectric drying of biological material is based on the product's ability to absorb electromagnetic radiation and convert inyo heat. In addition, lower energy application of the property can be utilitized for non-destructive measurement of water content.For a more broed application, measurement of the property anf the influencing factors is indispensable

The potential of sustainable biogas production from macroalgae in Indonesia

Indonesia is the second world's major macroalgae producer after China, contributing to 28% of the global macroalgae production. Indonesia increased its macroalgae farming output from less than 4 million tons in 2010 to over 9.9 million tons in 2019. It is expected to continue rising to 13 million tons by 2024. The contribution of macroalgal products is quite significant, 60.7% of the total national aquaculture production. To achieve sustainable energy development goals in many developing countries, including Indonesia, biomass to energy technology such as the production of biogas form macroalgae has been considered one of the best options. Therefore, we aim to investigate the potential application of biomass to energy technology via the production of biogas from macroalgae as an alternative source of local power generation. Indonesia's energy mix and several issues regarding macroalgae production are comprehensively reviewed. Additionally, we also discussed the process of macroalgal biogas production

Green algae to green fuels: Syngas and hydrochar production from Ulva lactuca via sub-critical water gasification

Biomass-derived energy is gaining more attention due to environmental issues and increasing energy demand. To ensure the sustainability of fossil energy substitution using biomass, diversification of sources, including marine organisms, is vital. Among various types of marine biomass discussed in the literature, the utilization of green algae Ulva lactuca for energy generation is still rare globally. Therefore, this study aims to investigate the potential of green fuel (syngas and hydrochar) production from U. lactuca (Chlorophyta) via sub-critical water gasification (SbWG). The experiments were conducted using a batch reactor at varying temperatures (300, 350, and 400 °C), reaction times (30, 60, and 90 min), and feedstock concentrations (1 and 5 wt%). The effect of temperature on gas composition was examined in detail. The results revealed that increasing temperature from 300 to 400 °C leads to an increase in the H2 content significantly from 2.21 % to 8.09 % within 90 min. However, increasing feedstock concentration from 1 to 5 wt% reduces the H2 fraction due to suppression of the steam reforming and water-gas shift reactions. Based on the ultimate analysis, the high severity of operating conditions leads to lower O/C and H/C atomic ratios owing to dehydration and decarboxylation reactions. It was confirmed by scanning electron microscope (SEM) analysis that more void structures existed in hydrochar than the algal feedstock. The SbWG process at varying temperatures and times can increase the energy contents of U. lactuca by over 47 %. Intriguingly, hydrochar obtained at 400 °C exhibited higher HHVs (i.e., 21.75–22.93 MJ kg−1) than typical low-ranked coals, making hydrochar more potential to be used as solid fuels. Finally, a reaction model was deduced, and the decomposition of U. lactuca was confirmed to follow the Arrhenius behavior