Judul: Aplikasi Metode Arrhenius dalam Pendugaan Umur Simpan Lada Hijau Kering (Dehydrated Green Pepper)
Abstrak: Pepper (Piper ningrum L.) is a kind of spices from family Piperaceae. Dehydrated green pepper has spesific flavor and natural green appearance. This kind of pepper also has higher sell value than black pepper and white pepper in international market. Prediction of shelf life aims to know shelf life of dehydrated green pepper in certain condition. Determination shelf life product with ASS (Accelerated Storage Studies) method using environmental condition parameter enables to accelerate degradation process of quality of food product. The right packaging and storage is expected to detain deterioration rate of dehydrated green pepper and increase shelf life. The objectives of the research is to know quality changing, to determine shelf life, and to obtain better packaging to defend quality of dehydrated green pepper. The packaging materials used in this research were plastic LDPE, PP, and aluminium foil. The storage has been done in temperatures 20°C, 30°C, and 40°C during 4 months. The analysis of dehydrated green pepper were colour, water content, volatile oil content, and sensory evaluation analysis. Based on this research, it is showed that dehydrated green pepper quality changed during 4 months of storage. The green colour of dehydrated green pepper decreased with a* value at storage temperature of 20°C, 300C, 400C increased by 0.0039%, 0.0068%, and 0.0169% per day for LDPE; 0.0017%, 0.0026%, 0.0162% per day for PP; and 0.001%, 0.002%, dan 0.0196% per day for aluminium foil. Water content at storage 200C dan 300C increased by 0.0127% dan 0.0249% per day for LDPE; 0.0115% and 0.0224% per day for PP; 0.0119%, 0.0126%, and at storage 400C increased by 0.0071% per day for aluminium foil. Water content at storage 400C decreased by 0.037% per day for LDPE dan PP. Volatil oil content of dehydrated green pepper at storage temperature of 20°C, 300C, 400C decreased by 0.0013%, 0.0014%, 0.0019% per day for LDPE; 0.0010%, 0.0012%, 0.0017% per day for PP; and 0.0004%, 0.0008%, 0.0009% per day respectively for aluminium foil. pH of dehydrated green pepper at storage temperature of 20°C, 300C, 400C decreased by 0.0001%, 0.0005%, 0.0002% per day for LDPE; 0.0002%, 0.0002%, 0.0001% per day for PP; and 0.00001%, 0.0001%, 0.0004% per day for aluminium foil. Based on a* value parameter with its critical point of +2.79, shelf life of dehydrated green pepper is 36 months 8 days (200C), 17 months 3 days (300C), 8 months 15 days (400C) for LDPE; 104 months 24 days (200C), 32 months 23 days (300C), 11 months 3 days (400C) for PP; 182 months 18 days (200C), 38 months 24 days (300C), 9 months 3 days (400C) for aluminium foil Thereby, the best packaging to maintain the quality of dehydrated green pepper is aluminium foil.
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Judul: Shelf Life Estimation of Red Ginger Powder  “Deherbanoer” Using Arrhenius Model Accelerated Shelf-Life Testing (ASLT)  Method
Abstrak: Jahe (Zingiber Officinale) merupakan tanaman rempah-rempah yang memiliki produktivitas tinggi di Indonesia. Kandungan senyawa dalam jahe memiliki beragam manfaat untuk kesehatan manusia, jahe dapat diolah menjadi berbagai macam produk sebelum dikonsumsi. Bubuk jahe merah “Deherbanoer” merupakan salah satu produk olahan jahe dari Kecamatan Bogor Tengah, Kota Bogor, Jawa Barat. Bubuk jahe merah selama proses penyimpanannya dapat mengalami penurunan kualitas yang dipengaruhi oleh kondisi lingkungan, sehingga perlu diketahui informasi mengenai umur simpan produk agar dapat dikonsumsi pada mutu terbaiknya. Penelitian bertujuan untuk mengetahui karakteristik awal, mengidentifikasi penurunan mutu selama penyimpanan, dan melakukan pendugaan umur simpan. Bubuk jahe merah disimpan menggunakan kemasan alumunium foil, metallized, dan polypropylene (PP) dalam kondisi penyimpanan dengan suhu 25, 35, dan 45°C selama 8 minggu. Parameter yang diamati selama penyimpanan adalah perubahan kualitas kadar air, kadar oleoresin, warna, angka kapang dan khamir. Hasil penelitian menunjukkan adanya perubahan mutu berupa peningkatan kadar air, penurunan oleoresin, perubahan intesitas warna, dan cemaran kapang. Penetapan umur simpan didasarkan pada parameter dengan laju penurunan mutu yang besar yaitu kadar oleoresin. Bubuk jahe merah “Deherbanoer” yang dikemas menggunakan alumunium foil memiliki umur simpan yang lama yaitu 11,21 bulan pada suhu 25°C, 9,68 bulan pada suhu 35°C, dan 8,4 bulan pada suhu 45°C., Ginger (Zingiber Officinale) is a high productivity spices plant in Indonesia. The content compounds within a ginger has various benefits for human health, ginger can be processed into various products before being consumed. Red ginger powder "Deherbanoer" is one of the processed ginger products from Central Bogor District, Bogor City, West Java. Red ginger powder, during the storage process, has being decreased in quality which affected by environmental condition, thus it is necessary to know the information about its shelf life so that it can be consumed at the best quality. This research was aimed to determine the initial characteristics, identify quality degradation during storage, and conduct estimated shelf life. Red ginger powder was packaged using aluminum foil, metallized, and polypropylene (PP) packaging in various storage conditions at 25, 35, and 45°C for about 8 weeks. The observed parameters during its storage were the change of water content quality, oleoresin content, color appearance, mold and yeast numbers. The results showed a change of qualities such as an increasing both in water content and color brightness, a decreasing in oleoresin content, and mold contaminated. Determination of shelf life was based on the parameter with a large rate of deterioration, namely oleoresin content. Red ginger powder “Deherbanoer” which packaged using aluminum foil has a best shelf life which are about 11.21 months at 25°C, 9.68 months at 35°C, and 8.4 months at 45°C.
Keyword: Arrhenius, packaging, red ginger powder “Deherbanoer”, shelf  life

Judul: Penggunaan Teorema Homeomorphy 2-Manifold dan Teorema Euler Poincare pada Torus 𝑇�� dan Simplicial Complex 𝐾��
Abstrak: Two dimensional topological spaces are said to be homeomorphic if they have the same topological invariant, where one of topological invariant used is an Euler characteristic. Homeomorphy 2-Manifold’s Theorem and Euler Poincare’s Theorem are used to distinguish two topological spaces. Homeomorphy 2-Manifold’s Theorem uses Euler characteristic to identify two dimensional topological spaces. Euler Poincare’s Theorem is an alternative way to find Euler characteristic with Betti number, which is topological invariant as well. The objective of this paper is to investigate the homeomorphism of torus 𝑇����� and simplicial complex 𝐾�����. Topological space torus and simplicial complex 𝐾����� have the same Euler characteristic, which is two. Based on Homeomorphy 2-Manifold’s Theorem topological space torus 𝑇����� and simplicial complex 𝐾����� is homeomorphic.
Keyword: simplicial, torus, Euler, homeomorphism, topology