Judul: Pendugaan Umur Simpan Tepung Lidah Buaya dengan Metode Kadar Air Kritis
Abstrak: Aloe vera is widely used in pharmaceutical and food industries. Aloe vera processing into Aloe vera powder is one of the utilization and preservation efforts of Aloe vera. The main objective of this research is to determine the shelf life of Aloe vera powder in the three types of plastic packaging, that are LDPE, OPP, and metalized plastic with acceleration method critical water content models. Critical quality parameter of Aloe vera powder was observed in this research is the change in texture, mainly caking. This research consists of two stages. First stage was the selection and training of panelists and the second stage was the determination of Aloe vera powder shelf life. Shelf life of Aloe vera powder in LDPE packaging with RH condition 75, 80, and 85 % respectively were 38, 33, and 29 days. In OPP packaging with RH condition 75, 80, and 85 % respectively were 255, 222, and 197 days. Meanwhile, in metalized plastic packaging with RH condition 75, 80, and 85 % respectively were 2095, 1828, and 1624 days. Packaging and RH condition are influential to prolong shelf life of Aloe vera powder. Metalized plastic, packaging with the smallest permeability, give the longer shelf life than the other packaging. But, based on economical factor and its shelf life factor, Aloe vera powder should be stored in OPP packaging in RH 75% which provides shelf life 255 days.
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Judul: Pendugaan Umur Simpan Keripik Ubi Ungu Menggunakan Metode Accelerated Shelf-Life Testing Pendekatan Kadar Air Kritis
Abstrak: Keripik ubi ungu merupakan produk inovasi olahan ubi jalar ungu yang cukup banyak dikembangkan oleh Industri Kecil Menengah (IKM) di beberapa daerah yang berpotensial seperti di Desa Ciloto. Namun, sebagai produk pangan yang sensitif terhadap penyerapan uap air, keripik ubi ungu memiliki umur simpan yang terbatas dan relatif pendek. Sehingga, untuk mengetahui umur simpan produk tersebut dilakukan pengamatan pendugaan umur simpan menggunakan metode akselerasi pendekatan kadar air kritis. Variabel yang digunakan yaitu kadar air awal, kadar air kritis, kadar air kesetimbangan, kemiringan kurva ISA, permeabilitas kemasan, luas kemasan, bobot padatan per kemasan, dan tekanan uap air jenuh pada suhu penyimpanan. Diperoleh nilai kadar air awal keripik ubi ungu sebesar 0,0103 g H2O/g padatan, nilai kadar air kritis sebesar 0,0287 g H2O/g padatan, nilai kadar air kesetimbangan yang semakin besar seiring meningkatnya kelembaban relatif. Model yang terpilih yaitu model Henderson karena memiliki nilai R2 yaitu sebesar 0,9788 dengan persamaan log(In(1/(1-aw))) = 0,6344+0,5446 In Me dan nilai slope sebesar 0,1720. Pendugaan terbaik pada umur simpan keripik ubi ungu yaitu pada penyimpanan kelembaban relatif 70% menggunakan kadar air kritis SNI, diperoleh umur simpan pada kemasan PP yaitu selama 31 hari dan aluminium foil selama 123 hari. Kata kunci: kadar air, kelembaban relatif, keripik ubi ungu, umur simpan., Purple sweet potato chips are an innovative product of processed purple sweet potato which is quite widely developed by Small and Medium Industries (IKM) in several potential areas such as in Ciloto Village. However, as a food product that is sensitive to moisture absorption, purple sweet potato chips have a limited and relatively short shelf life. Thus, to determine the shelf life of the product, observations were made to estimate the shelf life using the acceleration method of critical moisture content approach. The variables used are initial moisture content, critical moisture content, equilibrium moisture content, slope of the ISA curve, packaging permeability, packaging area, solids weight per package, and saturated water vapor pressure at storage temperature. The initial moisture content value of purple sweet potato chips was 0,0103 g H2O/g solids, the critical water content value was 0,0287 g H2O/g solids, the equilibrium moisture content value increased with increasing relative humidity. The model chosen is the Henderson model because it has an R2 value of 0,9788 with the equation log(In(1/(1-aw))) = 0,6344+0,5446 In Me and a slope value of 0,1720. The best estimate on the shelf life of purple sweet potato chips is at 70% relative humidity storage using SNI critical water content, obtained in PP packaging for 31 days and aluminum foil for 123 days. Keyword: moisture content, purple sweet potato chips, relative humidity, shelf life
Keyword: moisture content, purple sweet potato chips, relative humidity, shelf life

Judul: Cycle Hamilton pada Graf Lengkap, Graf Regular, dan Graf 2-Connected 4-Regular Berorder Kurang dari Sepuluh
Abstrak: Suatu graf disebut graf Hamilton apabila graf tersebut memuat cycle Hamilton, yaitu cycle yang melewati setiap vertex tepat satu kali. Menentukan keberadaan cycle Hamilton pada suatu graf dapat menggunakan syarat cukup yang berupa teorema-teorema yang telah diperkenalkan sejak tahun 1950-an. Beberapa syarat cukup yang dibahas dalam karya ilmiah ini adalah syarat cukup yang berhubungan dengan graf lengkap dan graf regular. Suatu graf lengkap berorder 𝑛������ ≥ 3 dan graf r-regular berorder 𝑛������ ≤ 2𝑟������ + 1 merupakan graf Hamilton, Karena kedua graf tersebut memuat cycle Hamilton. Selanjutnya, syarat cukup tersebut digunakan untuk menentukan keberadaan cycle Hamilton pada graf 2-connected 4- regular berorder kurang dari 10.
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular