Judul: Karakteristik Pengeringan Beku Sari Temulawak (Curcuma xanthorrhiza Roxb.)
Abstrak: In this study, the process of freezing is done by using media temperature stratified. It aimed to see the influence of the freezing system with media temperature stratified to the characteristic and porosity of freeze dried curcuma extract products. The quality of the freeze dried curcuma extract was analyzed from the value of the level of curcumin and generated pore size. The results analyzed visually showed that the pore size to scenario 2 (Tma = -15ºC, Tmf = -20ºC, Tmb = -20ºC) was larger then scenario 1 (Tma = -15ºC, Tmf = -15ºC, Tmb = -20ºC) and scenario 1 was larger than the pore size in scenario 3 (Tma = -20ºC, Tmf = -20ºC, Tmb = -20ºC). The difference of pore size was affected by the moisture content of the material and freezing rate, although the freezing rate had no significant dependability because measuring is not sure. In addition, the influence of the freezing process does not show definite effect of the freeze drying characteristics. Content of curcumin that obtained after the freeze drying process already meet the standards, that is of 2.66%.
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Judul: Pengaruh Metode Pengeringan terhadap Karakteristik Fisiko - Kimia dan Sidik Jari FTIR Ekstrak Temu Kunci (Boesenbergia  pandurata)
Abstrak: Temu Kunci (Boesenbergia pandurata) merupakan tanaman rempah yang mengandung vitamin A, vitamin C, dan senyawa lainnya. Beberapa penelitian telah menyatakan bahwa temu kunci memiliki aktivitas antioksidan khususnya berasal dari senyawa fenolik. Antioksidan terbukti dapat menstabilkan radikal bebas dan menekan stres oksidatif sehingga mencegah berbagai penyakit, seperti kanker. Temu kunci segar memiliki karakteristik cepat rusak sehingga berbagai metode pengolahan dilakukan untuk memperpanjang umur simpan. Dalam penelitian ini, temu kunci segar dikeringkan dengan 4 perlakuan, yaitu pengeringan oven, oven vakum, freeze dryer, dan fluidized bed dryer. Penelitian ini bertujuan memperoleh informasi terkait perbandingan metode pengeringan antara oven, oven vakum, freeze dryer, dan fluidized bed dryer terhadap karakteristik fisiko (profil warna) dan kimia (aktivitas antioksidan metode DPPH, total fenol), serta sidik jari FTIR temu kunci. Simplisia temu kunci yang dihasilkan melalui metode freeze dryer memiliki profil warna kecerahan dan aktivitas antioksidan yang paling baik. Hasil analisis one way ANOVA menunjukkan bahwa metode pengeringan oven, oven vakum, freeze dryer, dan fluidized bed dryer memberikan pengaruh nyata (α < 0.05) terhadap aktivitas antioksidan, total fenol, serta profil warna. Spektrum inframerah keempat metode pengeringan menunjukkan adanya perbedaan dalam intensitas serapan, namun gugus fungsi yang terdeteksi masih serupa karena berada dalam rentang sama. Intensitas transmitan sampel perlakuan freeze dryer paling rendah dibandingkan perlakuan lainnya, aktivitas antioksidan yang tertinggi berasal dari sampel temu kunci. Perlakuan pengeringan menggunakan freeze dryer merupakan metode terbaik berdasarkan karakteristik fisiko – kimia ekstrak temu kunci, diikuti oleh Fluidized bed dryer., Fingeroot (Boesenbergia pandurata) is a spice plant that contains vitamin A, vitamin C, and other metabolites. Several studies have shown that fingeroot has antioxidant activity, particularly from phenolic compounds. Antioxidants are known to stabilize free radicals and reduce oxidative stress, thus preventing various diseases, such as cancer. Fresh fingeroot has a short shelf life and tends to deteriorate quickly. Therefore, various processing methods are used to extend its shelf life. In this study, fresh fingeroot was dried using four treatments: oven drying, vacuum oven drying, freeze drying, and fluidized bed drying. The study aimed to compare these drying methods in terms of physical characteristics (color profile) and chemical properties (DPPH antioxidant activity, total phenols) as well as the FTIR fingerprint of fingeroot.The freeze-dried fingeroot had the best color profile and antioxidant activity. One-way ANOVA analysis showed significant differences (α < 0.05) in antioxidant activity, total phenols, and color profile among the oven drying, vacuum oven drying, freeze drying, and fluidized bed drying methods. The infrared spectra of the four drying methods exhibited differences in absorption intensities, although the detected functional groups were similar as they were within the same range. The freeze-dried samples showed the lowest transmittance intensity compared to the other treatments, the highest antioxidant activity in the fingeroot samples. The drying treatment using a freeze dryer is the most superior method based on the physicochemical characteristics of the fingeroot extract, followed by the fluidized bed dryer.
Keyword: Antioxidant, color, drying, FTIR, spice

Judul: Construction of Strongly Optimal Binary Linear Code with Minimum Distance 9 and 11
Abstrak: A binary linear code of length n over q F is a subspace of n q F . A code has three parameters that attached to it, namely length, dimension, and minimum distance. A code with length n, dimension k and minimum distance d is often called [n, k, d ]-code. Usually, when two parameters are given, then we want to find a code that has the best value for the last parameter. Based on Gilbert- Varshamov bound, if a [n, k, d ]-code exists and can not be expanded, we call it a strongly optimal code. In this paper, we construct strongly optimal code with minimum distance 9 and 11. In constructing the code, we created a theorem and algorithm based on Gilbert-Varshamov bound before we implement the algorithm to MAPLE programming language. Because of computational limitations, the program can only construct up to k = 10 for d = 9 and k = 12 for d = 11.
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