Judul: Pengembangan Produk Teh Celup Berbahan Baku Kelopak Bunga Rosela Merah Daun Mint dan Stevia
Abstrak: Teh celup adalah salah satu jenis produk minuman yang bisa dibuat dari berbagai macam tanaman. Penelitian ini bertujuan untuk mendapatkan komposisi teh celup berbahan baku kelopak bunga rosela merah, daun mint dan stevia. Karakterisasi kadar air bahan baku dilakukan setelah pengeringan ulang untuk mengetahui kesesuaiannya dengan SNI yang mensyaratkan kadar air maksimal 10%. Penelitian pendahuluan untuk memilih saringan disc mill dilakukan menggunakan rancangan acak lengkap satu faktor yaitu ukuran saringan dengan lima taraf yaitu 80 mesh, 40 mesh, 3 mm, 4 mm, dan penggilingan tanpa saringan (TS). Sebanyak dua gram serbuk kelopak bunga rosela yang dihasilkan dari setiap saringan dikemas dalam kantung teh celup. Setiap sampel teh celup selanjutnya diseduh dalam 150 ml aquades bersuhu awal 80 oC selama 3 menit. Nilai absorbansi air seduhan tersebut kemudian diukur menggunakan spektrometer pada panjang gelombang 520 nm. Formulasi komposisi dilakukan dengan cara mengkombinasikan ketiga bahan baku berdasarkan aturan yang telah ditetapkan yaitu berat bahan total adalah 2 gram/kemasan. Setiap bahan memiliki berat minimal 0,25 gram/kemasan dengan rentang kombinasi 0.25 gram. Komposisi terbaik dipilih melalui pengujian organoleptik warna, rasa, aroma dan after taste. Pengujian lanjut terhadap data absorbansi dan organoleptik dilakukan menggunakan uji lanjut Duncan (DMRT). Kadar air kelopak bunga rosela merah, daun mint dan stevia setelah pengeringan ulang berturut-turut yaitu 8.84%, 8.73%, 5.00%. Jenis saringan 4 mm dipilih karena menghasilkan serbuk dengan ukuran partikel yang sesuai sehingga memudahkan proses pencampuran dan pengemasan. Serbuk kelopak bunga rosela merah yang dihasilkan saringan 4 mm juga memiliki laju peluruhan ekstrak teh celup paling besar. Formula terbaik diperoleh pada kombinasi kelopak bunga rosela merah 1.25 gram, daun mint 0.25 gram, dan stevia 0,5 gram. Kombinasi tersebut mendapat penilaian terbaik pada parameter warna dan rasa.
Keyword: komposisi, teh celup, saringan disc mill, kelopak bunga rosela merah, daun mint, daun stevia

Judul: Kajian Pembuatan Teh Celup Dengan Daun Pegagan (Centella Asiatica L. Urban)
Abstrak: Trend of back to nature has been widely developed in the world. One of the products from crop gotu kola is an herbal tea. Herbal tea contains powerful herbs for health. Packaging form of bags has been made to increase the added value of gotu kola tea. Tea bags are packaged processed food products in the packaging bag made from filterpaper that can be presented instantly and quickly. Gotu kola plant contains many chemical substances that useful to human’s health. Gotu kola can be clean the toxins blood from the body,improve digestive disorders and delay wrinkles. In addition it can helpimprove stamina, memory, mentally, and also help balancingthe energy levels, decrease symptoms of stress and depression. The active agent of this plant can also increase IQ, mental ability, such as mentally weak disorder in children. Making gotu kola tea bags in this study consisted of two types, namely sweet type and non sweet type, stevia is used to be sweetener. Through organoleptic test, panelist were asked to express they response to several tests of taste, aroma and color of a tea bag steeping of gotu kola. The results of analytical of chemical praresearch for raw materials of herbal tea ie gotu leaves, green tea leaves, citrus leaves and stevia leaves showed that the water content range ie 5,88-7,43 % w / w (SNI: max 8 % w / w) ash content, ie 4,65 - 5,76 % w / w (SNI: max 8 % w / w); and fiber content, ie 10,23 - 12,74 % w / w (SNI: max 16 % w / w). But all of the samples do not follow the standard of ISO, in terms of water soluble ash content, ie 35,63-41,22 % w / w (SNI min 45 % w / w). Results of quality analysis from all the selected samples showed that all of the samples have been met with SNI, which are not torn after soaking for about 15 minutes both cold water and hot water. Based on the results of statistical calculations can be obtained that the panelists preferred formulation for non sweet type is to the G formula, the composition are from 20% grams of gotu kola ; 60% of green tea; and 20% of citrus leaves. Where as for sweet type is preferred to the D formula, the composition are from 42,86% of gotu kola; 28,57% of green tea; 14,285% of citrus leaves; and 14,285% of stevia.
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Judul: Dynamical System of Hepatitis B in Three Groups with Vaccination
Abstrak: The aim of this study is to modify the hepatitis B transmission model in three age groups involving vaccination from the model conducted by Zhoe and Zhang.The method used is to analyze the stability of the fixed point and its basic reproduction number (R_0). Performed stability analysis and numerical simulation to see population dynamics. Next, a sensitivity analysis of the parameters was carried out to see its effect on R_0. From the analysis obtained two fixed points, namely non-endemic and endemic fixed points. Non-endemic fixed points are locally asymptotically stable if R_0 <1 Meanwhile, the endemic fixed point is locally asymptotically stable if R_0 > 1. Hepatitis vaccination affects the number of susceptible population, because the more successful the vaccination, the smaller the number of susceptible populations so that the smaller the population will be infected.
Keyword: Dynamic, Hepatitis B, Vaccine, Mathematical model