Judul: Komponen volatil dan karakterisasi komponen kunci aroma buah andaliman (Zanthoxylum acanthopodium DC.)
Abstrak: Andaliman (Zanthoxylum acanthopodium DC.) adalah tumbuhan perdu yang banyak tumbuh liar di daerah Sumatera Utara. Buah andaliman mempunyai bau ke arah sitrus yang kuat dan segar sehingga biasa dimanfaatkan sebagai rempah oleh orang Sumatera Utara untuk menghilangkan bau amis pada masakan daging atau ikan. Penelitian akan aroma andaliman masih terbatas sekali, sehingga potensinya untuk dijadikan flavor alami belum banyak diketahui oleh masyarakat luas. Tujuan dari penelitian ini adalah menganalisa komponen volatil andaliman, terutama yang berperan pada kekhasan aroma andaliman dengan menggunakan GC-MS (Gas Chromatography Mass Spectrometry) dan menentukan komponen kunci aroma (potent odorant) dari ekstrak andaliman. Pada penelitian pendahuluan terlebih dahulu dicari metode ekstraksi yang terbaik guna mendapatkan ekstrak yang mempunyai aroma mendekati andaliman segar. Penilaian dilakukan secara organoleptik. Hasil ekstrak yang terpilih selanjutnya dianalisa dengan menggunakan GC-MS. Untuk mengetahui aroma dari masing-masing komponen dari flavor andaliman dilakukan uji dengan GC/O (Gas Chromatography Olfactometry). Penelitian dilanjutkan dengan metode AEDA (Aroma Extract Dilution Analysis) guna mengetahui komponen yang merupakan komponen kunci aroma dari ekstrak andaliman. Hasil dari uji skoring pada pemilihan metode ekstraksi terbaik menunjukkan bahwa maserasi merupakan metode yang terbaik dengan skor 3,71 dari skala 5, diikuti dengan metode destilasi vakum. Kedua metode tersebut dipilih untuk dianalisis dengan menggunakan GC-MS. Pada maserasi ada empat pelarut yang diuji, yaitu dietil eter, kloroform, etanol dan aseton. Dietil eter adalah pelarut terbaik dari segi intensitas aroma yang dihasilkan paling kuat. Pada ekstrak maserasi yang telah dideklorofilisasi dapat diidentifikasi sebanyak 24 komponen volatil. Penyusun flavor andaliman mayoritas merupakan golongan monoterpen teroksigenasi (46,54%). Golongan monoterpen hidrokarbon yang terdiri dari 5 komponen merupakan golongan terbanyak kedua, yaitu sebanyak 19,75%. Sisanya adalah golongan aromatik (15,70%), golongan seskuiterpen hidrokarbon (0,64%), golongan hidrokarbon (0,34%) dan 6 komponen yang tidak teridentifikasi (17,03%). Dari 46,54% golongan monoterpen teroksigenasi dapat dibagi menjadi 6 komponen monoterpen alkohol (5,33%), 3 komponen monoterpen aldehida (8,42%) dan 3 komponen monoterpen ester (32,79%). Komponen utama yang mempunyai luas area relatif tinggi (>10%) pada ekstrak andaliman diantaranya adalah geranyl acetate (32,04%) dan limonene (15,80%). Analisa dengan metode AEDA menunjukkan bahwa yang banyak memberikan kontribusi terhadap aroma adalah golongan monoterpen. Citronellal yang memberikan aroma sitrus, kuat, hangat adalah komponen kunci aroma andaliman dengan intensitas aroma paling tinggi (FD factor 128). Limonene yang juga salah satu komponen kunci aroma andaliman (FD factor 32) memberikan aroma kulit jeruk dan manis. Komponen kunci aroma lain pada andaliman meliputi beta myrcene, [Z] beta ocimene, linalool, 2 decenal [E}, beta citronellol, neral, geraniol, geranial, geranyl acetate, seskuiterpene, unknown compound dan alpha caryophyllene. ...
Keyword: 

Judul: Perubahan Senyawa Volatil dan Mati Rasa Andaliman (Zanthoxylum acanthopodium) oleh Berbagai Teknik Pengeringan
Abstrak: Andaliman (Zanthoxylum acanthopodium DC) is an endemic plant from North Sumatera, commonly used as spices and folk medicines. Andaliman has a robust citrus aroma and numbing trigeminal sensations. Unfortunately, the research, usage, and popularity of andaliman are much behind its related species, such as Z. piperitum (Japanese pepper) and Z. bungeanum (Sichuan pepper). The main hurdles in fresh andaliman usage are the fast rotting and rapid flavor degradation. Proper processing techniques by farmers and industries will be crucial to expand its usage. Drying could prevent andaliman from degradation by reducing the moisture content; however, its effects on volatiles, numbing compound, and aroma profile have not been fully understood. Unsaturated alkylamides (sanshools) have been reported to be responsible for the unique numbing sensation. Analysis of sanshools is usually conducted using column chromatography or High Pressure Liquid Chromatography; however, these methods tend to be time-consuming and requires a large amount of costly solvent. On the other hand, aroma analysis is conducted using Gas Chromatography-Mass Spectrometry (GC-MS), which requires researchers to use two types of analytical methods to get the complete picture of both the aroma and taste of andaliman. However, three studies managed to analyze sanshools by GC-MS, which will shorten the research timeline and reduce research costs. This research was composed of three main stages: drying of andaliman (sun, sunshade, shade, oven, and freeze drying), confirmation of the GC-MS parameter, analysis of the volatiles, sanshools, sensory and physical characteristics. The volatiles and sanshool analysis were conducted with GC-MS, while the sensory analysis used the Rate All That Apply-Hedonic method. Physical characteristics such as moisture, water activity, yield, bulk density, and color were analyzed. Statistical data analysis using Principal Component Analysis (PCA), one-way ANOVA, Duncan posthoc, Pearson’s correlation, and Partial Least Square regression analysis were conducted to evaluate the impact of drying on volatiles, numbing, and sensory profile as well as to determine the volatiles responsible for andaliman aroma quality. The logarithmic thin-layer drying model best-described andaliman drying kinetics. The drying process significantly altered andaliman appearance, aroma profile and physical properties. No significant difference was found in the yield of each drying method; however, shade drying resulted in the highest moisture and water activity, while sun drying and freeze drying resulted in the lowest moisture content and water activity. Freeze drying resulted in the lowest bulk density. All drying methods managed to produce andaliman with less than 17.90% moisture content and 0.6 water activity, indicating the drying targets have been achieved. Generally, drying increased the a*, indicating green color degradation, however, no significant difference was observed in the a* values of dried samples. GC-MS analysis of all chloroform andaliman extract managed to detect total of 67 peaks while identifying 42 compounds. However, 25 unidentified peaks could comprise of other sanshool isomers. Fresh and dried andaliman generally had similar total relative content of volatiles and chromatogram pattern, differing mostly in the individual compound quantities. The content of limonene, (E)-2-hexenal, geranial, α-pinene, sabinene, and β-myrcene as well as the intensities of citrus and green aroma tended to decrease. In contrast, the content of geranyl acetate, citronellal,
Keyword: Zanthoxylum, andaliman, drying, aroma, sanshool

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