Judul: Gingerol and shogaol contents, pungency intensity and anelists acceptance in oleoresin of gajah ginger (Zingiber officinale var. Roscoe), Emprit Ginger (Zingiber officinale var. Amarum), and Merah Ginger (Zingiber officinale var. Rubrum)
Abstrak: Ginger is one of traditional herb which is used widely in Indonesia. There are three main species of gingers in Indonesia i.e. “gajah” ginger, “emprit” ginger, and “merah” ginger. It is known that ginger contains bioactive components which also contribute to its flavor. Some of these bioactive components such as gingerol, shogaol, zingerone, and their derivatives are phenolic components which known as pungent properties of ginger. Homologs of gingerol, (6)-, (8)-, (10)-gingerol; and (6)-shogaol on “gajah”, “emprit”, and “merah” ginger was observed on this study along with sensory test (pungency intensity and hedonic test). The determination of (6)-, (8)-, (10)-gingerol and (6)-shogaol in dried ginger was measured by liquid chromatography with photodiode array detection (LC-PDA). The levels of (6)-, (8)-, (10)-gingerol and (6)-shogaol in the “gajah” ginger were 9.56 mg/g, 1.49 mg/g, 2.96 mg/g, and 0.92 mg/g, respectively; in the “emprit” ginger were 22.57 mg/g, 4.73 mg/g, 6.68 mg/g, and 2.24 mg/g, respectively; and in the “merah” ginger were 18.03 mg/g, 4.09 mg/g, 4.61 mg/g, and 1.36 mg/g, respectively. The levels of gingerols and shogaol found in “emprit” ginger were the highest compared to “gajah” and “merah” ginger. The pungency intensity of ginger oleoresin towards 30 panelists for “gajah”, “emprit”, and “merah” ginger, using 15 cm unstructured-line scale, was 2.25, 5.93, and 7.99, respectively. The result of hedonic test on the taste, aroma, and overall attributes of ginger oleoresin towards 78 panelists for “gajah” ginger using 7-category scales, were 4.14, 4.31, and 4.04, respectively; for “emprit” ginger were 4.26, 5.04, and 4.38, respectively; and for “merah” ginger were 4.42, 5.12, and 4.55, respectively. There was no significant difference of taste and overall acceptance among the three species. However, the aroma acceptance of “gajah” was significantly lower than “emprit” and “merah” ginger.
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Judul: Profil Senyawa Gingerol dan Shogaol pada Oleoresin Jahe Merah
Abstrak: Jahe merah (Zingiber officinale var Rubrum) merupakan salah satu jenis tanaman rempah yang banyak dibudidayakan di Indonesia. Pengolahan jahe dapat dilakukan dengan proses basah dan proses kering dengan produk akhir bubuk jahe dan konsentrat. Ekstraksi dapat dilakukan pada hasil olahan jahe menggunakan pelarut organik menghasilkan oleoresin. Penelitian ini bertujuan mengoptimasi jenis fase gerak dan mengkuantifikasi senyawa gingerol dan shogaol yang terdapat pada berbagai oleoresin. Metode penelitian yang digunakan meliputi penanganan bahan segar, pengolahan jahe dengan proses basah dan proses kering, ekstraksi oleoresin dari beberapa olahan jahe menggunakan etanol, optimasi analisis kuantitatif gingerol dan shogaol oleoresin menggunakan RP-HPLC. Kolom C-18 digunakan dengan air– asetonitril (ditemukan sebagai pelarut terbaik) sebagai fase gerak dengan sistem gradien. Kuantifikasi dilakukan pada panjang gelombang 280 nm. Oleoresin bubuk freeze dry memiliki jumlah kadar gingerol tertinggi (24,19 g/100g oleoresin). Jika tiga metode pengeringan diurutkan menjadi freeze dry>fluidized bed dryer>matahari-fluidized bed dryer. Sementara kadar shogaol tertinggi hingga terendah yaitu matahari-fluidized bed>fluidized bed dryer>freeze dryer dengan kadar tertinggi dimiliki oleh oleoresin bubuk matahari-fluidized bed (0,23 g/100g oleoresin) dengan nilai yang tidak berbeda nyata (p>0,05) sehingga metode pengeringan tidak berpengaruh terhadap kadar gingerol dan shogaol pada oleoresin. Proses distilasi menghasilkan ampas dengan kadar shogaol tertinggi (2,22 – 11,20 g/100g oleoresin) dengan urutan distilasi rebus>distilasi kukus pada skala pilot plant sementara distilasi uap>distilasi air pada skala laboratorium. Sementara urutan metode distilasi yang menghasilkan total kadar gingerol tertinggi (12,24 g/100g oleoresin) hingga terendah yaitu distilasi uap>distilasi air pada skala laboratorium dan distilasi kukus>distilasi rebus pada skala pilot plant. Berdasarkan skala distilasi yaitu skala pilot plant dan laboratorium, hanya distilasi skala laboratorium yang berpengaruh nyata terhadap kadar gingerol dan shogaol pada oleoresin hasil ampas distilasi (p<0,05). Analisis kadar gingerol dan shogaol pada olahan lain hasil teknologi proses basah menunjukkan oleoresin dari bubuk instan memiliki jumlah gingerol yang paling tinggi (32,84 g/100g oleoresin), namun ekstraksi oleoresin tidak efektif karena rendemen yang dihasilkan rendah. Senyawa shogaol dengan jumlah lebih besar (0,97 g/100g oleoresin) ditemukan pada oleoresin konsentrat jahe dibandingkan dengan bubuk instan jahe., Red ginger (Zingiber officinale var. Rubrum) is one of the most widely cultivated spices in Indonesia. Ginger processing can be done by wet process and drying process with ginger powder and concentrate as the final product. Extraction can be carried out on processed ginger using organic solvents which produce oleoresin. This study aims to optimize the mobile phase and to quantify gingerol and shogaol compounds contained in various oleoresins. The research methods used include handling fresh materials, ginger processing which utilize wet and dry methods, extracting oleoresin from several processed ginger using ethanol, optimizing quantitative analysis of gingerol and shogaol oleoresin with RP-HPLC. Column C-18 was used with water–acetonitrile (which found to be the best solvent) as the mobile phase with a gradient system. Quantification was carried out at a wavelength of 280 nm. Oleoresin from freeze dry powder had the highest gingerol content (24,19 g/100g oleoresin), if the three drying methods were ranked, it becomes freeze dry>fluidized bed dryer>sun-fluidized bed dryer. Meanwhile, the highest to lowest shogaol content were sun-fluidized bed dryer>fluidized bed dryer>freeze dryer with the highest content was obtained by sun-fluidized
Keyword: Gingerol, Oleoresin, Processing Method, Red Ginger, Shogaol

Judul: Bifurkasi Hopf pada Model Siklus Bisnis Kaldor Kalecki tanpa dan dengan Waktu Tunda
Abstrak: Business cycle model is one of dynamical system models in economic. One of the business cycles model is Kaldor-Kalecki model. Kaldor-Kalecki business cycle model that is written in delayed defferential equations, is a business cycle model that involves gross product and capital stock of a company. In this paper Kaldor-Kalecki business cycle model is analyzed using both nondelay and delay in time of capital stock. By Taylor expansion for the time delayed model, an analysis of stability around the fixed points has been done. Furthermore, by using Hopf bifurcation theorem, it can be shown that there exists periodic orbits and limit cycle. In the nondelayed model, changing the parameter of goods market could lead to the occurrence of Hopf bifurcation and the existence of limit cycle. Similarly, for the delayed model, it has been shown that changing the time delay parameter may result in the occurrence of Hopf bifurcation and limit cycle.
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