Judul: Optimasi Formula dan Proses Ekstrusi Ubi Jalar Ungu dengan Response Surface Methodology
Abstrak: Ubi jalar ungu (Ipomoea batatas var. Ayamurasaki) sebagai salah satu komoditas pertanian yang unggul karena warnanya yang menarik, mudah didapat, dan manfaat kesehatannya. Industri keripik ubi jalar hanya menggunakan ubi jalar dengan ukuran tertentu. Petani pun terkena imbas karena penyerapan hasil panen oleh industri tidak maksimal. Pengolahan ubi jalar ungu menjadi produk olahan menggunakan ekstruder pada skala industri masih belum dapat ditemui. Penelitian ini bertujuan untuk menentukan formula dan parameter proses ekstrusi ubi jalar ungu yang optimum untuk menghasilkan produk dengan karakteristik mutu yang baik. Ubi jalar ungu yang diolah dengan teknik ekstrusi menggunakan ekstruder ulir ganda pemasak (BEX-DS-2256). Optimasi formula dan proses dilakukan menggunakan Response Surface Methodology (RSM) dengan rancangan Combine D-Optimal pada program Design Expert 12.0. Percobaan dilakukan dengan 22 perlakuan yang merupakan kombinasi faktor-faktor konsentrasi ubi jalar ungu (60–70%), tepung tapioka (20–25%), tepung ubi jalar ungu (10–15%), dan suhu ekstrusi (60–70 oC). Perlakuan yang optimum adalah dengan konsentrasi ubi jalar ungu 62.66%, tepung tapioka 22.34%, tepung ubi jalar ungu 15%, dan suhu ekstrusi 62.53 oC. Kombinasi formula dan proses tersebut menghasilkan adonan ubi jalar ungu dengan kadar air 49.34% (bb), kelengketan 711.67 gf, dan derajat gelatinisasi 52.06% dengan nilai desirability 0.76., Purple sweet potato (Ipomoea batatas var. Ayamurasaki) is one of the leading agricultural commodities due to its attractive color, availability, and health benefits. The sweet potato chip industry only uses sweet potatoes of a certain size. Farmers are also affected because the absorption of crops by the industry is not optimal. The development process of turning purple sweet potatoes into processed products using industrial scale extruders is still can’t be found. This study aimed to determine the optimum formula and extrusion process of the purple sweet potato to produce a product with good quality characteristics. Purple sweet potato was processed by extrusion technique using a double screw extruder (BEX-DS-2256). The optimization of formulas and processes was carried out using the Response Surface Methodology (RSM) with the Combine D-Optimal design in the Design Expert 12.0 program. The experiment conducted 22 treatments that were a combination of purple sweet potato concentration (60–70%), tapioca flour (20–25%), purple sweet potato flour (10–15%), and extrusion temperature (60–70 oC). The optimum treatment was with a concentration of 62.66% purple sweet potato, 22.34% tapioca flour, 15% purple sweet potato flour, and an extrusion temperature of 62.53 oC. The combination of these formulas and processes resulted in purple sweet potato dough with a moisture content of 49.34% (bb), stickiness of 711.67 gf, and degree of gelatinization of 52.06% with a desirability value of 0.76.
Keyword: derajat gelatinisasi, ekstruder, kelengketan, optimasi, ubi jalar ungu

Judul: Formulation of High-Fiber Extruded Purple Sweet Potato (Ipomoea batatas L.) and Red Kidney Bean (Phaseolus vulgaris)
Abstrak: Rendahnya asupan serat pangan yang berkaitan erat dengan peningkatan risiko beragam penyakit tidak menular (PTM) masih menjadi masalah kesehatan terkait gizi pada masyarakat luas. Ubi ungu dan kacang merah merupakan pangan tinggi serat yang terjangkau dan mudah diakses di Indonesia. Penelitian ini bertujuan mengembangkan formulasi olahan ubi ungu dan kacang merah berupa ekstrudat tinggi serat. Tahapan penelitian terdiri dari optimasi formula, evaluasi sensori, uji karakteristik fisik yakni analisis warna dan tekstur, analisis proksimat, analisis serat pangan, baik larut dan tidak larut, dan analisis aktivitas air. Optimasi formula dilakukan menggunakan empat formulasi dengan perbandingan penggunaan tepung ubi ungu dan tepung kacang merah yang berbeda-beda yakni F0 (100:0), F1 (80:20), F2 (70:30), dan F3 (60:40). Ekstrudat diekstrusi pada suhu 60°C dan kecepatan ulir, umpan, serta pisau sebesar berturut-turut 45, 45, dan 50 Hz. Formula terpilih yakni formula F2 ditentukan berdasarkan hasil seluruh analisis. Satu takaran saji ekstrudat formula F2 diketahui mengandung mengandung energi, protein, lemak, karbohidrat, dan total serat pangan berturut-turut sebesar 129 kkal, 4,0 g, 0,3 g, 27,7 g, dan 6,0 g, serta memenuhi 6,0% kebutuhan energi serta 19,9% kebutuhan serat orang dewasa. Analisis aktivitas air menunjukkan bahwa formula terpilih memiliki aktivitas air sebesar 0,44%. Formula ekstrudat terpilih berpotensi memenuhi klaim sebagai pangan tinggi serat dan rendah lemak dengan umur simpan yang cukup panjang., The low intake of dietary fiber, which is closely related to the increased risks of various non-communicable diseases (NCDs), is still considered as a major health problem related to nutrition globally. Purple sweet potatoes and red kidney bean are high-fiber foods that are affordable and readily accessible in Indonesia. This research aimed to develop a formulation of high-fiber extrudate made from purple sweet potato and red kidney bean. This research was conducted through formula optimization, sensory evaluation, and analyses of color, texture, proximate, dietary fiber, and water activity. Optimization of the formula was carried out using four formulations with different ratios of purple sweet potato and red kidney bean flours, i.e. F0 (100:0), F1 (80:20), F2 (70:30), and F3 (60:40). The extrudate was extruded using a double-screw extruder at the temperature of 60°C, with the screw, feed and cutter speeds of 45, 45, and 50 Hz, respectively. The selected extrudate formula, formula F2, was determined based on the results of all analyses. A single serving of F2 extrudate was shown to contain energy, protein, fat, carbohydrates and total dietary fiber of 129 kcal, 4.0 g, 0.3 g, 27.7 g, and 6.0 g respectively, and contributes to 6.0% and 19.9% of energy and fiber needs for adults. Water activity analysis showed that the selected formula had a water activity of 0.44%. The results of all analyses showed that this extrudate was well accepted and may potentially be claimed as a high-fiber and low-fat food with long shelf life.
Keyword: analisis proksimat, makanan ekstrudat tinggi serat, kacang merah, optimasi formula, ubi ungu, formula optimisation, high-fiber extruded food, proximate analysis, purple sweet potato, red kidney bean

Judul: Thermal Characteristics and Dynamics of Tropical Cyclone over Western North Pacific Ocean: A Case Study of Typhoon Songda (Chedeng) 2011
Abstrak: The frequent occasion of Tropical Cyclone (TC) over Western North Pacific (WNP) Ocean lies from 10˚N to 26˚N and 121˚E to 170˚E. Sources of TC development come from warm ocean temperature where latent heat is released during condensation processes and subsequently concentrated in the boundary layer. Relative humidity at 850-700 hPa is responsible to produce the most intense storm. Meanwhile, weak vertical wind shear between 850-200 hPa is one of the dynamical factors that lead to the development of TC. Pressure level of 850-200 hPa is chosen to minimize the thermodynamic effect in the lower troposphere. Typhoon Songda (Chedeng in the Philippines) or TSC lasted from May 18th to 30th, 2011 and strengthened into powerful Super Typhoon stage between May 24th and 27th. Long curving track and the exhibition of all sequences of TC life cycle, TSC is then considered as an ideal case of TC. The objective of the study with case of TSC is to investigate the role of thermal characteristics and dynamics on TC intensity. The research is carried out by using Advanced Research of Weather Research and Forecasting model (WRF ARW model) version 3.3. Two domains are employed in the model. The first domain situate from 02˚N to 40˚N and 118˚E to 149˚E and cover spatial resolution () of 33.1 km. The second domain situate from 09˚N to 27˚N and 119˚E to 132˚E with of 11 km. Timestep of the model () is 120 seconds. The model is supported by the following physical parameterization, i.e., Yonsei University Scheme (YSU) in the boundary layer, Kain-Fritsch scheme (KF) in the cumulus, and WRF Single-Moment 3-class scheme in the microphysics. Initial meteorological condition prior to the formation of the cyclone is generated using WRF ARW standard-release model. Sensitivity of the model output is obtained from a selected single-parameter change scenarios, namely, 10 % to 20 % decrease and increase of wind shear initial data at 850-200 hPa, and by 10 % to 20 % decrease of relative humidity initial data at 850-700 hPa. The result showed that the negative correlations between wind shear and intensity are found in wind shear scenarios. Wind shears of 10 ms-1 which lead to strengthening of the wind intensity in the early period of Typhoon development are found in wind shear scenarios. The effect of wind shear changes on wind intensity is statistically significant in the 20 % wind shear scenarios. During mature stage, weak wind intensity occurred when wind shear increase as given in the WRF standard-release and the 20 % decreasing scenario. Different situation is found in the 20 % increasing scenario where wind shear tend to weak and lead to strong wind intensity at this stage. Meanwhile, the reduction of moisture supply at 850-700 hPa resulting from 20 % decreasing relative humidity play a major role in the weakening of wind intensity and reduces mechanical energy of the cycle process as much as 300 J kg-1.
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