Judul: Quality of instant edible canna (Canna edulis Kerr.) powder and its porridge processed by drum dryer
Abstrak: Edible canna (Canna edulis Kerr.) is one of local tubers that has high content of starch so it can be used for food diversification. Processing technology that has been applied so far is to make transparent starch noodle (Roisah, 2009) and canna starch (Ciptadi et al. 1980). Edible canna has a lot of fiber so it can be easily digested. The aim of this research is to explore the process characteristics and quality of drum dried instant canna powder that would be rehydrated into edible canna porridge. Dried edible canna had been succesfully made from edible canna slurry developed from cooked mashed red edible canna corm from farmers in Bogor district and then dried using double drum dryer. Preliminary research was applied to determine the best cooking time and RPM of the double drum dryer. Fifty minutes and three RPM were determined as the best in instant canna powder brightness so it were used in the following research phases. Two treatments were applied, 1)feed slurry composition at three levels, 1:2, 1:3, and 1:4 (ratio cooked mash edible canna to water) and 2)steam pressure at also three levels, 300 kPa, 400 kPa, and 500 kPa. The results indicated that dried canna powder produced at 500 kPa steam pressure combined with 1:4 feed slurry composition had the best moisture content that was 5.07% and it had the best brightness, 83.25. The organoleptic test, however, suggested that taste, aroma, and color of edible canna porridge rehydrated from dried instant edible canna powder was favoured for the combination treatment of steam pressure 500 kPa and 1:2 feed slurry concentration. Treatment of steam pressure 500 kPa and 1:3 feed slurry concentration had the highest viscosity that was 10 200 cp. The treatment of steam pressure and feed slurry composition had significant effect on moisture content, percentage of one hundreds mesh particle of instan canna powder, and the organoleptic test. While viscosity and brightness were not affected significantly.
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Judul: Time and Temperature Effects of Ultrasound Treatments on the Resistant Starch Content of Canna edulis Ker
Abstrak: Ultrasonication was applied to Ganyong (Canna edulis Ker) starch for three treatment of times (15, 30, and 45 minutes) at controlled temperature (30⁰, 45⁰, and 60⁰C). Ganyong as a local indigenous plant was chosen as the material in this study because it has big potential to produce resistant starch from its high content of amylose compared to other tuber’s starch, such as cassava, sweet potato, yam and arrowroot. Ultrasonication at 60⁰C and 45 minute was chosen as best treatment combination in this study due to the highest yield of resistant starch produced. Native canna starch was observed to have 1.45±0.24 % of resistant starch, however the number significantly increased to 48.19 ± 0.84% of resistant starch after modification (p<0.05). Further physicochemical changes of native and modified starch were observed. The results showed that there were no significant changes in the proximate analysis profiles before and after treatment. However, the ultrasonication significantly influence the pasting profiles (p<0.05) which was also expected due to the increase of starch granule size range from 30-160 μm to 45-179 μm after modification. The morphological changes were clearly observed by SEM and PLM, which showed swollen granule with rougher surface and fissures after modification. Thermal analysis using DSC did not significantly influenced the gelatinization temperature of the granule starch, however the increase of enthalpy (ΔH) occured from 2.99 to 10.86 J/kg. This result indicated the increase of resistant starch within canna starch granule.
Keyword: ganyong, Canna edulis Ker., resistant starch, ultrasonication

Judul: Invers dari Matriks Tridiagonal Jacobi
Abstrak: Suatu matriks berukuran n×n dinamakan matriks tridiagonal jika untuk . Karya ilmiah ini memberikan algoritma yang mudah untuk menemukan invers ( dari matriks tridiagonal Jacobi yang simetrik dan nonsimetrik. Setiap elemen pada matriks tridiagonal ini adalah bilangan real. Terdapat 3 lema dan 2 teorema untuk menentukan . Lema pertama menunjukkan persamaan utama dalam membuktikan lema-lema dan teorema-teorema selanjutnya. Invers dari matriks yang simetrik dibuktikan oleh lema kedua yang menunjukkan elemen-elemen baris ke- dari . Selanjutnya, lema kedua dilengkapi dengan teorema pertama yang menunjukkan elemen-elemen dengan . Invers dari matriks yang nonsimetrik dibuktikan oleh lema ketiga yang menunjukkan elemen-elemen dengan dan elemen-elemen dengan dibuktikankan oleh teorema kedua.
Keyword: symmetric, nonsymmetric, matrix