Judul: Characterizations of Walur Flour (Amorphophallus campanulatus var. sylvetris) and Its Application in Noodle and Cookies.
Abstrak: Walur (Amorphophallus campanulatus var. sylvestris) is a source of carbohydrate that is available locally and potentially to be developed as a food source. Walur is a type of tuber containing high oxalate content causing itchiness and irritation on lips. The objective of this research was to produce walur flour with low oxalic content and to apply it as flour-subtitute in noodles and cookies. Walur root had moisture content of 74,46%, ash 4,89%, fat 14,41%, protein 6,42%, and carbohydrate 74,28% in dry basis. Oxalic content of walur was reduced by boiling at 40 oC for 3 hours, soaking in HCl 0,2 N solution for 30 minutes, 1% sodium bicarbonate solution for 5 minutes, washing and soaking in sodium metabisulfite 1000 ppm solution for 5 minutes before dried. This treatment reduced 95% of oxalic content and obtained whiteness value of 69%. RVA profile showed that walur flour had A type gelatinization pattern. Noodles product with 30% walur flour substitution and cookies product with 50% walur flour substitution were most acceptable sensoricaly.
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Judul: Oxalate Reduction in Walur (Amorphophallus Campanullatus Var. Sylvestris), Characterizations and Applications of walur Starch on Cookies and Noodles
Abstrak: Walur (Amorphophallus campanulatus var. sylvestris) is a type of tuber containing high oxalate content (36058.8375 ppm) causing itchiness and irritation owhen consumed. Walur can be easily found in iles-iles plantation as gulma and produced with the triple amount of iles-iles root, 3.6 ton/ha. The objective of this research is to study the reduction of total oxalic content in walur and the application of walur starch to cookies and noodles. There are four main step in this research which are the characterization of physicochemical properties of walur tuber, reduction of oxalic content, characterization of physicochemical and functional properties of walur starch, and application of walur starch for cookies and noodle production. Walur tuber has moisture content of 74.46%, ash of 4.89%, fat of 14.41%, protein of 6.42%, and carbohydrate of 74.28% in dry basis. Walur starch has ovale and polygonale shape with size of 10-22 μm. RVA analysis showed that walur starch had A type gelatinization pattern. Reduction of oxalic content up to 93.18% can be achieved by soaking in HCl 0.2 N solution for 30 minutes, 1% sodium bicarbonate solution for 5 minutes and washing. Walur starch could be applied for cookies and noodles production. Organoleptic test showed cookies with 25% of walur starch and noodle with 60% of walur starch are the same acceptance with the control.
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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