Judul: IPB (Bogor Agricultural University)
Abstrak: Kopi seduh merupakan salah satu jenis minuman yang sangat populer di seluruh dunia karena cita rasa dan aromanya yang khas. Namun, di sisi lain kopi mengandung kafein yang diduga mempunyai efek yang kurang baik bagi kesehatan peminumnya, sehingga berdampak pada menurunnya minat minum kopi dan menurunkan tingkat konsumsi kopi di dalam negeri. Penelitian ini bertujuan untuk mengembangkan proses dekafeinasi kopi dalam reaktor kolom tunggal. Sedangkan secara khusus penelitian ini bertujuan untuk 1) Menentukan pengaruh suhu (60-70°C, 70-80°C dan 80-90°C) pada proses dekafeinasi kopi dalam reaktor kolom tunggal, 2) Menentukan pengaruh ukuran biji (<7.5 mm, 6.5mm–7.5mm), 5.5mm–6.5mm, dan < 5.5mm) pada proses dekafeinasi kopi dalam reaktor kolom tunggal, dan 3) Menentukan pengaruh lama proses pelarutan (2, 4, 6, dan 8 jam) terhadap kandungan kafein kopi biji dan cita rasa minuman kopi. Penelitian dilakukan dalam 2 tahap proses yaitu pengukusan biji kopi dan pelarutan kafein. Hasil penelitian menunjukkan pengembangan volume biji kopi mencapai nilai maksimum 32-38% untuk semua ukuran biji setelah proses pengukusan berlangsung 4 jam, demikian pula kadar air yang meningkat dari 12% menjadi 54-57% setelah proses pengukusan berlangsung selama 4 jam untuk semua ukuran biji.
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Judul: Inovasi Proses Produksi Kopi Bubuk
Abstrak: There are many kinds of processed coffee products that have been developed so far. One of them is ground coffee beans. Coffee drink as a result of ground coffee steeping still leaves leftover. Downsizing the bean size before roasting process was thought to have an effect on several parameters such as essence level and steeping leftover. The objective of this study was to determine the effect of grain size reduction and roasting duration on the formation of steeping leftover with better characteristics and taste. This research was conducted in several stages: downsizing coffee beans, roasting, grinding, proximate analysis and sensory evaluation. The bean size used was compared to the size of whole coffee beans, coffee beans with the size of 2mm-4mm, and coffee bean size of <2mm. The roasting time consisted of 30 minutes, 45 minutes, and 60 minutes at a temperature of about 180ºC - 200ºC. The best interaction occurred between the treatment of bean size reduction to <2mm with a roasting time of 60 minutes. The treatment could reduce the leftover of steeping coffee generally with a water content of 3,4 ± 0,0% db; essence level of 53,7 ± 0,9% db; steeping leftover of 355,2 ± 13,6% db; and a pH of 6,1 ± 0,1. All the parameters have met the ground coffee quality standard of SNI 01-3542-2004.
Keyword: Bogor Agricultural University (IPB), steeping leftover, downsizing, ground coffee, coffee

Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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