Judul: Screening Varietas Padi dan Penggunaan Kemasan Plastik Fleksibel untuk Meningkatkan Daya Tahan Simpan Beras: Studi Kasus Beras di Kalimantan Tengah.
Abstrak: Rice is an important commodity because being the staple food of the most of Indonesian people. During storage, the rice can be damaged due to environmental factors as well as postharvest pest. Sitophilus oryzae is postharvest insect pest that attack rice during storage causing quantity and quality losses. The objective of this research is to screening resistance of several local rice variety of Central Kalimantan, study effect of packages on S.oryzae mortality and determine appropriate packaging for rice storage. Eight rice varieties were tested against S.oryzae and then taken three variety (Siam Jurut, Siam Unus and Karang Dukuh) that packaged using “hermetic” laminat, polypropilen (PP) and low density polyetylen (LDPE). Result of the research showed that the lowest index of susceptibility was Siam Jurut, followed by Siam Palun, Siam Palas and Bayar Pahit that were be resistant varieties. Siam Unus had medium index of susceptibility. Rantul, Siam Pandak and Karang Dukuh had high Index of susceptibility. After storage, the resistant group had lower quantity losses, damaged grain and moisture content than susceptible group. The kind of plastic significantly effect to S.oryzae mortality. Total mortality of S.oryzae reached after three day for Siam Jurut, Siam Unus and Karang Dukuh in “hermetic” laminat plastic, six day for Siam jurut in PP plastic, seven day for Siam Unus and Karang Dukuh. In LDPE, total mortality reached after 20 storage day.
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Judul: Kajian Pengolahan dan Pendugaan Umur Simpan Beras Pratanak Dalam Kemasan Film Plastik
Abstrak: Parboiled rice has a high nutrient content and low glycemic index value, therefore, it is suitable to be consumed by people suffering diabetes mellitus. The purpose of this study was to study parboiled rice processing technique, examine its physico-chemical characteristics, and determine the shelf life of the parboiled rice during storage. The processing of parboiled rice is by soaking grain in 60 oC temperature for 6 hours, steaming at a temperature of 90 oC for 30 minutes, drying until the grain moisture content to 12-14%, milling and packaging. Determination of parboiled rice shelf life was done by using the critical moisture and Arrhenius methods in polypropylene (PP) and low density polyethylene (LDPE) plastics film packaging. The results showed that the treatment was able to increase the yield of milled parboiled rice, ash content, protein content and fat content, but it also decreased amylase and carbohydrate content. However, the physical quality of parboiled rice was still lower compared to that of the control based on head rice and broken rice contents. The shelf life of parboiled rice stored in LDPE and PP packaging by using the method of critical moisture at 84% RH and a temperature of 30% was 21.73 months and 26.43 months. Whereas the method of Arrhenius in LDPE and PP packaging based on the parameter of TBA (thiobarbituric acid) values at a temperature of 30oC was 10.55 and 13.13 months.
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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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