Judul: Pemisahan dan Pencirian Amilosa dan Amilopektin dari Pati Jagung dan Pati Kentang pada Berbagai Suhu
Abstrak: Amilose can be separated from amylopectin based on their distinct properties. Amylose is more crystaline, while amylopectin is amorphous. Separation was done by heating a solution of corn and potato with a ratio of 1:30, 1:45, 1:60 at 53, 55, 57oC for potato starch and 60, 70, 72 oC for corn starch for 1.5 hours. The results showed that amylose could be separated from amylopectin simply by using hot water. The results showed that temperature wais more influencing on the separation of amylose-amylopectin. The best separation results were at 60 °C and the ratio of 1:60 for corn starch with molecular weight 5.6919 × 105 g/mol for amylose and 81.2783 × 105 g/mol for amylopectin and at a temperature of 53 °C and the ratio of 1:60 for potato starch with molecular weight 4.2688 × 105 g/mol for amylose and for amylopectin 61.6797 × 105 g/mol. The temperature and the ratio of amylose : amylopectin obtained were closely similiar to those published in literatures. From the results obtained by DSC measurements the glass transition point at 1:60 ratio was at 70.10 oC for potato starches at temperature 57 oC and 40.76 oC for corn starch at 72 oC.
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Judul: Perbandingan isotermi sorpsi air dari amilosa, amilopektin, selulosa dan sukrosa
Abstrak: Penelitian tentang perbandingan isotermi sorpsi air dari amilosa, amilopektin, selulosa dan sukrosa bertujuan untuk membandingkan konstanta/parameter berbagai model matematik kurva isotermi sorpsi air yang diaplikasikan pada amilosa, amilopektin, selulosa dan sukrosa. Diharapkan data dasar hasil penelitian ini dapat digunakan untuk analisis produk campurannya. Penelitian yang dilakukan yaitu ekstraksi pati dari beras ketan dan penentuan kesetimbangan isotermi sorpsi dari amilosa, amilopektin selulosa dan sukrosa. Ekstraksi pati dari beras ketan dilakukan untuk mendapatkan pati dengan kadar amilopektin yang tinggi. Beras ketan dan pati yang diperoleh dianalisis kadar air, protein, lemak, pati dan amilosanya. Beras ketan memiliki kadar air sebesar 14.57% b.k., protein 7.31% b.k lemak 0.46% b.k., pati 80.35% b.k., amilosa 3.88% b.k. dan amilopektin 76.47% b.k. Pati hasil ekstraksi memiliki kadar air sebesar 12.98% b.k., protein 5.76% b.k., lemak 0.34% b.k., pati 80.56% b.k., amilosa 3.4% b.k. dan amilopektin 77.16% b.k. Isotermi sorpsi air diperoleh dengan cara memplotkan kadar air kesetimbangan terhadap RH. Kadar air kesetimbangan diperoleh dengan cara menyetimbangkan amilosa, amilopektin, selulosa dan sukrosa di dalam desikator yang berisi larutan garam garam-garam jenuh sampai diperoleh kadar air kesetimbangan.
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Judul: A Continuous Vaccination Strategy in the SVIR Epidemic Model
Abstrak: Vaccination is conducted to minimize the spread of a disease. The vaccination is usually done several times within a fixed time interval. In the SVIR model, it is assumed that individuals do not get immediate immunity following a vaccination program. So according to process of vaccination on SVIR model, there are two strategies, i.e. the continuous vaccination strategy (CVS) and the pulse vaccination strategy (PVS). In this study, only the CVS strategy in epidemic model SVIR is considered. Results of the study indicate that dynamics of the CVS system depends on the basic reproductive number. If the basic reproductive number is less than one, then the disease-free fixed point is asymptotically stable. It means that the disease will eventually disappear from the population. Conversely, if the basic reproductive number is greater than one, then the endemic fixed point is asymptotically stable, which means that the disease will remain exist in the population. Simulation result shows that the vaccination would minimize the spread of disease by reducing the basic reproductive number. If the time for the vaccinated recipients to obtain the immunity, as well as a possibility of vaccinated recipients to be infected are neglected, then the disease will be eradicated. This condition is called an over-evaluating effect of vaccination.
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