Judul: Penyiapan dan Karakterisasi Pati Nanokristalin dari Sagu dan Tapioka
Abstrak: Nanocrystalline starch is modified starch with particle size around 20-50 nm and has varied crystalline structure. As active compound or drug’s matrix carrier, nanocrystalline starch should be acid resistant, have low digestibility and high absorbing power in human intestine. This research used sago starch and tapioca because of their compatibility in forming low digestibility and high crystallinity starches. There were two steps of nanocrystalline starch production. The first was lintnerization for 2, 4, 6, and 24 hours, which aimed to hydrolyze amorphous area of starch that formed crystalline starch, whereas solubilization and ethanol precipitation generated the nanoparticle starch. The results showed that lintnerization generated crystalline sago starch and tapioca with lower digestibility and higher crystallinity compared to their native starch. Ethanol precipitation of crystalline starch produced starch nanoporous particles, and influenced to decreasing the digestibility and water and oil binding capacities, meanwhile increasing the solubility and swelling power.
Keyword: tapioca, sago, ethanol precipitation, lintnerization, nanocrystalline starch

Judul: Produksi Pati Asetat dengan Menggunakan Pati Sagu Nanokristalin
Abstrak: Native sago starch has limited application when it is used as an active ingredient or drug carrier matrix because it is not acid resistance, high digestibility, and low solubility. It inhibits its function as a protector so that the active ingredient does not reach its target. Acetylated nanocrystallinestarch is a modified starch that can improve the characteristic of starch produced through a lintnerized process, precipitation with ethanol, and substituted with acetate anhydride. This study aims to improve the starch and modified starch performance as a drug carrier matrix in the form of acetylated starch. Three types of sago starch used are native starch, crystalline starch, and nanocrystalline-starch acetylated by using acetate anhydride with 3 and 6% concentration. In general, native sago starch is easier to be acetylated compared to crystalline starch and nanocrystalline starch. The result shows that the effect of acetylation increases the solubility and swelling power, but decreasing the water absorption, oil absorption, and starch digestibility. The concentration of acetate anhydride affects the solubility, % acetyl, and substitution degree. The increasing of acetate hydride concentration from 3% to 6% causes the increasing of % acetyl from 0.05-0.53%, substitution degree from 0.01-0.02 point, and product solubility up to 7%.
Keyword: Bogor Agricultural University (IPB), nanocrystalline starch, crystalline starch, sago starch, acetylation

Judul: Cycle Hamilton pada Graf Lengkap, Graf Regular, dan Graf 2-Connected 4-Regular Berorder Kurang dari Sepuluh
Abstrak: Suatu graf disebut graf Hamilton apabila graf tersebut memuat cycle Hamilton, yaitu cycle yang melewati setiap vertex tepat satu kali. Menentukan keberadaan cycle Hamilton pada suatu graf dapat menggunakan syarat cukup yang berupa teorema-teorema yang telah diperkenalkan sejak tahun 1950-an. Beberapa syarat cukup yang dibahas dalam karya ilmiah ini adalah syarat cukup yang berhubungan dengan graf lengkap dan graf regular. Suatu graf lengkap berorder 𝑛������ ≥ 3 dan graf r-regular berorder 𝑛������ ≤ 2𝑟������ + 1 merupakan graf Hamilton, Karena kedua graf tersebut memuat cycle Hamilton. Selanjutnya, syarat cukup tersebut digunakan untuk menentukan keberadaan cycle Hamilton pada graf 2-connected 4- regular berorder kurang dari 10.
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular