Judul: Perbaikan proses produksi tepung jagung secara enzimatis menggunakan papain
Abstrak: Apparently, the increasing of national corn production and the number of substitutions reasearch about the wheat flour utilization using corn flour into a variety of processed food, such as noodles, cookies, biscuit or traditional and other processed foods, have not been able to encourage the growth of corn-based agroindustries as the corn flour quality produced by corn processing plant has not met the standards required. The objective of this research is to produce a corn flour production process engineering design using papain enzyme to produce corn flour with specification of 90% passes 80 mesh sieve and a 1.5% maximum of fat content. Research was initiated with characterization of corn samples (local corn Kodok variety and hybrid corn Pioneer 21 variety), degerminator modification, and the length of corn kernel soaking to make germ, tip cap and pericarp of endosperm separation more effective. It was continued with incubation of corn grits to decompose protein matrix on endosperm so it is easier to be milled, along with incubation process optimization. Optimization was performed using 2-Factor Completely Randomized Design, which enzyme concentration were 0.6; 0.7; 0.8; 0.9 and 1.0% or (425.4; 496.3; 567.2; 638.1; and 709 U/g) and incubation time period of 15, 18, 21 and 24 hours with two replications. Optimized respond variable was hardness of corn grits. Observation and examination carried out in this stage consist of yield, losses and fat content of grits generated by degermination, hardness and protein content of grits after incubation, grits morphology, starch granule birefringence and particle size distribution and visco-amylograph characteristic of corn flour produced. The next stage was the enzymatic corn flour production process design and production costs calculation. Addition of incubation process phase with the papain enzyme in the production process to improve corn flour particle size fineness was declared as novelty in this research. Degermination result showed the use of modified paddy polisher degerminator (type C degerminator) with 20 minutes corn seed soaking time gave the best result for both varieties with average grits yield 63.60%, weight losses 3.77%, and fat content decrease from 5.57% to 0.98% (db). On the other hand, the incubation using papain is capable to increase particle size fineness of corn flour produced hence it could meet the corn flour quality requirement (SNI No.01-3727-1995), at least 99% pass 60 mesh sieve and 70% pass 80 mesh sieves. Observation result using SEM showed that starch granule in local corn horny endosperm was spherical with size of 3-7 μm, while that of hybrid corn was polygonal with 3-12 μm size. In addition, there was protein matrix decomposition due to proteolytic enzyme work during papain incubation. The observation can resolve protein matrix decomposition by work of papain enzyme as shown by hardness and grits protein decreased after incubation. Observation result using polarized light microscope showed there was no birefringence damage on observed starch granule. The RVA testing result showed corn flour amylograph profile after incubation with papain 1% for 24 hours was similar to that of commercial corn starch. Optimization results using Minitab 16 software showed the optimum point of the incubation process for
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Judul: Effects of spontaneous fermentation during soaking of local variety of white corn (Zea mays L.) on physicals, chemical and functional characteristics of its flour
Abstrak: The uses of white corn in food industry in Indonesia are still limited. To explore the potential uses, evaluation of chemical physical, and functional properties of white corn flour is needed. The objective of this study was to evaluate chemical, physical and functional properties of white corn flour, and its changes as affected by spontaneous fermentation during soaking of white corn grits. Corn flour was prepared by soaking of white corn grits followed by drying and grinding. Soaking was done at closed pan and controlled temperature, to promote spontaneous fermentation. The resulted flour was fractionated using multiple sieve of 100 mesh (150 ìm), 150 mesh (106 ìm) and 200 mesh (75ìm) and analyzed for its chemicals, physicals and functional characteristics. Fermentation process as long as 24 hr will reduce gelatinization temperature (Tg) of resulted flour from 82oC to 76.2oC; but finally Tg would increase (85.2oC) at 72 hr of fermentation. Fermentation process of corn grits do not affect its peak viscosity (in the range of 493 -560BU), but will increase only after fermentation of more than 48-60 hr (648 -573 BU); and further fermentation would reduce the peak viscosity (550 BU)similar to that of flour resulted from process without fermentation. Flour resulted from corn grits after fermentation process of 12 hr has breakdown viscosity of 0 BU. This suggests that heat stability of flour produced from corn grits after 12 hr fermentation is higher that that of control flour (breakdown viscosity of 68 BU).
Keyword: gelatinization temperature, fermentation process, peak viscosity, breakdown viscosity

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