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: Isolasi dan identifikasi mikroorganisme indigenus dan aplikasinya pada fermentasi jagung serta karakterisasi sifat fisikokimia tepung yang dihasilkan
Abstrak: Corn is an important carbohydrate source in Indonesia. Local white corn is currently being developed including Anoman 1 (high amylose) and Pulut Harapan (low amylose) varieties. However, the utilization of corn flours and/or starches in native form have a less desirable physicochemical properties, especially with regards to retrogradation, syneresis, and low stability of pasta at high temperature and low pH properties. Consequently, there is a need to modify flour properties to increase the utilization. Traditionally, corn flour is made by soaking corn kernels in water. The spontaneous fermentation occurred during soaking and affected the physicochemical properties, but it’s difficult to achieve a consistent product. The purpose of this study to identify microorganisms that play a role in the fermentation process of corn, as well as the process of fermentation with the addition of a starter culture and studied the physicochemical properties of corn flour produced. The research was conducted in : (1) to isolate and identify microorganims which the role play during spontaneous fermentation of white local corn of Anoman 1 variety; (2) to design a starter culture of the microorganisms isolated to use for a controlled fermentation; (3) do the fermentation by adding a starter culture and characterize physicochemical properties of corn flour produced. Treatments consisted of: Spontaneous fermentation, i.e. water soaking of corn grits (as a control, SF); and fermentation with added starter culture containing microbes previously isolated without toxigenic microbe (CC); and (AC) fermentation of (CC) with additional amylolytic microbes after 16 hours of fermentation. The number of each microorganisms that added were 106 CFU / mL; (4) to study the physicochemical properties of corn flours of Anoman1 and Pulut Harapan varieties produced. Observations were done at 0, 36, 48, and 72 hours fermentation. The results showed that there were 16 microorganisms were identified included 8 species of molds (Penicillium chrysogenum, Penicillium citrinum, Aspergillus flavus, Aspergillus niger, Rhizopus stolonifer, Rhizopus oryzae, Fusarium oxysporum, Acremonium strictum), 3 species of yeasts (Candida famata, Kodamaea ohmeri, Candida krusei/incospicua), and 5 species of lactic acid bacteria, LAB (Lactobacillus plantarum1a, Pediococcus pentosaceus, L. brevis1, L. plantarum1b, and L. paracasei ssp paracasei3). Four molds and one yeast were amylolytic while none of the lactid acid bacteria (LAB). One from 8 species of molds identified was producing aflatoxin i.e. Aspergillus flavus. While all of yeasts and LAB species identified was non-toxigenic. So, the Aspergillus flavus was not used as a starter culture. All of non-toxigenic microbes identified, there were three (3) species of mold (Penicillium citrinum, Aspergillus niger, Acremonium strictum) and one (1) species of yeast (Candida famata) that were amylolytic, while all of LAB identified were non-amylolytic. The amylase activity changed during spontaneous fermentation (SF), where the activity was a maximum at 12 hours of fermentation. After that activity tended to decrease up to 72 hours of fermentation. To study the influenced of amylase activity to the flour during fermentation, was made the amylolytic culture that added after 16 hours fermentation to increase the activity . In general it can be concluded that the fermentation process caused the changes in the physicochemical properties of corn
Keyword: isolation, identification, microorganisms, physicochemical properties

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