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: 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