Judul: Potensi Antimikroba Kayu Siwak (Salvadora persica Wall.) terhadap Staphylococcus aureus dan Pseudomonas aeruginosa serta Aplikasi pada Bakso Daging
Abstrak: Preservation of processed meat products have been carried out with the aim of extending the shelf life. Preserving is one important factor considering the risks that may be posed and one of them is the use of hazardous chemicals as preservatives. One of food product which is vulnerable given the addition of formalin was the meatball. Siwak has been known to have antimicrobial activity but its application for foods has not been widely explored. The study consist of four phases, extraction of siwak well diffusion test, dillution broth to determine MIC, and applications in meatballs. Well diffusion test showed that siwak’s extract has antimicrobial activities against Staphylococcus aureus bacteria and Pseudomonas aeruginosa bacteria which have inhibition zones of 21.10 mm and 20.11 mm respectively. Dillution broth test showed that the minimum concentration which is can inhibit bacterial growth was 50% (v/v) of siwak’s aqueous extract. Application in meatballs showed that siwak extract can hold down bacterial growth up to 98,17% in Staphylococcus aureus bactery.
Keyword: natural preservative., antimicrobial activity, siwak, preservation

Judul: Potensi Antimikroba Daun Tin (Ficus carica) terhadap Staphylococcus aureus dan Pseudomonas aeruginosa serta Aplikasinya pada Produk Bakso
Abstrak: In Indonesia there are many abuse of formaline use in meatball. This study was conducted to explore antimicrobial activity of fig leaf and to find alternative of preservation technology which is effective and safe especially for meatball. Fig leaf has been used as medicine for various health problems but its application in food has not been widely explored. Based on the extraction with maceration method, extraction of fig leaf using ethanol as solvent showed a higher yield than using hexane. Based on the well diffusion assay, in Staphylococcus aureus plate the greatest inhibition diameter was found by 10%(w/v) or 100 mg/ml ethanol extract i.e 8.07 mm and the smallest by 10%(w/v) or 100 mg/ml hexane extract i.e 3.86 mm. In Pseudomonas aeruginosa plate the inhibition diameter of ethanol and hexane extract were 5.70 mm and 4.97 mm respectively. The minimum inhibition concentration of ethanol fig leaf extract against Staphylococcus aureus was 10 mg/ml or 10% (w/v). Therefore ethanol fig extract was applied in meatball with two treatments i.e. mixing and boiling. The concentration of ethanol fig leaf extract which was applied were 3, 5, 10(%). Based on Total Staphylococcus aureus counts, extract from both of treatments (5% and 10%) could reduce S. aureus in meatball till 6 hours at room temperature. Extract by mixing treatment could reduce S. aureus more than extract by boiling treatment. The most effective concentration from ethanol fig leaf extract was 5% (w/w) by boiling treatment. It could extend meatball’s shelf life till 72 hours in room temperature.
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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