Judul: Aplikasi Kitosan dengan Penambahan Ekstrak Bawang Putih sebagai Pengawet dan Edible Coating Bakso Sapi
Abstrak: Chitosan is biopolymer derived by deacetylation of chitin, a major component of the shell of crustacean such crab, shrimp and crawfish. Chitosan is suitable as natural preservative and antimicrobial of edible coating. The applications of chitosan in food industries for food formulation for binding, gelling and thickening and stabilizing agent. Chitosan has the antimicrobial activity that can inhibit the growth of bacteria and fungi. The objectives of the research were to enchance the antimicrobial capacity of chitosan by adding garlic extract and to apply it for extending the shelf life of beef meatball. Antimicrobial activities of chitosan and chitosan enriched with garlic extract were assessed by agar diffusion methods. It showed that chitosan solutions of 1% (w/v) enriched with garlic extract 2% (v/v) could inhabited Pseudomonas aureginosa and Bacillus cereus. The application chitosan enriched with garlic extract as preservative shelf life agent could extend the shelf life of meatball only for 12 hours while its application of chitosan as edible coating could extended the shelf life of meatball until 24 hours for the same condition (stored at room temperature). This result revealed that the application of chitosan with or without garlic extract as edible coating were more effective in controlling microbiological growth in meatball than as preservative agent. The physical analysis of the final product showed that the application of chitosan as preservative agent could increase the gel strength of meatball due to its gelling properties. The microstructure of meatball surface ware observed with SEM. The micrographs showed that the surface of meatball coated with chitosan were more smooth and compact that those of meatball without coatings.
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Judul: Penggunaan Khitosan Sebagai Antimikroba pada Bakso Daging Sapi yang Dibuat dengan Penambahan Wortel
Abstrak: Meatball is a perishable meat product, therefore it needs some preservative to make it has a longer shelf-life. In this study, the method used was factorial design with completely randomized design (CRD) as basic. Chitosan as natural preservative was added in meatball processing as much as 0%, 0.1%, and 0.3%. In addition, 5% of carrort was added too. Chitosan antibacterial activity was analyzed once, meanwhile meatball’s micribiological analysis (S. aureus, E. coli, and Salmonella), pH, and aw was conducted on day 0, 4, 8, and 12. One hundred percent chitosan was more effective to inhibit E. coli than S. aureus and Salmonella. Fifty percent of chitosan can reduce population of E. coli from 3.65 x 1011 to 2.66 x 108. The addition of 0.1% and 0.3% chitosan in meatball processing eliminized E. coli population since day 0 until 12 days storage. There was no interaction between chitosan level and storage period towards the meatball’s population of S. aureus, Salmonella, and aw value. Meatball’s pH decreased on day 12. Meatball contains 102.45 IU beta-carotene and contributes 1.46% and 2.05% women’s and men’s need of vitamin A, respectively. Chitosan can replace chemical preservative in meatball manufacturing and carrot addition can supply human’s need of vitamin A.
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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