Judul: Application of Edible Coating Bases Extract of Lindur (Bruguiera gymnorrhiza) and Chitosan on Peeled Off Shrimp
Abstrak: Peeled off shrimp is usually sold at supermarkets and displayed at an air conditioned equipped with lights. This condition causes the temperature of display room increase more than 10 °C from its initial temperature (-1.6 °C), therefore the products presented will suffer a quality degradation. Edible coating can be applied as a packaging to protect shrimps from any damage during storage, to extend the storage period and maintain products’ quality. Besides chitosan, the extract of fruit of lindur plant (that belongs to mangrove group) is suggested as have preservative and antimicrobial activities. In the present study, edible coating was formulated using a combination of chitosan (0 %, 1 %, 2 %) and lindur fruit extract (0 %, 1 %, 2 %). The study was conducted in two phases, there are introduction phase ( includes chemical analysis of fruit and flour lindur , characterization of chitosan (degree of deacetylation), making lindur flour, making of lindur extract, and analysis of antimicrobial activity. Primary Research Series using Black Tiger shrimp (includes TVB analysis, pH, TPC and hedonic sensory (color, aroma, texture and over-all) at 1 day and 7 days storage. Secondary Research Series using vannamei shrimp (includes TVB analysis, pH, TPC, Organoleptic Quality (texture, appearance and aroma of cooked and raw shrimp and flavor of cooked shrimp), Texture by Texture Profile Analyzer, and color analysis at 1 day , 4 days and 7 days storage . In experiments with the Black Tiger shrimp, edible coating from extracts lindur 1 % without chitosan (K0L1) and extract lindur 2 % without chitosan (K0L2 ) capable significantly lowering the pH value, TPC, and TVB compared with controls. Meanwhile, in experiments with shrimp Vannamei, edible coating from extracts lindur 2 % without chitosan (K0L2) capable of significantly lowering the pH value , TPC, and TVB peeled shrimp compared to controls on the storage 10 °C for 7 days. Physical parameters of color, texture and organoleptic characteristics of appearance, odor, texture, flavor and hedonic parameters also significantly different to the control parameters. The combination of chitosan and extracts lindur proved less than optimal in maintaining the microbiological parameters, physical parameters, and organoleptic parameters on peeled shrimp. I,oThis study demonstrated that lindur’s extract can be an alternative as antibacterial materials and it is effective as a natural preservative for peeled shrimp.
Keyword: edible coatings, lindur (Bruguiera gymnorrhiza), chitosan, peeled off shrimp

Judul: Aplikasi Khitosan sebagai Bahan Edible  Coating pada Produk Ikan Beku
Abstrak: Frozen process and storage is one of best method to keep fresheness of food during storage. Fish that processed and stored in frozen is potential for dehydration and microbial growth. Due to its antimicrobial agent, film formable, and good barrier of gas and moisture, chitosan try to be applied to frozen fish. This study consists of two steps, preliminary and main. Preliminary step was done to test pH of chitosan solution, antimicrobial, and water vapor permeability. Main step was done to test moisture content, total plate count, and organoleptic. This step used fish that filleted and coated by chitosan then stored in cold storage (-20 °C) for 15 days. The species of fish used is Sweetlips (Plectorhynchus sp.) with size 100-200 g (± 20 x 10 cm). Experimental design used in this research is Complete Random Factorial Design consisting of two factors. The first factor is the concentration of chitosan consisting of a three level, 1,0; 1,5; and 2.0% (b/v). Second factor is the concentration glycerol consisting of two level, 0,25 and 0,50 ml/g chitosan. The best combination of chitosan-glycerol then applied to the main step. The main step used fillet fish without coating and 0,4 mm thickness plastic (polypropylene/PP) wrapped as a benchmark. The preliminary step resulted chitosan with the concentration of 1,0% (b/v) and glycerol 0,25 ml/g chitosan as the best combination. This combination has pH value of 4,59; index of inhibition of E. coli 0,00; index of inhibition of S. aureus 0,03, and water vapor permeability (WVP) 1,6548 g.m-1.atm-1.day-1. Coating application on the frozen fish was done with the dipping method. The fish dipped for 30 seconds, then drained and kept in cold storage. The test of moisture content shows that in all samples of fish tend to show a decrease in moisture content. The value of moisture content of fish coated by chitosan is still lower then others. However, the value of the moisture content of the samples are still in tolerance of frozen fish (± 80%). For total plate count, the sample of fish coated by chitosan has a total value of microbes that lower than others. If compared with fish without coating, the value become 8-28 percent. If compared with the fish that wrapped with plastic, the value become 16-44 percent. In organoleptic (hedonic) test, by 17 panelists, the assessment indicates that the sample of the coating chitosan average ranged between normal (biasa) and quite like (agak suka). This range describes that the score of the assesment is above the average (score of 3-4).
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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. ,,,
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular.