Synthesis of graphite/PbTiO3 composite as a catalyst in photodegradation and photoelectrodegradation process of methyl orange have been conducted. The purposes of this research are to study the effect of radiation time, composition of composite, voltage and pH of solution for methyl orange degradation. Photodegradation process of methyl orange was carried out for 5; 10; 15; 20; 25 and 30 min. Ratio of graphite : PbTiO3 (w/w) were varied at 1:3; 1:2; 1:1; 2:1 and 3:1. Meanwhile, the applied voltages were 7.5; 10 and 12.5 V and the photoelectrodegradation was conducted under pH condition of 3; 7; and 11, respectively. The result showed that optimum composition of graphite/PbTiO3 in the methyl orange photodegradation was obtained at 1:1 ratio for 30 min with degradation up to 90.43% ± 0.062. The degradation reaction follows first order reaction with a rate constant of 0.0688 min-1. The optimum voltage is 10 V, in which it reduced the methyl orange concentration up to 92.65% ± 0 with a rate constant 0.0941 min-1 for first order reaction. The optimum pH is pH = 11, that provide methyl orange reduction up to 95.28% ± 0.082.

<p>The addition of garlic powder to gelatin from chicken claw waste was potentially developed as a natural preservative in food, especially for meat. Preparation of gelatin/garlic biocomposite was performed in three stages: synthesis of gelatin from chicken claw, garlic powder preparation as allicin source and preparation of biocomposite gelatin/garlic. The preparation of dry biocomposites was done by weighing the gelatin and garlic powder in weight ratio of 1 : 1 and 1 : 2 (w/w) in the total mass of 0.75 grams. For wet biocomposite preparation, the mixture of the powder was solved in 5 mL of lactic acid 2 %. Functional groups of gelatin, garlic and biocomposite were analyzed by <em>f</em><em>ourier transform infrared spectroscopy</em> (FTIR). The antibacterial activity of biocomposite against <em>Staphylococcus aureus</em> were tested using disc diffusion method. This test was performed on garlic powder, solvent and gelatin/garlic biocomposites powder in the ratio of 1 : 1 and 1 : 2 in 2 % lactic acid solvent. The biocomposite with a weight ratio of gelatin : garlic of  1 : 1 had the optimum diameter of inhibition zone. The effectiveness of biocomposite gelatin/garlic as natural preservative applied in meat was also physically studied by organoleptic analysis. Organoleptic analysis through the hedonic test was conducted on the parameters of color, smell, and texture of gelatin/garlic biocomposites-coated meat. The results showed that the addition of garlic can increase the effectiveness of gelatin as a natural preservative of meat for four days stored in closed packaging at room temperature.</p>

The addition of garlic powder to gelatin from chicken claw waste was potentially developed as a natural preservative in food, especially for meat. Preparation of gelatin/garlic biocomposite was performed in three stages: synthesis of gelatin from chicken claw, garlic powder preparation as allicin source and preparation of biocomposite gelatin/garlic. The preparation of dry biocomposites was done by weighing the gelatin and garlic powder in weight ratio of 1 : 1 and 1 : 2 (w/w) in the total mass of 0.75 grams. For wet biocomposite preparation, the mixture of the powder was solved in 5 mL of lactic acid 2 %. Functional groups of gelatin, garlic and biocomposite were analyzed by <em>f</em><em>ourier transform infrared spectroscopy</em> (FTIR). The antibacterial activity of biocomposite against <em>Staphylococcus aureus</em> were tested using disc diffusion method. This test was performed on garlic powder, solvent and gelatin/garlic biocomposites powder in the ratio of 1 : 1 and 1 : 2 in 2 % lactic acid solvent. The biocomposite with a weight ratio of gelatin : garlic of  1 : 1 had the optimum diameter of inhibition zone. The effectiveness of biocomposite gelatin/garlic as natural preservative applied in meat was also physically studied by organoleptic analysis. Organoleptic analysis through the hedonic test was conducted on the parameters of color, smell, and texture of gelatin/garlic biocomposites-coated meat. The results showed that the addition of garlic can increase the effectiveness of gelatin as a natural preservative of meat for four days stored in closed packaging at room temperature.

ABSTRAKGelatin dari cakar ayam telah berhasil diisolasi menggunakan metode hidrolisis asam dengan empat tahapan utama yaitu pelunturan lemak, demineralisasi, ekstraksi dan pengeringan. Rendemen hasil isolasi diperoleh sebesar 6,21 % b/b dari berat basah cakar ayam. Uji efektivitas gelatin sebagai bahan pengawet dilakukan secara fisika, kimia dan mikrobiologi yang diaplikasikan pada daging dan ikan meliputi analisis organoleptik, analisa bilangan peroksida, uji daya hambat dan perhitungan jumlah bakteri. Analisis organoleptik menggunakan uji hedonik memperlihatkan adanya perbedaan signifikan untuk parameter warna dan tekstur antara sampel yang dilapiskan gelatin dan sampel kontrol pada konsentrasi 1:1 (b/b). Pengujian bilangan peroksida dengan iodometri menunjukkan penggunaan gelatin pada daging dan ikan dapat menurunkan bilangan peroksida. Hasil uji daya hambat terhadap bakteri Staphylococcus aureus menunjukkan gelatin dengan konsentrasi 15 % memberikan zona hambat (zona halo) paling besar yaitu 19,44 ± 2,11 mm. Perhitungan jumlah bakteri memperlihatkan gelatin dapat menekan pertumbuhan bakteri sampai 75 %. Secara keseluruhan, hasil-hasil analisa tersebut menyimpulkan bahwa gelatin dari cakar ayam berpotensi untuk digunakan sebagai pengawet alami daging dan ikan karena memiliki aktivitas antibakteri yang terbukti secara fisika, kimia dan mikrobiologi.Kata Kunci : cakar ayam, daging, gelatin, ikan, pengawet alami ABSTRACT Gelatin has been successfully extracted from chicken clawsby acid hydrolysis method through four major stages of degreasing, demineralization, extraction and drying. The yield of extracted gelatin obtained from wet chicken claws was about 6.21 % (w/w). The effectiveness of gelatin as preservative applied in beef and fish was physically, chemically and microbiologically studied by organoleptic analysis, peroxide test, bacteria inhibition test and number calculation, respectively. Organoleptic analysis by hedonic test shows there were significant differences for color and texture parameters between gelatincoated samples and control samples at concentrations of 1:1 (w/w). Peroxide number analysis by iodometry indicates the use of gelatin in the preservation of meat and fish decreased the oxidation number. The result of inhibition test againts Staphylococcus aureus bacteria shows the gelatin concentration of 20 % provided greatest halo zone diameter

<p>The addition of garlic powder to gelatin from chicken claw waste was potentially developed as a natural preservative in food, especially for meat. Preparation of gelatin/garlic biocomposite was performed in three stages: synthesis of gelatin from chicken claw, garlic powder preparation as allicin source and preparation of biocomposite gelatin/garlic. The preparation of dry biocomposites was done by weighing the gelatin and garlic powder in weight ratio of 1 : 1 and 1 : 2 (w/w) in the total mass of 0.75 grams. For wet biocomposite preparation, the mixture of the powder was solved in 5 mL of lactic acid 2 %. Functional groups of gelatin, garlic and biocomposite were analyzed by <em>f</em><em>ourier transform infrared spectroscopy</em> (FTIR). The antibacterial activity of biocomposite against <em>Staphylococcus aureus</em> were tested using disc diffusion method. This test was performed on garlic powder, solvent and gelatin/garlic biocomposites powder in the ratio of 1 : 1 and 1 : 2 in 2 % lactic acid solvent. The biocomposite with a weight ratio of gelatin : garlic of  1 : 1 had the optimum diameter of inhibition zone. The effectiveness of biocomposite gelatin/garlic as natural preservative applied in meat was also physically studied by organoleptic analysis. Organoleptic analysis through the hedonic test was conducted on the parameters of color, smell, and texture of gelatin/garlic biocomposites-coated meat. The results showed that the addition of garlic can increase the effectiveness of gelatin as a natural preservative of meat for four days stored in closed packaging at room temperature.</p>