This study aimed to evaluate the effectiveness of red dragon fruit (Hylocereus polyrhizus) peel extracts addition on beef sausages. Red dragon fruit peel extracts were obtained by maceration using solvent at pH 5. Phytochemical characteristics, total phenols, antioxidant, and antimicrobial activity of the peel extracts were observed. Antioxidant and antimicrobial activities of the extracts were associated with high phytochemical compounds and total phenols contained in the extracts. Red dragon fruit peel extracts with various percentages (0%, 20%, 30%, and 40%) were added on beef sausages, and their physicochemical characteristics, nutrients, antioxidant activity, and microbiological profile were analyzed. The data were analyzed using analysis of variance and Duncan's multiple range test. Results showed that the addition of red dragon fruit peel extracts significantly reduced texture values, but increased intensity of luminosity, intensity of red color, and intensity of yellow color (P<0.05) beef sausages. It could be concluded that red dragon fruit peel extract containing phytochemical compounds was effective as an antibacterial agent and natural antioxidant. The addition of red dragon fruit peel extracts was effective in increasing the antioxidant activity and decreasing TBARS values. The addition of red dragon fruit peel extract did not affect the reddish colorization of beef sausages, but it was capable of increasing the yellowish colorization on beef sausage.Keywords: antimicrobial, antioxidant, beef sausage, red dragon fruit peel extract ABSTRAK Penelitian ini bertujuan untuk mengevaluasi efektivitas penambahan ekstrak kulit buah naga merah (Hylocereus polyrhizus) pada sosis daging sapi. Ekstrak kulit buah naga merah dihasilkan dengan maserasi menggunakan pelarut pH 5, dan dilakukan pengamatan karakteristik fitokimia, total fenol, aktivitas antioksidan, dan antimikrob. Hasil analisis menunjukkan bahwa ekstrak kulit buah naga merah memiliki aktivitas antioksidan dan antimikrob alami karena memiliki kandungan senyawa fitokimia dan total fenol dalam ekstrak yang tinggi. Ekstrak kulit buah naga merah dengan persentase berbeda (0%, 20%, 30%, dan 40%) ditambahkan pada pembuatan sosis, dan dilakukan pengamatan karakteristik fisikokimia, zat gizi, aktivitas antioksidan, dan mikrobiologi. Data diolah dengan analisis ragam (ANOVA) dan dilanjutkan uji perbandingan berganda menggunakan uji Duncan. Hasil analisis menunjukkan bahwa penambahan ekstrak kulit buah naga merah menurunkan nilai tekstur, tetapi meningkatkan intensitas kecerahan, intensitas warna merah, dan intensitas warna kuning secara signifikan (P<0.05) sosis daging sapi. Dapat disimpulkan bahwa ekstrak kulit buah naga merah yang mengandung komponen fisikokimia, efektif sebagai antimikroba dan antioksidan alami. Penambahan ekstrak kulit buah naga merah mampu meningkatkan aktivitas antioksidan, dan menurunkan nilai thiobarbituric reactive substance (TBARS). Penambahan ekstrak kulit buah naga merah belum efektif meningkatkan intensitas warna merah sos...

Bacteriocins produced by Indonesian lactic acid bacteria Lactobacillus plantarum IIA-1A5, IIA-1B1, IIA-2B2 were purified and characterized. Plantaricin W gene had been successfully amplified from all strains. This amplicon showed the expected 200 bp size of plantaricin W gene. This bacteriocins purified from L. plantarum IIA-1A5, IIA-1B1, and IIA-2B2 were named plantaricin IIA-1A5, IIA-1B1, and IIA-2B2. Purification by cation exchange chromatography increased the purity (fold) and activity of plantaricins. Purity of plantaricin IIA-1A5 was increased by 3.13 fold with specific activity 13.40 AU/mg. Plantaricin IIA-1B1 had 2.98 fold purity with specific activity 5.12 AU/mg, while purity of plantaricin IIA-2B2 was 1.37 fold with specific activity 7.70 AU/mg. All plantaricins could inhibit the growth of pathogenic bacteria, such as Escherichia coli, Salmonella typhimurium, Bacillus cereus, and Staphylococcus aureus. Plantaricins could be digested by trypsin. Stability of plantaricins at 80 oC for 30 min and at 121 oC for 15 min were affected by type of plantaricin and species of pathogenic bacteria. Generally, plantaricin IIA-1A5 was better as antimicrobial agent than plantaricin IIA-1B1 and plantaricin IIA-2B2

No abstract

Salah satu tujuan pengawetan pangan adalah untuk memperpanjang masa simpan. Bahan pengawet alami dapat digunakan sebagai senyawa antimikroba, salah satu contohnya adalah bakteriosin yang diproduksi oleh bakteri asam laktat. Tujuan penelitian ini adalah untuk mengevaluasi aktivitas antimikroba bakteriosin yang diproduksi oleh bakteri asam laktat indigenus Lactobacillus plantarum 2C12 yang diisolasi dari daging sapi lokal dan mempelajari kualitas bakso yang ditambah dengan pengawet bakteriosin 0,3%, nitrit 0,3% dan kontrol (tanpa pengawet) selama penyimpanan (0, 3 dan 6 hari) pada suhu dingin (4 o C). Hasil penelitian menunjukkan bahwa bakteriosin yang diproduksi oleh L. plantarum 2C12 mampu menghambat pertumbuhan bakteri patogen Escherichia coli, Staphylococcus aureus and Salmonella Typhimurium. Efektivitas bakteriosin sebagai pengawet alami pada produk bakso dicapai dengan menghambat pertumbuhan total mikroba dan E.coli, yang tidak berbeda dengan nitrit. Penambahan bakteriosin dari L. plantarum 2C12 juga tidak berpengaruh terhadap perubahan kualitas fisik dan kimia bakso, sesuai dengan Standar Nasional Indonesia (SNI 01-3818-1995) untuk bakso.Kata kunci: bakso, bakteriosin, L. plantarum 2C12, pengawet alami ABSTRACTOne purpose of food preservation is to extend the shelf life of foods. Biological preservations can be conducted by adding antimicrobial substances, such as bacteriocin produced by lactic acid bacteria and has been characterized as biopreservatives. The aims of this research were to evaluate antimicrobial activity of bacteriocin produced by indigenous lactic acid bacteria Lactobacillus plantarum 2C12 isolated from local beef and to study the quality of beef meatball with 0.3% bacteriocin as biopreservative at different storage times (0, 3, and 6 days) in cold temperature (4 o C), compared to 0.3% nitrite and control (without preservative). The results showed that bacteriocin from L. plantarum 2C12 could inhibit pathogenic bacteria such as Escherichia coli, Staphylococcus aureus and Salmonella Typhimurium. Bacteriocin was effective as well as nitrite as biopreservatives of meatballs by inhibiting the growth of total microbes and E. coli. The addition of bacteriocin did not lead the physical and nutritional changes in the meatballs. The quality of meatball with bacteriocin treatment conformed with Indonesia National Standard of meatball.

Egg white lysozyme (EWL) has considerably a wide functional protein exhibiting antibacterial activity mainly against Gram-positive bacteria. The EWL is widely applied in food industry and is considerably safe. Despite its high potency, EWL of Indonesian poultry has never been studied and exploited. This study was aimed to purify EWL from two Indonesian poultry: kampung chicken and Cihateup duck, and compared to egg of commercial laying hens. The eggs in this study were obtained from field laboratory of Faculty of Animal Science, Bogor Agricultural University (IPB) and classified in AA quality based on the interior quality. First attempt to purify the EWL was performed by using ethanol precipitation yielding purified EWL which was still contaminated by other proteins, hence designated as partially purified EWL. Final concentrations of partially purified EWL of kampung chicken, commercial laying hens, and Cihateup duck were about 5800, 5400, and 5500 μg/mL, respectively. To confirm whether the use of ethanol in the purification affecting EWL antibacterial activities, the activities were examined against Staphylococcus aureus. It demonstrated that the partially purified EWL exhibited ability to inhibit S. aureus at 6 and 26 h suggesting that the method was feasible as it did not interfere EWL antibacterial activities. Yet, based on SDS-Page, purity was the issue in ethanol precipitation method. Further attempt using ion exchange chromatography at pH 10 successfully purified lysozyme as indicated by a single band corresponding to lysozyme size (~14 kD) free from bands of other proteins. Altogether, a single step of ion exchange chromatography is sufficient and promising to isolate EWL from Indonesian poultry for various industrial purposes.Key words: Indonesian poultry, lysozyme, egg, kampung chicken, Cihateup duck ABSTRAK Lisozim putih telur memiliki fungsi yang luas, salah satunya adalah memiliki aktivitas sebagai antibakteri terutama terhadap bakteri Gram positif. Lisozim dari putih telur �uga banyak diapli-. Lisozim dari putih telur �uga banyak diaplikasikan di industri pangan dan dinyatakan aman untuk pangan. Sampai saat ini lisozim dari putih telur yang berasal dari unggas lokal (Indonesia) belum dipela�ari dan dikembangkan. Tu�uan penelitian ini adalah melakukan purifikasi putih telur dari telur unggas lokal, yaitu ayam kampung dan itik Cihateup dibandingkan dengan telur ayam ras. Sampel telur yang didapatkan dari Laboratorium Lapang Fakultas Peternakan diklasifikasikan pada grade AA berdasarkan kualitas interior. Tahap pertama purifikasi lisozim putih telur dengan presipitasi etanol menghasilkan protein lain selain lisozim (purifikasi parsial). Konsentrasi lisozim putih telur hasil purifikasi parsial telur ayam kampung, ayam ras dan itik Cihateup masing-masing adalah 5800, 5400, dan 5500 ug/mL. Untuk melihat efek penggunaan etanol dalam proses purifikasi terhadap aktivitast antibakteri lisozim, kemampuan daya hambat lisozim terhadap Staphylococcus aureus telah dianalisis. Lisozim putih telur hasil pu...