Judul: The Application of Ultraviolet Light and High Pulsed Electric Field Method to reduce Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922 in Goat Milk
Abstrak: Susu kambing memiliki keistimewaan karena tinggi kandungan protein dan vitamin A, memiliki jumlah laktosa yang lebih sedikit sehingga tidak menyebabkan diare, serta memiliki globula lemak susu yang lebih kecil dan seragam sehingga mudah diserap organ pencernaan. Masyarakat mempercayai bahwa susu kambing segar lebih berkhasiat bagi kesehatan, sementara hasil penelitian Taufik et al. (2008) menyatakan bahwa rendahnya kualitas mikrobiologis susu kambing segar yang beredar di pasaran. Metode konvensional yang umum digunakan untuk menginaktivasi mikroorganisme patogen pada susu adalah metode termal. Proses termal tidak hanya membunuh mikroorganisme berbahaya, namun juga berpotensi mengakibatkan perubahan sensori seperti rasa, warna, tekstur, dan flavour dengan adanya cooked flavor (terlalu masak atau gosong), serta kehilangan sebagian kandungan nutrisi dan sifat fungsional susu. Alternatif teknologi nontermal yang dapat diaplikasikan pada bahan pangan diantaranya adalah radiasi sinar ultraviolet (UV) dan High Pulsed Electric Field (HPEF). Penelitian ini bertujuan untuk mengetahui efektivitas aplikasi kombinasi ultraviolet dan High Pulsed Electric Field dalam mereduksi bakteri patogen Gram positif Staphylococcus aureus dan Gram negatif Escherichia coli pada susu kambing, serta perubahan karakteristik fisik dan kimia yang diakibatkan oleh metode tersebut. Penelitian ini terbagi atas penelitian pendahuluan dan penelitian utama. Penelitian pendahuluan meliputi penentuan jumlah dosis UV yang optimal dengan taraf perlakuan penggunaan 1, 2, atau 3 reaktor UV berdasarkan karakteristik fisik, kimia dan reduksi TPC (Total Plate Count), dan dilanjutkan dengan penentuan frekuensi HPEF dengan taraf perlakuan frekuensi 10 Hz, 15 Hz, atau 20 Hz. Penelitian utama yaitu mengaplikasikan kombinasi dosis UV dan frekuensi HPEF terbaik untuk menginaktivasi Staphylococcus aureus atau Escherichia coli yang direkontaminasi dalam susu segar dengan populasi 105 cfu/ml. Spesifikasi dosis UV yang digunakan 2,27 kGy, sedangkan perangkat HPEF memiliki kuat medan listrik 31,67 kV/cm, kuat arus 0,11 mA, dan jarak antar elektroda 3 mm. Rancangan percobaan yang digunakan pada penelitian pendahuluan adalah Rancangan Acak Lengkap (RAL) untuk mempelajari pengaruh aplikasi kombinasi UV dan HPEF yang berbeda terhadap karakteristik fisik (berat jenis, pH, viskositas, konduktivitas, titik beku dan panas spesifik) dan kimia (kadar protein, lemak, dan laktosa) susu kambing segar, sedangkan penilaian pengaruh aplikasi UV dan HPEF terhadap kualitas mikrobiologis susu diinterpretasikan secara deskriptif. Penelitian pendahuluan menunjukkan bahwa penggunaaan jumlah reaktor UV maupun frekuensi HPEF yang berbeda tidak berpengaruh (P>0,05) terhadap karakteristik fisik dan kimia susu kambing. Dosis UV terbaik untuk menekan pertumbuhan TPC adalah 3 reaktor UV, dan frekuensi HPEF terbaik adalah 15 Hz. Perlakuan kombinasi radiasi sinar UV dan frekuensi HPEF mampu mereduksi Staphylococcus aureus ATCC 25923 sebesar 36,58% atau Escherichia coli ATCC 25922 sebesar 7,41%.
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Judul: Development Ultraviolet (UV) and High Pulsed Electric Field (HPEF) combination pasteurization system for goat’s milk
Abstrak: Some efforts have been addressed in order to fulfill the demand of consumers towards goat’s milk products to produce a high quality and effective process for inactivating pathogenic bacteria without damaging the physical, chemical properties of milk, has minimal affects which causes quality and nutritional degradation and reduce, sensory acceptance value. One of alternative method is combination of the ultraviolet (UV) and high pulsed electric field (HPEF). The UV pasteurization instrument uses three reactors constructed in series system at UV-C 10 W and 253.7 nm wavelength with specification 1.80 J/cm2 dose per reactor. The specification of HPEF instrument is 31.67 kV/cm, 0.11 mA, oscilatory and 7.0 pulses for high electric field voltage, electrical current, pulse form and number of pulses, respectively with goat’s milk rate at 4.32 ± 0.71 cc/second. The material for the experiment was fresh goat’s milk sterilized using autoclave at 115oC for 3 minutes and ready for recontamination using Salmonella Typhimurium ATCC 14028, Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922. The bacteria were obtained from Integrated Laboratory of Faculty Animal Science, Bogor Agricultural University which had been grown in 105 cfu/ml concentration. The statistical analysis was conducted using Complete Randomized Design. Observed variables were total bacteria, pathogenic bacteria (S. Typhimurium, E. coli dan S. aureus) and physical, chemical properties before and after treatment. The result showed that the inactivation reduction rate using series system of UV series-HPEF at 5.50, 7.00 and 10.00 pulses were 70.00%; 89.49% and 85.67% respectively. The statistical analysis showed that the physical, chemical properties among treatments were insignificantly different (P>0.05). Inactivation rate was 0.52; 0.98 and 0.84 log cycle or 11.78; 22.04 and 19.01 log cfu/ml/hour, respectively; D value was 0.09; 0.05 and 0.05 hour, respectively. Whereas bacteria pathogen inactivation rate of Salmonella Typhimurium ATCC 14028, Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923 was 0.28; 0.07 and 0.19 log cycle, respectively. The observation of cell damage using SEM (Scanning Electron Microscopy) showed that Salmonella Typhimurium ATCC 14028 and Staphylococcus aureus ATCC 25923 cell had formation changes.
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Judul: Kontraksi pola graf klausa Bahasa Indonesia menggunakan metode knowledge graph
Abstrak: Knowledge graph is a new method of knowledge representation. In principle, knowledge graph consists of concept and relationship. There are already rules of constructing wordgraphs of noun, verb, adverb, adjective, preposition, and phrase. However to be able to represent the meaning of Indonesian text we still need other rules to represent clause and sentence. This research is mainly focused on constructing a subordinative clause graph and building rules of subordinative clause graph formation. In this research, subordinative clause is classified by analyzing the subordinative relationship (time, condition, if-relation, purpose, consessive, resemblace, because-relation, result, way-relation, tool-relation, complementation, attributive, equative, and comparative) and the structure of clause (the combination of subject, predicate, object, complement, and description). After the result of constructing subordinative clause graph is analyzed and formulated, the subordinative clauses are classified based on the same conjunction graph pattern and clause structure graph pattern, and we get 13 conjunction graph patterns and 48 clause structure graph patterns for subordinative clause in Indonesian.
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