Inaktivasi residu oksitetrasiklin dalam telur dengan mineral logam divalen :: Implikasinya pada pengolahan dan keamanan pangan

HINTONO, Antonius, Promotor Prof. Dr. Ir. Mary Astuti, M.S

2008 | Disertasi |

Larutan oksitetrasiklin dalam air relatif tidak tahan panas, dan kompleks oksitetrasiklin dengan logam divalen bersifat inaktif; namun residu oksitetrasiklin dalam telur masih menunjukkan aktivitasnya walaupun telur mengandung mineral logam divalen dan telah diolah dengan panas, sehingga berpotensi tidak aman bagi konsumen. Penelitian ini mempelajari peran mineral logam divalen dan pemanasan dalam inaktivasi oksitetrasiklin dan residu oksitetrasiklin pada telur. Penelitian dilakukan dengan percobaan secara in vitro dan in vivo. Secara in vitro, larutan oksitetrasiklin ditambah garam mineral logam divalen (kalsium, magnesium dan zat besi), dipanaskan dan diuji aktivitas antibakterinya; larutan oksitetrasiklin ditambah protein telur (ovalbumin, konalbumin, fosvitin) dan zat besi lalu dipanaskan dan diuji aktivitas antibakterinya. Secara in vivo, ayam diberi oksitetrasiklin lewat air minum dengan dosis 2 g/l air minum selama 7 hari berturut-turut; telur beresidu oksitetrasiklin dimasak dan diuji kandungan residu dan aktivitas antibakterinya; zat besi ditambahkan pada ransum dan diberikan pada ayam yang juga diberi oksitetrasiklin; telur beresidu oksitetrasiklin, yang masih menunjukkan aktivitas antibakteri setelah pemasakan, ditambah zat besi, dipanaskan dan diuji kandungan residu oksitetrasiklin dan aktivitas antibakterinya. Hasil menunjukkan bahwa residu oksitetrasiklin beserta aktivitas antibakterinya sudah ditemukan dalam cangkang dan putih telur pada hari kedua pemberian oksitetrasiklin pada ayam, sedangkan dalam kuning telur baru ditemukan pada hari keempat pemberian. Residu masih terdeteksi baik pada putih maupun kuning telur hari ke-7 penghentian oksitetrasiklin. Pemanasan putih telur 70 – 80oC selama 15 – 20 menit dapat mengurangi residu oksitetrasiklin, tetapi tidak dapat menghilangkan dan menginaktifkannya; sedangkan pemanasan kuning telur 70oC selama 15 menit sudah dapat menghilangkan residu oksitetrasiklin 1,55 ppm dan aktivitasnya, namun tidak dapat menghilangkan residu oksitetrasiklin 3,74 ppm dan aktivitasnya. Magnesium dan protein telur berperan dalam ketahanan panas oksitetrasiklin. Oksitetrasiklin yang ditambah magnesium masih menunjukkan aktivitas antibakterinya pada pemanasan 100oC selama 20 menit. Protein telur dapat mempertahankan aktivitas antibakteri oksitetrasiklin pada pemanasan 70oC selama 20 menit dan menghambat penurunan aktivitas pada pemanasan 80oC selama 20 menit. Zat besi paling efektif menginaktifkan oksitetrasiklin dibandingkan kalsium dan magnesium, namun demikian konalbumin dalam putih telur dan fosvitin dalam kuning telur dapat menghambat kemampuan zat besi dalam menginaktifkan oksitetrasklin. Peningkatan zat besi dalam putih dan kuning telur dapat mengurangi residu oksitetrasiklin dan menurunkan aktivitasnya, dan dengan pemanasan dapat menginaktifkannya; namun demikian peningkatan zat besi ransum ayam hanya dapat meningkatkan zat besi kuning telur, tetapi tidak dapat meningkatkan zat besi putih telur.

Oxytetracycline in aqueous solution is relatively unstable to heat and complex of oxytetracycline and divalent metal is inactive, however oxytetracycline residue in egg still shows its activity although egg contains minerals of divalent metal and has been processed by heat so that is potentially not safe for consumer. This research aim was to study the role of divalent metals and heating in inactivation of oxytetracycline and oxytetracycline residue in egg. The study was conducted by in vitro and in vivo experiments. By in vitro, oxytetracycline solution was added by minerals of divalent metal (calcium, magnesium and iron), heated and evaluated for their antibacterial activity; oxytetracycline solutions were added by egg proteins (ovalbumin, conalbumin, phosvitin) and iron, heated and evaluated for their antibacterial activity. By in vivo, laying hens were administered oxytetracycline via drinking water with dose 2 g/l for 7 succcessive days; the eggs containing oxytetracycline residues laid by the hens were cooked and evaluated for their residue and antibacterial activity; iron was added to diet and fed to laying hens where as the laying hens were administered oxytetracycline; eggs containing oxytetracycline residues, which still showed the activity after cooking, were added by iron, heated and evaluated for the oxytetracycline residues and their antibacterial activity. The results indicated that oxytetracycline residues and their activity had been found in egg shells and whites since the 2nd day of administering oxytetracycline, whereas in yolks since the 4th day. The residues were still found both in egg whites and yolks on the 7th day of stopping oxytetracycline administration to hens. Heating egg whites at 70 to 80oC for 15 to 20 minutes could reduce, but not eliminate and inactivate the residues of oxytetracyline, whereas in yolks heating at 70oC for 15 minutes had been able to eliminate 1.55 ppm of oxytetracycline residue and its activity, however it could not eliminate 3.74 ppm of oxytetracycline residue and its activity. Magnesium and egg proteins had role in the heat stability of oxytetracycline. Oxytetracycline added by magnesium still showed it activity at heating 100oC for 20 minutes. Egg proteins could also maintain activity of oxytetracycline at heating 70oC for 20 minutes and retarded the decrease of activity at heating 80oC for 20 minutes. Iron is the most effective in inactivating oxytetracycline compared to calcium and magnesium, however conalbumin of egg white protein and phosvitin of yolk protein could reduce the ability of iron to inactivate oxytetracycline. Increasing iron in egg whites and yolks could reduce oxytetracycline residues and decrease their activity, and by heating, could inactivate its. however the increase of iron in hens diet could increase iron in yolk only, but not in egg white.

Kata Kunci : Oksitetrasiklin,Ayam,Telur,Residu,Aktivitas antibakteri,Mineral logam divalen,Pemanasan, oxytetracycline, hen, egg, residue, antibacterial activity, divalent metal, heating