ABSTRAK
Air terozonasi merupakan salah satu solusi untuk mempertahankan kualitas tahu. Ozon memiliki sifat antimikroba yang tinggi dan sudah diakui keamanannya jika dikontakkan dengan produk pangan. Tujuan dari penelitian ini adalah untuk melihat pengaruh durasi kontak serta penggantian air terozonasi dalam mempertahankan mutu tahu. Parameter mutu yang diamati adalah perubahan jumlah total bakteri mesofil aerobik TBMA , pH, kadar air, dan kadar protein. Tahu dikontakkan dengan air terozonasi 0,32 mg O3/L selama 40, 80, dan 120 menit serta dilakukan penggantian air terozonasi 0,32 mg O3/L sebanyak 1 dan 2 kali selama 120 menit. Hasil menunjukkan bahwa semakin lama durasi kontak, semakin rendah laju penurunan mutu tahu. Durasi kontak selama 120 menit mampu mendesinfeksi TBMA sebanyak 51 dan menekan laju perubahan pH, kadar air, dan kadar protein. Selain itu, penggantian air terozonasi yang semakin sering juga dapat menekan laju perubahan mutu tahu. Pada 2 kali penggantian, jumlah TBMA terdesinfeksi mencapai 96 . Penelitian ini menunjukkan bahwa perlakuan dengan 2 kali penggantian air terozonasi mampu mempertahankan mutu tahu paling baik dibanding perlakuan lainnya.

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ABSTRACT
Ozonated water is one of many solutions to preserve the quality of tofu. Ozone is an anti microbial agent and already recognized as safe to be contacted with food. The aim of this research is to see the effect of exposure time and replacement of ozonated water in preserving tofu rsquo s quality. The quality parameters that are observed in this research are total mesofilic aerobic bacteria TMBA , pH, water content, and protein level. The tofu is exposed to ozonated water 0,32 mg O3 L for 40, 80, and 120 minutes. For water replacement, tofu is exposed to ozonated water 0,32 mg O3 L for 120 minutes and the water replacement occurred once and twice unreplaced water is observed as well . 120 minutes exposure is able to disinfect 51 TMBA and suppress the rate of change in pH, water content, and protein level in tofu. Moreover, water replacement every 40 minutes is able to disinfect 96 TMBA and suppress the rate of change in pH, water content, and protein level as well. This research shows that replacing ozonated water every 40 minutes is the most effective treatment among others in preserving the quality of tofu.