153 A. Che Rohani, O. Normah, T. Zahrah, C.M. Che Utama and I. Saadiah J. Trop. Agric. and Fd. Sc. 37(2)(2009): 153–161 Quality of fsh fllet from pond-raised red tilapia and its utilisation in the development of value-added product (Kualiti flet tilapia kolam tanah dan penggunaannya untuk pembangunan produk tambah nilai) A. Che Rohani*, O. Normah**, T. Zahrah***, C.M. Che Utama**** and I. Saadiah**** Keywords: tilapia fllet, tilapia quality, muddy favour, value-added product Abstract The eating quality, fllet yield, protein and fat contents of pond-raised red tilapia were evaluated. The effects of water depuration process on the removal of muddy taste and the development of a value-added product were also studied. The skin- on fllet yield ranged 32–33% while the protein and fat contents of the fllets ranged 16–17% and 1– 4% respectively. The fllet yield and protein content were not signifcantly (p >0.05) affected by the types of feed. However, the fat content of tilapia fed with the commercial feed and traditional feed were signifcantly higher (p <0.05) than those fed on formulated feeds with and without vitamin E. No depuration was required for fsh fed with formulated feeds. Fish fed on commercial and traditional feed need at least 8 h of water depuration process to leach out the muddy taste and increase their acceptability. Geosmin was not detected in all samples. Tilapia fllet battered with tempura battermix comprising 62% wheat four, 30% corn starch and 8% rice four was the most acceptable. *Food Technology Research Centre, MARDI Station, Kuala Terengganu, P.O. Box 3, 20700 Kuala Terengganu, Terengganu, Malaysia **Food Technology Research Centre, MARDI Headquarters, Serdang, P.O. Box 12301, 50774 Kuala Lumpur, Malaysia ***Technical Services Centre, MARDI Headquarters, Serdang, P.O. Box 12301, 50774 Kuala Lumpur, Malaysia ****National Prawn Fry Production and Research Centre, Department of Fisheries, Kg. Pulau Sayak, 08500 Kota Kuala Muda, Kedah, Malaysia Authors’ full names: Che Rohani Awang, Normah Omar, Zahrah Hj Talib, Che Utama Che Musa and Saadiah Ibrahim E-mail: cra@mardi.gov.my ©Malaysian Agricultural Research and Development Institute 2009 Introduction The term ‘off-favour’ in freshwater fsh is used to describe the objectionable favour due to the accumulation of odorous compounds within the fsh tissue produced from biological origins (Smith et al. 2008). It is estimated that over 30% of the potential revenue from catfsh industry in the United States of America is lost from off-favour contamination (Eagle et al. 1995). The problem of off-favours in the catfsh industry in the United States of America has been studied by many researchers (Johnsen and Lyold 1992; Lorio et al. 1992; Johnsen and Dionigi 1994; Johnsen and Bett 1996; Johnsen et al. 1996). The compounds responsible for this problem were reported to be geosmin and 2-methylisoborneol (MIB) produced by bacteria, actinomycetes and blue-green algae such as Oscillatoria (Johnsen and Bett 1996; Johnsen et al. 1996). An ‘earthy/musty’ off-favour was attributed to MIB while an ‘earthy/rotten wood’ off-favour was attributed to geosmin. Fish can rapidly absorb these compounds