FISHERIES RESEARCH INSTITUTE,MOA,TAIWAN

The stunt tilapia which either raised in fresh or in brackish water, its anal fin give spine hardness in highest value (2.06；2.15 kg/mm), and followed by ventral fin (1.77；1.51 kg/mm) and dorsal fin (1.38；1.17 kg/mm ), vertebrae and opercular series give the lower value. Besides the anal fin, the spine hardness of tilapia raised in brackish water usually give the higher value than that of raised in fresh water. The distribution of higher hardness dorsal fin ranged from 7th to 14th of the spine, the ventral or anal fin ranged from 1st to 2nd of the spine. The vertebrae or opercular series of handless did not show the apparent difference with each other. The calcium/phosphate ratio varied with the different portion of the fin. The tilapia raised in fresh water has the higher hardness, but those raised in brackish water higher calicium in fin shows the different trend. The spine of farm tilapia could be softened by heating at 121℃, 2.01 atm for 60 min. However, further study on the appearance and texture of products was needed.