FILLET QUALITY DIFFERENCE OF TRIPLOID RAINBOW TROUT (ONCORHYNCHUS MYKISS) CULTURED UNDER DIFFERENT MODES

To investigate the fillet quality differences of triploid rainbow trout cultured under different modes, about 4 kg commercial fish cultured under cage culture (W), recirculating aquaculture system (G) and flowing pond (C) were used to analyze 111 quality indicators related to biometrical parameters, fillet texture, odor and nutritional quality. Results showed that there were significant quality differences between three groups. Fish cultured in cages obtained the highest value of hue (Hab°), hardness, cohesiveness, springiness, chewiness, liquid losses and water losses (P<0.05) and the lowest level of 1-heptanol, heptanal, octanal, nonanal odor activity value (OAV) and total OAVs (P<0.05). The condition factor, red/green chromaticity, lightness, salt soluble protein content, total fatty acids content and n-3 fatty acid content of triploid rainbow trout cultured in recirculating system were significantly higher than those in other groups (P<0.05). Fish cultured in flowing pond showed the lowest value of the condition factor, yellow/blue chromaticity, chroma (Cab*), moisture content, lipid content, n-3 fatty acid content, poly-unsaturated fatty acids (P<0.05) and the highest level of fillet yield, adhesiveness, fillet glycogen, 1-octen-3-ol, 2,3-octanedione, pentanal, heptanal, octanal, (E)-2-decenal OAV and total OAVs (P<0.05). In summary, cage cultured fish obtained firm and springy fillet with low content of volatile flavor compounds, recirculating system cultured fish had a reddish fillet color and high content of poly-unsaturated fatty acids, flowing pond cultured fish had a slender body shape, relatively high fillet yield and high content of volatile flavor compounds.