Chemical, Physical and Sensorial Compositions of Farmed and Wild Yellow Perch (Perca flavescens), Southern Flounder (Paralichthys lethostigma) and Coho Salmon (Oncorhynchus kisutch)
This study compared chemical, physical and sensorial properties of wild and farmed fish.
Farmed yellow perch fillets showed higher lipid contents (2.78% vs. 1.39%); softer texture (0.41 J/g vs. 0.53 J/g); whiter color (higher L* and lower b*values); different fatty acid profile (higher n-3/n-6 ratio), and mineral composition, when compared to their wild counterparts. Similar amino acid profiles and flavor were found between treatments.
Dietary protein by itself influenced color and flavor of yellow perch fillets. Yellow perch fed the highest protein concentrations exhibited higher b* (yellow) values and overall flavor was significantly different (p ¡Ü 0.05) between fish fed a 45% and 55% crude protein (CP) diet.
A 12-week feeding trial determined that southern flounder protein requirement to achieve maximum weight was around 50% CP.
Farmed southern flounder were found to be higher in lipid content (3.04 % vs. 1.61%), softer (0.24 J/g vs. 0/33 J/g), different in color (lower a* [green to red]), mineral, fatty acid composition (higher n-3/n-6 ratio) and flavor, than wild.
The effect of a crab meal-supplemented diet, on flavor and body composition of flounder was analyzed. The inclusion of crab meal as a flavor enhancer affected the flavor and also influenced color of the fillets (lower L* [lightness] and higher b* values).
Wild, farmed and growth-enhanced transgenic coho salmon (market-size) were compared, regarding their body composition and nutritional value. All treatments showed highest lipid levels in the ventral frontal sections and lowest in the tail (p ¡Ü 0.05). Overall wild fish showed lower lipid levels and firmer values in the tail sections (p ¡Ü 0.05). The insertion of the growth hormone gene affected lipid deposition, texture and color, since transgenic fish showed firmer texture than farmed and similar lipid contents even when fed a high-energy diet. L*, a* and b* values were similar for wild and transgenic coho in most of the body zones. Fillet mineral and amino acid profiles were similar across all groups. No differences were observed in flavor between farmed and wild coho, while panelists preferred the appearance of farmed, when compared to transgenic coho.
Advisor:Ewen McLean; Sean F. O''Keefe; George J. Flick, Jr; Susan E. Duncan; Steven R. Craig
School:Virginia Polytechnic Institute and State University
School Location:USA - Virginia
Source Type:Master's Thesis
Keywords:food science and technology
Date of Publication:12/02/2004