Color and flavor analyses of fillets from farm-raised rainbow trout (Oncorhynchus mykiss) fed low-phosphorus feeds containing corn or wheat gluten

Rainbow trout were fed one of three diets for 12 weeks: a low phosphorus diet containing corn gluten, a low phosphorus diet containing wheat gluten, or a commercial control diet. Fillets were analyzed by a colorimeter and by sensory preference tests. Raw fillets from fish fed the corn gluten-based diet had the highest b* values (yellow color) and received significantly lower visual acceptance scores than fillets from the other dietary treatments. Dietary supplementation with 100 μg/g canthaxanthin increased the a* values (red color) and improved visual preference scores of raw fillets from the corn-gluten fed fish. Incorporation of either corn gluten or wheat gluten into the diet did not adversely affect flavor of the fillets.