Axe

Group 1

Summer flounder * Flathead sole * Black rockfish ' Sheepshead • Atlantic cod ■ Gag — Pacific Ocean perch Gray triggerfish — Sablefish — Silver hake Thorneyhead rockfish -Tilefish — Redbanded rockfish — Golder tilefish Yellowtail grouper — Scamp Channel catfish — Silvergray rockfish — Rex sole — Rock sole White grunt — Speckled hind — Snowy grouper — Black sea bass —1 Goosefish, south — Yellowfin tuna — Hammerhead shark ■— Thresher shark

Group 2

Starry flounder —i

Ladyfish —j-Sandbar shark —1 Tiger shark -Lemon shark -Sharpnose shark -Atlantic herring -

Group 3

Figure 5. Grouping diagram (modified tree) of 74 species by cluster analysis showing their relationships (amalgamations) based on four significant flavor attributes.

identified with the meaty flavors prominent in some species of tuna and shark. Although organic sulfides occur naturally in fish, natural feeds such as Spiratella heliciana, a plankton that contains dimethyl-/?-propiothetin that can be converted to DMS, can also contribute to different flavors in fish.

In addition to the various flavors attributed to organic sulfides, alcohols, ketones, and phenols have also been identified as producing their own set of characteristic flavor notes in fish. Phenols are known to cause medicinal flavors and aromas in shrimp and crayfish and possibly are responsible for the metallic-bitter or iodoformic odors and flavors sometimes seen in flatfish, such as Dover or English sole. These flavors and odors are also found in natural feeds, such as algaes and seaweeds.

Fishy odors and flavors, in contradistinction to the desirable fresh-fish flavor, predominantly found in cooked dark-muscled fish like herring or mackerel and sometimes in gadoids (cods, haddocks, hakes, and pollock), are generally caused by the presence of TMA. TMA is easily formed by the breakdown of trimethylamine oxide, which can be accumulated through the diet. The combination of lipid oxidation with TMA appears to contribute to the overall fishy odor and flavor.

The fish oil flavor, identified in the NMFS nomenclature work, was associated with the initial oxidation offish lipids (triglycerides and fatty acids) and is best described as resembling a light cod liver oil similar to the oils used in packing sardines, and also containing grassy notes (odor of fresh-mown grass) as in fresh king or coho salmon, or a nutty-buttery or light creamy flavor characteristic of the mild-flavored black cod (sablefish).

Because of their close relationship to the environment, fish frequently reflect this connection with off-flavors or taints. For example, descriptors such as earthy, muddy, or musty are often used to describe the flavor of catfish or trout that are raised in artificial environments. Although these flavor notes are often attributed to artificial feeds, the flavors can also be caused by microorganisms living in the water, soil, or pond detritus where the fish are raised. In the marine environment, muddy flavor found in bream were identified as coming from the blue-green algae Oscil-latoria agardhii. These off-flavors are also thought to be produced by heterocyclic organic compounds such as 1,10-írans-dimethyl-íra/is-(9)-decolol or geosmin and 2-methyl-lisoborneal and are the metabolic products of certain species of cyanobacteria and actinomyces.

It is easy to see that edibility profiling combined with the clustering technique provides useful tools for establishing a rational basis for the development offish edibility groups that can be conveniently used in marketing fishery products. Results from the nomenclature studies conducted by NMFS laboratories show that, although they are complex, fish can indeed be classified into groups according to their inherent flavor characteristics. These studies also suggest that flavor profiling can be used to classify new or commercially underutilized species of fish into edibility groups as they enter the market. Because we limited ourselves to the subject of flavor profiling in this section, only a small portion of the NMFS nomenclature work was described here. However, more species were evaluated but were not included in this discussion because the minimum replicate requirements were not met. Considerably more work remains to be done to complete the edibility profiling.

Berry Boosters

Berry Boosters

Acai, Maqui And Many Other Popular Berries That Will Change Your Life And Health. Berries have been demonstrated to be some of the healthiest foods on the planet. Each month or so it seems fresh research is being brought out and new berries are being exposed and analyzed for their health giving attributes.

Get My Free Ebook


Post a comment