Reported about 1 year ago
Many seafood enthusiasts often store fresh fish at home but are puzzled by the yellowing of frozen fish. The Fisheries Agency explains that the yellowing is due to the oxidation of the oils in the fish upon exposure to air. While low-temperature storage can slow down the oxidation process, it cannot completely prevent it. If there is air present during storage, the oils in the fish will continue to oxidize, causing the color change. Despite modern technology allowing for good preservation of fish freshness, the issue of yellowing persists even when fish are stored in the freezer at home.
Source: YAHOO