Summary
Highlights
Seafood is any form of sea life consumed by humans, primarily fish and shellfish. It is broadly classified into three categories: white fish, oily fish, and shellfish.
White fish, found in tropical and subtropical environments, have less than 5% fat and possess backbones, cartilage, bones, gills, and fins. Fish are further categorized by their skeletal structure: flat fish (horizontally swimming, both eyes on top), round fish (vertically swimming, eye on each side), and boneless fish (cartilage instead of bones, often smooth skin without scales). Oily fish have a fat content of 10-25% and are rich in polyunsaturated fatty acids, with herring, sardines, and salmon as examples.
Shellfish have shells and indigestible skin. They are typically cooked when sold, except for oysters and scallops. There are two main types: crustaceans (shells act as shields, turn coral red when cooked, like crabs and lobsters) and mollusks (soft-bodied with hard, inedible shells). Mollusks are divided into univalves (one shell), bivalves (two hinged shells), and cephalopods (no outer shell, only a single internal shell called a pen, like squid and octopus).
Fish generally have a torpedo shape, with a rounded nose, thick middle, and tapered tail. Key external parts include the head (mouth, nostrils, gill cover), gills (for breathing by absorbing oxygen from water), scales (protective covering, preventing injury and disease, and indicating age), lateral line (detects vibrations for navigation and food finding), and fins (aid in swimming, balance, and turning). Specific fins like the dorsal, pectoral, pelvic, caudal, ventral, and anal fins all have distinct functions for stability, movement, and propulsion.
To choose fresh fish, look for bright, clear, bulging eyes; bright skin color; firm flesh; scales that adhere strongly; and a clean, briny water smell. Gills should be a rich red color. For fillets, look for vibrant flesh, and if skin is present, it should appear pristine. Avoid strong, pungent aromas and milky liquid in packaging, which indicates spoilage. The flesh should be firm to the touch. For frozen fish, avoid frost or ice crystals as they indicate prolonged storage or thawing and refreezing.
Fish can be purchased in various market forms, some ready to cook and others requiring preparation. The video visually presents different market forms and cuts of fish, concluding this part of the lesson to be continued in a subsequent video.