Like most seafood, crab has an interesting nutritional value, offering an appreciable amount of protein as well as a low fat content. Crab is also an excellent source of vitamin B12 , selenium and other nutrients essential for the maintenance of health.

Active ingredients and properties

The active ingredients of crab have not been the subject of specific studies. However, we note some studies showing interesting results on the benefits of eating fish and seafood. First, a study of more than 14,000 women showed that the more they eat fish and seafood, the lower the risk of colorectal cancer ¹ . Another study, carried out with Chinese men, showed that the weekly consumption of at least one meal of fish or seafood would decrease the risk of fatal myocardial infarction , compared to a less consumption ². At present, the beneficial effects of consuming fish and seafood cannot be associated with any particular active ingredient; clinical studies are necessary in order to identify the components concerned. On the other hand, the presence of omega-3 fatty acids in these marine products could have an important role to play.

Omega-3 fatty acids. Crab contains eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), two fatty acids from the omega-3 family. They contribute to good immune, circulatory and hormonal functioning. Several epidemiological and clinical studies have shown that the consumption of omega-3 fatty acids, mainly from fatty fish, could exert favorable effects on cardiovascular health , including the reduction of mortality from cardiovascular disease ³ . These fatty acids are known to lower blood pressure , blood triglycerides and the formation of blood clots .

Even if the optimal amounts of omega-3 fatty acids to consume have not been firmly established, scientific evidence shows that the daily consumption of 500 mg to 1,800 mg of EPA and DHA would make it possible to benefit from the related benefits. ⁴ . The consumption of 100 g of crab (about 200 ml of flesh) provides almost 500 mg. For comparison, crab contains about five times less EPA and DHA than salmon, a fatty fish.

Crab and methylmercury

Some fish and seafood at the top of the food pyramid contain significant amounts of methylmercury. Methylmercury is a form of organic mercury that is very toxic at high exposure rates. Methylmercury is the most common form of mercury in fish. In humans, methylmercury is easily absorbed into the bloodstream; it is disseminated throughout the body and concentrated in certain points such as the brain and in pregnant women or the developing fetus. Crab is one of the crustaceans with a very low concentration of mercury. There is therefore no recommendation on the maximum frequency of consumption of it.

Most important nutrients

See the meaning of the nutrient source classification symbols

 Zinc. Crab is an excellent source of zinc. Zinc is involved in particular in immune reactions, in the production of genetic material, in the perception of taste, in the healing of wounds and in the development of the fetus. Zinc also interacts with sex and thyroid hormones. In the pancreas, it participates in the synthesis (production), the storage and the release of insulin.

 Selenium. Crab is an excellent source of selenium, meeting 80% of daily needs. This mineral works in conjunction with an antioxidant enzyme, preventing the formation of free radicals in the body. In addition, it helps to convert thyroid hormones to their active form.

 Copper. Crab is an excellent source of copper. As a constituent of several enzymes, copper is necessary for the formation of hemoglobin and collagen (protein used for the structure and repair of tissues) in the body. Several copper-containing enzymes also help the body’s defense against free radicals.

 Vitamin B12. Crab is an excellent source of vitamin B12, which works in concert with folic acid to make red blood cells. In addition, vitamin B12 is useful for the health of nerve cells and cells that make bone tissue.

 Phosphorus. Crab is a good source of phosphorus (see our fact sheet on Phosphorus nutrients ). Aside from its essential role in the formation of bones and teeth, phosphorus participates among other things in the growth and regeneration of tissues. It helps keep the blood pH in normal. It is also one of the constituents of cell membranes.

 Magnesium. Crab is a good source of magnesium. It participates in bone mineralization, muscle contraction, transmission of nerve impulses, dental health and the proper functioning of the immune system.

 Iron. Crab is a good source of iron for women and an excellent source of iron for men, as their respective needs for this mineral differ considerably. It is essential for the transport of oxygen in the blood and the formation of red blood cells. In addition, it plays a role in the production of new cells, hormones and neurotransmitters.

 Vitamin B2. Crab is a good source of vitamin B2, also known as riboflavin. This vitamin plays a role in the energy metabolism of all cells. In addition, it contributes to tissue growth and repair, hormone production and the formation of red blood cells.

 Vitamin B3. Crab is a good source of vitamin B3, also called niacin. This vitamin takes part in many metabolic reactions and contributes especially to the production of energy starting from carbohydrates, lipids, proteins and alcohol which we ingest. It also plays a role in the DNA formation process.

Iodine. The crab contains iodine. Iodine is used in the composition of thyroid hormones necessary for the regulation of growth, development and metabolism. The exact value of the iodine content of the crab is not available from the Canadian Nutrient File .

Source: Health Canada. Canadian Nutrient File , 2005.

Precautions

Crab is a food rich in purines, precursors of uric acid. Thus, people suffering from gout must limit their consumption in order to prevent the onset of seizures. In people with this condition, there is an abnormally high amount of uric acid in the blood, causing specific symptoms, such as joint pain. The purines in certain foods help to further increase the concentration of uric acid in the blood, which is why it is important for people with gout to limit their consumption.

Among food allergens of animal origin, crustaceans and molluscs frequently cause allergic reactions in hypersensitive individuals ⁵ . Crab contains an allergenic protein called tropomyosin ⁶ , also identified in shrimp and lobster. This protein could be present in other seafood, hence the possibility of cross-reactions . The Canadian Food Inspection Agency recommends that people with allergies to these foods consult an allergist before introducing new ones into their diet. It is interesting to know that the allergy to a crustacean can ultimately lead to an awareness of certain air allergens, such as dust mites.⁵ . The reverse relationship was also observed.

As is the case for all crustaceans, the crab has been consumed by humans since time immemorial, in all latitudes. Easy to harvest, as long as we know its habits, it made the happiness of our ancestors, who only had to wait for the ebb and flow of the tide to collect this abundant protein harvest. Of course, to prepare the crabs, you need a few rudimentary tools to break their shell. However, it is likely that our prehistoric ancestors knew of the very great, albeit temporary, vulnerability in which this animal found itself when it was moulting. Because, if the crab grows, its shell, it is not endowed with any elasticity, so that it is necessary, several times in its existence, to get rid of this prison of chitin to make one of size superior.

Historically, these soft-shelled crabs have been sought after by fishermen for the succulence of their flesh, but also because they are easy to prepare. Even today, they are considered a product of great finesse and are offered for a short period of the year in fishmongers.

Of the 4,500 species of crab listed, which live in all latitudes of the globe, only a few are commercially exploited, the majority counting animals whose size is too small to justify the costs that must be incurred to fish them and transform them. Those that are found most commonly in trade are snow crab , the king crab , the Dungeness crab , the blue crab , the rock crab and rock crab . However, as global stocks are dwindling, it is anticipated that many other species will be exploited in the future.

Land crab hunting

We especially know the sea crab, but in many countries of the South, we also eat the land crabs , which we harvest in the forest or on the coast. On the island of Palau (Fiji), the women bring the crabs home to raise them in pens before feeding their families. Thanks to the food they provide – coconut, rice, leaves of various trees – they reach a considerable size. They constitute a significant protein intake for the local population and an additional income for families.

Choose well

Crabs are sold alive with their shell (hard or soft), or cooked and frozen. Live crabs must be active and therefore react when touched. The shell of cooked crabs should be a nice bright, moist orange, the legs and claws should be intact. They must be heavy in the hand, a sign that they were caught well after the moulting period (the flesh is less abundant when the moulting is recent) and have a good smell of ocean, without trace of ammonia.

Frozen crab should not be discolored or show signs of frost burn. Avoid products with ice build-up, which indicates that they have been caught and frozen for too long. Handle with delicacy, frozen paws and tongs break easily.

The modern food industry has created new products imitating the appearance and taste of crab and marketed in the form of sticks, crumbs or slices. Surimi , from traditional Japanese technology, is the best example. It is in fact a pulp of fish flesh less expensive than crab (for example, pollock used in Quebec), to which we add flavors, dyes intended to give them the characteristic color of this crustacean, as well as water, starch, egg white and various additives (sorbitol, sugar, polyphosphate, monosodium glutamate, etc.).

Preparation

The simplest way to prepare the crab is to boil it  : fill a large pot with water, add half a cup of vinegar and salt, bring to a boil, immerse the crabs in water, and cook 18 to 20 minutes. Shell and remove the gills and viscera by scraping them with your thumb or the edge of a spoon. Rinse under water to clean it well. It can be served as is with garlic butter or incorporate the flesh in various preparations.

Culinary dishes

• In gazpacho: dice and cook for 30 seconds in boiling water, eggplant, zucchini, red, yellow and green peppers, cucumbers and onions. Drain and put in the refrigerator. Mix tomato juice with a little oil and wine vinegar, thicken with breadcrumbs, season with coriander leaves and stir into vegetables. Let cool for three hours in the refrigerator and serve garnished with a piece of crab meat.
• Thai crab claws: mix chicken broth with oyster sauce, soy sauce, a little sesame oil and honey, and put on the heat. In another saucepan, put crab claws, Chinese vermicelli, ginger, soy sauce, coriander leaves, green onions and finely chopped garlic, small corn on the cob (or corn chunks regular, previously blanched), thin slices of mushroom, snow peas or fine beans. Cover with broth and cook for ten minutes. Serve in bowls, keeping only part of the liquid.
• Japanese bites: process the crab meat in a food processor with a beaten egg, soy sauce, a little honey and cornstarch, and a few drops of ginger juice (finely cut the rhizome, put in a muslin and press to extract the juice). Stuff Chinese cabbage leaves with this mixture and tie with a string. Cook for seven or eight minutes, covered in a little dashi broth, seasoned with soy sauce and mirin. Remove the string, cut into slices and serve with thin strips of snow peas blanched in boiling water. Coat with a few spoonfuls of the cooking broth.
• Creole crab: brown pieces of onion, pepper and celery in oil. Cook for five minutes. Add garlic, hot pepper, basil, bay leaf and water, and cook for about 20 minutes. Add pieces of tomato and tomato sauce, finely chopped okra (optional), as well as cooked crabmeat and, if desired, shrimp and oysters. Simmer for ten minutes and serve.
• In a gratin: place pieces of crab in a baking dish. Prepare a béchamel, add grated cheese, thin onion rings, hot pepper if desired and cook over low heat until the cheese melts. Pour over the crab, put in an oven set at 230 ° C (450 ° F) and leave the time for the cheese to be golden.
• Crab omelette: melt shallots in a mixture of butter and oil, add crabmeat and cook for a few minutes. Beat eggs with the herbs of your choice (tarragon, dill, parsley, chives, lemon balm), pour the mixture over the crab and cook for three or four minutes. Turn the omelette over and cook for a few more minutes, then serve with a green salad.
• Crab cakes: cook eggplant slices in the pan or in the oven until the flesh is tender. Brown the onion, celery and garlic in the pan and cook in the food processor with the eggplant. Put in a bowl and stir in chopped crabmeat, salt, pepper and season with thyme, marjoram or herbs of your choice. Leave to cool, add breadcrumbs, grated Parmesan cheese, shape into patties that will be sautéed in olive oil. Serve and garnish with fresh parsley.





• Crab Stuffed :many recipes exist for this preparation. In the Dominican Republic, it is prepared as follows: cook crabs, break the claws and legs to recover the flesh and remove the soft part of the abdomen to recover the flesh from the body. Rinse the shells. Crumble the flesh before mixing it with bread crumbs soaked in milk (about one third of bread crumbs for two thirds of crab meat). Sauté green onions with thyme, chives and hot pepper and add the crab mixture. Cook for a few minutes, then fill the shells with the mixture. Sprinkle with breadcrumbs and put in the oven (medium intensity) for ten minutes. Serve with plantains cooked with their skin in boiling water for ten minutes, then peeled and sliced,
• Serve the crabmeat in a sandwich or in a salad with the vegetables of your choice, for example arugula, grated white radish, thin slices of mushrooms, etc. Or with endives, apples and walnuts. Or in this exotic salad: crabmeat, pineapple, cucumber and avocado slices, fresh (or, failing that, dried) coconut pulp, finely chopped lettuce. Drizzle with vinaigrette and garnish with fresh cilantro.
• Niçoise revisited: replace the tuna with crabmeat in this classic salad which, in one of its many variants, includes cooked potatoes, white beans, endive or radicchio leaves, capers , black olives, herbs and a mustard vinaigrette.
• The crab Louis uses cold generally, shredded lettuce with or without boiled eggs. Garnish with a sauce made of mayonnaise, heavy cream, Worcestershire sauce, chili sauce, green pepper, finely sliced ​​green onions. Consume only occasionally! We can “thin” it by replacing the cream and mayonnaise with yogurt and adding a little balsamic vinegar. Paprika can substitute for chili sauce.
• Crab bean stew: soak cannellini beans (or regular white beans) the day before. In a saucepan, sauté peppers, onion and garlic. Add cumin, coriander leaves, oregano and one or two cloves. Add the beans, vegetable or chicken broth, or fish stock, and cook until the beans are tender. Add grated cheese, sour cream or yogurt and crabmeat. Reheat and serve.
• We can stuff tomatoes, peppers, artichoke hearts with the flesh. Add it to seafood soups or bouillabaisse, in paella or prepare it in tempura with other seafood and vegetables.
• Spring rolls: stuff rehydrated rice cakes with crabmeat, soy sprouts, thin strips of carrot and cucumber, mint, snow peas, cut lengthwise. Form rolls. To serve, dip in a hot sauce or soy sauce diluted with water and lemon juice, and enjoy.
• Soft shell crab: place the crabs in a universal pan, garnish each with a knob of butter and a tablespoon of lemon juice. Spend five minutes under the grill. Serve on toast, pouring the cooking liquid over the crabs.

Soft-shelled crab (or soft crab): keep it in the refrigerator in a humid container.

Hard-shelled crab: at most, seven days in the refrigerator in a bag full of ice, but preferably cook it on the day of purchase. Frozen crab keeps for a few months, but the longer it is stored, the better.

Global warming may spell the end for many crab species, study published in 2003 in the journal Scienceby a researcher in marine biology from Stanford University. For the purposes of this study, crabs belonging to four different species were placed under observation in aquariums where the water temperature was adjusted to match that of their natural environment. Then it was gradually raised until the heartbeats of the crabs, controlled by sensors, stopped, indicating that they were dead. This has made it possible to establish the temperatures above which, depending on the species, these animals cannot survive. According to this researcher, the results indicate that if the global temperature increases from 4 ° F to 6 ° F, as predicted by some experts, the survival of the crabs of the species studied (two of which live in the waters bordering Oregon and two in the Gulf of California) will be in real danger,

Previous studies have concluded that at least one species of crab living in the waters bordering the northwest coast of North America has disappeared from its habitat, while other species have moved north, the water temperature is now too high.

These negative effects on crab populations are added to those of pollution by chemical substances, urban or industrial development of coastal regions, overfishing or illegal fishing, bycatch (young crabs or females including fishing is prohibited, but which accidentally ends up in nets or cages) and disturbanceof their habitats by the various fishing gear that combs the seabed. However, populations of some species appear to be in very good health, particularly in places where fisheries regulations and stock management are well carried out. This is particularly the case for Dungeness crab and snow crab (particularly that which is caught on the Atlantic coast of Canada). Among the less protected species, but whose status is not currently threatened, are the northern crab and king crab (with the exception of that which comes from Russia, where the stocks are threatened).