Oyster is basically an exotic, nutritious sea-food ingredient that is used in various types of dishes across the globe to impart a certain distinctive taste, aroma and visual appeal to food. With a tough exterior shell that functions to protect the rather smooth, slippery, mass of flesh inside, it is considered a delicacy by some while many others are simply averse to its slimy appearance.
Oysters are commonly found in ocean beds, especially in shallow waters and usually appear in large colonies. Among the different oyster varieties, the most acceptable and highly harvested species include the Eastern American Oyster and the Pacific Oyster.
Depending on the surface or object they attach themselves to, oysters may attain different shapes from elliptical to oval or pear-shaped. The outer appearance, at first instance, is certainly not visually appealing but after much cleaning, a whitish gray exterior and porcelain white inner surface would be noticed. One might find it tough to open the oysters as they possess strong adductor muscles that help keep the shells tightly shut owing to their protective instincts.
It was perhaps the Ancient Greek and Roman cultures that first introduced the use of oysters as a pre-drink snack as it was believed to encourage or incentivise people to drink. The Native Americans living by the coastal regions of the Northern America indulged in oysters as a regular staple food. In fact, early colonial settlers would gorge on oysters - raw or cooked by the dozens. In the mid 18th century, during the period of the Gold Rush, a pricey preparation was created by the Chefs at Cary House christened ‘Hangtown Fry’ using a luxurious combination of eggs and oysters.
Oysters are valued for their intense taste which is irresistible to most seafood lovers. In terms of cooking techniques, Oysters offer several options - boiling, baking, broiling, frying or sautéing. Many seafood lovers prefer to eat oysters in the raw form. Seasoning oyster dishes with special sauces and spices like parsley, garlic and sage, thyme further enhance their rich flavor.
Several popular Oyster dishes are consumed by people around the world; one of the most celebrated ones being “Oysters Rockefeller”, a creation of Jules Alciatore, a descendant of the famed Antoine's Restaurant located in New Orleans. The dish was named after the rich Rockefeller family, as a generous amount of butter was used to enrich the dish.
Oysters find use in either the raw or boiled forms in salads, as part of sea-food dishes – appetizers, main course rice dishes, soups, and stews among others. Other preparations such as stir fries and many regional curries such as the typical Indian Oyster Masala curry which cooks the oysters in a spiced mixture –which may again be prepared dry with a coated masala or in thick gravy.
Herbs that complement oysters including thyme, sage, fennel seeds, paprika, and parsley may be used to season salads, flavour marinades and enhance the taste of different oyster recipes.
Other well known Oyster Preparations-
• American Style Baked Oysters – which consists of oysters immersed in a buttery white sauce with celery, green peppers, seasoned with salt and pepper and topped with cheese gratings. [1 serving provides ~ 506 calories]
• Barbequed Oysters - Opened Oysters barbequed on a grate after marinating in lime juice and black pepper. [1 serving provides ~ 326 calories]
• Cream of Oyster and garden vegetable soup – using cream and chicken broth; whole fragrant spices- cloves, bay leaves, cinnamon; dried herbs – thyme, sage, oregano and carrots, celery, mushrooms, onions etc. in a delectable creamy soup. [1 serving provides ~ 420 calories]
• Oyster Cream Casserole – using a sauce consisting of, cream, butter, Worcestershire sauce, and layering the casserole dish with corn, sauce and oysters and baking till done. [1 serving provides ~ 448 calories]
• Oyster Pate – A Delicacy that uses smoked oysters, toasted pecans, parsley, mayonnaise, tobacco sauce and plenty of cream cheese. This high calorie preparation provides 1132 calories per serving.
Other culinary uses of oysters-
• Seafood special salads with a combination using squids, shrimps, boiled eggs, scallions, fresh herbs and dressings with freshly squeezed lime juice, pepper and salt.
• Oyster Omelette with the delicately flavours of dill, mushrooms and oysters.
• Oyster sandwich with lettuce, tomato, onions, cheese slices, seasoned with salt and pepper.
Appetizers prepared by various processes –
o Grilled oysters topped with a special sauce of butter, wine, parsley and lime juice.
o Breading and frying or grilling to form crunchy oyster fritters or croquettes.
o Specialty French Oyster Gumbo, a well known French appetizer.
Various Regional uses of Oysters-
• Oyster Soufflé, that makes an excellent accompaniment for roast beef or turkey roast dinner.
• Oyster Pie that forms an integral part of an American Thanksgiving meal.
Further, Oyster sauce is used as a flavourful base in Chinese cuisine to produce delicious items like Chicken or Tofu in Oyster sauce.
Likewise a Ceylonese Oyster Curry which begins with sautéing of shallots, garlic with whole spices - cinnamon, cloves and bay leaves and then adding green pepper; seasoning with turmeric, curry powder and simmering in coconut milk. Finally, oysters along with their liquor are spooned in, and ultimately the curry is seasoned with a dash of lemon juice.
Word of caution: Oysters are extremely sensitive to the quality of water and highly susceptible to pollution commonly witnessed along coastal regions. They tend to absorb pollutants and have a high likelihood of retaining toxins in their flesh making them poisonous and thus detrimental for human consumption.
Oysters are considered to be a low-calorie food item, but are believed to be quite satiating due to the high amount of protein contained in them.
One serving of 6 medium sized oysters (~84.0 g) provides –
• 57 calories, 19 calories coming from fat.
• Total fat content of 2.1 g, saturated fat of 0.6 g, polyunsaturated fat of 0.8 g and monounsaturated fat is 0.3 g. Cholesterol content is 45 mg.
• Sodium content is 177 mg
• Total carbohydrate content is 3.3 g
• Total protein content is 5.9 g
• Based on % daily values – oysters supply 4 % Calcium, 5 % Vitamin C and 31 % Iron.
• The favourable aspects of including oysters as part of the diet are – their negligible sugar content, high manganese, magnesium and phosphorus content. Also, being very good sources of Vitamin B 12, Copper, Selenium (beneficial in fighting arthritis, cataracts, cancer), and Zinc (for immunity) apart from Vitamins C, B, A, D and even some omega 3 fats (required for normal brain function). Vitamin B 12 is important for the appropriate functioning of nerve fibres as well as in the activation of folic acid. Both Vitamins B-12 and B-9 are essential in regulation of haemoglobin synthesis, and are responsible for the proper functioning of iron in the body.
• Unfavourable aspects are the associated high cholesterol and sodium intake as oysters are usually consumed by the dozen.
Benefits of Oyster Consumption-
• As the soft meat of oysters is quickly cooked and easily digested, nutrient losses are less and the ease of digestion is high, offering maximum nutrients laying minimal strain on the digestive system.
• These act as a concentrated packet of anti-oxidants that boost immunity and prevent infections, and exhibit anti-cancer and anti-aging properties.
• Oysters are sometimes considered brain food as they contain proteins rich in the amino acid tyrosine. The brain uses this amino acid to produce neurotransmitters that may help enhance mental functions and elevate mood.
• Oysters are particularly good for Anaemics owing to the high Iron content.
According to the Interstate Shellfish Sanitation Authorities, certain strict guidelines are to be followed in oyster consumption-
1. Oysters must be harvested from approved water bodies
2. Packed under extremely sanitary conditions
3. Held at appropriate freezing temperatures. A quick freezing technique (in the oyster liquor) that avoids ice crystal formation and thereby minimizes tissue damage.
4. Cooking to internal temperatures of 140 F or higher for over 5 minutes ensures destruction of harmful microorganisms.
5. Individuals suffering from chronic illnesses of the stomach, liver, blood or individuals with immune disorders must avoid raw oysters.
6. The benefit of cooked oysters over raw oysters is obviously the elimination of any bacterial contamination. In terms of Nutritional values, there is not a very marked difference between raw and cooked oysters except that some B-vitamins may be lost through cooking and similarly Vitamin C losses may occur through oxidation.
Abraham Lincoln cherished Oysters so much so that he held parties at his Illinois home where only oysters formed the highlight of the menu and nothing else.
In some cultures, oysters are consumed for their aphrodisiac properties.