Vitamin A is a group of unsaturated nutritional organic compounds, that includes retinol, retinal, retinoic acid, and several provitamin A carotenoids, among whichbeta-carotene is the most important.Vitamin A has multiple functions: it is important for growth and development, for the maintenance of the immune system and good vision. Vitamin A is needed by the retina of the eye in the form of retinal, which combines with protein opsin to form rhodopsin, the light-absorbing molecule necessary for both low-light (scotopic vision) and color vision.Vitamin A also functions in a very different role as retinoic acid (an irreversibly oxidized form of retinol), which is an important hormone-likegrowth factor for epithelial and other cells.

In foods of animal origin, the major form of vitamin A is an ester, primarily retinyl palmitate, which is converted to retinol(chemically an alcohol) in the small intestine. The retinol form functions as a storage form of the vitamin, and can be converted to and from its visually active aldehyde form, retinal.

All forms of vitamin A have a beta-ionone ring to which an isoprenoid chain is attached, called a retinyl group. Both structural features are essential for vitamin activity.The orange pigment of carrots (beta-carotene) can be represented as two connected retinyl groups, which are used in the body to contribute to vitamin A levels. Alpha-carotene and gamma-carotene also have a single retinyl group, which give them some vitamin activity. None of the other carotenes have vitamin activity. The carotenoid beta-cryptoxanthin possesses an ionone group and has vitamin activity in humans.

Vitamin A can be found in two principal forms in foods:
-Retinol, the form of vitamin A absorbed when eating animal food sources, is a yellow, fat-soluble substance. Since the pure alcohol form is unstable, the vitamin is found in tissues in a form of retinyl ester. It is also commercially produced and administered as esters such as retinyl acetate or palmitate.
-The carotenes alpha-carotene, beta-carotene, gamma-carotene; and the xanthophyll beta-cryptoxanthin (all of which contain beta-ionone rings), but no other carotenoids, function as provitamin A in herbivores and omnivore animals, which possess the enzyme beta-carotene 15,15'-dioxygenase which cleaves beta-carotene in the intestinal mucosa and converts it to retinol.In general, carnivores are poor converters of ionone-containing carotenoids, and pure carnivores such as cats and ferrets lack beta-carotene 15,15'-dioxygenase and cannot convert any carotenoids to retinal (resulting in none of the carotenoids being forms of vitamin A for these species).

Ingredients

Serves 4
-3 to 4 small purple potatoes (or small red-skinned potatoes), sliced thinly
-4 4-ounce salmon fillets
-6 tablespoons olive oil, divided
-1 cup pecans, finely chopped
-1/2 teaspoon salt, plus additional for seasoning ramps and potatoes
-1/2 teaspoon pepper, plus additional for seasoning ramps and potatoes
-9 ounces baby spinach (or other green)

Directions 

Heat 2 tablespoons of the oil in a large skillet over medium heat. Add the potatoes and cook 3 to 5 minutes, until just starting to brown. Stir, flipping potatoes onto other side, and season with salt and pepper. Continue to cook until tender and golden-brown.
Meanwhile, combine the pecans, 1/2 teaspoon salt, and 1/2 teaspoon pepper in a bowl. Brush salmon fillets with thin coating of oil, then press pecan mixture all over fillets. In a separate pan, heat another tablespoon of oil over medium heat. Cook the salmon in the pan, 5 to 6 minutes per side, until it is opaque and easily flakes in the middle. (If the pecans are darkening too early, you can finish the fish in a 400°F oven for about 5 minutes.) Remove the salmon from heat and set aside.
When the potatoes are tender, spoon them into a bowl and cover, then set aside while you finish the dish. Heat the last tablespoon of oil in pan, add spinach and sauté until just barely wilted, about two minutes.
Plate each serving of salmon with some potatoes and greens.

Ingredients

-1 head garlic
-3 pt. cherry tomatoes
-2 large bell peppers, cut into ½-inch chunks
-2 medium zucchini, cut into ½-inch chunks
-¼ cup olive oil
-½ tsp. smoked paprika
-1 cup frozen corn kernels, thawed
-4 Tbs. sherry vinegar or red wine vinegar

Directions

1. Preheat oven to 450°F.

2. Rub papery skin off garlic, and cut off top of head to expose clove tips. Place on square of foil, and drizzle with 1 Tbs. water. Wrap garlic, and roast 35 to 40 minutes, or until soft.

3. Toss tomatoes, bell peppers, zucchini, and oil with paprika in large bowl. Season with salt and pepper, if desired. Spread on 2 baking sheets, and roast 35 to 40 minutes, or until vegetables are browned and tender, stirring once. Cool 10 minutes.

4. Squeeze roasted garlic cloves into bowl of food processor; add half of roasted vegetables and 1 cup water. Blend until smooth, then transfer to large bowl or saucepan. Pulse remaining vegetables in food processor until chopped, then stir into puréed soup with corn and vinegar. Warm, if necessary.

STORE/SERVE Refrigerate up to 3 days, or freeze up to 3 months. If frozen, thaw in refrigerator overnight. Serve hot or cold.

Ingredients

-1 cup fresh breadcrumbs
-⅓ cup grated Parmesan cheese
-1 Tbs. plus 2 tsp. olive oil, divided
-1 Tbs. unsalted butter
-8 oz. cremini mushrooms, quartered (2 cups)
-3 cloves garlic, minced (1 Tbs.)
-2 bunches Tuscan kale, stemmed, torn into bite-size pieces (8 cups)
-1 15.5-oz. can white beans, rinsed and drained
-1 cup low-sodium vegetable broth
-2 tsp. lemon juice

Directions

1. Combine breadcrumbs, Parmesan, and 2 tsp. oil in small bowl. Set aside.

2. Heat remaining 1 Tbs. oil and butter in large ovenproof skillet or Dutch oven over medium heat. Add mushrooms; increase heat to medium-high. Stir, cover pan, and cook 5 to 6 minutes, or until mushrooms are lightly browned, stirring occasionally.

3. Uncover pan, add garlic, and stir 30 seconds. Add kale, and cook 2 minutes, or until wilted. Add beans, broth, and 3/4 cup water. Cover, and simmer 6 to 8 minutes, or until liquid has reduced by about three-quarters. Stir in 1 tsp. lemon juice, and remove from heat. Add 1 more tsp. lemon juice, if desired.

4. Heat broiler to high. Sprinkle breadcrumb mixture over stew, and broil 3 minutes, or until topping is golden.

Ingredients

-3 Tbs. olive oil, divided
-1 large onion, thinly sliced (1¼ cups)
-2 cloves garlic, minced (2 tsp.)
-1 tsp. ground coriander
-1 large head cauliflower, sliced into ½-inch-thick slices (6 cups)
-4 cups low-sodium vegetable broth
-2 medium apples, peeled and cut into small pieces (2 cups)
-1 ½ Tbs. sugar
-1 tsp. curry powder
-½ cup toasted hazelnuts, chopped
-2 Tbs. chopped parsley

Directions

1. Heat 2 Tbs. oil in large saucepan over medium-high heat. Add onion, sauté 5 to 7 minutes, then add garlic and coriander, and cook 1 minute. Add cauliflower, broth, and 11/2 cups water, and bring mixture to a simmer. Reduce heat to medium-low, and simmer 20 to 25 minutes, or until cauliflower is tender. Cool.

2. Blend cooled soup in blender or with immersion blender until smooth, adding more water if soup is too thick. Season with salt and pepper, if desired.

3. Heat remaining 1 Tbs. oil in large skillet over medium-high heat. Place apples in single layer in skillet, and cook 5 to 7 minutes, or until apples start to brown, stirring occasionally. Sprinkle sugar over apples, and cook 3 to 5 minutes more, or until sugar melts and starts to caramelize. Stir in curry powder, and sauté 30 seconds. Transfer apples to large plate, spreading apart to keep from sticking together when sugar hardens.

4. To serve: ladle warm soup into bowls, and top with caramelized apples, hazelnuts, and parsley.

Ingredients

-3 slices white bread
-4 tomatoes
-⅓ cup toasted slivered almonds
-2 Tbs. olive oil
-2 Tbs. red wine vinegar
-1 clove garlic, minced (1 tsp.)
-½ tsp. paprika
-½ tsp. ground cumin
-5 cups seedless watermelon cubes (1¾ lb.)

Directions

1- Place bread in large, shallow bowl; cover with water; and let stand 5 minutes. Squeeze excess moisture out of bread, and transfer to blender or food processor.

2- Bring large pot of water to a boil. Score bottoms of tomatoes with an X, and drop in boiling water 30 seconds. Remove from water, cool slightly, then peel and chop.

3- Transfer tomatoes to blender or food processor along with almonds, oil, vinegar, garlic, paprika, and cumin. Purée until smooth. Add watermelon, and blend until smooth. Strain soup through fine-meshed strainer before serving.

Ingredients

-8 ounces pasta
-1/2 cup olive oil
-3 cloves garlic, minced-2 cups chopped tomatoes,pushed through a sieve
-4 anchovy filets, rinsed and chopped
-2 tablespoons tomato paste
-3 tablespoons capers
-20 Greek olives, pitted and coarsely chopped
-1/2 teaspoon crushed red pepper flakes

Directions

Bring a large pot of lightly salted water to a boil. Cook pasta in boiling water for 8 to 10 minutes or until al dente; drain.
Heat oil in a skillet over low heat; cook garlic in oil until golden. Add sieved tomatoes, and cook 5 minutes. Stir in anchovies, tomato paste, capers, olives, and red pepper flakes. Cook 10 minutes, stirring occasionally.
Toss pasta with sauce, and serve.