Plant pigments

Composition of vegetables

Chlorophylls

• Green, and responsible for the green color of leaves.
   

• Enabling plants to produce oxygen during photosynthesis, it is critical to sustaining our life on earth.

Plant pigments

Composition of vegetables

Chlorophylls

• Chlorophyll has structural features similar to heme.
  
   

• Bilirubin, which produces a yellow color, has recently been found in plants.

Plant pigments

Composition of vegetables

Carotenoids

• Pigment that absorbs blue and indigo light, and that provides rich yellows and oranges.

• The distinctive colors of mango and carrots are due to various forms of carotene.

Plant pigments

Composition of vegetables

Carotenoids

• As the yellow of butter and other animal fats.
   
• This pigment is important to our diet, as the human body breaks down each carotene molecule to produce two vitamin A molecules.

Plant pigments

Composition of vegetables

Flavonoids

• Flavonoids are the yellow plant pigments seen most notably in lemons, oranges, and grapefruit.

• Many of the foods that we eat, including dark chocolate, strawberries, blueberries, cinnamon, walnuts, grapes, and cabbage, contain flavonoids.
   

• These chemicals lower cholesterol levels, and many have antioxidant properties. 

Plant pigments

Composition of vegetables

Betalains

• Play an important role in attracting animals to flowers and fruit, and produce a similar range of colors.

• The betalains consist of two sub-groups, red-violet (betacyanin) and yellow to orange (betaxanthin) pigments.
   
• They only occur in a few plant families, and always independently of anthocyanins.

• Is a broad name for a wide variety of compounds produced by plant.
   
• They are found in fruits, vegetables, beans, grains and other plants.
   
• Each photochemical comes from variety of different plant sources and has different proposed effect on and benefits for the body.

Beta carotene

Proposed benefits

• Immune system
• Vision
• Skin health
• Bone health 

Food Sources

• Sweet potato
• Carrots
• Broccoli
• Pumpkin  

Lycopene

Proposed benefits

• Cancer prostate
• Heart health 

Food Sources

• Tomatoes
• Watermelon
• Red pepper
• Pink grapefruit 

Resveratrol

Proposed benefits

• Lung health
• Cancer
• Inflammation
• Heart health

Food Sources

• Peanuts
• Grapes   

Anthocyanidins

Proposed benefits

• Blood vessel health

Food Sources

• Blueberry
• Blackberry
• Cranberry
• Raspberry
• Strawberry
• Red potatoes
• Red onions   

Isoflavones

Proposed benefits

• Menopause
• Lower cholesterol
• Bone health
• Joint inflammation 

Food Sources

• Soybeans

Selecting & Purchasing Fresh Vegetables

• Use the following questions as a guide:
  
    How often do you purchase fresh vegetables?
  
    Where do you purchase fresh vegetables?
  
    What factors do you consider when selecting and purchasing vegetables?
  
    What is challenging for you about purchasing fresh vegetables?

Identifying your own habits when selecting vegetables

Selecting & Purchasing Fresh Vegetables

• First look at the items appearance and the texture.
   
•  Make sure the vegetables are not bruised or damaged.
   
• Some vegetables should feel heavy for its size.
   
• High quality, fresh vegetables are young, crisp and brightly colored .

Selecting Vegetables

Selecting & Purchasing Fresh Vegetables

• Be patient, cause it may take you longer to select your items.
   

• Look to see how the vegetables are priced.
   

• Learn how to use a produce scale.
   

• Ask for help.

Purchasing  Vegetables

Processed vegetables

Food processing is any deliberate change in a food that occurs before it’s available for us to eat. It can be as simple as freezing or drying food to preserve nutrients and freshness, or as complex as formulating a frozen meal with the right balance of nutrients and ingredients. 

• The goal of processing is to deter microbial spoilage and natural physiological deterioration of the plant cells.

Processed vegetables

Canned

• Putting foods into metal cans or glass jars.
  
   
• Canning is a process that extends the shelf life of perishable foods.
   
• Vegetables are often cut into pieces, packed in cans, and put through severe heat treatment to ensure the destruction of microorganisms that cause food spoilage or food borne illness, and then the cans are cooled to room temperature, labeled, and packaged for storage or immediate distribution.

Processed vegetables

Canned

• The canning process does not affect the fiber content.
   
• The heating process increases the solubility, which increases use by the body.
   
• The nutrient most susceptible to destruction in canning is vitamin C.
   
• Properly processed canned vegetables can be stored at room temperature for years. 

Processed vegetables

Canned

• Packed at peak of freshness when the flavor is the greatest.
   
• They also may have been treated with chemicals to help slow the spoilage process and to enhance color for quick sale.

Processed vegetables

Canned

Canned vegetables are also safe as well as nutritious, especially when low sodium or sodium-free choices are made.

Processed vegetables

Frozen

• The high quality of frozen foods is mainly due to the development of a technology known as the individually quick-frozen (IQF) method.
   
• IQF is a method that does not allow large ice crystals to form in vegetable cells. Also, since each piece is individually frozen, particles do not cohere, and the final product is not frozen into a solid block. 

Processed vegetables

Frozen

Frozen vegetables processed quickly after harvest only lose about twenty percent of their nutrition.
 

Frozen foods have outstanding quality and nutritive value.

Preparation of vegetables

Dry-heat:

• The heat is transfered to the food item without using any moisture.
   
• Involves high temperatures, meaning 300°F or hotter.

Preparation of vegetables

Dry-heat:

• Heat the pan for a minute
   
• Add a small amount of fat
   
• Let the fat get hot
   
• Add the food to the pan.

Sautéing & Pan-Frying

Preparation of vegetables

Dry-heat:

Cooking an item by enveloping it in hot, dry air, generally inside an oven and at temperatures of at least 300°F.

Roasting & Baking

Preparation of vegetables

Dry-heat:

The food is quite close to the heat source (open flame). 

Broiling & Grilling

Preparation of vegetables

Dry-heat:

Involves submerging the food in hot liquid fat.
 

Keeping the oil at temperatures between 325°F and 400°F.

Deep-Frying

Preparation of vegetables

Dry-heat:

The key to keeping the oil hot is to fry items in small batches, as introducing too much food to the oil will cool it off.

Deep-Frying

Preparation of vegetables

Moist-heat:

Liquid or steam is used to cook the food.
 

Flavored liquids, such as broth or wine, can be used as the heat transfer medium and will also add flavor during the cooking process.

Preparation of vegetables

Moist-heat:

• Dropping food into boiling water briefly and then submerging the food into ice water.
   
• Blanching is used to loosen the skin on vegetables.
   
• Vegetables are often blanched prior to freezing to maintain their color and freshness during storage.

Blanching

Preparation of vegetables

Moist-heat:

Water boils at 212° F.
 

Boiling water has large, vigorous bubbles, which can disrupt or damage delicate foods.

Boiling

Preparation of vegetables

Moist-heat:

Partially or fully submerging food into water or another liquid that has reached 160-180° F.
 

Foods to be cooked without being disrupted or damaged.

Poaching

Preparation of vegetables

Moist-heat:

Involves the transfer of heat through vaporized water or other liquids.
 

​Retains more nutrients than food.

Steaming

Preparation of vegetables

Moist-heat:

Pressure cookers utilize steam and pressure to increase the cooking temperature above the boiling point of water.

Steaming

Changes during heating

Texture

• Sometimes they have added baking soda to the cooking water the cellulose become soft , creating mushy texture.
   
• Solubilization of hemicellulose is responsible for most of the loss of firnmess especially in the presence of alkaline solutions.
   
• Thus, the vegetable that is heated in the NaOH solution will exhibit the poorest texture of all the heated products. 
   
• But it increases the cooking losses of both thiamin and vitamin C.

Changes during heating

Flavor

• The flavor of vegetables is comprised of various combinations of acids, sugar and volatile oils.
   
• Some of these components decompose during cooking and evaporate.
   
• Flavors also vary according to the intensity of the temperature you use in cooking.

Changes during heating

Flavor

• Flavor change according to the cooking method.
   
• Roasted vegetables are quite different in both appearance and flavor than the same vegetables cooked by steaming.
   
• In the case of beans, the longer they cook, the more flavor they lose—some by evaporation, and some by dissolving in the cooking water.

Changes during heating

Odor

• Food odors contribute to the perception of flavor.
   
• The strong odors of cooked onion  can be reduced by shortening the heating time, adding a little amount of vinegar to the cooking water.

Changes during heating

Color

• When green vegetables are heated or exposed to acid, the magnesium gets removed from the center of the ring structure of chlorophyll and replaced by an atom of hydrogen.
   
• This results in a change from chlorophyll to pheophytin

Changes during heating

Color

The color of the vegetable changes from bright green to olive-gray.

Changes during heating

Color

Putting the vegetables into enough boiling water and leaving the cover off the pot for the first few minutes allows a large part of the volatile acids that would react with the chlorophyll either to vaporize or to dissolve in the water.

Changes during heating

Nutrient retention

• Careful preparation of vegetables conserves important nutrients.
   
• Leaching the greatest cause of mineral loss in vegetables.
   
• Cook the vegetables using a little water as possible.
   
• Cook just to the point of doneness and no further.

Changes during heating

Nutrient retention

• Leave the skin on whenever possible.
   
• Cut vegetables into fewer larger pieces rather than many smaller pieces.
   
• Heating increase the amount of protein available from legumes by destroying the enzymes known as protease inhibitors.

Legumes

Is a class of vegetables that includes beans, peas and lentils.

Legumes

• Legumes are typically low in fat, contain no cholesterol.
   
• High in folate, potassium, iron and magnesium.
   
• Contain beneficial fats and soluble and insoluble fiber.
   
• A good source of protein, legumes can be a healthy substitute for meat, which has more fat and cholesterol.

Composition of legumes

• Legumes are relatively rich source of protein.
   
• High in carbohydrates (soluble fibers).
   
• Moderate lipid content.
   
• Source of minerals and vitamins.
   
• Also contain water

Composition of legumes

Amount per 100 g
 

Total fat: 0.4 g

   Saturated fat: 0.1 g

   Polyunsaturated fat: 0.2 g

   Monounsaturated fat: 0.1 g
 

Total carbohydrates: 14 g

   Dietary fiber: 5 g

   Sugar: 6 g
 

Protein: 5 g

Vitamins

  Vitamin A: 15 %

  Vitamin C: 66%

  Vitamin B6: 10%
 

Minerals

  Potassium: 244 mg

  Iron: 8 g

  Magnesium: 8 g

Peas

Composition of legumes

Amount per 100 g
 

Total fat:0.4 g
 

Total carbohydrates: 20 g
 

Protein: 9 g

Vitamins

  Vitamin B6: 10%
  Vitamin C: 2%
 

Minerals
  Iron: 18 g
  Potassium: 369 mg

  Magnesium: 9%

Lentils

Composition of legumes

Amount per 100 g
 

Total fat: 6 g

Total carbohydrates: 61 g

   Dietary fiber: 17 g

   Sugar: 11 g
 

Protein: 19 g

Vitamins

  Vitamin B6: 25 %

  Vitamin C: 6%
 

Minerals

  Iron: 34%

  Magnesium: 28%

  Calcium: 10%

  Potassium: 875 mg

  Sodium: 24 mg

Chick pea

Composition of legumes

Amount per 100 g
 

Total fat: 0.5 g

Total carbohydrates: 63 g

   Dietary fiber: 13 g

Protein: 20 g

Vitamins

  Vitamin B6: 20 %
 

Minerals

  Iron: 27%

  Magnesium: 31%

  Potassium: 1254 mg

  Sodium: 5 mg

Beans

Preparation of legumes

First Step

Pick through the legumes, discarding any discolored or shriveled ones or any foreign matter.

Preparation of legumes

Second Step

Soaking in room-temperature water

Quick soak: 1 pound of dried legumes and 10 cups of water to a boil.
Cover and set aside and let legumes soak for 1 to 2 hours at room temperature.

Preparation of legumes

Second Step

Soaking in room-temperature water

Slow soak: cover 1 pound dried legumes with 10 cups water. Cover and refrigerate for at least 4 hours or overnight.

Don't forget to discard the soaking water before cooking.

Storage of vegetables

Refrigerated

• Should be kept in perforated plastic bags in the produce drawers of the refrigerator.
   
• Use all refrigerated vegetables within a few days since longer storage results in loss of freshness and flavor. 
   
• Vegetables are best stored in the crisper section of the refrigerator.

Storage of vegetables

Refrigerated

Make sure to separate vegetables from meat and dairy products to avoid possible contamination by bacteria.

Storage of vegetables

Dry storage

• Certain types of produce are best left out of the refrigerator.
   
• Instead, they should be stored in a cool, dry place, such as potato, lemons, onion, garlic.. 
   
• Recommended storage times for dried foods range from 4 months to 1 year.
   
• The higher the temperature, the shorter the storage time.

Storage of vegetables

Dry storage

• Glass containers are excellent for storage because any moisture that collects on the inside can be seen easily.
   
• Foods can spoil if moisture is reabsorbed during storage.
   
• Foods affected by moisture, but not spoiled, should be used immediately or redried and repackaged.

Moldy foods should be discarded.

Shelf life of vegetables

• Depend on how you handle them.
   
• Depend on the type of vegetables.
   
• There are many factors that affect a vegetable's life, from the time you get it into your kitchen to the time you prepare it.

Shelf life of vegetables

1-2 Days:
 

Artichokes

Asparagus

Basil

Broccoli

corn

Dill

Watercress

Shelf life of vegetables

2-4 Days:
 

Arugula

Cucumbers

Eggplant

Lettuce

lime

Zucchini

Shelf life of vegetables

4-6 Days:
 

Brussels sprout

Cauliflower

Leeks

Lemons

Oregano

Parsley

Peppers

Spinach

Tomatoes

Shelf life of vegetables

7+ Days:
 

Beets

Cabbage

Carrots

Celery

Garlic

Hard Squash

Onions

Potatoes