Ẩm thực - Chapter 16: Understanding vegetables

 Chapter 16Understanding Vegetables 1Chapter Objectives1. Describe the factors that influence texture, flavor, color, and nutritional changes when cooking vegetables.2. Cook vegetables to their proper doneness.3. Judge quality in cooked vegetables, based on color, appearance, texture, flavor, seasonings, and appropriateness of combination with sauces or other vegetables.4. Perform the pre-preparation tasks for fresh vegetables.5. Calculate yields based on trimming losses.6. Determine the quality of frozen, canned, and dried vegetables.7. Prepare vegetables using the batch cooking method and the blanch-and-chill method.8. Store fresh and processed vegetables.2VegetablesWere at one time, abused, neglected, and unimportant.Today, vegetables are appreciated for their nutrition, variety, flavor, eye appeal, and sophistication.Vegetables are highly perishable.3Controlling Quality Changes During CookingCooking affects vegetables in four ways:TextureFlavorColor NutrientsHow much is changed of each will determine the final products quality.4Fiber - Fiber structures of vegetables (including cellulose and pectins) give them shape and firmness.Fiber is made firmer by acids and sugars.Fiber is softened by heat and alkalis.Starch is another vegetable component that affects textureDry starchy foods must be cooked in enough water to absorb moisture and softenMoist starchy vegetables have enough moisture of their own but must be cooked to be eatenDonenessA vegetable is done when it has reached its peak degree of tenderness.Most vegetables are best cooked al dente (firm to the bite).Cooked vegetables cannot be kept hot very long.Controlling Texture Changes5Controlling Flavor ChangesCooking produces flavor loss. To keep to a minimum:Cook as short a time as possibleUse boiling salted waterAdd only enough water to cover vegetablesSteam vegetables when appropriateStrong Flavored Vegetables - When cooking strong flavored vegetables, cook uncovered and with lots of water.Strong flavored vegetables are from the onion and cabbage families or root vegetables.6Cooking Produces Flavor ChangesSome vegetables change flavors. Cook as short a time as possibleAvoid overcooking because some vegetables develop a strong and unpleasant flavor when overcooked.7Young, freshly harvested vegetables have a high sugar content. As they mature or sit in storage the sugar turns to starch.To serve sweet-tasting vegetables: Serve young fresh vegetables that have not been stored longFor older vegetables use a little sugar in the cooking water to compensate for the lack of natural sweetnessCooking and Sweetness8White VegetablesWhite pigments called flavones are the primary coloring compounds in white vegetables and in the white parts of vegetables like celery, cucumbers, and zucchiniWhite pigments stay white in acid and turn yellow in alkaline water. To keep vegetables white, add acid to the water. Red Vegetables: Red pigments called anthocyanins are found in only a few vegetable Acids turn them brightAlkalis turn them green or blue-green (not appealing) Controlling Color Changes9Green Vegetables- Green coloring called chlorophyll is present in all green plants. Acids turn green vegetables to a drab olive green.To protect the color of green vegetables:Cook uncoveredCook for the shortest amount of timeCook in small batches to prevent long holding timesYellow and Orange Vegetables - Yellow and orange pigments are called carotenoids, and they are very stable.They are not really affected by acids and alkalis.Long cooking times dull the colorShort cooking times retain the color and vitamins and mineralsAlways cook vegetables in as little liquid as possibleControlling Color Changes (cont’d)10Controlling Nutrient LossesThe six factors responsible for most nutrient loss:High temperatureLong cookingLeachingAlkalis (baking soda, hard water)Plant enzymesOxygen11Controlling Nutrient Losses (cont’d)Pressure steamers cook quicklyBraising uses low heat but long cooking timeBaking eliminates leaching of vitamins and mineralsBoiling is faster than simmeringCutting vegetables into small pieces decreases cooking time12General Rules of Vegetable CookeryDon’t overcookCook as close to service time as possibleIf you need to cook it ahead of time undercook and chill rapidly, reheat at service timeNever use baking soda with green vegetablesCut vegetables uniformlyStart most vegetables cooking in boiling water, but start roots and tubers in cold water.Cook green vegetables uncoveredCook red and white vegetables in slightly acid liquid. Cook green vegetables in neutral liquid.Do not mix batches of cooked vegetables13Standards of Quality in Cooked VegetablesColorAppearance on plateTextureFlavorSeasoningsSaucesVegetable combinations14Handling VegetablesFreshWashingSoaking Peeling and cuttingTrimming loss15Classifying Vegetables as Used in the KitchenThe Gourd family (squashes)Seeds and Pods (beans, okra , peas)Tender-Fruited Vegetables (avocado, eggplant, tomatoes)Roots and Tubers (beets, carrots)The Cabbage Family (Brussels sprouts, cauliflower)The Onion Family (garlic, shallots, onions)Leafy Greens (spinach, lettuce, chicory)Stocks, Stems, and Shoots (asparagus, celery, fennel)Mushrooms 16Fresh Vegetables: Evaluating and PreparingArtichokesAsparagusAvocadosBamboo ShootsBeans, FavaBeans, Fresh ShellBeans, LimaBeans, SnapBeetsBok ChoyBroccoliBrussels SproutsCabbage, Green, Red, and SavoyCabbage, ChineseCactus Pads or NopalesCarrotsCauliflowerCeleryCelery Root or CeleriacChayoteChestnutCorn17Fresh Vegetables: Evaluating and Preparing (cont’d)CucumberEggplantFennelFiddlehead FernGarlicGreens, Cabbage family (collards, turnip greens, kale)JicamaKohlrabiLeeksLettuceMushroomsOkraOnions, DryOnions, Green (scallions) ParsleyParsnipsPea Greens or Pea ShootsPeas, GreenPeas, Edible PodPepper, SweetPeppers, Hot, or ChilesPotatoes, white18Fresh Vegetables: Evaluating and Preparing (cont’d)Potatoes, sweetRadishesRutabagasSalisfyShallotsSorrelSoybeansSpinachSquash, SummerSquash, Winter, including pumpkinSquash, BlossomsSunchokes or Jerusalem ArtichokesSwiss ChardTomatoesTomatillosTurnips and RutabagasWater ChestnutsWatercress19MushroomsCultivated Exotic MushroomsShiitakeOyster mushroomsEnoki mushroomsCremini MushroomsPortobello Mushrooms Wild MushroomsMorelBoleteChanterelleBlack trumpet20Processed VegetablesThe quality of frozen or canned vegetables never equals that of freshHandling Frozen VegetablesChecking QualityTemperatureLarge ice crystalsSigns of leaking on the cartonFreezer burnCooking Cook frozen vegetables from the frozen state21Handling Canned VegetablesChecking qualityReject damaged cans in receiptKnow the drained weightCheck the gradeCookingHandling Dried VegetablesThere are two basic types of dried vegetables:Dried LegumesFreeze-Dried and Other Dehydrated VegetablesProcessed Vegetables (cont’d)22Production and Holding Problems in Quantity CookingBatch Cooking Cooking in smaller batches closer to meal serviceBlanch-and-Chill Method23Storage – Fresh and FrozenFresh vegetablesPotatoes, onions, and winter squash are stored at 50°-65° F in a dry placeOther vegetables stored in the refrigeratorPeeled and cut vegetables need extra protection from drying and oxidationStore fresh vegetables for as short a time as possibleKeep refrigerators and storage areas cleanFrozen vegetablesStore at 0° F or cooler, in original containers, until ready to useDo not refreeze vegetables24Storage – Dried and CannedDried vegetablesStore in a cool (less than 75° F) in a dry, well-ventilated placeKeep well sealed and off the floorCanned vegetablesKeep in cool, dry place, away from sunlight and off the floorDiscard damaged cans25Storage - LeftoversDo not create them in the first placeDon’t mix batchesCool quickly, and use with caution. Remember the danger zone26Clip art images may not be saved or downloaded and are only to be used for viewing purposes.Copyright ©2007 John Wiley & Sons, Inc.27