Pigments in Vegetables: Chlorophylls and Carotenoids

ISBN-13: 9781461358428 / Angielski / Miękka / 2012 / 351 str.

Jeana Gross

Opis

Vegetables contain several classes of pigments: the green chlorophylls; the yellow, orange, and red carotenoids; the red, blue, or violet anthocyanins; andthered-violet betalains. Thisbookcoversthechlorophyllsandthecarot- enoids, the two chief classes of vegetable pigments, and is the first major compilationofthis kind. Structure, physical and chemical properties, and analytical methods, in- cluding special methods adapted for certain vegetables, are discussed first, and are then followed by a discussion of physiological and biochemical as- pects, including location, biosynthesis, and biochemical changes during plant developmentand senescence. Both pigment classes have extremelyimportant biological functions. The chlorophylls are of paramount importance in photosynthesis. The carot- enoids, besides their photofunction, have a highly significant role in nutri- tion. Someofthem havevitaminA value and, possibly, a rolein the preven- tion of human cancer. The chlorophyll distribution table includes all ofthe currentlyavailable quantitativedataonvegetables. The discussion of carotenoid distribution describes the unique carot- enoids found invegetablesandincludesqualitativeandquantitativedistribu- tion tables for the most common vegetables. These tables summarize all of the publisheddata to date, but they are far from complete. However, appli- cationofrecentlyavailabletechniques should fill theenormousgaps, update old data, and permit an accurate assessment of the vitamin A value of the food. Suchcompletedatawould also make it possible to usecarotenoid dis- tributioninthetaxonomyofvegetables. The presentations of pigment distribution also consider the changes in pigmentcontentduring storageand processing. Thebookalsoincludesapresentationoffactors affectingpigmentsynthe- sis in vegetables (e.g., phytohormones) and environmental factors (e.g., light, temperature), as well as fertilizers and pesticides.

Spis treści

Chlorophylls.- Structure.- Physical Properties.- Chemical Properties.- Derivatives.- Chlorophyllides.- Pheophytinsaandb.- Pheophorbidesaandb.- Allomerized Chlorophylls.- Pyrochlorophylls.- Analytical Methods.- Extraction.- Chlorophyll Determination.- Separation of Plant Pigments.- The Chloroplast.- Chemical Composition.- Development.- Function.- The Photosynthetic Unit.- Spectroscopic Properties of Chlorophyll in vivo.- Biosynthesis.- Step 1. Formation of b-Aminolevulinic Acid.- Step 2. Pyrrole (Porphobilinogen) Formation.- Step 3. Cyclic Tetrapyrrole Formation (Uroporphyrinogen III).- Step 4. Porphyrin Side-Chain Modifications.- Step 5. Oxidation of Protoporphyrinogen IX to Protoporphyrin IX.- Step 6. Magnesium Chelation of Protoporphyrin IX to Mg Protoporphyrin IX.- Step 7. Esterification of Mg to Protoporphyrin IX.- Step 8. Isocyclic Ring Formation (Protochlorophyllide).- Step 9. Protochlorophyllide Reduction to Chlorophyllide.- Step 10. Esterification of Chlorophyllidea.- Step 11. Biosynthesis of Chlorophyllb.- An Alternative Chlorophyll Biosynthetic Pathway.- Distribution in Vegetables.- Asparagus.- Beans.- Broccoli.- Peas.- Potato.- Cucurbitaceae.- Degradation.- Leaf Senescence.- Enzymes Involved in Chlorophyll Biodegradation.- Chlorophyll Bleaching—Lipoxygenase Peroxidases and Oxidases.- Chlorophyll Turnover.- Influence of Stress Conditions on Chlorophyll Degradation.- Degradation During Fruit Ripening.- Degradation During Processing and Storage of Green Vegetables.- Stabilization of Chlorophylls in Processed Green Vegetables.- Storage in Controlled Atmosphere.- Food Coloring.- Effect of Phytohormones on Chlorophyll Metabolism in Vegetables.- Cytokinins.- Gibberelin.- Ethylene.- Carotenoids.- Definitions and Nomenclature.- Structure and Classification.- Physical Properties.- Spectroscopic Properties.- Stereochemistry.- Geometrical Isomerism.- Absolute Configuration.- Chemical Properties.- Chemical Tests.- Oxidation.- Chemical Oxidation.- Autoxidation.- Photooxidation (Light Effect).- Enzymatic Oxidation.- Analytical Methods.- Extraction.- Saponification.- Quantitative Determination.- Removal of Sterols.- Carotenoid Separation.- Identification.- Biosynthesis.- Formation of Mevalonic Acid.- Formation of Geranylgeranyl Pyrophosphate.- Formation of Phytoene.- Desaturation of Phytoene.- Formation of Cyclic Carotenes.- Formation of Xanthophylls.- Functions.- Photofunctions.- The Violaxanthin Cycle.- Antioxidants.- Biological Function: Role of Carotenoids in Human Nutrition.- Uses.- Colorants.- Medicinal Applications.- Localization.- Chloroplasts.- Chromoplasts.- Carotenoids in Vegetables.- Changes During Storage Cooking and Processing.- Unique Carotenoids.- Carotenoid Distribution in Vegetables.- Asparagus.- Balsam Pear.- Green Beans.- Lima Beans.- Mung Beans.- Soybeans.- Broccoli.- Cabbage.- Carrots.- Cassava.- Cauliflower.- Cucumber.- Lettuce.- Lupin.- Maize.- Pea.- Chick-peas.- Pepper.- Potato.- Sweetpotato.- Pumpkins and Squashes.- Spinach.- Tomato.- Turnip and Swedish Turnip or Rutabaga.- Yam.- Factors Affecting Cartenoid Biosynthesis.- Phytohormones.- Light.- Temperature.- Fertilizers.- Pesticides.- Miscellaneous.- References.