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Lecture 12

Lecture 12 - 16 Notes

13 Pages

Course Code
Biology 2217B
Richard Gardiner

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Lecture 12: Starchy Staples  High producers of starch in a nutritional manner Starch  Mostly root crops  Mostly of tropical origin o Farmed now in temperate climates as well  Most propagate asexually o Advantage: exact same plant is produced, faster process  Economically important  Among first plants domesticated by humans  Normally low in protein and oils  Made and stored in plastids o Chloroplasts in leaves, and amyloplasts in roots  Breakdown of starch begins in the mouth o Salivary enzymes, slightly sweet taste  In traditional diets, provides the lion’s share of carbohydrates o Diversity of food sources has given more developed countries a variety of alternatives Roots and Modified Stems  Stems o Stolons or runners – horizontal stems, long internodes, found above ground o Rhizhome – horizontal underground stems o Bulb – vertical underground stem; food reserves in leaves o Corm – vertical underground stem; store food reserved in stem  Storage roots o Tuber – enlarged storage tips of rhizome o Tuberous root – fleshy fibrous roots, enlarged with food reserves o Taproot – biennial plants  Stem tubers: Potato o True yams o Formed on underground stems (rhizomes) o “Eyes” are buds formed at nodes  Tuberous storage roots: Sweet potato o Often misnamed as yams o Modified fibrous roots enlarged with food reserves  Corms: Taro o Fleshy, erect underground stems (storage is in the stem, not in the leaves as in bulbs) Solanaceae  Simple, alternate leaves  Flowers are 5-mers  Sepals and petals fused into a tube  Fruit is a berry or capsule  85 genera, ca. 2800 species  Includes tomato, potato, tobacco, eggplant, datura, and deadly nightshade Potatoes  White, sweet, and yams  Each a different species in a different family White Potato  Origin: Andean highlands at about 3500 m above sea level  Collected wild about 8000 years BP and cultivated shortly after  “Freeze dried” to make “Chuno” o Preserves well  Nutritional value o Chiefly starch, some protein, minerals and vitamin C  Grows well in cool climates o High productivity / unit area  Spanish Conquistadores took potato to Spain o Spread to the rest of Europe  Reproduction chiefly vegetative  Genetic uniformity  Susceptible to inbreeding depression o Irish potato famine  Now with about 6000 cultivars, some are blight resistant  Worldwide controversy about GT and GMO crops o Genetically engineered beetle-resistant varieties were rejected by McCain in 1998 o Roundup Ready potatoes developed but not released  Nobles wanted peasants to subsist on potatoes, to save wheat for nobility and export o Easy to cultivate o Matures in 4 months o High production o Easy to prepare – boil and serve Sweet Potato  Tropical perennial from S. America, dicot o Cultivated as an annual in temperate climates  Enlarged edible storage roots o Sweet, with lots of beta-carotine  Two types o Cream-to-light yellow colored flesh, non- sweet flavor, dry texture o Yellow or deep orange, moist texture, distinct flavor, high sugar content (often misnamed as yams)  Warm season crop  Introduced to Spain by Columbus  Rich in CHO (more sugar and calories, less starch compared to white potato); rich in certain vitamins, especially A (from beta-carotene) and C  80% of world production comes from China o U.S. accounts for 1% of production Wild Yams  Monocot  Tropical stem tuber  Different spp. are native to Arica, Asia and S. America  An African species is now most commonly grown around the world  Varies in size from palm-size to 40 kg / 2-3 m  Propagated from “eyes” as in potato  Oxalic acid (poison, irritant) just beneath skin, so peeling is necessary  Usually boiled and mashed  Chiefly starch, about 2% protein, some vitamins and minerals th th  Herbal remedy in 18 and 19 centuries for cramps and birthing problems  Source of diosgenin, converts in body to progesterone o Used to make the first birth-control  Grows best in humid sub-tropical conditions  Grows deep – difficult to harvest Taro  Colocasia esculenta, Araceae o Monocot  Chiefly starch, 2% protein, high Ca  Believed to be originated in Southeast Asia o Spread Easy and West  Grows in wet, tropical conditions  Propagated by corm tops or ‘cormels’  Must be cooked to break down the irritating crystals (like rhubarb)  Tropical tuber eaten by native Hawaiians  Corms are steamed, crushed, made into dough, and allowed to ferment naturally by microbes. Doughy paste eaten with fingers or rolled into small balls; traditional staple  Can be cooked similar to potatoes or processed into flour, chips, breakfast foods, etc. Cassava  Manihot esculenta, Euphorbiaceae o Dicot  Other names: Yuca, mandioca  30% starch, <1% protein o Protein deficient  Originated from S. America o Brazil, Zaire, Nigeria are now leading producers  Large herbaceous shrub up to 10ft with tuberous roots similar to large sweet potatoes  Fleshy roots contain poisonous compounds  Survives adverse conditions o Heat, drought, pests, and high-acid soil  Tropical root crop, needs a good rainy season  Reproduced by stem cuttings – portion of stem and axillary bud  Often waxed for shipping, decays rapidly  May produced either cassava starch or tapioca ‘pearls’ o Moist starch is heated in shallow pans, causing it to form beads o Not to be confused with Sago  Like tapioca, but made from Sago Palm or Sago Cycad – but this contains beta-methylamino L- alanine – a potent neurotoxin)  Two types – sweet and bitter o Both contain cyanide (HCN) o Bitter is more toxic (also more resilient in nature)  Plant must be detoxified before consumption o Peeling and grating the flesh causes HCN production o Squeeze contents to expose to enzymes and to squeeze out some of the toxic leachate o Pulp stands overnight and the remaining toxins are removed by cooking heat o Sometimes drying in the sun is enough to remove the cyanide gas Jerusalem Artichoke  Healianthus tuberosus o Dicot  Pilgrims named this staple after “New Jerusalem” they were carving out the wilderness  Weedy, hardy, easily-cultivated perennial that produces tubers  10% protein, 76% carbohydrate inulin, no oil or no starch o Inulin is digested into fructose, which is 1.5x sweeter than sucrose  Folk remedy of diabetes  Eat fresh, cooked or pickled Arrowroot  Introduced back to Europe by early American settlers, who learned of it from the Arawak, the native Caribbeans  Named the plant aru-aru, which means “meals of meals”, indicating how highly they valued the starchy food made from the arrowroot tubers  Also used arrowroot tubers to draw poison from wounds inflicted by poison arrows, which is where the name “arrowroot” apparently came from in English  Maranta sp.  23% starch  Tubers are pulped to produce milky liquid that is dried to make the starch  Light, white powder  Biscuits, puddings, jellies, cakes, etc.  Gluten free Breadfruit  Artocarpus altilis  Nutritious starchy melon weighing between 2 -5 lbs  Food source for African slaves in the plantations of the Caribbean  Although a fruit, it has the starchy consistency of unripe potatoes  As it ripens, it softens to about the consistency of a mango but without the sweetness  The reason for the name “breadfruit” is that when eaten before it is ripe, breadfruit not only feels like fresh bread, but also tastes like it Cattail  Roots may be ground into a flour and eaten  Sticky sap between the leaves is an excellent starch and can be used to thicken soups and broths  White-colored shoots at the base of the leaf clusters can be boiled/steamed/sliced and eaten raw  Also used for tinder, ethanol production, bedding, life vest stuffing, etc. Bananas and Plantains  Musa spp (Musaceae) o Monocot  Native to Indo-Malaysia (including Papa New Guinea), N. Australia and SE Asia  Sweet soft-fleshed ones are known as bananas, and starchy, firm-fleshed ones as plantains o Bananas are usually eaten raw, and plantains, cooked  Two fungal diseases are causing massive crop losses in banana plantations Lecture 13: Fruits and Vegetables Botanical Definition  Fruit – ripened plant ovary that contains seeds o Apricots, tomatoes, oranges, pineables, nuts, beans, squash and bell peppers  Vegetable – leaves, stems, roots and other plant parts that don’t contain seeds o Rhubarb, lettuce, celery, broccoli, radishes and carrots Culinary Definition  Fruit – sweet, fleshy parts of a plant (rhubarb is a culinary fruit)  Vegetable – savory plant parts that can be eaten unsweetened or salted (tomatoes and squash are culinary vegetables) Brassicaceae  Mustard family  Many are Mediterranean in origin  Phytochemicals important in diet o Cancer prevention  Form original wild type of Brassica oleracea o Wide variety have been developed by artificial selection  Broccoli, cauliflower, cabbage, brussel sprouts  Waxy coating protects from salt, cold and drought Apiaceae  Carrot family  Several vegetables and many herbs  Temperate plants originating from Mediterranean / Eurasia  Celery (Apium graveolens), carrot (Daucus carota), and parsnip (Pastinaca sativa)  Carrots and parsnips are biennials Asparagaceae, Alliaceae  Formerly included in the Liliaceae, but most lilies are toxic  Asparagus are stems, onions are bulbs  Onions make us cry because volatile sulphides disperse when cut  Onions (Allium cepa) – Afghanistan  Garlic (Allium sativum) – Middle East  Leeks (Allium porrum) – Mediterranean  Chives (Allium schoenoprasum) – Eurasia and northern N. America Fruits and Vegetables  Two prominent families: o Cucurbitaceae – gourd or cucumber family o Solanaceae – nightshade or potato family Cucurbitaceae  Gourd or cucumber family  Fruit is a pepo o Central/S.America  One of three main staples of American Natives o Corn, beans, squash  Various Cucurbita spp. o Pumpkin, the acorn, hubbard and butternut, squashes, and zucchini  Cucumber – Cucumis sativus – Asia  Watermelon – Citrullus lanatus – Africa Solanaceae  Nightshade or potato family  Many poisonous and hallucinogenic species  Most of the fruits are berries o Most originated in Central/S. America  Potatoes (Solanum tuberosum), tomatoes (Lycopersicon esculentum, from the Mayan ‘xtomatl’), and bell & chilie peppers (Capsicum spp.) have their origins in C or S America and were widely domesticated in Mexico  Eggplant (Solanum melongena) – Asia Peppers  Includes sweet peppers, chilies, and cayenne  Several varieties  Capsaicin determines heat o An amide, with a ‘vanilloid’ structure similar to one in vanilla, black pepper and ginger o Found chiefly in seeds and placental region  Medicinal use as topical pain reliever, and in pepper spray Nuts  Botanically – a dry, hard, single-seeded fruit produced by an ovary of fused carpels  Culinary – any large, oily kernel found within a shell and used in food  Order: Fagales, Family: Fagaceae  Almond – edible drupe seed  Brazil – seed from capsule  Peanut – legume seed  Pine – coniferous seed  Pistachio – seed from thin-shelled drupe  Coconut – dry, fibrous drupe  Gingko – gymnosperm seed Lecture 14: Sugar Plants Carbohydrates  Compounds of high importance o Provide energy through oxidation o Supply carbon for the synthesis of cell components o The serve as a form of stored energy o Form part of the structures of some cells and tissues  Most have a sweet taste o Fructose is sweetest (73% sweeter than sucrose)  Solids at room temperatures  Extremely soluble in water How we Taste Sugars  Chemosensory o Varies among individuals and species o Multipoint attachment theory  Multiple binding sites between receptor and substance o Very ancient evolutionary origins Sweetness  Not yet fully understood  Van der Waals forces on molecules  Have an effect on sweet receptors – large proteins Fructose  Naturally occurring  Fruits, vegetables, honey  Sweetest of the naturally occurring sugars Sucrose  Naturally occurring carbohydrate o Fruits and vegetables o Sugar cane and sugar beets  Table sugar Barley  Germinating barley contains malt  Comes from endosperm  Almost pure maltose  In brewing  In confections Sources  Sap – cane juice, sorghum syrup, maize sugar, agave nectar, maple syrup, palm sugar  Roots – sugar beet, yacon syrup, licorice root  Flowers – barley malt, brown rice malt  Fruits – watermelon sugar, pumpkin sugar, dates, carob molasses  Leaves – stevia Sugarcane  Large perennial grass  Saccharum officinarum  Grows only in tropical and sub-tropical climates  Grows to height of 2.7 to 6.0 m and stem is source of sugar  India, Brazil, Cuba, Pakistan, Philippines, West Indies, South Africa, Australia Lecture 15/16: Psychoactive Plants Chemistry and Pharmacology  Mode of activity: o Ingestion by various routes o Circulation o Absorption into bloodstream o Activity  Affect neurotransmitters o Mimics: agonists o Inhibitors: antagonists Nervous Systems  Parasympathetic nervous system: responsible for daily functions, basic body responses  Sympathetic nervous system: responsible for fight or flight response Classes of Psychoactive Compounds  Most are alkaloids o Organic compounds, contain nitrogen o Examples: codeine, morphine, heroin, cocaine, nicotine, caffeine, mescaline, atropine, hyoscyamine, scopolamine, ergotami
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