Vegetable Oils

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Vegetable Oils
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Where is the oil located?

• Plants use stored oil as food for germinating
  embryo, caloric content is high so is efficient
  storage material. Double that of carbohydrates
  and proteins.
• Oil can be stored in endosperm (castor, coconut),
  cotyledons (peanut, soybean), scutellum (corn),
  fruit pulp (palms and olives).
• Seeds have organelles called as glyxosomes that
  convert fatty acids into carbohydrates during
  germination.

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Oils

• Mainly hydrocarbons made up of
• Glycerol (backbone) with three fatty acids
  chemically bonded to it - triglycerides

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Cholesterol
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Unsaturation

• The number of double bonds determines the level
  of saturation.
• Vegetable oils are complex mixtures and
  saturation levels cannot be calculated directly
  very easily
• saturation is determined by Iodine method,
• Iodine breaks 's and is incorporated. Amount of
  Iodine left over is determined. Iodine values
  range from 7 to gt200. 70 are called fats (solid
  at room temperature) and higher values correspond
  to more unsaturation.

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Unsaturation and Iodine Value

• Drying - gt150 thin film will dry into impervious
  coating
• Semidrying - 100-150
• Nondrying - 70-100
• Fats 70

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http//discovermagazine.com/2001/mar/featchemistry
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Soap making

• Soap is salt of fatty acid

                                            3NaOH           3 RCOO- Na                                            
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Soap Making

• Water lye (Base)
• Add oil or fat
• Glycerol and fatty acids separate
• Fatty acids will react with base to form salt of
  fatty acid
• Head which is soluble in water
• Tail soluble in oil

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Oil Paints and Varnishes

• Drying or semidrying oils (linseed tung oil)
• oil paints are boiled with heavy metal containing
  compounds (Mg, Co, Pb) which help oils absorb
  oxygen and form a hard film
• varnishes are produced by mixing boiled oils with
  resins or gums
• enamels are varnishes pigments
• paints do not contain gums or resins
• Latex paints - alkyd resins which are
  manufactured from fatty acids cleaved from
  vegetable oils, water soluble

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Linoleum and Jojoba

• Made up of Oils gums synthetic resins
  pigments
• oils are "blown" which thickens them and makes
  them soluble in petroleum oils (resins)
• linoleum is not used much in U.S. anymore.
• Jojoba - oils is esters rather than
  triglycerides, originally thought to be good
  substitute for sperm oil but is not because of
  high temperature breakdown however is useful in
  medicine and cosmetics.

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Extraction

• Grinding with stones- cold pressing high
  quality
• Steam driven stone press
• hot pressing
• Screw press - continuous feed
• Solvent extraction - follows screw press, hexane

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Refining

• Removal of free fatty acids
• Degumming - removes mucilaginous material
• Bleaching - removal of pigments
• Deodorized - steam heating
• Winterize - prevents clouding by chilling oil and
  filtering out particles.
• Hydrogenation - yields vegetable lards, margarine
  and cheese substitutes

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Drying OilsHigh in double bonds in FA

• Linseed oil - Linum usitatissimum, seeds,
  water-repellent glaze
• mostly non-edible oils
• due to unpleasant flavor
• Cyanogenic glycosidesand
• rapid rancidity due to lots of double bonds.
• also source of flax
• Tung oil - Aleurites (Euphorbiaceae), seeds,
  poisonous (not edible), used in paints,
  waterproof coverings and caulking. Once grown in
  U.S. but most now comes from China.

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Semi-drying OilFew double bonds in FA

• Safflower oil - Carthamus tinctorius, thistles,
  oil is from seeds, used in cooking oils, salad
  dressings, margarine, high I value so low in
  calories but oxidizes readily
• Produces dye
• Soybean oil Glycine max already covered, stores
  well, used in salad and cooking oils and
  artificial "fluffy" products.
• Sunflower oil - Helianthus annuus - native North
  American plant but development of large-headed
  cultivars is largely credited to Russians used
  as salad and cooking oil paints, varnishes and
  resins added to diesel fuel.Considered equal to
  olive oil, used for production of margarines.
• Corn oil Zea mays salad dressing and
  margarines, stable but smokes at high temp.
• Sesame oil - Sesamum indicum, from Ethiopia,
  highly resistant to oxidation due an antioxidant
  compound called sesamolin, most is consumed and
  produced in Africa, Middle East, India and China
• Cottonseed oil Gossypium barbedensis byproduct
  of cotton fiber production, must remove gossypol
  (toxic to most animals except cows) Wesson oil,
  hydrogenation ---gt Crisco
• Rapeseed oil - Brassica napus, edible oil but
  possibly toxic, most useful as machine oil as an
  lubricant

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Non-drying Oil

• Peanut oil - Arachis hypogaea, premium cooking
  oil
• Olive oil - Olea europea, obtained from fruit
  pulp,
• Gentle pressing of the olive virgin oil
• Further pressing first, second grade oils
• Has monounsaturated fat good for health.
• Castor oil - Ricinus communis
• Laxative ricinoleic acid
• poison - ricine (alkaloid) and ricin (highly
  toxic protein) used in soaps, paints,
  lubricants

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Vegetable Fat

• Oil palms - Elaeis guinensis, distinct oils are
  obtained from fruit pulp and seeds
• kept separate due to differences in chemical
  composition used in soap, candles, margarine and
  shortenings
• U.S. diets are avoiding fats and palm oils are
  taboo.
• Coconut oil - Cocos nucifera, cosmetics and
  nondairy "dairy" products
• At 20oC becomes semisolid at 15oC becomes
  brittle
• Has free fatty acid caprylic acid - smell
• Shea butter Butyrospermum parkit
• 50 saturated fat

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Relative effect of fats on Total Cholesterol
Oil or Fat MyristicacidC140 PalmiticacidC160 LinoleicacidC182 AlphaLinolenicAcidC183 DietaryCholesterol  Delta TC  Change in cholesterol level
Butterfat 11 27 2 1 273 1788 
Canola oil 0 4 22 10 0 -514 
Coconut oil 18 9 2 0 0 1674 
Corn oil 0 11 58 1 0 -870 
Grape seed oil 0 8 73 0 0 -1196 
Lard 2 26 10 0 77 630 
Olive oil 0 13 10 1 0 88.6 
Safflower oil 0 7 78 0 0 -1310 
Soybean oil 0 11 54 7 0 -908 
Sunflower oil 0 7 68 1 0 -1142 
Not high-oleic
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Wax

• Long chain alcohol and long chain fatty acid
• Jojoba wax Simmondsia chinensis
• Seeds contain liquid wax
• Similar to sperm whale oil

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