Vegetable Oils

1. Vegetable Oils

2. 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.

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

4. Cholesterol

5. 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 >200. 70 are called fats (solid at room temperature) and higher values correspond to more unsaturation.

8. Unsaturation and Iodine Value • Drying - >150 thin film will dry into impervious coating • Semidrying - 100-150 • Nondrying - 70-100 • Fats 70

9. http://discovermagazine.com/2001/mar/featchemistry/

10. Soap making • Soap is salt of fatty acid

11. 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

12. 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

13. 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.

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

15. 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

16. 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.

18. 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 ---> Crisco • Rapeseed oil - Brassica napus, edible oil but possibly toxic, most useful as machine oil as an lubricant

19. 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

21. 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

22. Relative effect of fats on Total Cholesterol * Not high-oleic

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