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Oils and fats
By
Abdul moiz Dota
Food Engineering
U.A.F
OUTLINE: OILS AND FATS
Importance
o All cultures
o Required in diet
Botanical
o Many families
Economics
o Multiple plant u...
Chemistry
o Triglycerides
o Short vs long chain fatty acids
o Unsaturated vs saturated fatty acids
o Soaps-saponification
...
Isolation
o Extraction methods
o Crushing/expression
Introduction
• Oils (liquid) and fats (solid) common
and important items in the diet of
humans.
• Most of the ones we use ...
• In contrast to essential oils, these substances
are made up of triglycerides and are not
volatile.
• Triglycerides conta...
• Triglycerides are a food reserve for the
germinating embryo.
• Similar oils and fats are obtained from
animals.
• In gen...
• Sites of unsaturation lower the boiling point
and increase the sensitivity to oxygen.
• The oils with 2 or 3 sites of un...
• The properties of highly unsaturated
oils that make them valuable also make
them undesirable for food products
because t...
• Non-drying-saturated- typically tropical plants
palm, peanut, olive, rape, castor, almond
• Drying oils-highly unsaturat...
Extraction methods
• The seeds are usually cleaned and then
dehusked.
• Crushing - today done mostly with rollers. A screw...
• Expression - cold and hot (where seeds
are cooked first). For an outline of the
complete process, see pg. 229.
• Extract...
Subsequent treatment of oils
• After isolation, the oils are treated for several
reasons.
• In many cases, the oils are tr...
• Bleaching is usually done with Fuller's earth
or activated charcoal.
• Deodorizing is often done with steam.
• Winterizi...
Uses of fats and oils
• Almost all oils and fats come from seeds
(except for olive and avocado). They are
required in the ...
• Lubricants
• Soap - now largely replaced by
synthetic detergents
• Paints - now largely replaced by
synthetic polymers.
...
Major oilseed crops
• Table pages 230-231.
• Linseed oil
• This is probably the oldest domesticated oil
seed crop. Flax or...
• Linseed oil alone still used to finish
many wood products. Linseed oil is
used as an edible oil in some parts of
the wor...
Flax in the Pampas of Argentina
Flax, Linum usitatissimum, Linaceae
Tung oil, Aleurites fordii, Euphorbiaceae

• Tung oil is mostly from China.
• This small tree has fruits that contain a
hi...
Tung, Aleurites fordii,
Euphorbiaceae
Safflower oil, Carthamus tinctorius,
Asteraceae or Compositae
• Safflower oil is unsaturated and is considered
to be a goo...
Safflower, Carthamus tinctorius, Asteraceae
Soybeans (Glycine max)
• Soybeans are, of course, an ancient crop as
previously described.
• In the Orient they are not us...
Glycine max, soybean
Soybean harvest
soybeans
Sunflower (Helianthus annuus)
Asteraceae
• The sunflower was domesticated about 5000
years ago in Mexico and has become a ...
Sunflowers,
Helianthus annuus,
Asteraceae
• The cultivated types of sunflowers
today are much larger than the wild
ones. The plant is still a common weedy
species i...
Corn or maize (Zea mays)
• Corn, of course, is cultivated for other
purposes, but also for oil. The oil is a minor
by-prod...
Male and female corn structures

Carolina Biological Supply Co.
Sesame (Sesamum indicum,
Pedaliaceae)
• Sesame oil an ancient crop. It probably arose
in India.
• On the other hand, the c...
Sesame, Sesamum indicum, Pedaliaceae

Courtesy Dr. Dorothea Bedigian
Courtesy Dr. Dorothea Bedigian
Sesame seed
Cotton (Gossypium hirsutum, Malvaceae)
• Cotton widely grown for fiber.
• The seeds used as a source of edible oil for
tho...
Cotton, Gossypium hirsitum, Malvaceae
Cotton field and cotton boll
Rape or canola, Brassica napus,
Brassicaceae or Cruciferae
• Rapeseed or canola commonly grown in
Canada and in Europe.
• ...
Canola, Brassica napus, Brassicaceae or
Cruciferae, in Ontario

Courtesy Dr. Clint Chapple
Flax and canola in Manitoba

Courtesy Dr. Ellis McLeod
Rapeseed in Germany
Peanut oil, Arachis hypogaea, Fabaceae
or Leguminosae
• Peanut oil widely used in the tropics.
• It is especially common i...
Arachis hypogaea, peanut in flower
Pollinated ovary going under the soil
Primitive peanut relative - Arachis villosa
Olive oil (Olea europaea, Oleaceae)
• Olive oil is another ancient crop from the Near
East. At least 3500 B.C. in Crete.
•...
Olives, Olea europaea,
Oleaceae
Castor bean (Ricinus communis,
Euphorbiaceae)
• Castor bean probably grew in both Asia and
Africa when it was domesticated...
Castor bean
(Ricinus
communis,
Euphorbiaceae)
Castor bean
(Ricinus
communis,
Euphorbiaceae)
• Castor oil is still used as a laxative. The
seeds are highly toxic but the compounds
responsible are not soluble in the ...
Palm and palm kernel oils
• Oil palms (Elaeis guineensis, Arecaceae) differ
from most other oil seeds in that both the fru...
African oil palm (Elaeis guineensis,
Arecaceae)

National Geographic
• The African oil palm is probably the most
widely cultivated today.
• Pg. 240. The plant is only semicultivated. The
frui...
Cooking dende oil from
oil palms

Courtesy Axel Walther
Coconuts (Cocos nucifera, Arecaceae)
• Coconut oil is isolated from copra, the “meat”
that is removed from the seeds and d...
Coconuts (Cocos
nucifera, Arecaceae)
Extracting copra from coconuts in Oceania
Courtesy Dr. S. Glassman
• The press cake also used as a cattle
feed.
• Coconut oil used in shampoos, hand
lotions, suntan creams, non-dairy
produc...
Other oilseeds
• In some countries, crambe (Crambe abyssinica,
Brassicaceae or Cruciferae) is used. It is
similar to rape ...
Niger seed, Guizotia abyssinica,
Asteraceae
Shea butter tree,
Butyrospermum parkii,
Sapotaceae
The fats from the fruits are
used as a food in West Africa
and in cosme...
Soap
• Soaps are the salts of fatty acids. Potassium
and sodium soaps are the most commonly
used.
• Magnesium and calcium ...
Device for isolating “caustic” potassium carbonate from wood ashes
• Oils and fats are treated with lye (sodium
hydroxide or potassium hydroxide) to yield
salt of the fatty acids. Formerly,...
Paints
• Many polyunsaturated oils are incorporated
with pigments into paints and varnishes.
• Linseed oil and tung are am...
• Vegetable oils are heated with heavy
metal salts to catalyze polymerization
before being used in paints. These help
the ...
oli & fat Assignment no 6
oli & fat Assignment no 6
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Transcript of "oli & fat Assignment no 6"

  1. 1. Oils and fats By Abdul moiz Dota Food Engineering U.A.F
  2. 2. OUTLINE: OILS AND FATS Importance o All cultures o Required in diet Botanical o Many families Economics o Multiple plant use o Press-cake
  3. 3. Chemistry o Triglycerides o Short vs long chain fatty acids o Unsaturated vs saturated fatty acids o Soaps-saponification o Polymerization - paints + Non-drying + Drying + Semi-drying o Precursors for plastics o Petroleum substitute
  4. 4. Isolation o Extraction methods o Crushing/expression
  5. 5. Introduction • Oils (liquid) and fats (solid) common and important items in the diet of humans. • Most of the ones we use come from seeds (or animals). • The use of seed oils is ancient.
  6. 6. • In contrast to essential oils, these substances are made up of triglycerides and are not volatile. • Triglycerides contain fatty acids and glycerol. • The structures of the fatty acids determine many of the properties of the oils and fats.
  7. 7. • Triglycerides are a food reserve for the germinating embryo. • Similar oils and fats are obtained from animals. • In general, the longer the chains of the fatty acids, the higher boiling the oils or fats are. • Peanut oil has lots of C20 fatty acids and is high boiling.
  8. 8. • Sites of unsaturation lower the boiling point and increase the sensitivity to oxygen. • The oils with 2 or 3 sites of unsaturation polymerize readily and have often been used in paints.
  9. 9. • The properties of highly unsaturated oils that make them valuable also make them undesirable for food products because they tend to turn rancid readily. • Unsaturated oils can be converted to saturated oils by hydrogenation with a catalyst (usually nickel). This raises the melting point. • Originally done by Wesson. Pg. 221.
  10. 10. • Non-drying-saturated- typically tropical plants palm, peanut, olive, rape, castor, almond • Drying oils-highly unsaturated (polyunsaturated) linseed, tung, soy bean, hempseed, nut, poppy, safflower • Semi-drying oils (moderately unsaturated) cottonseed, sunflower, sesame, croton, corn. • Many important oils are listed on page 230231. • Many seeds contain quite large quantities of oils. Sesame seed, for example, is more than half oil.
  11. 11. Extraction methods • The seeds are usually cleaned and then dehusked. • Crushing - today done mostly with rollers. A screw press makes it possible to have a continuous feeding of seeds. The oil flows out (pg. 229, 227). • Because there is still 2-4% oil in the meal, the material is extracted again with solvents in some cases. • In some cases, the kernels are broken or flaked before extraction.
  12. 12. • Expression - cold and hot (where seeds are cooked first). For an outline of the complete process, see pg. 229. • Extraction - solvents (petroleum ether (hexane), chlorinated solvents). • Boiling - centrifugation
  13. 13. Subsequent treatment of oils • After isolation, the oils are treated for several reasons. • In many cases, the oils are treated with caustic soda to remove any free fatty acids present. • The oil may then be degummed, bleached, deodorized, and/or winterized. • Degumming is done by mixing the oil with water and centrifuging.
  14. 14. • Bleaching is usually done with Fuller's earth or activated charcoal. • Deodorizing is often done with steam. • Winterizing is cooling down the oil and removing materials that precipitate out. • The fatty acids and triglycerides that precipitate out are called "foots". • Most oils are treated to render them odorless and tasteless (and interchangeable).
  15. 15. Uses of fats and oils • Almost all oils and fats come from seeds (except for olive and avocado). They are required in the diet of most animals. • Margarine and shortening are made by hydrogenation.
  16. 16. • Lubricants • Soap - now largely replaced by synthetic detergents • Paints - now largely replaced by synthetic polymers. • Chemical precursors - nylon, polymers probably the best petroleum substitute. • Press cake is usually used for livestock feed • Biofuels
  17. 17. Major oilseed crops • Table pages 230-231. • Linseed oil • This is probably the oldest domesticated oil seed crop. Flax or linseed (Linum usitatissimum, Linaceae) is from the Near Eastern Center. Fossil linseed shows signs of selection by 6000 B.C. • In the time of the Egyptians, coffins were painted with mixtures of linseed oil and resin. • The plant is also used for fiber.
  18. 18. • Linseed oil alone still used to finish many wood products. Linseed oil is used as an edible oil in some parts of the world, but has largely been replaced by other oils. • Flax seed a major source of omega-3fatty acids and may be valuable in human diets.
  19. 19. Flax in the Pampas of Argentina
  20. 20. Flax, Linum usitatissimum, Linaceae
  21. 21. Tung oil, Aleurites fordii, Euphorbiaceae • Tung oil is mostly from China. • This small tree has fruits that contain a highly unsaturated but inedible oil. • Tung oil one of the best quality furniture finishing oils. • The press cake is highly toxic.
  22. 22. Tung, Aleurites fordii, Euphorbiaceae
  23. 23. Safflower oil, Carthamus tinctorius, Asteraceae or Compositae • Safflower oil is unsaturated and is considered to be a good quality salad oil. • Safflower was domesticated in the Mediterranean area. This species is only known in cultivation. • Safflower was probably first grown for the yellow dye it produces.
  24. 24. Safflower, Carthamus tinctorius, Asteraceae
  25. 25. Soybeans (Glycine max) • Soybeans are, of course, an ancient crop as previously described. • In the Orient they are not usually used for oil purposes. Europeans began to press them back in the 1700's. • Today, almost all soybeans used in the U.S. are pressed for oil. The soybean is about 1325% oil. • The press cake is used for feeding livestock and as a human food additive.
  26. 26. Glycine max, soybean
  27. 27. Soybean harvest
  28. 28. soybeans
  29. 29. Sunflower (Helianthus annuus) Asteraceae • The sunflower was domesticated about 5000 years ago in Mexico and has become a major crop. • The seeds were widely eaten by the American Indians. • The crop was highly modified in Europe, however. It is an especially an important crop in the former Soviet Union.
  30. 30. Sunflowers, Helianthus annuus, Asteraceae
  31. 31. • The cultivated types of sunflowers today are much larger than the wild ones. The plant is still a common weedy species in much of the Midwest. • See sunflower diagram on pg. 234.
  32. 32. Corn or maize (Zea mays) • Corn, of course, is cultivated for other purposes, but also for oil. The oil is a minor by-product of corn milling to isolate starch. The corn is steeped in sulfurous acid and then lightly macerated to separate the embryo from the endosperm. • Diagram pg. 235. • The oil is isolated from the embryos. Most refined corn oil used for margarine and salad oils.
  33. 33. Male and female corn structures Carolina Biological Supply Co.
  34. 34. Sesame (Sesamum indicum, Pedaliaceae) • Sesame oil an ancient crop. It probably arose in India. • On the other hand, the close relatives of sesame are mostly from Africa. • The oil has a relatively strong flavor and is much used in Chinese cooking. • Sesame oil commonly used in Africa, the Middle East, India, and China. • The seeds themselves are also widely eaten.
  35. 35. Sesame, Sesamum indicum, Pedaliaceae Courtesy Dr. Dorothea Bedigian
  36. 36. Courtesy Dr. Dorothea Bedigian
  37. 37. Sesame seed
  38. 38. Cotton (Gossypium hirsutum, Malvaceae) • Cotton widely grown for fiber. • The seeds used as a source of edible oil for thousands of years. • Cotton seed contains a toxic compound, gossypol. A problem in utilizing the press cake. • David Wesson's process of purification with caustic soda, steam and fuller's earth removed much of the gossypol. • Shortening was first made by hydrogenation of cottonseed oil.
  39. 39. Cotton, Gossypium hirsitum, Malvaceae
  40. 40. Cotton field and cotton boll
  41. 41. Rape or canola, Brassica napus, Brassicaceae or Cruciferae • Rapeseed or canola commonly grown in Canada and in Europe. • The oil used for both a lubricant and as an edible oil. It is largely used to make margarine in Europe. • Selection for low erucic acid lines (canola) for edible purposes and cultivation of erucic acid lines for lubricant purposes. • The press cake of limited value for feeding livestock.
  42. 42. Canola, Brassica napus, Brassicaceae or Cruciferae, in Ontario Courtesy Dr. Clint Chapple
  43. 43. Flax and canola in Manitoba Courtesy Dr. Ellis McLeod
  44. 44. Rapeseed in Germany
  45. 45. Peanut oil, Arachis hypogaea, Fabaceae or Leguminosae • Peanut oil widely used in the tropics. • It is especially common in Africa and in France. • Peanut oil higher boiling than most other oils and imparts a pleasant taste to the food.
  46. 46. Arachis hypogaea, peanut in flower
  47. 47. Pollinated ovary going under the soil
  48. 48. Primitive peanut relative - Arachis villosa
  49. 49. Olive oil (Olea europaea, Oleaceae) • Olive oil is another ancient crop from the Near East. At least 3500 B.C. in Crete. • Olive oil was also used as a cleanser, for annointing, as a lamp oil, for medicine, and as a food stuff. • Olive oil comes from both the fruit pulp and from the seed. • There are many different grades of olive oil.
  50. 50. Olives, Olea europaea, Oleaceae
  51. 51. Castor bean (Ricinus communis, Euphorbiaceae) • Castor bean probably grew in both Asia and Africa when it was domesticated. • Seeds at least 6000 years old have been found in Egyptian tombs. • The oil was probably used in medicine and as a lamp oil. • Castor oil is also a precursor for plastics.
  52. 52. Castor bean (Ricinus communis, Euphorbiaceae)
  53. 53. Castor bean (Ricinus communis, Euphorbiaceae)
  54. 54. • Castor oil is still used as a laxative. The seeds are highly toxic but the compounds responsible are not soluble in the oil. Pg. 239. • Today most castor oil is used for soaps, paints, and Turkey red oil. It is also used widely as a lubricant. • The press cake is too toxic for any use except fertilizer.
  55. 55. Palm and palm kernel oils • Oil palms (Elaeis guineensis, Arecaceae) differ from most other oil seeds in that both the fruit pulp and the seed are used. • Actually a series of palms are used. Another one is Oribignya oleifera (native to S. America). There is also a comparable Asian species.
  56. 56. African oil palm (Elaeis guineensis, Arecaceae) National Geographic
  57. 57. • The African oil palm is probably the most widely cultivated today. • Pg. 240. The plant is only semicultivated. The fruits are harvested when ripe. • Most consumers in isolated, rural areas make their own oil by boiling the fruits and collect the oil as it floats to the top. • Commercially, the fruits are pressed quickly after cooking with steam. The kernels are extracted later. • Palm oils are used for soap and candles, but also in margarine and for shortening.
  58. 58. Cooking dende oil from oil palms Courtesy Axel Walther
  59. 59. Coconuts (Cocos nucifera, Arecaceae) • Coconut oil is isolated from copra, the “meat” that is removed from the seeds and dried. Coconuts are widely used in the tropics for just about everything. • Coconuts originated in southeastern Asia. • In the 1800's, people started to use coconut oils to make soap. • Coconut oil also mixes with many other oils and has a pleasant taste.
  60. 60. Coconuts (Cocos nucifera, Arecaceae)
  61. 61. Extracting copra from coconuts in Oceania Courtesy Dr. S. Glassman
  62. 62. • The press cake also used as a cattle feed. • Coconut oil used in shampoos, hand lotions, suntan creams, non-dairy products, cosmetics.
  63. 63. Other oilseeds • In some countries, crambe (Crambe abyssinica, Brassicaceae or Cruciferae) is used. It is similar to rape seed oil. • Grapeseed oil (Vitis vinifera, Vitaceae) is used in countries where grapes are commonly grown for wine making. • Hempseed oil (Cannabis sativa, Cannabaceae) oil is used in some Near Eastern countries.
  64. 64. Niger seed, Guizotia abyssinica, Asteraceae
  65. 65. Shea butter tree, Butyrospermum parkii, Sapotaceae The fats from the fruits are used as a food in West Africa and in cosmetics worldwide
  66. 66. Soap • Soaps are the salts of fatty acids. Potassium and sodium soaps are the most commonly used. • Magnesium and calcium soaps are found as bathtub ring. • Lead and zinc are used to make medicinal soaps • Lithium soaps are used to make lubricants. • Aluminum soaps are used for waterproofing.
  67. 67. Device for isolating “caustic” potassium carbonate from wood ashes
  68. 68. • Oils and fats are treated with lye (sodium hydroxide or potassium hydroxide) to yield salt of the fatty acids. Formerly, extracts of wood ashes were used. Potassium gives soft soaps and sodium gives hard soaps. • Detergents often made by sulfonation of other types of organic molecules. • Saponins from plants used in some societies as soap or detergent substitutes. • Coconut oil is still the most commonly used oil for soap.
  69. 69. Paints • Many polyunsaturated oils are incorporated with pigments into paints and varnishes. • Linseed oil and tung are among the most common of this type. • The Flemish combined pigments and oils to make oil paints in the 15th century. They perfected technique of painting over the pictures with glazing, and translucent coatings over an undercoating in order to give an illusion of depth. • Pg. 223.
  70. 70. • Vegetable oils are heated with heavy metal salts to catalyze polymerization before being used in paints. These help the oil to absorb oxygen. • Varnishes also include resins. • In general, today, people have shifted to water-based paints.
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