(5,6) Fats and Oils Flashcards

(33 cards)

1
Q

what is lipid

A

lipid is organic compound formed mainly from alcohol and fatty acid combined together by ester linkage

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2
Q

what are the chemical properties of lipids

A
  • non polar compound
  • insoluble in water
  • soluble in non polar organic solvent (ether, chloroform, benzene, acetone)
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3
Q

what are 4 lipids classification and it’s definition

A
  1. simple lipids: fatty acid ester with alcohol (fats/ oil and wax)
  2. compound and conjugated lipids: lipids contain additional substance (e..g sulfur, phosporus, amino acid, carbohydrate, protein)
  3. derived lipids: substance (above) derived by hydrolysis
  4. large molecular weight alcohols found in nature and combines with fatty acid (e.g cholesterol)
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4
Q

what is triglycerides

A

ester fatty acids with glycerol

contain glycerol (H-C-H-OH) and fatty acid chains -> triglycerides and 3H2O

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5
Q

functional properties of triglycerides

A

found in plant and animals, compose one of the major food groups of our diet

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6
Q

chemical properties of triglycerides

A
  • solid or semisolid triglycerides at RTP is called as fat, also occur predominantly in animals
  • liquid triglycerides is called oils and originate in plants
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7
Q

mention the highest and smallest fat content in %

A

highest: butter: butter, walnut, peanut, cheese, hamburger (or beef)

smallest: cod, asparagus, rice, oats, barley

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8
Q

mention sources of fats/ oil in animals

A

beef, pork, sheep, and butterfat

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9
Q

mention sources of fats/ oils in vegetable

A

palm, coconut, soybean, sunflower, olive, corn, rice bran, cocoa oil

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10
Q

mention sources of fats/ oil in marine

A

cod liver, tuna fish, whale, halibut, mackerel oil

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11
Q

what are the most and least supply for oils and fats

A

highest supply is vegetable oil and the least is marine oil

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12
Q

define chemical structure of fatty acids

A

(please refer to internet), but here’s the brief

(R-C–O-OH)
- OH is acid group
- R is non polar and hydrophobic end (Fat-soluble tail

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13
Q

mention 3 types of length found in fatty acids

A
  1. short chain: 2-6 Carbon, liquid at RTP
    2.medium chain: 8-12 Carbon
  2. long chain: 14+ Carbon, most common type of fatty acid
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14
Q

chemical properties of saturated fatty acids

A
  • all C in fatty acid bound to H
  • usually more solid at RTP
  • higher melting point
  • more stable
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15
Q

chemical properties of saturated fatty acids

A

some C form a double bond with each other instead of binding to hydrogen
- monounsaturated FA (MUFA): has 1 (C–C) double bonds
- polyunsaturated FA (PUFA): has 2 (C–C) double bonds
- more liquid at RTP
- lower melting point
- less stable

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16
Q

what is trivial nomenclature of FA

A

this type is a derived from biological source, non-systematic historical names, the most frequent naming system used in literature

e.g palmitoleic acid

17
Q

what is systematic nomenclature of FA

A

derived from IUPAC rules, counting begins from carboxylic acid end, double bonds labelled with cis-trans isomer or E-Z notations

e.g (9Z)-octadecenoic acid

18
Q

what is Δ^x nomenclature of FA

A
  • each double bond indicates by Δ^x, where double bond is located on the xth C-C bond, counting from carboxylic acid end
  • each double bond is preceded by cis/ trans prefix, indicating the conformation of molecule around bond

e.g linoleic acid designed as cis-Δ^9, cis-Δ^12 octadecadienoic acid

19
Q

what is n-x nomenclature of FA

A
  • for individual compound and classifies by their biosynthetic properties in animals
  • double bond is located on the xth C-C bond, counting from terminal methyl towards carbonyl carbon
20
Q

what is lipid number nomenclature of FA

A
  • it takes from C:D where C is the number of carbon atoms in FA and D is number of double bond
  • this types is considered as ambiguous since FA can have same number. So, it’s usually paired with Δ^x or n-x term
21
Q

what is the difference between stearic acid and oleic acid

A

stearic is a typical long chain saturated FA while oleic is typical monounsaturated FA

for the structure please refer to slide 11 and 12

22
Q

define palmitic, linoleic, and elaidic acid

A

palmitic acid: primary saturated FA in most diets (25% beef or pork fat and 5-10% of sunflower, peanut oils)

linoleic acid: polyunsaturated omega-6 FA, colorless, insoluble in water, occurs in nature

elaidic acid: oleic acid trans isomer (trans-9-octadecanoic acid), found in margarine, fried foods

for the structure please refer to slide 12

23
Q

examples of saturated FA

A

butyric, caproic, caprylic, capric, lauric, myristic, palmitic, stearic, arachidic

24
Q

examples of unsaturated FA

A

oleic, elaidic, linoleic, linolenic, eleostearic, moroctic, arachidonic

25
sources of unsaturated FA
1. linoleic acid (LA): corn, sunflower, and cottonseed oil 2. linolenic acid (LNA): flaxseed, canola, and soybean oil
26
sources of DHA and EPA
1. fish, fish oils, and marine: herring, mackerel, salmon, trout, phytoplankton, and algae 2. soybean, flaxseed, and canola oil
27
what is EFA (essential fatty acid)
FA which are not synthesized in the body and they should be supplied in the diet - omega 6: linoleic acid (LA) - omega 3: alfa linolenic acid (LNA)
28
what is the relationship between fatty acid and melting point
the more hydrogen, the more saturated, the higher melting point
29
what is the relationship between fatty acid and water solubility
the more hydrogen, the more saturated, the lower water solubility
30
effect of double bond on the melting points
the melting point of unsaturated FA decreases with an increase in double bond
31
what is hydrogenation
addition of H to a double bond of unsaturated FA in the presence of catalyst (nickel, organometallic compound)
32
function of hydrogenation
permits to convert liquid oil into plastic fats for production of margarine and shortenings
33
selective vs non-selective hydrogenation
selective: H added to the most unsaturated FA. This selective hydrogenated oils are more resistant to oxidation - selectivity is increased by increasing hydrogenation temperature - selectivity is decreased by increasing pressure and agitation