(5,6) Fats and Oils Flashcards
what is lipid
lipid is organic compound formed mainly from alcohol and fatty acid combined together by ester linkage
what are the chemical properties of lipids
- non polar compound
- insoluble in water
- soluble in non polar organic solvent (ether, chloroform, benzene, acetone)
what are 4 lipids classification and it’s definition
- simple lipids: fatty acid ester with alcohol (fats/ oil and wax)
- compound and conjugated lipids: lipids contain additional substance (e..g sulfur, phosporus, amino acid, carbohydrate, protein)
- derived lipids: substance (above) derived by hydrolysis
- large molecular weight alcohols found in nature and combines with fatty acid (e.g cholesterol)
what is triglycerides
ester fatty acids with glycerol
contain glycerol (H-C-H-OH) and fatty acid chains -> triglycerides and 3H2O
functional properties of triglycerides
found in plant and animals, compose one of the major food groups of our diet
chemical properties of triglycerides
- solid or semisolid triglycerides at RTP is called as fat, also occur predominantly in animals
- liquid triglycerides is called oils and originate in plants
mention the highest and smallest fat content in %
highest: butter: butter, walnut, peanut, cheese, hamburger (or beef)
smallest: cod, asparagus, rice, oats, barley
mention sources of fats/ oil in animals
beef, pork, sheep, and butterfat
mention sources of fats/ oils in vegetable
palm, coconut, soybean, sunflower, olive, corn, rice bran, cocoa oil
mention sources of fats/ oil in marine
cod liver, tuna fish, whale, halibut, mackerel oil
what are the most and least supply for oils and fats
highest supply is vegetable oil and the least is marine oil
define chemical structure of fatty acids
(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
mention 3 types of length found in fatty acids
- short chain: 2-6 Carbon, liquid at RTP
2.medium chain: 8-12 Carbon - long chain: 14+ Carbon, most common type of fatty acid
chemical properties of saturated fatty acids
- all C in fatty acid bound to H
- usually more solid at RTP
- higher melting point
- more stable
chemical properties of saturated fatty acids
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
what is trivial nomenclature of FA
this type is a derived from biological source, non-systematic historical names, the most frequent naming system used in literature
e.g palmitoleic acid
what is systematic nomenclature of FA
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
what is Δ^x nomenclature of FA
- 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
what is n-x nomenclature of FA
- 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
what is lipid number nomenclature of FA
- 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
what is the difference between stearic acid and oleic acid
stearic is a typical long chain saturated FA while oleic is typical monounsaturated FA
for the structure please refer to slide 11 and 12
define palmitic, linoleic, and elaidic acid
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
examples of saturated FA
butyric, caproic, caprylic, capric, lauric, myristic, palmitic, stearic, arachidic
examples of unsaturated FA
oleic, elaidic, linoleic, linolenic, eleostearic, moroctic, arachidonic
sources of unsaturated FA
- linoleic acid (LA): corn, sunflower, and cottonseed oil
- linolenic acid (LNA): flaxseed, canola, and soybean oil
sources of DHA and EPA
- fish, fish oils, and marine: herring, mackerel, salmon, trout, phytoplankton, and algae
- soybean, flaxseed, and canola oil
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)
what is the relationship between fatty acid and melting point
the more hydrogen, the more saturated, the higher melting point
what is the relationship between fatty acid and water solubility
the more hydrogen, the more saturated, the lower water solubility
effect of double bond on the melting points
the melting point of unsaturated FA decreases with an increase in double bond
what is hydrogenation
addition of H to a double bond of unsaturated FA in the presence of catalyst (nickel, organometallic compound)
function of hydrogenation
permits to convert liquid oil into plastic fats for production of margarine and shortenings
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
