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Morgan.liberatore
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What are the four major componenets making up foods and living systems?
Lipids, Carbs, Proteins, Water
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Where are lipids extracted form?
Lipids are extracted form a variety of biological sources- mainly plant and animal sources
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How are lipids characterized?
All lipids are characterized by their datty sensation and lubrication properties
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Describe the soluability of lipids
Lipids are insoluble in water and soluble in non-polar organic solvents such as hexane, chloroform or ether
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How are lipids obtained?
By extracting dry biologican materials with hydrophobic organic solvents
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What are the subclasses of the Bloor Lipid Classification System?
- Simple Lipids
- Compound Lipids
- Derived Lipids
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What are the sub-categories of simple lipids?
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What are the sub-categries of compound lipids?
- Phospholipids
- Glycolipids
- Lipoproteins
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What are the sub-categories of derived lipids?
- Free fatty acids
- Fatty alcohols
- Hydrocarbons and oxygenated hydrocarbons
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How much of the extractable lipid is of the simple lipid class?
>90%
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How much of the extractable lipid is made up of phospholipids?
3-5%
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What is the general decinition of simple lipids?
Esters of fatty acids connected to an alcohol (OH)
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What are the two sub-categories of simple lipids?
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What is the definition of a fat?
Esters of fatty acids connected specifically to glycerol
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In fats, how are fatty acids connected to the glycerol?
Via an ester linkage
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What is another term for fats?
Triacylglycerols or triglycerols
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How are fats triglyceride mixtures?
Any fat represents millions of unique triglyceride compounds
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What does the term 'fat' imply?
That the material is predominantly compose of triglycerids and also that it has a soldi character at room temperature
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What is implied by the term 'oil'?
Triglycerides which have a lower melting point and are liquid at room temperature
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What is the definition of a wax?
Esters of fatty acids esterified to an alcohol, OTHER than glycerol
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What is a 'true wax'?
A fatty acid esterified to a simple fatty alcohol
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What are most waxes formed from?
Generally, most waxes are formed from longer chain aliphatic fatty acids and alcohols and tend to be solid
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What is a common food application for waxes?
- Sealing foods to prevent moisture loss (cheese)
- As a polishing agend (apples)
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What is jojoba oil?
A liquid wax which is largely comprised of linear esters of mono-unsaturated long chain fatty acids esterified to fatty alcohols
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What are some uses of jojoba oil?
Used extensively in cosmetics and is also used as a low-calorie food ingredient with properties similar to olestra
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Why is jojoba oil so low in calories?
It cannot be attacked enzymatically or digested
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What is an example of a fatty acid esterified to a complex alcohol
cholesterol
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What is the general definition of a compound lipid?
Compound lipids consist of a simple lipid (generally of the triglyceride type) conjugated (joined) to a non-lipid molecule
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What are the sub-categories of compound lipids?
- Phospholipids
- Glycolipids
- Lipoproteins
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What are the sub-categories of phospholipids?
- Lecithins
- Cephalins
- Inositols
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What is the definition of glycolipids?
Contain sugar and other moieties (often phosphorous)
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What is a lipoprotein?
Proteins complexed with lipid
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What is a triglyceride with one of their fatty acids replaced with a phosphoric acid known as?
Phospholipids
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In a phospholipid what is the phosphoric acid in turn commonly conjugated with?
Some other non-lipid molecule, usually a nitrogen base
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What is the fundamental structural unit of a phospholipid?
Phosphatidic Acid
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What are the sub-classes of phospholipids?
- Lecithins
- Cephalins
- Phosphatidyl inositols
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What is the 'x' constituent attched to the phosphate group in the lecithin group?
Choline
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What is the 'x' constituent attached to the phosphate group in the cephalin group?
Ethanolamine
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What is an example of a sub-class with a non nitrogenous ngroup attached to phosphatidic acid?
Inositol
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How do phospholipids differ as a group relative to fats/waxes?
Phospholipids have both hydrophobic and hydrophilic moieties in their molecular structure
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Why do phospholipids have excellent emulsifiying properties?
Because they contain both hydrophobic and hydrophilic moieties
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What is a glycolipid/sphingolipid?
Combination of glycerol or a glycerol-like backbone, fatty cids, carbohydrate and/or a nitrogen group
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What is a somple glycolipid?
Comtains most of the elemebts of triglycerides (glycerol and 2 fatty acids) but a sugar has replaced one of he fatty acids and there is no phosphorous
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How does the sugar moiety affect a glycolipid?
The sugar procides some polarity to the molecule
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What is a sphingolipid?
Similar to a phospholipid, glycerol-like backbonem butalso conains nitrogen and has no ester linkage in the side chains
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Why can sphingolipids be classified as either a phosphilipid or glycolipid?
Because sphingolipids often ontain either phosphate or carbohydrate
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What types of lipids are commonly associated with cell membranes in both plants and animals?
Glycolipids and Sphingolipids
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Why are cell membrane lipids important?
They are structurally important in therms of membrane permeability and transport of materials in and out of the cell
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What is a lipoprotein?
complex structured protein-lipid complexes, their actual detailed structure is still being researched
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What types of lipid materials are associated with the structure of the lipoprotein?
Either simple or compound lipids an be associated with the lipoprotein
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What common type of food is rich in lipoproteins?
egg yolk
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What are lipoproteins used for?
Natural emulsifiers
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How are lipoproteins used in our body?
Lipoproteins circlate in our blood stream to carry lipids to tissues for metabolism or storage
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What are derived lipids?
- Constituents derived fro the simple or compound lipid categories, but whih cstill retarin their hydrophobic character
- This includes: Fatty Acids, Fatty alcohols, hydrocarbons and oxygenated derivatives thereof
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What is a fatty acid?
Short to long chain aliphatic hydrocarbons with a carboxxyl group at one end and which may contain double bonds
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What are short chain fatty acids important for?
Flavor compounds
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How are short chain fatty acids released?
Can be released from lipids by lipolysis and can contribute to flavor, either good or bad
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Describe the flavor capabilities of long chain free fatty acids
Longer chain free fatty acids have no flavor per se, but in the presence of mineral salts can give off a soapy flavor
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How can you lower the smoke point of oils?
Presence of free fatty acids in fats and oils can lower their smoe point when used for frying
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What are short chain alcohols often used for?
They are often major cobtributors to aroma and flavor
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What does Hexanol have the odor of?
Freshly mown grass
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How are terpenes built?
Terpenes are built up from fundamental isoproene unit (5 carbons, 2 conjugated double bonds)
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How are essenial oils typically obtained?
Essential oils are typically obtained by steam distillation from plant materials
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What are monoterpenes important for?
Monoterpenes and their oxygenated derivatives are important natural aroma and flavor constituents found in essential oils
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Why are monoterpenes easily extractable?
Low molecular weight and volatile
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Which terpenes contribute more to the taste component of flavor?
Sesqui and higher terpenes are less volatile and contribute to the tast component of flavor
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What is an oleoresin?
Oleoresins are sesquiterpenes which have higher boiling point fractions
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What is the common name for the oxygenated derivatives of carotenes?
Xanthophylls
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