FNS Chapter 5 - Lipids 2020
bile
contains bile salts and phospholipid lecithin- these are the key elements of emulsify fats Bile salts surrounds the products of fat digestion , forming Micelles- water soluble globules with fatty core -199
free fatty acids-they are unattached
fatty acids that are not joined to glycerol of triglyceride Butyric acid: gives butter flavor Caproic, caprylic and capric acid -strong unpleasent odor present as fatty acid in spoiled food
omega-9 fatty acid-can be burned for energy
Any polyunsaturated fatty acid in which the first double bond starting from the methyl (CH3) end of the molecule lies between the ninth and tenth carbon atoms.
omega-6 fatty acid-can be burned for energy
Any polyunsaturated fatty acid in which the first double bond starting from the methyl (CH3) end of the molecule lies between the sixth and seventh carbon atoms.
omega-3 fatty acid-P183- can be burned for energy
Any polyunsaturated fatty acid in which the first double bond starting from the methyl (CH3) end of the molecule lies between the third and fourth carbon atoms.
lipophilic- fat loving
Attracted to fat and fat solvents; fat-soluble, and fat solvent
adipose tissue
Body fat tissue.
hydrophilic-p 178
Can mix with or dissolve in water ("water-loving"). ___ compounds are polar and soluble in water.
glycerol- thick, smooth liquid often used in food industry Backbone of triglycerides
Chemically is an alcohol that contains three carbon atoms, each of which has an attached hydroxyl group (-OH). It forms the backbone of mono-, di-, and triglycerides.
phospholipid- about 2 % of dietary lipids
Compounds that consist of a glycerol molecule bonded to two fatty acid molecules and to a phosphate group with a nitrogen-containing component. Phospholipids have both hydrophilic and hydrophobic regions that make them good emulsifiers. Phosholipids are soluble both fat and water Major constituent in cell membranes, blood and body fluids
excess fat
___ ___ in the diet is linked to obesity, heart disease, and some types of cancer.
Fats contribute to
food texture, flavor, and aroma If fats are removed to boost the flavor ; sugar, sodium, or other additives are used
hydrolysis p190
is the process that occurs in products containing unrefined fats and oils
Fat digestion p198
-In mouth; lingual lipase +dietary phospholipids provide emulsification -Stomach-gastric lipase - Small intestine-fat stimulates the release of cholecystokinin CCK and the secretin from duodenal cells, - CCK signal gallbladder to contract and send bile to duodenum , -Secretin signal pancreas to reduce pancreatic juice in pancreatic lipase
Phospholipids in foods
-used as emulsifiers by food industry -eggs, liver, soybeans, wheat germ, peanuts
saturated fatty acid
A fatty acid completely filled by hydrogen with all carbons in the chain linked by single bonds. Ex: stearic acid -in chocolate and meat fats, solid at room temp., Ex: palmitic acid this 2 ex. affect the blood cholesterol differently
unsaturated fatty acid- susceptible to spoilage by oxidation
A fatty acid in which the carbon chain contains one or more double bonds.
Secretin
A hormone secreted by the small intestine (duodenum) in response to low pH (e.g., from stomach acid). It promotes the release of bicarbonate from the pancreas to act as a buffer.
chylomicron-203
A large lipoprotein particle formed in intestinal cells following the absorption of dietary fats. A ___________ has a central core of triglycerides and cholesterol surrounded by phospholipids and proteins.
Triglycerides stored- major lipids in body and diet -Add flavor and texture
In body fat cells: as adipose tissue In food we call triglycerides as " fats (solid) and oils( liquid) "
lecithin
In the body, a phospholipid with the nitrogenous component choline. In foods, lecithin is a blend of phospholipids with different nitrogenous components.
enterocytes
Intestinal cells.
monoglycerides
Molecules composed of glycerol combined with one fatty acid.
diglycerides
Molecules composed of glycerol combined with two fatty acids.
omega-6 linoleic or omega-3 alpha-linolenic acids
Name the two essential fatty acids.
conjugated linoleic acid (CLA)-source of fuel energy for the body
A polyunsaturated fatty acid in which the position of the double bonds has moved so that a single bond alternates with two double bonds. Ex; small trace amount in caw milk Benefits: Anticancer, antiatherosclerotic, antidiabetic, and antiobesity
cholesterol- is the best known Sterol page 196 -Not needed in diet our body can synthesize it -liver is the main site for synthesize cholesterol, and also the intestine -197
A waxy lipid (sterol) whose chemical structure contains multiple hydrocarbon rings. Precursor in the synthesis of sex hormones, adrenal hormones (cortisol), Vitmain D, liver uses cholesterol to manufacture bile salts, component of cell membrane ( in nerve and brain tissue)
elongation-liver adds carbon in this process -to: build storage, structural fats, to manufacture the fat in breast milk or to make fatty acids for use in other compounds
Addition of carbon atoms to fatty acids to lengthen them into new fatty acids.
lipophobic-fat fearing
Adverse to fat solvents; insoluble in fat and fat solvents.
fatty acids- determines the characteristics of fat if it''s solid or liquid at room temp.
Compounds containing a long hydrocarbon chain with a carboxyl group (COOH) at one end and a methyl group (CH3) at the other end. Ex Of major fatty acid: in olive oil is oleic acid liquid at room temp, but solid in refrigerator Ex: in soybean oil, linoleic acid -thin liquid in room temp.- also abundant in flaxseed oil, -p181
fat & saturated fat
Diets high in ___ and ___ ___ tend to increase blood levels of LDL cholesterol and increase risk for heart disease.
oxidation
Oxygen attaches to the double bonds of unsaturated fatty acids. Rancid fats are oxidized fats, oxidized fat damage body -tissues, especially blood vessels -exposure to light increases the oxidation Vit E inhibits oxidation, that's why antioxidants are added to oils -Negative side effect of processing: plant sterols, healthful phospholipids , and other phytochemicals are removed, and most Vit E is lost
steatorrhea
Production of stools with an abnormally high amount of fat.
lipoprotein -transport lipids in the lymph and blood
They consist of a central core of triglycerides and cholesterol surrounded by a shell composed of proteins and phospholipids. The various types of lipoproteins differ in size, composition, and density.
micelles
Tiny emulsified fat packets that can enter enterocytes. The complexes are composed of emulsifier molecules oriented with their hydrophobic part facing inward and their hydrophilic part facing outward toward the surrounding aqueous environment.
phospholipids- synthesized by our body p193 Function: 1.-Cell membrane-bi layer 2.-Lipid transport -195-In stomach break fat into tiny particles to help digestion, in the intestine from bile continue emulsifying , coat the surface of lipoproteins 3-Emulsifier ( =lecithins)195
___ are made of glycerol, two fatty acids, and a phosphate group with a nitrogen-containing component.
fatty acids, cholesterol
____ _____—long carbon chains with methyl and carboxyl groups on the ends—are components of both triglycerides and phospholipids and are often attached to ___________.
cholesterol
_____ is found in cell membranes and is used to synthesize vitamin D, bile salts, and steroid hormones. High levels of blood cholesterol are associated with heart risk
Emulsifier
a compound with both water-soluble and fat-soluble portions that can attract fats and oils into water, combining them.
lipid absorption-200-201 -most fat absorption takes place in duodenum or jejenum -Lacteals in small intestine absorb dietary lipids -Monoglycerides and fatty acids ....Most triglycerides, cholesterol and phospholipids join protein carrier to form lipoprotein, when these cells leaves the intestinal cells is called chylomicron Long chain fatty acids and monoglycerides are absorbed into lymphatic system
-Absoroption of glycerol and short chain and medium chain directly absorb into bloodstream -1-2 hr After you eat dietary fats appear in the bloodstream Fat level peak after 3-5 hr, cleared by 10 hr
triglycerides- stored fat in our body Triglyceride Function: 3.-Insulation and Protection- visceral fat=adipose tissue around organs subcutaneous fat -fat under the skin 4. Carrier of Fat=Macronutrient carrier - Soluble Compounds -ADEK + carotenoids and other fat soluble phytochemical lycopene -from tomatoes are absorbed more if served with oil or salad dressing -Removing lipids from food, ex: milk also removes fat-soluble vitamins, but vit A is usually replaced Vit E is not replaced in wheat bread, the lipid rich germ portion of wheat is removed during refinement to white flour 5. Sensory qualities- fat contributes to flavor, odor and texture !!! Fat makes baked goods tender and moist
1: -Energy source ( 60%of body resting energy needs) Fat is also protein sparing -Fat is the preferred fuel of muscle tissue at rest 1 g of fat =9 kilocalories 2. Energy Reserve -FAt stored inside fat cells called adipocytes, which for body fat tissue called adipose tissue
sterols=cholesterol Made in our body Sterols in food: in animal origin food -HIgh in brain, liver, and organ meats, some in muscle tissue Fat soluble Also found in butter fat portion of dairy product Egg yolk, , breast milk, Whale liver and plants contain cholesterol precursor squalene
A category of lipids that includes cholesterol ( which part of cell membrane). _______ are hydrocarbons with several rings in their structures.
ester- triglyceride is an ester P 187
A chemical combination of an organic acid (e.g., fatty acid) and an alcohol. When hydrogen from the alcohol combines with the acid's hydrogen and oxygen, water is released and an _____ linkage is formed. A triglyceride is an _____ of three fatty acids and glycerol.
phosphate group
A chemical group (-PO4) on a larger molecule, where the phosphorus is single-bonded to each of the four oxygens, and the other bond of one of the oxygens is attached to the rest of the molecule. Often hydrogen atoms are attached to the oxygens. Sometimes there are double bonds between the phosphorus and an oxygen.
hydrogenation- creatfes most of the trans fatty acids in our diets -protects fat from oxidation
A chemical reaction in which hydrogen atoms are added to carbon-carbon double bonds, converting them to single bonds. _____________ of monounsaturated and polyunsaturated fatty acids reduces the number of double bonds they contain, thereby making them more saturated.
squalene
A cholesterol precursor found in whale liver and plants.
eicosanoids=prostanoids (P184) When fatty acid reaches 20 carbones the body converts into one of more of the eiscosanoids : thromboxanes, prostaglandins, prostacyclins, lipoxin, leukotrienes
A class of hormonelike substances formed in the body from long-chain fatty acids.
esterification-187 Produces: triglycerides, diglycerides ( 2 fatty acid attached to a glycerol) and monoglycerides
A condensation reaction in which an organic acid (e.g., fatty acid) combines with an alcohol with the loss of water, creating an ester.
olestra
A fat replacer that can withstand heat and is stable at frying temperatures. _______, whose trade name is Olean, is a sucrose polyester: Sucrose (instead of glycerol) is the "backbone" molecule, with six to eight fatty acids attached (instead of triglyceride's three). The fatty acid arrangement prevents hydrolysis by digestive lipases so the fatty acids are not absorbed
monounsaturated fatty acid (MUFA) ex: canola oil, olive oil, peanut oil, safflower oil
A fatty acid in which the carbon chain contains one double bond.
polyunsaturated fatty acid (PUFA)- found in vegetable oils , plant food ex; sunflower oil, corn oil, soybean oil, cottonseed oil
A fatty acid in which the carbon chain contains two or more double bonds.
choline
A nitrogen-containing compound that is part of phosphatidylcholine, a phospholipid. _______ is also part of the neurotransmitter acetylcholine. The body synthesizes _______ from the amino acid methionine.
Cholesterol and sterols are purely absorbed compare to triglycerides -200
About 50% of dietary cholesterol are absorbed -Certain fibers bind bile salts and cholesterol-it is recommended eating food rich in fiber to lower cholesterol
alpha-linolenic acid-ALA Omega-3 fatty acid -p185 3 types of Omega-3 fatty acid are used by the body: ALA, EPA, DHA Plant are excellent source of ALA; Flaxseed, canola, soybean, walnut, wheat germ Benefits: improves inflammatory condition, , ulcerativ colitis, and Chron's disease, cardiovascular disease;lower tryglycerides, raise HDL, improves blood circulation, reduce clotting, lower blood pressure Type 2 diabetes mellitus: reduce insulin resistance Renal disease: Preserves renal function Mental function; reduces the severity of alzheimer's disease,depression, bipolar, improve ADHD Growth and development ; retina of the eye , neurodevelopment, and function of the brain
An essential omega-3 fatty acid that contains 18 carbon atoms and three carbon-carbon double bonds (18:3). Can be elongated and desaturated to EPA, and DHA- -The eicosanoids derived from EPA overall effect: dilating blood vessel, discouraging blood clotting, reducing inflammation-thus omega-3 reduces the risk of vascular disease ex for EPA and DHA: mackerel, salmon, trout, sardines, herring
linoleic acid p184 Ex: seeds, nuts, corn oil Small amount of -arachidonic acid an Omega-6 found in: Meat, poultry, eggs but not in plant food
An essential omega-6 fatty acid that contains 18 carbon atoms and two carbon-carbon double bonds (18:2).
fat replacers-208 Ex:olestra -FAt replacers are carbohydrates, Ex starches, fibers , vegetable gum, cellulose , maltodextrin -Or proteins -or fat based- withstand heat: ex OLestra (olean), caprenin, salatrim
Compounds that imitate the functional and sensory properties of fats, but contain less available energy than fats. Small intestine cannot absorb olestra- people with fat malabsorption suffer from diarrhea, gas and cramps
LDL contains a high percentage of cholesterol (which makes its density low), while HDL contains a high percentage of protein (making it a higher density).
Describe the difference between LDL and HDL in terms of cholesterol and protein composition.
Lipids
Energy-rich organic compounds, such as fats, oils, and waxes, that are made of carbon, hydrogen, and oxygen that dissolve in organic solvent, such as alcohol, ether, acetone, but not water soluble
elongated & desaturated, eicosanoids
Essential fatty acids are elongated and desaturated, in the process of making "local hormones" called eicosanoids ( called local hormone , they dont' circulate in blood) These compounds regulate many body functions. Such as:inflammatory process, blood clotting, blood vessel dilation and conostriction
adipocytes
Fat cells.
visceral fat
Fat stores that cushion body organs.
subcutaneous fat
Fat stores under the skin.
Food never contains only saturated of unsaturated it contains of mixture of both
Food fats with more unsaturated fatty acid have lower melting points and more likely to be liquid at room temp -food rich in saturated fat solid at room temp. have higher melting point
20-35
For adults, the Acceptable Macronutrient Distribution Range (AMDR) for fat is __ to __ percent of calories.
Oils are triglycerides. Triglycerides contain a glycerol molecule and three fatty acids. These fatty acids can vary in three main ways: length, saturation, and omega number. An oil such as corn oil has more polyunsaturated fatty acids attached to glycerol than it does monounsaturated or saturated fatty acids. Therefore, corn oil is known as a mostly polyunsaturated fat but, like all oils, it contains a mixture of fatty acid.
How can different oils contain a mixture of polyunsaturated, monounsaturated, and saturated fats?
desaturation body synthesizes oleic acid ( omega 9 fatty acid) by desaturation
Insertion of double bonds into fatty acids to change them into new fatty acids.
hydrophobic
Insoluble in water. Lipids are hydrophobic- water fearing
1. energy source (9 kilocalories per gram) 2. energy reserve (triglycerides in fat cells) 3. insulation and protection (visceral and subcutaneous fat) 4. carrier of fat-soluble compounds 5. contribute sensory qualities to foods
List the many functions of triglycerides.
cell membranes & lipoproteins
Phospholipids are components of ___ ___ and ___. Their unique affinity for both fat and water enables them to be effective emulsifiers in foods and in the body.
Recommended intake-205 At least 2 weekly serving of oily fish; tuna or salmon 20-35% calories from fat, 45-65 carbs, 10-35% protein -Page 206
Saturated fat no more then 10% of total calories or 1/3 cholesterol less then 300 milligram ALA- essential fatty acid 1.1 g for woman, 1.6 g for men KIDS 30-40% 1-3 YEAR 25-35% for 4-18
lanugo
Soft, downy hair that covers a normal fetus from the fifth month but is shed almost entirely by the time of birth. It also appears on semistarved individuals who have lost much of their body fat, serving as insulation normally provided by body fat.
lacteals
Specialized lymphatic capillaries in the intestines that take up lipids as well as lymph.
phytosterols -197 -Reduce intestinal absorption of cholesterol, used as cholesterol lowering food ingredients in vegetable oil spreads
Sterols found in plants. __________ are poorly absorbed by humans and reduce intestinal absorption of cholesterol. They have been used as a cholesterol-lowering food ingredient.
high-density lipoproteins (HDL)-204 Protect agains -heart disease and atherosclerosis
The blood lipoproteins that contain high levels of protein and low levels of triglycerides. Synthesized primarily in the liver and small intestine, HDL picks up cholesterol released from dying cells and other sources and transfers it to other lipoproteins.
low-density lipoproteins (LDL)-204 -Increses the risk of heart disease and atherosclerosis
The cholesterol-rich lipoproteins that result from the breakdown and removal of triglycerides from intermediate-density lipoprotein in the blood.
essential fatty acids- Ex: omega-6 linoleic acid , omega-3 alpha-linoleic acid
The fatty acids that the body needs but cannot synthesize, and which must be obtained from diet. These must come from food Deficiency is rare; ex malabsorption, prolonged intravenous feeding Symptoms of deficiency: scaly skin rash, and dermatitis, poor growth in children, lowered immune response
nonessential fatty acids
The fatty acids that your body can make when they are needed. It is not necessary to consume them in the diet. Ex: Saturated fat and Omega-9 fatty acid
intermediate-density lipoproteins
The lipoproteins formed when lipoprotein lipase strips some of the triglycerides from VLDL. Containing about 40 percent triglycerides, this type of lipoprotein is more dense than VLDL and less dense than LDL. Also called a VLDL remnant.
lipoprotein lipase-located in capillary walls
The major enzyme responsible for the hydrolysis of plasma triglycerides.
chain length
The number of carbons that a fatty acid contains. Foods contain fatty acids with chain lengths of 4 to 24 carbons, and most have an even number of carbons. In organic chemistry the scientific naming of fatty acid counts from the carbon at the acid end ( -COOH)
very low density lipoproteins-203
The triglyceride-rich lipoproteins formed in the liver. ____ enters the bloodstream and is gradually acted upon by lipoprotein lipase, releasing triglyceride to body cells.
triglycerides, phospholipids and sterols
There are three main classes of lipids: ___, ___ & ___.
linoleic (omega-6) acid and alpha-linolenic acids (omega-3)
Two polyunsaturated fatty acids, ___ ___ and ___ ___ ___, are essential; they must be supplied in the diet. Phospholipids and sterols are made in the body and do not have to be supplied in the diet.
cis fatty acid
Unsaturated fatty acid in which the hydrogens surrounding a double bond are both on the same side of the carbon chain, causing a bend in the chain. Most naturally occurring unsaturated fatty acids are ___ _____ _____.
trans fatty acids- Raise LDL and associated with reducing plasma high-density lipoprotein HDL, therefore increase the risk of heart disease
Unsaturated fatty acids in which the hydrogens surrounding a double bond are on opposite sides of the carbon chain. This straightens the chain, and the fatty acid becomes more solid. You can find it in: meats and dairy product from cow and sheep just small amount
The positive consequences of hydrogenation include a longer shelf life (protects against oxidation) and an improved texture for the food containing the hydrogenated lipid. The main negative consequence of hydrogenation is that it makes a fat more saturated, and partial hydrogenation creates trans fatty acids. This makes the fat less healthful.
What are the positive and negative consequences of hydrogenating a fat?
The fat's saturation. Typically, the harder a fat is at room temperature, the more saturated it is. Conversely, the softer a fat is at room temperature, the less saturated it is
What does the hardness or softness of a triglyceride typically signify?
Only foods from animal sources contain cholesterol. Organ meats such as brain and liver contain very high levels. Other sources are egg yolks, meats, and dairy products.
What foods contain cholesterol?
Triglycerides largest category of lipids. Triglycerides contain a glycerol molecule and 3 fatty acids. These fatty acids can vary in length and saturation.
What is the most common form of lipid found in food?
saturated fatty acids- found mostly in animal foods and tropical oils Ex: coconut oil, butter, palm oil, beef tallow
___ ___ ___ have no double bonds between carbons in the chain, monounsaturated fatty acids have one double bond, and polyunsaturated fatty acids have more than one double bond.
lipids, fat & oils
______ are a group of compounds that are soluble in organic solvents but not in water. ____ and ____ are part of the lipids group.
digestibility of fat 199
abnormal to find more then 6-7% of ingested lipids in fecal matter Steatorrhea -production of fatty acid stools- indicates fat malabsorption -breast milk is easily digestible, it has it's own lipase which enhances fat digestion Enterocytes-intestinal cell
Triglycerides
are food fats and storage fats. They are composed of glycerol and three fatty acids.
