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HNSC 1200 Unit 5

Terms in this set (81)

What is the role of fats in food
- provide essential nutrients
- provide concentrated source of energy and raw materials for making needed products
- provide taste, smell, and texture to foods
- stimulate appetite and contribute to feelings of fullness
- can be used for heat transfer without burning food during the heat transfer
How can fats become part of our foods
- added during food processing
- added during for prep
- added at the table
- found naturally
3 types of lipids
- sterols
- phospholipids
- triacylglycerols (triglycerides)
what are triglycerides made up of
- 3 fatty acids and a glyceride backbone
what is glycerol
- organic compound
- 3 carbon long and has 3 hydroxyl groups
what are fatty acids made up of
- chains of carbon atoms and an organic acid terminal (-COOH)
What are fatty acids classified by
- chain length
- degree of saturation
fatty acid chain length
- short: 2-4 carbons
- medium: 6-10 carbons
- long: 12 or more carbons
- shorter fatty acids are softer and melt more readily at room temp
- generally have even number of carbons
Fatty Acids: Degree of Saturation
- no hydrogens means unsaturated and a double bond present
- 1 point of unsaturation= monounsaturated fatty acid (MUFA)
- 2 or more points unsaturation= polyunsaturated fatty acid (PUFA)
- 0 points of unsaturation = saturated fatty acid
what does saturation refer to
- number of hydrogen atoms a fatty acid chain is holding
- more hydrogens, the more saturated
what type of saturation are fish oils and vegetable oils
- PUFA and some are MUFA
what type of saturation are animal fats
- most are saturated
What is butyric acid?
- found in butter
- has 4 carbon atoms, single bonds and is saturated
What is stearic acid?
- found in beef
- had 28 carbon atoms, single bonds and is saturated
What is palmitic acid?
- found in palm oil and cocoa butter
- has 16 atoms, single bonds and is saturated
what is oleic acid?
- monounsaturated
- found in olive oil and canola oil
- has 18 carbon atoms, one double bond and is unsaturated
What is linoleic acid?
- found in most foods like oilseeds
- polyunsaturated
- has 18 carbon atoms and 2 double bonds separated by two single bonds
What is conjugated linoleic acid?
- has 18 carbon atoms and 2 double bonds separated by one single bonds
- found in ruminants but not non-ruminants
What is Linolenic acid?
- found in soybeans and hempseed
- polyunsaturated
- has 18 carbons atoms and 3 double bonds
forms of unsaturated fatty acids
- cis: Hydrogen atoms and double bonds are in the same side
- trans: hydrogen atoms and double bonds on different side
comparing cis and trans fatty acids
- trans has higher melting point
- trans can be found naturally in meats, poultry, and processed milk products
- most trans come from processing during hydrogenation
What is hydrogenation?
- hydrogens are added to unsaturated fatty acids
- hydrogen attached to the point(s) of unsaturation, making the fatty acid saturated, aka more solid at room temp
hydrogenated fats
- more resistant to oxidation
- more resistant to breakdown from high temps, and longer shelf life
what happened to the health benefits when fats are hydrogenated
- lose health benefits
- affects the fatty acids and the vitamins
what creates trans fattty acids
- during hydrogenation, some unsaturated fatty acids change shape instead of becoming saturated, creating usual shape
what does consuming trans fatty acids do
- pose risk to heart health and arteries by raising levels of bad cholesterol and lowering levels go good cholesterol
- produce inflammation
what is a phospholipid
- 2 fatty acids attached to glycerol backbone and 1 phosphorus molecule
- phosporous makes phospholipid soluble in water (emulsifier )
what are emulsifying agents
- substances that facilitate emulsion formation
What are emulsifiers?
- substances that keep water and fat dispersed in one another
phospholipids
- play key role in the structure of cell membrane
-
what its lecithin
- phospholipid found in egg yolk
and mayo
what is a sterols, give an example
- large molecules consisting of interconnecting rings of carbon atoms with a side chain of carbon, hydrogen and oxygen
- cholesterol
why is cholesterol important
- important in structure of cell membranes, essential in all cells and necessary for optimal body functioning
- made by body so not essential
what does cholesterol do
- raw material needed to make bile, to help fat digestion
- forms major part of plaques, which makes arteries smaller and causing heart attacks
phytosterols
- cholesterol in plants
- not well absorbed from gastrointestinal tract and can interfere with cholesterol absorption
what is the winterization of fats
- a process to produce salad oils that do not crystallize at refrigerator temps
- lower melting point than unwinterized
Explain the process if winterization
- lowing temp of oil to point which the triglycerides with high melting points crystallize (2-0) then filtered to remove the crystals
what happens to winterized oils at lower temps
- they become cloudy due to some go the triglycerides molecules crystallizing or becoming solid
rancidity
- The chemical spoilage that commonly occurs with fats and fatty foods
- nuts and wheat germ do this
- lounger stores, greater risk
- casques off flavour and rancid ours
- more common in high unsaturated
(polyunsaturated) than saturated or monounsaturated
oxidative rancidity
- Occurs with the unsaturated fatty acid portions of triglycerides
- beings with addition of oxygen to carbon atom next to a double bond, which forms hydroperoxide, which break down into volatile products
- can be prevented or slowed with antioxidants
hydrolytic rancidity
- shortens fatty acid chain
- room temp butter is an example
- breaking of the triglycerides structure, resulting in the production of glycerol and free short chain fatty acids
- breaking of chemical bonds due to the addition of water and enzyme activity
what are fat replacers
- ingredients that replace some or all of the functions of fat and may or may not provide energy
what are artificial fats
- zero energy fat replacers are ingredients that are chemically synthesized to mimic the sensory and coking qualities of naturally occurring fats
-partically or fully resistant to digestion
what are carbohydrate based replacers
- plant polysaccharides
- digested ones provide 4 Kcal per gram, not all digested
- can withstand heat
- include derivatives of cellulose, maltodextrin, gums, modified starched and polydextrose
what are protein based replacers
- blended with gun to form gel
- provide 1.3-4 Kcal per gram
- used to manufacture low fat frozen and refrigerated products
what are fat based replacers
- fat molecules created with fewer carbons atoms in the structure, meaning fewer calories
- long chain of fatty acids can be combined with sucrose to produce sucrose polyester
What are omega-3 fatty acids?
- double 6 carbons from the end of its chain
- 5-10% of energy from n-6 fatty acid
- seeds, nuts, whole grain
3 types of omega 3
- ALA, alphalinolenic, from plants
- EPA, eicosapentaenoic, from fish
- DHA, docosahexaenoic, from fish
benefits of EPA/DHA
- decreases serum triglyceride and cholesterol levels
- protect against cardiovascular and inflammatory diseases
- lower blood pressure
- slow progression of atherosclerosis
- may inhibit cancer development
- helps retina form
- help brain development
what are proteins
- compounds made up of carbon, hydrogen, and nitrogen
- arranged in amino acids
- 2 aa= dipeptide
-3 aa= tripeptide
- 3> aa = polypeptide
shape of protein
- electrical charges make either globular with is water soluble or fibrous with is not water soluble
protein structure
- primary: linear sequence of aa
- secondary: repeating pattern of linear aa, with alpha-helix or beta sheet
- tertiary: 3-D, globular shape
- quaternary: globular proteins combine and form more complex structure
Digestibility of proteins
- animal aa are easily digested and absorbed (>90%)
- legumes (80-90%)
- grain product (70-90%)
- cooking make them more digestible
amino acid composition of proteins
- high biological value proteins have ample amounts of essential aa
Protein hydration
- water binding capacity of proteins related to aa composition
- more charged aa, greater hydration capacity
protein surface properties
- proteins are amphiphilic, acts as a water-oil interface
- help stabilize emulsions
- involved in production of food foams
flavour binding protein
- proteins bind to flavour molecules
- enhance flavour of processed foods
denaturation and coagulation of proteins
- unfolding of proteins structure without breaking peptide bonds
- changes properties
- less functional once denatured
- when proteins are denatured, they can bond with other denatured proteins, making newly shaped molecules
proteins as enzymes
- name include substrate or substance they act on
- name can describe reaction
- used in meat tenderizers or clotting of milk
- enzymatic browning is growing reaction that occurs when exposed to oxygen
caramelization
- series of chemical reactions, when sugar are heated to temp greater than melting point
- begins with dehydration and ends with polymerization
- too extensive are bitter dark and extensive are light brown
-less sweet
- average temp is 200C
caramel is made up of
- 50% digestible CHO, 25% non digestable CHO, 25% polycyclic aromatic hydrocarbons
maillard reaction
- reaction between carbonyl group of carbohydrates and amine group of aa or protein at high temp
- fragmentation and polymerization leads to formation of brown pigment called melanoidins
- may result in formation of acrylamide that may be carcinogen
Fat soluble vitamins
- Vitamins A, D, E, K
water soluble vitamins
- 8 B vitamins: thiamin, niacin, riboflavin, pantothenic acid, folate, biotin, B6 and B12
- vitamin C
Major minerals
calcium, chloride, magnesium, phosphorus, potassium, sodium, sulfur
trace minerals
iron, zinc, copper, manganese, iodine, selenium, chromium, fluoride, molybdenum
meat
- major competes of meats are water, fat, and protein with vitamins and minerals
- red meat has no carbohydrates
- poultry has low fats and high protein
- high water content and neutral pH make it susceptible to spoilage
- meat has visible fat called marbling
- fish flesh is highly perishable due to high levels of unsaturated fatty acids and has high levels of TMAO, trimethylamine oxide
milk and dairy products
- milk is important source of quality protein, minerals, B vitamins, energy, low amount of iron, and fortified with vitamin A and D
- milk proteins: casein (80%) and whey (20%)
- during cheese making, acids ro rennin is added to coagulate most of casein
- milk is homogenized
- whole milk (3.25% fat), reduced fat (2%), low fat (1%), skim (0-.5%)
- fluid milk and yogurt are pasteurized to kill microorganisms
- whey proteins are composed mostly of beta and alpha lactoglobulin
homogenized
- process that decreases the size of the fat globules dispersed in milk so that they are more optimally dispersed
- freezing destroys this
pulse, Nuts, and Oilseeds
- pulse are beens, peas and lentils
- contain higher protein content, 18-45%
- contain little amounts go gliding and glutelin, most of proteins are water soluble
- low fat
-nuts provide protein, unsaturated fats, fibre, vitamins, minerals and phytochemicals
cereals
- protein content 15-17%
- in wheat, protein principles are gliadins and gluten, 80% of the endosperm protein
- hydrated gluten complex forms 3-d viscoelastic networks to give flavour and characteristics
- gluten is formed from gliadins and glutelin after hydration and mixing of wheat flour
4 types of plant protein
-Albumins-soluble in water.
- Globulins-soluble in salt solutions but insoluble in water.
-Gliadins-soluble in 70-90% alcohol.
- Glutelins-insoluble in neutral aqueous solutions, saline solutions or alcohol. Can only be solubilized by dilute alkaline solution.
emulsification of eggs
-lipoproteins and phospholipids present in the egg yolk help to keep fat dispersed in water.
foaming of eggs
- proteins in the egg white have a high capacity to form strong protein films that surrounds air bubbles to produce stable foams.
- The foams can become six to eight times the original volume
coagulation of eggs
-egg white proteins can set and form a gel during heating.
eggs
-shell is about 94% CaC03 with small pores that allow C02 and water to escape, while allow 02 in.
-contain protein, fat, vitamins, minerals and a small amount of carbohydrates, with the yolk containing the fat and cholesterol and most of the calories (75%), while the white is the more protein-rich portion.
- Major protein of the egg white is ovalbumin, also find conalbumin, ovomucoid, lysozyme and avidin.
- Major proteins of the yolk are the lipoproteins- high density lipoproteins and low density lipoproteins.
Cultured (fermented) milk
- Bacterial cultures are added to ferment the lactose into lactic acid. This increased acidity results in a thickened consistency. Examples include yogurt, sour cream, buttermilk and kefir.
evaporated milk
- Canned milk with 60% of the water removed
- fortified with vitamin D and C
sweetened condensed milk
- a canned product where approximately half of the water content is evaporated out of the milk prior to canning and to which a high percentage of sugar is added.
skim milk powder
- The water content of the milk is removed, first through the use of a vacuum and then by spray drying (see unit 2 for more information drying methods). This form of milk can be used in baked goods and can be added to water to reconstitute fluid milk.
Ultra High Temperature (UHT) milk
-the milk is heated for approximately 2-6 seconds at 300oF to remove all viable microorganisms, i.e., the product is sterile.
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