Unit 5

When the caramelization reactions are not too extensive

a desirable caramel flavour and light brown colour results.

Shorter chain fatty acids tend to be

softer and melt more readily at room temperature

Gliadins

soluble in 70-90% alcohol.

Globulins

soluble in salt solutions but insoluble in water.

Albumins

soluble in water.

When unsaturated fatty acids are hydrogenated,

some change shape instead of becoming saturated. This process creates unusually shaped unsaturated fatty acids that look like saturated fatty acids. These fatty acids are referred to as trans fatty acids. Consuming trans fats poses a risk to heart health and arteries by raising levels of bad cholesterol, and lowering levels of good cholesterol in our body. They also produce inflammation. The DRI committee recommends that people consume as little trans fat as possible.

The degree of saturation affects

the temperature at which fat melts - The more unsaturated the fat, the more liquid it tends to be at room temperature, e.g., vegetable oil.

Where there is no hydrogen attached,

this is a point of unsaturation, and a double bond occurs. This occurs especially in the fatty acids of plants and fish.

Saturated fatty acids, being linear, tend to pack

tightly, and therefore also have a higher melting point

Each species makes its own characteristic types of

triglycerides

The presence of a carbon-carbon double bond in the chain renders the fatty acid

unsaturated

The exception is tropical oils (palm, coconut) which are low in

unsaturated fatty acids but high in saturated fatty acids

Water-soluble vitamins

vitamin C and the 8 B vitamins: thiamin, riboflavin, niacin, pantothenic acid, folate, biotin, B6 and B12.

Fat-soluble vitamins

vitamins A, D, E and K.

proteins role in food

water binding, gel formation, thickening, emulsion, foam formation (e.g., egg whites, whip cream) and the Maillard reaction.

1 point of unsaturation =

monounsaturated fatty acid (MUFA)

Winterization of fats

- A process to produce salad oils that do not crystallize (i.e., become cloudy) at refrigerator temperatures. - Oils can become cloudy at lower temperatures because some of the triglyceride molecules crystallize or become solid. - Involves lowering the temperature of oil to a point at which the triglycerides with high melting points crystallize (approximately 2oC - 0oC). The oil is then filtered to remove the crystals and the remaining oil has a lower melting point and does not crystallize at refrigerator temperatures.

How fat becomes part of our food

- Added during food processing - Added during food preparation - Added at the table - Found naturally in foods

Hydrolytic rancidity

- Hydrolysis involves breaking of chemical bonds due to the addition of water and enzyme activity. - Hydrolytic rancidity is the result of the breaking of triglyceride structure composed of short chain fatty acids. Results in the production of glycerol and free short chain fatty acids such as butyric acid and caproic acid (found in butter). - The short chain fatty acids are volatile and produce off flavours and odours. - Heat acts as a catalyst for this reaction, which can cause problems when wet foods are deep-fried. This introduces water to the oil, making the oil prone to hydrolytic rancidity, especially when the oil has not been heated (as heat breaks down the enzymes that also fuel hydrolytic rancidity). - Butter stored at room temperature can be at risk for hydrolytic rancidity, because this temperature is an ideal environment for the enzymes that contribute to the rancidity, and because butter contains water. Therefore, butter should be stored in the fridge or freezer.

Oxidative rancidity

- Occurs primarily with the unsaturated fatty acid portions of triglycerides. - Reaction begins with the addition of oxygen to carbon atoms next to a double bond in a fatty acid. The reaction results in formation of hydroperoxide. - Hydroperoxide molecules readily breakdown into volatile products that have off odours and flavours characteristic of rancid fat (e.g., ketones, alcohols and aldehydes). - Oxidative damage can be prevented or slowed down through the use antioxidants such as BHT (butylated hydroxytoluene, an antioxidant and antimicrobial compound) or vitamin E (an antioxidant).

Monounsaturated acids

- Oleic acid

Protein-Surface Properties

- Proteins are amphiphilic so can act as a water-oil interface because they exhibit both hydrophobic and hydrophilic characteristics, helping to stabilizing emulsions (food system—salad dressings, bologna, sausages, ice cream, soups, cheese and sauces). - They are also involved in the production of food foams: foams are unique in that the dispersed phase is a gas within a liquid phase (food system—sponge cakes, whipped toppings, beer froth and ice cream).

Triglycerides

- Triglycerides are the major form of fat found in foods and in our body - They are made up of 3 fatty acids and a glycerol backbone. Glycerol is an organic compound 3-carbons long and has 3 hydroxyl groups (-OH) - Very few fatty acids are found free in the body or in foods, most are incorporated into triglycerides - atty acids are made of chains of carbon atoms (-C) and an organic acid terminal (-COOH)

Effects of processing on unsaturated fats

- Unsaturated fatty acids can be found in both cis and trans form, dependent on their structure at the double bond. In the cis form, the hydrogen atoms on the double bond are on the same side as the double bond. In the trans form, the hydrogen atoms are on opposite sides of the double bond from one another - Trans fatty acids have a higher melting point than the cis fatty acids. - Trans fatty acids can be found naturally in meat, poultry and processed milk products. - However the majority of trans fatty acids in our diet are formed during the process of hydrogenation.

Artificial fats

- Zero-energy fat replacers that are chemically synthesized to mimic the sensory and cooking qualities of naturally occurring fats, but are totally or partially resistant to digestion. - Some products contain artificial fats, while others use conventional ingredients in unconventional ways, or alter preparation methods to reduce fat and calories.

commonly used methods to inhibit enzymatic browning in foods

- addition of acidulants (eg: citric acid, ascorbic acid) - addition of reducing agents - blanching - refrigeration and freezing

Saturated acids

- butyric - stearic - palmitic

Potential benefits of EPA/DHA

1. Heart disease (supported by most studies) 2. Have been shown to decrease serum triglyceride and cholesterol levels 3. Both fatty acids have been reported to protect against cardiovascular and inflammatory diseases 4. Cause relaxation of the blood vessels, resulting in a lowering of blood pressure 5. May slow the hardening of arteries, slowing the progression of atherosclerosis 6. Infant growth and development (strong evidence) 7. DHA concentrates in the cortex of the brain, important for normal brain development in infants 8. DHA helps the retina to form, important for normal vision development in infants 9. Cancer (research promising, but need further evidence) 10. Cancer development may be inhibited due to altered cell metabolism

lipids are composed of

carbon, hydrogen and oxygen

Polyunsaturated acids

- linoleic - linolenic

fats do play an important role in health, such as

- providing us with energy stores - insulating our bodies from extreme temperatures - providing texture and taste properties in food

The fatty acids are classified by:

1) Chain length 2) Degree of Saturation (double bonds, C=C) 3. Type of double bond

There are two types of rancidity:

1) Oxidative rancidity 2) Hydrolytic rancidity

Edible lipids are categorized into 3 major groups:

1) Triglycerides (95% of the lipids found in foods- include fats and oils) 2) Phospholipids 3) Sterols

There are three main types of omega-3 fatty acids:

1. ALA 2. EPA 3. DHA

Plant Proteins can be divided into four broad groups based on solubility properties.

1. Albumins 2. Globulins 3. Gliadins 4. Glutelins

Plant protein crops

1. Cereals 2. Pulse, Nuts and Oilseed (Legume) Storage Proteins

Varieties of milk

1. Cultured (fermented) milk 2. Evaporated milk 3. Sweetened condensed milk 4. Ultra high temperature (UHT) milk 5. Skim milk powder

Functional characteristics of eggs

1. Emulsification 2. Foaming 3. Coagulation

Fats as Functional Foods and Nutraceuticals Conjugated linoleic acid (CLA)

1. In linoleic acid, the two double bonds are separated by two single bonds 2. --CH=CH-CH2-CH=CH- 3. In conjugated linoleic acid, the two double bonds are separated by one single bond 4. --CH=CH-CH=CH- 5. CLA is an essential fatty acid found mostly in animal products such as milk and meat 6. Meat of ruminants (cows, sheep) and other animals that chew the cud contains more CLA than non-ruminant meats such as turkey, chicken and pork. This is because bacteria in the stomach of ruminants convert linoleic acid to CLA, which is absorbed into the animal tissue. 7. Non-ruminants do not have this type of bacteria, so they cannot produce CLA.

Carbohydrate-based replacers

1. Plant polysaccharides 2. protein-based replacers 3. fat-based replacers

we can alter the preparation method by:

1. adding water or whip air into foods 2. adding non-fat milk to creamy foods 3. using lean products instead of high fat 4. baking rather than fry foods

The vitamins are divided into:

1. fat-soluble 2. water-soluble

Long

12 or more carbons

Chain length: short

2-4 carbons

Food foam

2-phase system where air is dispersed in a continuous liquid or solid phase

average temperature required for caramelization is

200 C

Chains can be as short as

4 carbons and can be 24 carbons long or more

Caramel consists of

50% digestible CHO, 25% non-digestible CHO, and 25% polycyclic aromatic hydrocarbons.

Medium

6-10 carbons

fats density calorie is

9 calories per gram and contribute the most to satiety after a meal - Unique to mouthfeel and flavour

Proteins are compounds made up of

carbon, hydrogen, oxygen and nitrogen

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.

Potential Health Benefits of CLA

CLA may play potential roles in cancer prevention. In some animal studies, CLA has been shown to inhibit cancers, lower cholesterol, improve diabetes, improve immune function and potentially lower body fat. However other studies have shown no effect, or even negative effects (like liver hypertrophy and insulin resistance when CLA isomer supplements are used), so research on humans has been limited. CLA is available in pills sold as over the counter products in grocery and drug stores.

It is difficult to find a fat substitute that will perform well in all food products.

Common food ingredients such as fibre, sugar/carbohydrates, and proteins can take the place of fats. Even though they still provide calories, they provide far less calories than fat would. To gain FDA consent to use fat replacers in a product, it must be proven that little energy is contributed, that it is non-toxic, that it does not build up in body tissues, and does not rob the body of essential nutrients.

Secondary structure

foldings or coilings within a protein structure that are stabilized by hydrogen bonding

Digestibility

In general, amino acids from animal protein are most easily digested and absorbed (>90% of protein absorbed). Legumes are next (~80-90%) followed by grain and plant proteins (70-90%). Cooking with moist heat (e.g., steaming or poaching) improves protein digestibility, where as dry heat methods (e.g., broiling) can impair it.

some (e.g., canola oil and olive oil) are also rich in

MUFAs

Most vegetable and fish oils are rich in

PUFAs

Flavour Binding

Proteins bind to flavour molecules. They can also be used to enhance the flavour of processed food (food system - simulated meats (e.g., textured soy protein, tofu)).

Amino acid composition

The balance of amino acids in a protein determines its biological value and nutritional quality. High biological value proteins are ones with ample amounts of all essential amino acids. Low quality proteins do not. Within a single day of restricting essential amino acid intake, the body starts to limit the breakdown of working proteins and reduce amino acid use for fuel to conserve the essential amino acids it currently has.

Rancidity

The chemical spoilage that commonly occurs with fats and fatty foods is called rancidity - Causes off-flavours and rancid odours. - The longer a fat is stored, the greater the risk for rancidity. - Fats and oils exposed to heat, oxygen and light are more likely to become rancid (i.e., fats and oils used for cooking). - Highly unsaturated fats/oils such as polyunsaturated fats are much more susceptible than saturated or monounsaturated fats. - Foods that easily go rancid are nuts, wheat germ and whole wheat flour. - Fats that have become rancid should be discarded, as they will transfer their off-flavours to the foods they are used in/with.

Protein Hydration

The water binding (hydration) capacity of proteins is related to the amino acid composition. The more charged amino acids, the greater the hydration capacity. Protein molecules can entrap water because of their hydrophilic characteristics (food system—sausages, cakes and breads). Gelatin can thicken products and increase viscosity by forming gel matrixes. (food system—soups, gelatin desserts and dairy products).

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.

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.

Evaporated milk

a canned product, where over half of the water content (~60%) is evaporated out of the milk prior to canning. In Canada, evaporated milk is fortified with Vitamins D and C.

Caramelization

a series of reactions involving dehydration, isomerization, and polymerization, resulting n the formation of polymeric caramels (caramel colloids). Caramels are responsible for the dark brown colours of certain foods ○ A series of chemical reactions occur when sugars are heated to temperatures greater than their melting point. ○ Begins with dehydration and ends with polymerization that yields brown colours. ○ Dry sugar or a sugar solution are heated until it first melts into a clear liquid and then becomes a smooth, brown mixture.

Proteins are arranged in strands of amino acids. Amino acids are the building blocks of proteins. All amino acids have the same chemical backbone:

a single carbon atom, with an amine group and an acid group attached.

When the hydrogen atoms on adjacent carbon atoms are on the opposite sides of the double bond,

a trans configuration occurs

Fatty acid

aliphatic chains with a carboxylic acid functional group - 2 essential fatty acids in the human body: linoleic acid and alpha-linolenic acid

Mineral:

an element other than carbon, hydrogen, oxygen, and nitrogen that is present in food. Minerals is heat stable and are classified as major or trace, depending on their concentrations in plants and animals.

Glycerol is the

backbone of any triglyceride molecule (3-carbon compound with 3 alcohol- hydroxyl groups, each of which is esterified with a fatty acid

Cholesterol serves as the raw material for making

bile, therefore it is important for fat digestion

Enzymes

biocatalysts that speed up the rate of biochemical reactions, without getting destroyed themselves. Not all proteins are enzymes, but all enzymes are proteins. Each enzyme catalyzes a specific type of reaction

When the reactions are too extensive (beyond caramel formation)

bitter dark coloured compounds are formed.

lipids can be heated to temperatures higher than the

boiling point of water - can be used for heat transfer during food preparation without burning the food - enable sautéing, deep-fat frying and pan-frying, resulting in the formation of unique textures and flavours

Major minerals are

calcium (Ca), phosphorus (P), potassium (K), sodium (Na), chloride (Cl), magnesium (Mg) and sulphur (S).

Enzymes act as

catalysts that speed up chemical reactions without being used in the reaction itself. - Enzymes do not stop functioning when an animal is slaughtered or when a plant is harvested; therefore, we must consider enzyme activity when dealing with foods.

Minerals are heat stable and can impact the

chemical and physical properties of foods

Double bonds can exist in a

cis or trans configuration in 3-dimensional space

Protein complementation

combining 2 or more different protein sources to have a better amino acid balance than when consuming either protein alone

Proteins

complex polymers of amino acids

Protein coagulation

congealing and separating out of denatured proteins

Peptide bond

covalent bond between the nitrogen of one amino acid with the carbon of the carboxylic group of the adjacent amino acid. Also known as an amide bond

Fatty acids can also be classified by

degree of saturation

Fats in the diet can affect the type of triglycerides made because

dietary fats are often incorporated into triglycerides in the body.

Coagulation

egg white proteins can set and form a gel during heating. They can help to bind food mixtures together, such as meat loaf, meat patties and manicotti.

Lecithin is a phospholipid found in

egg yolk. In mayonnaise, the lecithin blends the vinegar with the oil and keeps it from separating.

The EFAs can be used by the body to make

eicosanoids, which are biologically active compounds that regulate body functions. - act somewhat like hormones. They can effect muscle relaxation and contraction, blood vessel dilation and constriction, blood clot formation, blood lipid regulation and immune response to injury and infection.

Caramel is widely used in the

food industry both for flavour and colour properties (e.g., dessert toppings, ice cream, pudding, candies like caramels and peanut brittle).

Because processing typically results in nutrient loss,

foods may have nutrients added back through a process called enrichment. Foods may also be fortified with nutrients in an attempt to reduce the incidence of specific nutrient deficiencies (e.g. milk is fortified with vitamin D.

Lipids are formed by

esterification reactions between a glycerol molecule and 3 molecules of fatty acids; the result is a triglyceride (lipid) - All 3 fatty acids involved in the reaction may be identical, or they may be distinct. The properties of triglycerides are dependent on the structure of the fatty acids present therein

Generally, most fatty acids have an

even number of carbon atoms

Cholesterol is important in the structure of cell membranes, therefore is part of

every cell and is necessary for optimal body functioning.

Essential fatty acids (EFAs) are

fatty acids that the body cannot make itself, that we must get from foods. (linoleic and linolenic acid)

Tertiary structure

final 3 dimensional structure of protein that involves numerous noncovalent interaction between amino acids

The American Heart Association recently released recommendations to include two to three

fish meals per week, and Eating Well with Canada's Food Guide encourages Canadians to have two meals with fish per week.

A series of reactions such as fragmentation and polymerization eventually lead to the

formation of brown pigments called melanoidins. - In most cases this is a highly desirable reaction such as in baking and roasting (e.g., baking bread, browning a piece of meat, roasting coffee beans). - It can be undesirable, e.g., browning and off-flavour development of skim milk powder stored over a long period of time. - May result in the formation of acrylamide, which may be a carcinogen. Foods that tend to have higher levels of acrylamide include potato chips, french fries, crackers, bread and cereals.

Stearic acid

found in beef has 18 carbon atoms, single bonds and is saturated.

Butyric acid

found in butter has 4 carbon atoms, single bonds and is saturated.

Oleic acid

found in olive oil and canola oil has 18 carbon atoms, one double bond and is unsaturated (monounsaturated).

Palmitic acid

found in palm oil and cocoa butter has 16 atoms, single bonds and is saturated.

EPA (eicosapentaenoic acid)

from fish sources

DHA (docosahexaenoic acid)

from fish sources too

ALA (alphalinolenic acid)

from plants sources

Linoleic acid

has 18 carbon atoms and 2 double bonds. It is found in most foods especially oilseeds such as canola and soybean.

Linolenic acid

has 18 carbon atoms but contains 3 double bonds and is found mostly in soybean and hempseed.

Caramelized sugar is less sweet then table sugar, but

has a stronger flavour - The darker the caramel, the less sweet it is.

Quaternary structure

how multiple peptide chains are aggregated together by hydrogen bonds, disulfide linkages, and salt bridges into a final specific protein shape

Protein quality helps to determine

how well a diet supports the growth of children and the health of adults. It is influenced by the digestibility of the protein and its amino acid composition. 1. digestibility 2. amino acid composition

Hydrogenation is a process where

hydrogen is added to unsaturated fatty acids (e.g., turning vegetable oil into hard margarine). The hydrogen attaches at the point(s) of unsaturation (the double bond), and the fatty acid becomes saturated (no longer has a double bond). This makes the fatty acid more solid at room temperature and increase the shelf life.

Each amino acid has a distinctive side chain which gives it its

identity and chemical nature.

Unsaturation bends the fatty acid molecule at the position of the double bond, which means the

molecules cannot pack tightly, and less energy is required to melt them

Minerals are

inorganic nutrients that do not contribute energy, but act as co-factors in energy-yielding reactions. - Sixteen minerals are currently known to be essential in human nutrition and can be broken down into two groups based on their amounts found in the human body: major minerals and trace minerals.

Glutelins

insoluble in neutral aqueous solutions, saline solutions or alcohol. Can only be solubilized by dilute alkaline solution.

Vitamins function only if they are

intact - Due to their organic nature, they are vulnerable to destruction by heat, light, storage conditions and chemical agents. Cooking vegetables for short times at moderate temperatures, using small amounts of water helps to preserve the vitamins.

Trace minerals are

iron (Fe), iodine (I), zinc (Zn), chromium (Cr), selenium (Se), fluoride (F), molybdenum (Mb), copper (Cu) and manganese (Mn).

Sterols

large molecules consisting of interconnecting rings of carbon atoms, with side chains of carbon, hydrogen and oxygen.

Primary structure

linear arrangement of amino acids in a protein chain

Emulsification

lipoproteins and phospholipids present in the egg yolk help to keep fat dispersed in water. Used in products such as mayonnaise, salad dressings, sauces (like hollandaise and béarnaise), ice cream and some cakes.

Enzymes are used in foods such as

meat tenderizers (bromelain, papain), clotting of milk (rennin or chymosin). Enzymatic browning is an undesirable browning reaction that occurs when some fruits and vegetables such as banana, apple, potato are cut and exposed to oxygen - The browning reaction can be blocked by denaturing the enzyme using heat or by excluding oxygen by covering the surface of the food or by adding ascorbic acid (vitamin C)

Palm kernel oils are a good source of

medium-chain fatty acids such as caproic (6 carbons), caprylic (8 carbons), and lauric (12 carbons) acids

Fatty acids with an odd number carbons or branched chains are found in

microorganisms and dairy fat

Butyric acid commonly found in

milk and dairy products (4 carbons)

When given linolenic acid, the body can make other

omega-3 f.a's. Two specific omega-3 f.a's are receiving great interest from research - EPA and DHA, however the body only makes limited amounts of these omega-3's. They are found abundantly in the oils of certain fish (deep sea, fatty fish like salmon, char, mackerel, herring, cod, etc.).

Linolenic acid which is an example of an

omega-3 fatty acid

Linoleic acid which is an example of an

omega-6 fatty acid

Amino acids

organic molecules containing carbon, hydrogen, oxygen, and nitrogen. 22 amino acids are found in nature. The basic structure of amino acids involves an alpha-carbon atom linked to an amino (NH2) group, a carboxylic group (COOH), a hydrogen atom, and a side group denoted by the letter R

Lipids are organic compounds soluble in

organic solvents but not in water

Vitamins

organic, nutritionally essential compounds that are mostly heat labile. They are classified as water soluble or fat soluble - organic nutrients that do not contribute energy. They facilitate the release of energy from carbohydrate, fat and protein.

Points of unsaturation are more vulnerable to oxidation which is when

oxygen mixes with the fat, causing it to go rancid, taste "off". That is why we store cooking oil in tightly sealed containers. Therefore, the hydrogenated fats are more resistant to oxidation (no points of unsaturation), are more resistant to breakdown from high cooking temperatures and will have a longer shelf life. It also has a higher smoking point, so is more suitable for frying.

Long-chain fatty acids include

palmitic acid (16 carbons) and oleic acid (18 carbons) and their unsaturated forms

Amino acids are joined together by

peptide bonds to form proteins. 1. 2 amino acids = dipeptide 2. 3 amino acids = tripeptide 3. >3 amino acids = polypeptide

Long-chain fatty acids have a higher melting point than their

short-chain counterparts

Acetic acid is the

shortest fatty acid (2 carbons)

Plants do not manufacture cholesterol but they do manufacture other sterols called

phytosterols. - not well absorbed from the gastrointestinal tract and may actually interfere with absorption of cholesterol. - some types of foods such as margarine (e.g.,Becel's Pro.activ) are fortified with phytosterols to help reduce the amount of cholesterol absorbed into the blood stream.

2 or more points unsaturation =

polyunsaturated fatty acid (PUFA)

Protein complementation is the

practice of combining two or more plant protein sources to provide a more complete array of amino acids. This is important in a vegetarian lifestyle.

Enzymatic browning

process whereby the enzyme polyphenol oxidase (PPO) catalyzes the oxidation of phenols into brown-coloured melanins

A diet short in any of the essential amino acids limits

protein synthesis. In building a protein, no other amino acid can fill another's spot. If a cell building a protein cannot find a needed amino acid, protein synthesis stops and the partial protein is released. These partially completed proteins are not stored until the amino acid is available. They are instead dismantled and the amino acids are released back into circulation. They are either picked up by other cells, or are dismantled and used for other purposes.

Complete proteins

proteins containing all essential amino acids. Examples include meat and dairy proteins and soybeans

Foaming

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. Used in foods such as soufflés, fluffy omelets, meringues and some cakes (e.g., angel food).

Incomplete proteins

proteins that lack one or more essential amino acid. Most plan proteins are incomplete proteins

Continuous denaturation (unfolding) can lead to

recombination of the protein molecules in different ways to produce a new molecular shape. The newly shaped molecules may bond together to form a continuous network referred to as coagulation

Fat replacers are ingredients that

replace some or all of the functions of fat and may or may not provide energy.

Animal fats are generally the most

saturated

0 points of unsaturation =

saturated fatty acid

Fatty acids that do not have any double bonds between the individual carbon atoms are called

saturated fatty acids

Maillard reactions

series of nonenzymatic reactions between reducing sugars and amino acids at high temperatures that result in browning - Reaction between the carbonyl group (CO) of carbohydrates and amine group (NH2) of an amino acid or protein at high temperatures.

he side chains make the amino acids differ in

size, shape and electrical charge (positive, negative or neutral).

When the hydrogen is added,

some of the unsaturated fatty acids become more saturated and the oil hardens and becomes easier to spread. Once hydrogenated, the unsaturated fats lose their health benefits. Hydrogenation affects not only the fatty acids in fats, but the vitamins as well. For example, it decreases the activity of vitamin K in the body.

Cholesterol is an example of a

sterol

Vitamin D is another example of a

sterol that is made from cholesterol. Some of our sex and stress hormones are steroid hormones, for which cholesterol is a precursor.

The electrical charges of the amino acids (caused by the side chain) cause the

strand to bend and coil, as amino acids attract and repel one another. This forms either a globular shape (soluble in water), or a fibrous shape (insoluble in water). The amino acids with electrically charged side chains attract water and are oriented on the outside of the protein structure. The neutral amino acids repel water and are attracted to one another, so orientate in the centre of the protein away from body fluids. These interactions give each protein a unique structure.

Phospholipids play a key role in the

structure of cell membranes - They are typically present in foods in relatively small amounts but play important roles as emulsifying agents, i.e., substances that facilitate emulsion formation

Emulsifiers are

substances that keep water and fat dispersed in one another

Names of enzymes often include the

substrate or substance on which they act, and have an "ase" ending, e.g., lactase (acts on lactose), protease (acts on proteins), lipase (acts on lipids). - The name of an enzyme may also describe the reaction that is catalyzed, e.g., oxidase (catalyzes oxidation reactions).

Protein denaturation

the disruption of bonds that make up the tertiary and secondary structure of proteins. Can occur through the addition of heat, alcohol, acids, salts, enzymes, and mechanical shear - involves unfolding of protein structure without breakage of peptide bonds. Denaturation is caused by cooking, freezing, changes in pH, salts enzymes and mechanical action. - Denaturation changes the original properties of the protein. In most cases, denatured proteins are less soluble. If it is an enzyme, functional ability will be lost

A cis configuration arises when

the hydrogen atoms attached to the carbon atoms are on the same side of the double bond

Cholesterol forms

the major part of the plaques that narrow the arteries in atherosclerosis, an underlying cause of heart attacks and strokes. Cholesterol can be made by the body so therefore is not essential.

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.

Nonenzymatic Browning

the most common type of browning in processed foods. These reactions occur at elevated temperatures and include the caramelization of sugars and Maillard reactions between amino acids and sugars

Saturation refers to

the number of hydrogen atoms a fatty acid chain is holding. The more hydrogen atoms attached, the more saturated the fatty acid is.

Phospholipids

the resulting diglyceride when one of the fatty acids in a triglyceride is replaced by a phosphate group - similar to triglycerides, however they have only 2 fatty acids attached to the glycerol backbone and 1 phosphorus molecule. - The phosphorus molecule makes the phospholipid soluble in water. This gives phospholipids the role of keeping fats dispersed in water

Cereals

◊ Have protein contents not greater than 15-17%. e.g., wheat, corn, rye, rice, oats, barley. ◊ In wheat, the principal proteins are the gliadin and glutelin fractions, which represent about 80% of the endosperm protein. ◊ Gluten is a complex formed from gliadins and glutelins following hydration and mixing of wheat flour. ◊ The hydrated gluten complex forms a 3-dimensional viscoelastic network that gives wheat flour its valued dough and bread-making characteristics.

Pulse, Nuts and Oilseed (Legume) Storage Proteins

◊ Pulses are beans (e.g., Navy beans, kidney beans, black beans, etc.), peas (e.g., split peas, chickpeas) and lentils. ◊ Contain higher protein contents, ranging from 18-45%, e.g., peas, lentils, beans, soybean, canola, mustard. ◊ Contain very little amounts of gliadin and glutelin. Majority of the proteins are soluble in water or salt solutions. ◊ Most pulses offer protein of good quality, while being low in fat. ◊ Legumes include pulses, soybeans, seeds and peanuts. ◊ Nuts are grown on various trees and ground plants. ◊ Provide protein, unsaturated fat, fibre, vitamins, minerals and phytochemicals

Animal Proteins Meat

○ Broadly defined, meat includes muscle tissue and organs of beef, veal, lamb, pork, poultry and fish. ○ Red meat has negligible carbohydrate content as the glycogen is used up in the continuing metabolic process after slaughter. ○ Major components of meat are water, fat and protein, as well as some vitamins and minerals. ○ Poultry tends to have a lower fat content and slightly higher protein content per weight than red meat. ○ High water content and neutral ph makes meat susceptible to spoilage- this can be reduced by curing (salt addition) or drying. ○ Other processing of meat includes grinding, canning and freezing. ○ Meat usually has some visible fat within the muscle called marbling (seen as white streaks or drops in the muscle). Presence of fat increases juiciness and gives better eating quality. Due to health concerns some animals are now bred to have leaner meat (less marbling, lower fat content). ○ The colour of meat is often used to judge freshness and it is usually wrapped in material that is permeable to oxygen to preserve the red colour. Without oxygen, beef is normally bluish-purple. When meat is not fresh it turns brown. ○ Fish flesh is highly perishable because of the high levels of unsaturated fatty acids which can be readily oxidized. ○ Fish fat is rich in a chemical called trimethylamine oxide (TMAO).After capture, the TMAO is converted to trimethylamine (TMA), which is responsible for the 'fishy' odour.

Eggs

○ Eggs have an outer shell, and have 2 major inner parts- the egg white and the egg yolk. The shell is about 94% CaC03 with small pores that allow C02 and water to escape, while allow 02 in. ○ They 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.

Fat-based replacers

○ Fat molecule created with fewer carbon atoms in the structure (a shorter length of fatty acids). Therefore, fewer calories are provided. ○ Long chain fatty acids can be combined with sucrose to produce a compound known as sucrose polyester. - The idea of fat-replacers for weight loss is mixed. Many people assume that when they eat a food that has less fat they can eat more of it, however labels reveal that many lower fat foods have similar calorie contents as their full fat counterparts. Some studies have shown that if portion sizes remain similar, some weight loss can result.

Plant polysaccharides

○ Include derivatives of cellulose, maltodextrins, gums, modified starches and polydextrose ○ Some are digested, so provide 4 kcal per gram, however others are not digested, so are virtually non-caloric ○ They produce a mouthfeel that is similar to that associated with fat but they do not taste like fat and do not function like fat in cooking ○ Can withstand heat, however cannot be used for frying e.g., Oatrim - made from hydrolyzed oat flour, used in baked goods and salad dressings

Milk and dairy products

○ Milk is the near perfect food- it is an important source of high quality protein, minerals, B vitamins, and energy, and is fortified with vitamins A and D, however contains very low amounts of iron. ○ Milk is composed of two protein fractions: ○ casein (~80% total milk protein) ○ whey (~20% total milk protein) ○ During the manufacture of cheese, acid or rennin (an enzyme also know as 'rennet') is added to coagulate most of the casein proteins while the whey is the liquid portion of milk that remains after cheese production Go to: www.youtube.ca. Search for and view the video entitled: "How it's Made: Cheese": https://www.youtube.com/watch?v=FHmXAb3G0ek ○ Whey proteins are composed mostly of beta-lactoglobulin, alpha-lactalbumin. ○ Milk is homogenized, a process that decreases the size of the fat globules dispersed in milk so that they are more optimally dispersed. ○ Freezing destroys this process, hence the fact that when most milk products are frozen and then thawed, there is some separation of fat and liquid. ○ Milk is classified as whole (3.25% milk fat [M.F], reduced fat (2% M.F), low-fat (1% M.F) or fat-free (skim milk, no more than 0.5% M.F). ○ During processing, fluid milk and yogurt are pasteurized to kill microorganisms.

Omega-6 (n-6) Fatty Acids

○ Polyunsaturated fatty acids that have the first double bond on the sixth carbon atom from the methyl end. These essential PUFAs, when consumed in moderate amounts, help regulate metabolism, stimulate growth of skin and hair, and maintain bone health. Dietary sources include palm, soybean, rapeseed, and sunflower oils ○ Omega-6 fatty acids get their name because of a double carbon bond 6 carbons from the end of its chain. Linoleic acid is an example of an omega-6 fatty acid. ○ DRI recommendation: 5-10% energy from n-6 fatty acids ○ Sources: vegetable oils, seeds, nuts, whole grain products

Omega-3 (n-3) Fatty Acids

○ Polyunsaturated fatty acids that have their first double bond on the third carbon from the methyl end of the fatty acid chain. They are essential to the human diet and include docosahexaenoic acid (DHA), eicosatetraenoic acid (EPA) and alpha-linolenic acid (ALA) ○ Omega-3 fatty acids get their name because of a double carbon bond 3 carbons from the end of its chain. Linolenic acid is an example of an omega-3 fatty acid. ○ DRI recommendation: 0.6-1.2% energy from n-3 fatty acids ○ Sources: flaxseed, flaxseed oil, canola oil, fish (especially deep sea fish) ○ Research has shown that a higher intake of the omega-3 fatty acids can often improve the health of the heart. Our ratio of intake of omega-3 to omega-6 fatty acids is important, so we can improve this ratio by increasing our intake of omega-3 fatty acids and by keeping our intake of omega-6 fatty acids at a moderate level.

Protein-based replacers

○ Proteins are blended with gums to form gels, which have similar functions and structure as fat ○ They provide 1.3 to 4 kcal per gram used ○ Used to manufacture low-fat frozen and refrigerated products such as ice cream and other dairy products (e.g., can provide texture to cheese), but cannot be used for frying or at high temperatures (the protein coagulated at high temperatures and function is compromised). ◊ e.g., 'Simplesse' is a microparticulated protein, which is produced by reshaping milk and egg white protein into tiny round particles. The process produces protein particles so small that they are perceived as fluid by the mouth.

The Role of Fats in foods

○ Provide essential nutrients (e.g., essential fatty acids, fat soluble vitamins) ○ Provide concentrated source of energy & 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 heat transfer

Research on Omega-3 and Omega-6

○ Research first began on these fatty acids when researchers were trying to determine why people in Greenland and Alaska, with high fat diets, had such low rates of heart disease. ○ Research led to the high marine-based diet with an abundance of fish and an abundance of these heart healthy fatty acids. The low incidence of cardiovascular disease in Inuit population has been attributed to the high omega-3 to omega-6 ratio in their diet which is based principally on fish products. Fish oil contains a high omega-3 to omega-6 ratio. ○ The EPA/DHA content tends to be higher in grilled, baked or broiled fish. Fish used for frying in a fast food setting and in frozen products (eg.. fish sticks), tend to be species with lower DHA/EPA content. ○ It is preferred to get your EPA/DHA from food rather than supplements at this point. Many studies are showing greater benefit from the DHA/EPA in foods. Also, fish oil supplements may raise LDL cholesterol levels in some individuals, and high intakes of omega-3's (>3g/day) can increase bleeding time, interfere with wound healing, and suppress immune function. Supplements also lack the other important nutrients that fish provides (protein and minerals such as iodine, selenium). Fish oil supplements may be made from the skin and livers of fish, increasing the risk of contamination from pesticides, industrial contaminants and heavy minerals such as mercury. Unless the pill is refined to eliminate these, the contaminants will become further concentrated in the pill. Therefore, it is important to choose a reputable brand. Also, fish oils naturally contain high levels of two of the most potentially toxic vitamins, A & D, although many supplement companies remove these vitamins from their supplements. Lastly, little is known about the long-term effects of fish oil supplements.