Nutrition 119 Exam 1
Boiling Point is the temperature at which a liquid begins to boil and changes to a gas.
-212°F (100°C) at sea level; requires 540 calories (0.54 kcal) to boil & vaporize -After point is reached, additional heat will not increase temperature or cook food faster -Heat of vaporization - Amount of heat required to convert liquid to a gas Bubbles start to break the surface when water reaches 212 degrees or 100 degrees at sea level- this is the temperature at which the liquid begins to change to gas The water will not get hotter nor will the food cook faster no mater how much heat is added and this is why a rolling boil is often recommended Keeping the temperature at a slow rolling boil is also more gentle on foods and results in less evaporation.
Elevation & Boiling Point
-As altitude increases, boiling point decreases (1o F for every 500-foot increase) or (1o C for every 960-foot increase) -Occurs because there is less air & atmospheric pressure pushing down; steam is faced with less resistance -Artificial pressure can be created by pressure cookers; speeds up heating time -960 ft increase in elevation decreases waters boiling point by 1 degree Celsius
Poaching (Gentle)
-Associated with delicately flavored foods that do not require lengthy cooking times (eggs, fish, fruit) -Food placed in liquid held at temperatures between 160 F to 180 F
Stewing
-Associated with smaller -Pieces of meat first cooked -Addition of liquid -Cooking time is usually shorter than braising
When to flavor
-At the beginning, middle and end of cooking process -Heat will help release flavors but too much cooking can result in loss of flavor -Whole spices take longer and ground spices release fast
Proteins in food preparation
-Binding water: cakes and custards -Forming gels -Thickening -Producing foams -Browning reactions -Meringues -Non-enzymatic browning reactions Food industry- adding milk, meat, egg , soy gelling nature- binds and stabilizes Confections- gums, desserts Ice Cream, puddings pies
Maillard Reaction
-Chemical reaction between amino acid (from protein) and sugar. Exp. Browning of surface meat when cooked -Produces unique flavors as it browns various foods The reactions responsible for the cooked color and flavor on bread crusts, chocolate, coffee beans, dark beers and roasted meats, all foods that are not Primarily SUGAR. Non enzymatic browning resulting from a chemical reaction between AMINO ACIDS and a reducing sugar usually requiring heat to create new, distinct flavor compounds. Result is varying degrees of browning and also textures and FLAVOR- they provide a more meaty and complex flavor than carmelization because it involves AMINO ACIDS which adds Nitrogen and sulfur into the mix. Very large molecules are created which are responsible for deep brown hue on the crusts of roasted and grilled meats -Toast from white bread -Vanilla cake- turning brown -Baked crust on breads
Carbohydrates in food preparation
-Contributing sweetness -Solubility -Crystallization -Color (through browning reactions) -Moisture absorption -Texture -Fermentation -Food preservation
Steaming
-Cooking by exposure to steam -Steamers (placed above simmering water) -Baking in parchment paper or foil -Pressure cooking Uses convection to transfer from steam to food Decreases the cooking time by trapping the steam that escapes from the boiling water.
Factors that influence food choice:
-Cultural -Religious Beliefs -Ethnic heritage or Traditions -Preference -Economic and Marketplace Factors -Emotional and Psychological Effects -Habits
When to season
-End of cooking process (esp. liquid foods) -Last step in most recipes "adjust the seasoning" -For larger pieces of food, start of cooking process
General concepts in flavor building
-Every ingredient should have a purpose -Ingredients can work together by harmonizing and contrasting -When two ingredients contrast, be sure they balance -Consider not only the components of the single recipe but also the other items that will be served with it on the plate. -Simpler is usually better
Freezing Point is the temperature at which liquid turns to solid
-Freezing = 32°F/0°C at normal atmospheric pressure -Heat of solidification - Occurs when at least 80 calories (0.08 kcal) are lost per gram of water -Water expands & becomes less dense when frozen -Adding anything to water, e.g., salt or sugar, lowers freezing point, but too much slows freezing --> i.e. frozen desserts made with large quantities of sugar take extra time to freeze. The lower temperature decreases water's kinetic energy, or the energy association with motion, which slows the movement of the water molecules until they finally set into a compact configuration. Pure water freezes at 32 degrees-but adding anything else to the water changes its freezing point- adding salt or sugar, will LOWER the freezing point, adding too much however slows down the freezing- think of frozen desserts.
Conduction
-Heat transfer due to contact of molecules vibrating in place -Occurs when two objects (or parts) at different temperatures are in contact with each other -Heat flows from the warmer to the cooler object until they are both at the same temperature Transfer rate is proportional to Temperature (T) gradient - rate of vibration of one vs. the other. Some solids conduct better than others: Liquids & gases, conduct very little Conduction occurs from the outer surface of the food to the inside also. This happens by DIRECT Contact- most straightforward methods When we cook, water is lost upon heating. High Temperature conduction sears the outside, protecting from further water loss. Inside is still cold.
Radiation
-Heat transfer due to energy waves (emr) emitted by one and absorbed by another object -Both conduction and convection require matter to transfer heat -Does not rely upon any contact between the heat source and the heated object -For example, we feel heat from the sun even though we are not touching it
To cook food means to heat it in order to make certain changes to it.
-It makes food taste better -Destroys Microorganisms -Makes food easier to digest
Odor of food contributes immeasurably to the pleasure of eating.
-May be index to quality of a food -Olfactory organ - not of the taste buds- is impaired when a person has a cold -The pleasant sensations in eating come more from odor than from taste
Salt
-Most important seasoning ingredient -Chemical name is Sodium Chloride (NaCl) -Iodized for nutritional purposes -Amount used is dependent on food being prepared and personal preference -Beware of over use from health as well as taste issues
Taste
-Most influential factor in food selection -Gustatory: Relating to the sense of taste -Taste occurs when substance stimulates the taste buds -Taste buds connected to the brain via nerve cells -A substance must be dissolved in liquid or saliva
Pepper
-One of the most widely used spices in the world -Peppercorns: Black, green and white -Color depends on the berry's ripeness -Chemical in black pepper is "piperine" -Piperine responsible for the pungency of black pepper
Caramelization
-Oxidation of sugars -Complex process: melting, boiling, decomposition, condensation with loss of water, reaction and rearrangement of molecules, flavor production, and color production -Excess heat will burn sugar instead of caramelize -Non-enzymatic reaction -Flavor- initially sweet and odorless and then develops acidity some bitterness and rich aroma
Roasting and Baking
-Process of surrounding a food with dry, heated air in a closed environment -Roasting usually applies to meat -Baking refers to fish, fruits, vegetables, starches, breads and pastry items -Heat is transferred by convection to the food's surface and then penetrates the food by conduction Cooking uncovered is essential to roasting - covering holds in steam, changing the process from a dry heat to a moist heat cooking
Fats in food preparation
-Tenderizing in baked foods -Contribute to leavening -Promote moistness -Major components of salad dressings -May be heated to high temperatures -Contribute to flavor Leavening- Creaming of fat and sugar Frying foods- oils can reach extremely high temperatures Flavor compounds dissolve in fat so fats are important carriers of flavor Salad dressings- creating emulsions of two immiscible items
Monosodium Glutamate (MSG)
-The sodium salt of glutamic acid -A common amino acid -"Chinese restaurant syndrome" -Today is produced by a fermentation technique -World production stands at about 250,000 tons Umami: Savory- Certain amino acids (20 essential) Glutamic acid- the flavor of a protein that has began to break down a little bit through enzyme activity through long cooking soy sauce, blue cheese, cured meats and aged cheeses
Heat Transfer is the movement of thermal energy from high to low temperature.
-The temperature difference is the driving force, the push for heat transfer -The greater the temperature, the faster heat transfer When you 'heat' something, you are transferring energy to it The difference in temperature = T gradient T gradient determines rate or speed of heat transfer Small difference in temperature = slow transfer Big difference= fast transfer
Red Pepper (or Cayenne)
-Unrelated to black pepper -Same family as chiles, paprika and bell peppers -Chemical in red pepper is "capsaicin" which can cause a burning sensation of the hands Used in tiny amounts it gives spicy hotness to sauces and soups without actually altering the flavor In larger amounts it gives both heat and flavor to many spicy foods such as those from India and Mexico
Deep-Frying
-Uses conduction and convection to transfer heat -Food is submerged in hot fat -Although conceptually similar to boiling, deep-frying is not a moist-heat cooking method because the liquid fat contains no water -Boiling point 212 F, deep frying temperature 400 F
Sauteing
-Uses conduction to transfer heat from a hot sauté pan to food with the aid of a small amount of fat -Heat then penetrates the food through conduction -High temperatures are used to sauté
Grilling
-Uses heat source located beneath the cooking surface -Woods such as mesquite, hickory or fine clippings can be used to create special flavors
Broiling
-Uses radiant heat from an overhead source to cook foods -Temperature at the heat source can be as high as 2000 F
Braising
-Usually large pieces of meat -First browned in fat -Addition of a small amount of liquid Braising means to cook covered in small amount of liquid usually after browning - combination cooking method because the product is first browned using dry heat and then cooked with liquid.
All living things contain The Six Key Atoms or elements:
1. Carbon 2. Hydrogen 3. Nitrogen 4. Oxygen 5. Phosphorus 6. Sulfur Building blocks of ORGANIC (LIVING) Material - any carbon containing compounds.
Radiation occurs when energy is transferred by waves from a source to the food. The waves themselves are not actually heat energy but are changed into heat energy when they strike the food being cooked.
2 types common in cooking: Infrared and microwaves. There is no need for a transfer medium - this would just get in the way Infrared- broiling is a familiar example - electric element or ceramic element heated by a glass flame becomes so hot it gives off infrared radiation which cooks the food. High intensity infrared ovens are designed to heat food rapidly
Size and temp and individual characteristics of food small roast cooks faster than a large one
A steak chilled takes longer to broil than one that has been sitting at room temperature
Functions of Water in Food: Acids and Bases
Acid: molecule that donates protons or Hydrogen (H+) ions -Has sour taste -Stronger acid has greater tendency to donate hydrogen ion Base: molecule that accepts the proton -Usually has OH- group in search of proton -Has bitter taste or soapy
Atoms combine to create molecules (composed one or more atom types) or compounds (substance whose molecules are composed of unlike atoms). Molecules & compounds combine to create all substances on earth.
All elements/atoms have the capacity to join together with similar or different elements to produce molecules or compounds which then combine to create all substances on Earth.
Proteins (CHON)
Amino acids (peptides) Building blocks of the body -Consist of substances called amino acids -Complete proteins: contain all nine essential amino acids -Incomplete proteins: lack one or more of the essential amino acids Average adult needs 50-60 grams per day: Essential for growth and building body tissues- Body can only synthesize about half of the compounds or amino acids needed to produce protein 20 total and of 9 are essential- these can not be made in the body or can't be made in sufficient amounts and need to be obtained from foods Essential amino acids are important in vegetarian diet planning
Functional Properties of Water in Food
Among its many uses in food preparation, its two most important functions are as a transfer medium for heat and as a universal solvent - a substance in which another substance is dissolved in Potato heated by itself in a pan will burn, but surrounding that same potato with water, ensures that the heat will evenly distribute -Transfer heat more efficiently as well- which explains why a potato heats faster in boiling water than an oven- because the concept of specific heat- water has a higher specific heat than other substances it buffers changes in temperature- more energy is required to increase the temp of 1 gram of water than 1 gram of fat- the specific heat of oil is 0.5- so it heats twice as fast as water C02 release- baked products - water allows baking powder and other rising agents to work.
Those foods that provide essential amino acids in the proportions needed by the body are high quality proteins or complete proteins- these include animal proteins such as meats, poultry, fish, eggs, milk and dairy products.
Animals obtain proteins from plants or from other animals that have fed on plants from which they form new proteins of higher biological value -Lower quality proteins or incomplete proteins are low in one or more essential amino acids- these include your plant proteins, including beans peas, grains, vegetables nuts and seeds -Although plant proteins are incomplete it does not mean they are low quality- they can become complete proteins by combining two sources: beans higher with rice
What is food?
Any substance that provides nutrients necessary to maintain life and growth when ingested.
At the group level, acculturation often results in changes to culture, customs, and social institutions. Noticeable group level effects of acculturation often include changes in food, clothing, and language.
At the individual level, differences in the way individuals acculturate have been shown to be associated not just with changes in daily behavior, but with numerous measures of psychological and physical well-being.
Guidelines for using herbs and spices
Be familiar with each spice's aroma, flavor, and effect on food. (Spice charts) Don't use stale spices and herbs and don't buy more than you can use in about 6 months. Use good quality spices and herbs. It doesn't pay to economize here. Whole spices take longer to release flavors than ground spices, so allow for adequate cooking time. When in doubt add less than you think you need (you can always add more) Herbs and spices added to uncooked foods need several hours for flavors to be released and blended.
Flavor
Broader concept than either taste or aroma The combined sense of taste, odor, and mouth feel Aroma provides about 75% of the impression of flavor
Some organic compounds can be broken down by the body to create ENERGY
Calories needed to sustain life- Carbohydrates, fat, protein, and alcohol are the only sources of calories from the diet.
Chemical and Physical change in cooking
Chemical -New substance is formed -New properties -Can't undo -i.e. cooking an egg Physical: mix or phase change -No new substance -Can be reversed 'easily' -i.e. melting an ice cube Chemical changes can not be undone but physical changes can be reversed
Nutrients
Chemical compounds that are present in foods There are six categories of nutrients: -Water -Carbohydrates -Lipids -Protein -Vitamins -Minerals
Water is a polar molecule
Contains a positive and negative side overall has a neutral charge -Hydrophilic: Molecule that "loves" water -Hydrophobic: molecule that repels water Water and oil repel each other because fats have an even distribution of charge. However, not completely neutral in the sense that the water molecule has a negative pole and a positive pole, making it what we call dipolar.
The effects of heat
Depending on temperature & method of cooking: -Proteins may or may not denature & coagulate -Starches may or may not gelatinize -Sugars may caramelize or burn -Fats may or may not melt -All four above can brown by Maillard Reaction -Water may or may not evaporate
Storage of Herbs and Spices
Depends on age, type, and source of the spice Whole spices retain flavor well, but quality decreases during long storage Flavor of ground spices and herbs is lost much more readily because of their greatly increased surface area Should be stored in cool, dry place, in airtight containers The American Spice Trade Association indicates that dried herbs and spices should kept below 60 degrees for optimum potency and replaced every 12 months Herbs and spices deteriorate rapidly when exposed to air, light, and heat They keep best in airtight, opaque (not see through), containers stored in cool, dry places Testing freshness of a particular spice or herb is done by crushing it in the palm of your hand and then sniffing it to detect its intensity.
Appetite
Desire to eat or reject food. -Desire for food, usually after seeing, smelling, or thinking about food. Even after you feel full, your appetite can make you keep eating. It can also stop you from eating even though you are hungry. This might happen when you are sick or feeling stressed
Speed of heat transfer:
Different cooking methods transfer heat at different rates- Air is a poor conductor of heat while steam is much more efficient- A jet of steam will easily burn your hand but you can safely reach into an oven at a very high temperature- this is why it takes longer to bake potatoes than to steam them.
Standards of Doneness:
Different for every type of food and food and for every cooking method We will look at these cooking methods for each food we learn about: meats, poultry, fish, vegetables, starches and other foods.
Microwave cooking, the radiation generated by the oven penetrates partway into the food where it agitates the molecules of water. Interaction with polarized (dipolar) molecules (water protein and some carbohydrates)
Dipolar molecules align in the microwave electromagnetic field- dipolar molecules rotate rapidly and heat is produced by friction Microwaves penetrate from 1-2" do not cook from the inside out. Only impacts water molecules, a completely waterless material will not heat in the microwave oven. Plates will become hot only when heat is conducted by hot foods.
Discrimination or Difference Testing
Discriminate between/among samples -Detect differences -Detect flavors Is it tomato or salt flavor that is the difference between these products: determines whether or not a food company should buy an expensive ingredient to replace a more expensive ingredient in formulating a food product The type of panel required for this type of testing would normally be a highly trained panel.
Cooking methods: Dry Heat
Dry heat are those in which the heat is conducted without moisture that is by hot air, hot metal, radiation or hot fat -Notice: Fat (oil) is considered "DRY" Medium: Air -Roast -Bake -Broil -Grill Medium: Fat -Saute -Pan-fry -Deep-fry
Affective Tests
Evaluation is done by a panel of individuals from the general public using a scoring system based on various characteristics that can be judged using the senses (more based on preferences or pleasure testing) -Designed for the general public (consumer testing) -Tests for Liking Also known as consumer testing, this type of testing is concerned with how well products are likely to be accepted. Determines the acceptability or preference between products. -Usually large (50 or more) panels of untrained personnel are recruited for this type of testing, although smaller focus groups can be utilized to gain insights into products. -Hedonic scales are used: pleasure scales from one extreme to another: like extremely to dislike extremely
Unlike other substances water becomes less dense when completely frozen, which is why ice floats. Think of ice as a low energy form of water.
Expands as well...think of water's ability to burst pipes once frozen- due to the expansion. In food...it has the ability to rupture cells in plants and meats, diminishing the potential food's textural quality.
Green peppercorns are picked unripe and preserved before their color darkens
Fairly expensive and used in special recipes in luxury restaurants- they may come in wet-pack peppercorns dried versions are also available
Fats/Lipids (CHO)
Fatty acids-- building blocks Insoluble in water-- has a hydro "phobic" tail repels water Feel "greasy" Three major groups -Triglycerides -Phospholipids -Sterols Can be liquid or solid at room temperature- liquid fats: oils Solid fats- butter lard
Heat Management: Doneness and Cooking Times
Food is "done" when two things have happened: -The interior temperature has risen to the desired degree -The desired changes have taken place in the food The time it takes to achieve doneness is affected by three factors: -Cooking temperature -The speed of heat transfer -Size, temperature, and individual characteristics of the food
Culture is a factor influencing food choice. It is learned- not inherited like eye color
Foods relished in some parts of the world may be spurned in another- insects and bugs provide protein sources for 10% of the protein world wide
Water in foods is either free or bound form
Free -Largest amount and easily separated from food -Held inside the cells, maintains properties of free water and may be removed by pressure- largest amount found in food and easily separated- examples of free water- the water in fruits Bound -Incorporated into the chemical structure of food (e.g., in bread) & not easily removed -Part of the molecule structure: Bound water is not easily removed , has reduced mobility and resistant to freezing or drying. It does not retain properties of free water. examples like carbohydrates, fats, and proteins or bound water found in bread- it is resistant to freezing and drying and it is not readily available to act as a medium for dissolving salts acids or sugars. Composition of water -One oxygen atom flanked by two hydrogen atoms H2O Whether it is free or bound, the chemical structure remains the same.
High nutrient density foods provide many nutrients per calorie-
Fruits and vegetables and whole grains
Desired changes:
Gelatinization of starches, coagulation of proteins, breaking down of connective tissues, carmelization of sugars, -Many factors must be taken into account when choosing a cooking method: meats fish vegetables - flavor, appearance, browning etc.
White pepper is from the ripe berry from which the dark outer skin has been removed
Ground white pepper is more important in food-service kitchens- its flavor is slightly different from that of black pepper and it blends well in small amounts with many foods- its color makes it undetectable in light colored foods
Convection
Heat transfer by the movement of air, steam, or liquid (including hot fat). The process that carries the heat from the heat source to the food. There are two kinds of convection: -Natural -Mechanical Usually the most efficient way to transfer heat in liquids and gases (Natural convection) Hot liquids and gases rise, while cooler ones sink- In any oven, kettle of liquid or deep fat fryer, a constant, natural circulation distributes heat. Convection is where Temperature gradient really matters.: The greater the distance between the hot element & the food, the more important convection is. Air and water take up more space (become less dense) when their molecules absorb energy and move faster and so they rise when they heat up and sink as they cool off.
Heat Management: The higher the temperature (T), the faster the heat transfer & the shorter the cooking time.
Heat transfer medium determines available T range: Air - no T limit; broiler element can reach 2000 °F Oil - 40 °F - 450 °F or 5 - 260 °C Water - 32°F <T>212 °F or 0<T>100 °C No matter how much heat we apply, liquids can't get hotter than their Boiling Point Steam can get up to ~250 °F or ~120 °C Greater temperature difference between the foods edge and center means this will happen faster. A smaller temperature difference within the food will help the exterior retain moisture and produce more uniform cooking- low and slow roasting temperature (roasting).
Everything physical in the universe is made from atoms/elements some of the smallest particles in existence.
How are they identified??- By their number of protons and electrons Protons- are positively charged particles in the atom's nucleus Electrons- are negatively charged particles surrounding the nucleus (think of rings around Saturn) The number of Electrons- negatively charged particles, on the outside of the atom dictates how many bonds that particular atom can form and what kind of substance can be formed Nitrogen- is capable of forming 3 bonds Oxygen- can form 2 bonds Hydrogen only 1 bond - this bond is called covalent bonding
People choose foods and beverages based on a number of factors:
How foods look, taste, but also eating for cultural and religious values which we talked about last week and health, psychological and social needs (as well as budget).
Water molecules: Very small molecule consisting of three atoms—one oxygen atom flanked by two hydrogen atoms.
Hydrogen is positive Oxygen is negative One water molecule is able to form up to four hydrogen bonds- however, these bonds are weak and easily broken and reformed Water has an overall neutral charge. The "neutrality" is derived form it's two hydrogen atoms, each with one positive charge, being balanced by the two negative charges of water's one oxygen atom. Overall=neutral.
Gas ignites --> heats pan --> excites molecules --> transfer heat to food/oil or water
In order for food to be cooked, heat must be transferred from a heat source (such as gas flame or electric element) to and through the food -A small piece of chicken will heat faster on a grill vs. a large whole chicken
Taste Buds
In the middle of each taste bud is a pore, similar to a little pool where saliva collects. When food comes in contact with the cilia (small hair like projections from the gustatory cells) the gustatory cells relay a message to the brain via one of the cranial nerves The brain in turns translates the nervous electrical impulses into a sensation people recognize as taste The more moisture or liquid the more the molecules triggering flavor can dissolve and spread over the tongue coming in contact with the taste buds
How about when you have a cold and you feel you can not taste anything?
It is actually not your taste buds that are impaired but rather the olfactory or organ related to smell which is impaired.
A calorie is a measurement of energy
It is defined as the amount of heat needed to raise the temperature of 1 kilogram of water by 1 degree C
For a substance to produce an odor:
It must be volatile (evaporating readily at normal temperatures and pressures ) Molecules of the substance must make contact with receptors or channels on cilia in the olfactory epithelium Since only volatile molecules in the form of gas carry odor, and since heat converts many substances into their volatile form it is easier to smell hot foods vs. cold foods. -These volatile substances come in contact with the receptors in the olfactory epithelium (sit behind the nasal cavity)- this is the size of a quarter -Temperature is important- heat makes molecules more volatile
Seasoning
Item added to enhance the natural flavors of a food without dramatically changing its flavor. (Salt is the most common)
Flavoring
Item that adds a new taste to a food and alters its natural flavors (flavoring includes herbs, spices, vinegars and condiments)
Other Basic Seasonings
Lemon Juice- sauces and soups Fresh herbs- are almost superior to dried herbs Onions- garlic shallots- members of the onion family as well as carrots and celery- use fresh onion and garlic over dried versions Rinds- zesting sauces, flavorful oils in the rind Wine and brandy - chicken marsala Mustards- mustard seeds, vinegars and other spices Soy sauces- salty
Water as a universal solvent- SOLVENT- a liquid in which another substance is dissolved- Iced tea- Sugar
Makes it possible to form salts- which occurs when positive ion combines with a negative ion as long as it is neither hydrogen or hydroxyl - combining acids and bases or a metal and non metal.
Sensory Evaluation
Measurements determined by using the senses of sight, smell, taste, and sometimes touch for the purposes of evaluating consumer products The discipline requires panels of human assessors, on whom the products are tested, and recording the responses made by them SUBJECTIVE (opinions and feelings) for evaluation for sensory: Human Panelists -Uses measurements based on the senses- mostly sight, smell and taste (sometimes touch) OBJECTIVE tests- which utilizes uses mechanical equipment to test properties such as tenderness and volume, viscosity- concrete facts- % fat in a food, amount of salt vs. how salty something may be. -Most companies use a combination of both since it could become costly to use human panelists.
Avoid cooking in the microwave:
Microorganisms are not killed: Listeria salmonella, camppylobacter Food with membranes may explode Lack of surface browning, cooking periods are not long enough- tender Some foods (like bread can become tough) Uneven cooking- hot and cold spots in food Because microwaves penetrate no more than 2 inches into foods, heat is transferred to the center of large pieces of food by conduction, just as in roasting Because microwaves do not penetrate metal, aluminum foil and other metals
Radiation in cooking
Microwave cooking -Relies on radiation generated by a special oven to penetrate the food -Affects water molecules primarily -Therefore, a completely waterless material (i.e. plate) will not get hot
Foods consist of varying amounts of these nutrients:
Milk is 80% water, meats are primarily protein, potatoes and starches are primarily carbohydrates. Most foods contain a combination of the 6 major nutrient groups When looking at the human body you can see that it is largely made up of water- 60-70%
Cooking Methods: Moist Heat
Moist: are those in which the heat is conducted to the food product by water or water based liquids such as stocks or sauces or by steam. Different cooking methods are suited for different kinds of food- some meats are high in connective tissue and are tough unless tissue is broken down slowly by moist heat - those meats low in connective tissue and naturally tender - they are best with dry heat to a rare or medium done stage Medium: Water -Poach -Simmer -Boil Medium: Steam -Steam -Pressure cooking Medium: Dry/Moist -Braising -Stewing
If one of my First Generation Italian family members moved to America, and continued to speak Italian and followed their norms from Italy, etc., they may NOT become highly acculturated to American Culture.
Now if the grandchildren of this immigrant will start in American Schools and will attend American college, dresses and shares the same values of the friends they have met in this country, this individual will be highly acculturated into American culture.
Descriptive Testing
One product, multiple characteristics -Flavors: how strong, bitter, acidic -Texture profiles -Create a scale describing intensity: 1-10 Enables researchers to characterize their products through selective, critical scoring of specific attributes of each sample (how strong or bitter a coffee may be) or Fruity or Dry a wine may be or what vanilla tones can be noted in a wine; how pungent a cheese could be Requires a panel that is well trained.
FLAVORING INGREDIENTS CAN BE ADDED AT THE BEGINNING, MIDDLE OR END DEPENDING ON COOKING TIME, PROCESS OR INGREDIENT
Only a few flavorings can be added successfully at the end of cooking- fresh herbs- sherry or flamed brandy, and condiments - like mustard and Worcestershire sauce- most flavors need heat to release their flavors and time for flavors to blend. Whole spices take the longest - ground spices release flavors more quickly and do not require as long of a cooking time. Too much cooking results in loss of flavor- volatile nature and they evaporate.
Calories fuel our bodies like gas does cars, unlike cars, your body does not shut down even when we are sleeping we are using energy.
Over half of calories used by the body, about 60% are used solely for vital life functions such as maintaining temperature, breathing, and our heartbeats 10% is used for digestion and absorption of nutrients from the food we eat 30% is used for physical activity which is dependent on the person
Hunger
Physical need for food. -A normal sensation that makes you want to eat. Your body tells your brain that your stomach is empty. This makes your stomach growl and gives you hunger pangs. Hunger makes some people feel lightheaded or grouchy. Everyone is different. Hunger is partly controlled by a part of your brain called the hypothalamus, your blood sugar (glucose) level, how empty your stomach and intestines are, and certain hormone levels in your body
Protein are unique because in addition to containing carbon, hydrogen, and oxygen, they also contain nitrogen.
Proteins are large molecules made up of hundreds or thousands of small building blocks called amino acids joined together by peptide linkages.
Taste Panels
Randomly selected to experts who are highly trained - 5 people- free of colds, chew no gum before testing, have not ingested food for one hour before, nonsmokers, not color blind, and have no strong likes or dislikes- gender/age too - seated at tables, cubicles, booths, etc.
Food Culture
Refers to the ways in which humans use food. -Culture influences food habits by dictating what is acceptable to eat, creating a "Food Culture" -Manners around food- In some parts of India , only the right hand is used for eating and manipulating utensils; the left hand is used for restroom duties
Foods with empty calories provide few nutrients-
Refined sugar and starches
Carbohydrates (CHO)
Saccharides (sugars & starches) Made of: -Carbon (C) -Hydrogen (H) -Oxygen (O) -One molecule of H2O for each carbon Simple Carbohydrates : Sugars Complex Carbohydrates: starches Most important source of food energy Classified by the number of basic sugar units linked together or saccharides
THE MOST IMPORTANT TIME FOR A SEASONING LIQUID FOODS IS AT THE END OF THE COOKING PROCESS
Salt and other seasonings are also added at the beginning of cooking particularly for large pieces of food so they are absorbed
Preference Testing
Select preferred product -Choose between pairs -Rank liking of several products
Sight- Eyes receive 1st impression of foods
Shape, Color, Consistency, Serving size, Appearance
Sensory impressions that impact our food choices
Sight, smell, tasting and sounds -Senses may be trained by culture
Different materials have different conduction rates
Solid metal has free electrons which can move in collisions in addition to atomic vibration. i.e. More ways of transferring energy. -There isn't much resistance to heat transfer in & out of metals. -Heat up quickly, cool down quickly Ceramic pans don't have free moving particles (electrons) They only transfer heat by vibration -Everything is tightly bound up. -Ceramic pans resist heat transfer (both in & out) -Takes longer to heat up, but stays hot longer - like pizza stones So metal pans have both vibration & Collison heat transfer Metals transfer heat faster than ceramics which only transfer heat by vibration Heat moves rapidly through copper and aluminum, more slowly in stainless steel, more slowly yet in glass and porcelain. Air is a poor conductor of heat
Hearing
Sounds play a role in evaluating quality -Tapping a melon -Crunching of vegetable when chewing The way a food communicates while it is being prepared -Sizzling, crunching, popping, bubbling, swirling, pouring, squeaking, dripping, exploding, and crackling -Most are affected by water content -Give clues to a food's freshness and/or doneness Some of these sounds are due to the water content of foods- which can also be a sign of their freshness- especially for fruits and vegetables.
What are some advantages of microwave cooking?
Speed- 2-10 times faster Energy conservation- 1/3 less fuel use Reheating precooked foods Defrosting Glass or ceramic should be used in microwave cooking- poor conductors and don't have free moving particles
Water becomes gas at 100 degrees Celsius (a very low temperature for boiling and vaporizing). This heat of phase transition is higher for liquid to gas than solid to liquid.
Steam escapes during heating while the remaining water holds at 100 degrees This makes water useful for cooking Heat of vaporization is the calories required to turn water into steam at 100 degrees For 100 degree water to become steam (540 kcal/kg) of water is required (heat absorbed by escaping high-energy steam which then cools and evaporates.
Fresh Herbs
Superior to dried herbs A good rule of thumb is amount of fresh minced herb used is approximately twice that called for with the dried product Freeze or dry for later use Fresh herbs should be used whenever cost and availability permit Can be grown in backyard or window box gardens Dried herbs are more concentrated than fresh, and powdered herbs are more concentrated than crumbled. Each herb is slightly different.
Supporting Flavors
Support and enhance the primary flavors of the main ingredients.
The Five Tastes
Sweet: Aspartame, saccharine, fructose, sucrose Sour: -Vinegar, citric acid, ascorbic acid Salty: -NaCl (sodium chloride), KCl (potassium chloride) Bitter: -Caffeine, quinine, greens like escarole, dandelion Umami or Savory: -MSG (monosodium glutamate) flavoring properties in mushrooms
What is it about a food or a beverage that causes them to choose it over others?
Taste is generally a major contributing factor to food selection.
Humans have about 9,000-10,000 taste buds.
Taste receptor cells degenerate and are replaced on an average of every 10 ½ days As individuals age, the number of taste buds decline Atrophy of the papillae begin about age of 45 As people age they may find themselves using more salt, spices, and sugar in their food because the number of taste buds diminish with age -Medication may impact this as well.
Temperature is a measure of molecular activity -The higher the temperature, the faster the molecules are moving
Temperature is independent of amount- can be a measure of the molecular activity (the higher the temperature the faster the molecules are moving) 1 cup or 1 drop or 1 gallon of boiling water all have the same temperature Heat (thermal energy) depends on amount and is associated with the motion of atoms or molecules 1 drop of boiling water has far less thermal energy than 1 gallon of boiling water but they have the same Temperature (212 Degrees).
Economic and Marketplace Factors:
The budget a person has expendable for food will impact what they can afford. -The Avian Flu hitting the mid-west is impacting production of eggs is impacting the current marketplace and cost for eggs and poultry items. Food Availability -Local food -Imported Economics -Low income families: Spend 48% of income on food -High income families: Spend 8% of income on food -Food insecurity
Spice
The buds, fruits, flowers, bark, seeds and roots of plants and trees, many of which grow in tropical climates used as a flavoring; usually used in dried form, either whole or ground.
Convection in cooking
The cooking medium (air, water, oil) transfers heat to the food - usually doesn't enter the food, just delivers the energy When heating water in a pan, the hotter water at the bottom rises to the cooler area of water at the top of the pan The bubbles of steam start at the bottom and rise up Natural convection: hot liquids and gases rise while cooler ones sink Convection ovens -A fan increases cooking efficiency by circulating hot air around the food -Forced air movement displaces the boundary layer of air around the food Mechanical: in convection ovens and steamers, fans circulate heat- this heat is transferred more quickly to the food and the food cooks faster. -Stirring is a is a form of mechanical convection
If the atoms in H20 do not change, how is water able to exist as a gas (steam or humidity), liquid (water) or solid (ice)?
The distance between the molecules determines these differences and the distances are influenced by temperature. At very low temperatures, ICE forms as water molecules line up very close together Elevating the temperature, increases the Molecular movement of water molecules against each other, pushing them further away from each other. In liquid, water molecules move away from each other. When enough energy is applied, ice melts into a liquid . Continued heating transforms liquid water into a gas or steam by giving the molecules freedom to move even further apart and escape into the air. They move as they reach Freezing, boiling or melting point. The variations of water from solid to liquid to gas are called changes in state. In spite of the obvious differences in states, they DO NOT involve any CHEMICAL changes to the structure- they are just PHYSICAL state changes
Gelatinization
The increase in volume, viscosity and translucency of starch granules when they are heated in a liquid - when the liquid is heated the hydrogen bonds holding the starch together weaken, allowing water to penetrate the starch molecules, causing them to swell until their peak thickness is reached.
Eating
The ingestion of food to provide nutritional/medicinal needs for energy and growth.
Herb
The leaves of certain plants that usually grown in temperate climates used as a flavoring; either dried or fresh.
The more flavors you combine the harder you have to balance them all.
The more competing flavors you have, the more you have to take care that those primary flavors of the main ingredients are not lost.
Primary Flavor
The most important flavors of a given preparation are those of its main ingredients.
Dipolar molecules have poles with partial charges that oppose each other and this dynamic contributes to some of water's very unique properties.
There is attraction between the Positive and negative sides of the molecule. Polar molecules: loves water and has an uneven distribution of charge on molecule - forms hydrogen bonds with water and other polar molecules- exp- all sugars, glycerol, alcohol some amino acids Non Polar- Hydrophobic or lipophillic- even distribution of charge- repelled by water and attracted to lipids: long chain fatty acids, triglycerides and some amino acids
The body benefits from energy and nutrients in the foods at the cellular level.
These nutrients: Fulfill one or more of the following functions: -Supply energy for bodily functions -Build and replace cells that makeup body tissues -Regulate body processes
When people choose a particular food they evaluate it consciously or unconsciously primarily how it looks, smells, tastes, feels and even sounds. Essentially this is how we perceive the food we are about to consume.
These sensory factors are more important to consumers than nutritional considerations in making choices.
It takes more energy to heat water than any other substance presently known. Water's high specific heat (specific heat of 1) makes it unique compared to other compounds on earth. Given the same amount of heat, a metal pan or the oil in it will become burning hot, while water will become only luke warm.
This important characteristic of water enables animals including people with their high water contact to withstand that very hot or cold temperature This specific heat (1 calorie will raise 1 gram of water 1 degree C) is used as a measure against all other substances are compared Water differs from other compounds in the amount of energy it takes to reach its specific freezing, melting and boiling points Esp. specific heat of oil is less than water = 0.5 oil will heat up twice as fast as water.
Vitamin, Minerals or water do not supply calories
This is because they are inorganic (or do not contain CARBON) and therefore do not contain calories.
Ionization
This occurs when particles dissolve in water - molecular solutions are those particles that remain as is in their molecular form- flavored sugar to make a beverage like lemonade- ionic solutions occur when the molecules ionize into electrically charged ions- salt Sodium chloride is dissolved in water.
Different areas of the tongue are associated with the five basic types of tastes: sweet, sour, bitter, salty and umami (or savory) Which is the Japanese word meaning delicious.
Tip of the tongue is more sensitive to sweet and salty while the sides are sensitive to SOUR and the back of the tongue is responsible for BITTER- this is why BITTER tastes tend to LINGER -The time it takes you to determine these are split seconds for salt vs. maybe a full second for bitter
Texture
Touch -Texture: Perceived through sight, touch (fingers/utensils), and mouth feel -Consistency: Firmness, thickness -Astringency: Dry, puckery feeling in mouth -Temperature: hot, cold, warm Texture (mouthfeel) may be the deciding factor in a product's appeal Tactile properties: -Graininess -Brittleness -Consistency -Chewiness Kinesthetic/Mechanical chewing properties sensations based on sensitivity of tongue and teeth Chemical and physical effects based on molecular response- pungency
Condiment
Traditionally any edible substance added to a food to contribute flavoring. Also refers to cooked or prepared flavorings. (BBQ sauce, ketchup)
Molecule
Unit composed of one or more types of atoms held together by chemical bonds.
Coagulation
Unraveled strands of protein molecules link up with each other - form clumped meshwork. -SALT would speed up the coagulation of proteins by weakening the bonds of the protein structure which is why it is used frequently in cheese making to help produce a firm curd.
Denaturation
Unraveling of coiled, folded structure of protein. Results in loss of biological properties. -Adding things like SUGAR to egg whites when they are being whipped can stabilize the denaturation of the protein- so adding this at the end of the process will stabilize it
Considered safe: Microwaves, heat lamps, coals oven burners, toasters, etc. that are "low frequency", non-ionizing radiation
Unsafe -IONIZING -X-Rays -Gamma rays -Cosmic rays -Ultraviolet rays (UV) Safe -NON-IONIZING -Radio waves -Microwaves -Infra-red waves -Light waves
Analytical tests or Effective testing
Uses a Trained sensory panelist to evaluate food samples and provide guidance for improvement for products-- discernable differences in foods- somewhat objective
Simmering (Faster)
Uses a liquid that is bubbling gently at a temperature of about 185 F-205 F.
Boiling (Rapid)
Uses large amount of rapidly bubbling liquid at 212 F
Pan-Frying
Uses moderate amount of fat
Odor of food
Volatile molecules -Molecules capable of evaporating like a gas into air Olfactory -Relating to the sense of smell Smell is almost as important as appearance when people evaluate a food item for quality and desirability Although the sense of smell is not as acute in human beings as it is in many other mammals, most people can differentiate between 2,000-4,000 odors whiles some highly trained individuals can distinguish as many as 10,000
Water is slow to heat
Water has an abnormally high specific heat, the amount of energy required to raise its temperature by a given amount Water will absorb quite a bit of energy before its temperature rises Bring to boil reduce temperature and continue to boil- rolling boil- less fuel is used only exception is reductions.
Water is the simplest of all nutrients, yet most important.
Water is necessary for: assimilating, digesting, absorbing, transporting, metabolizing, and excreting nutrients & by-products Human body is 60-70% water; losing 10% can result in death Food has a water content from 0-95+% -Fruits & vegetables - 70-95% -Whole milk - Over 80% -Most meats - Just under 70% Water brings to each living cell the ingredients that it requires and carries away the end products of its life-sustaining reactions- digestion, absorption of nutrients, metabolism and excretion of nutrients all depend on water.
Hydrolysis
Water molecule breaking a sugar molecule into smaller molecules- lipids into smaller particles Cornstarch to yield corn syrup
The point at which water boils is reached when the pressure produced by steam , called vapor pressure, equals the pressure of the atmosphere pushing down on earth. At this point the natural pressures of the atmosphere are not strong enough to push back on the expanding gases of boiling water. Temperature at which vapor pressure is exerted by liquid just exceeds the vapor pressure of the atmosphere.
Water requires 540 calories of energy per gram to boil and vaporize This heat of vaporization- required to convert liquid to gas is quite a bit higher than the 80 calories needed to melt ice. Serious burns can result from steam because the amount of heat required to produce it is so high.
Specific Heat is the heat required to raise the temperature of 1 gram of a substance 1oC
Water takes more energy to heat than of all substances - e.g., same amount of heat to make oil to burning hot would only make water lukewarm -This property enables animals & humans to endure hot and cold temperatures Water's specific heat is 1.00 (1 calorie will raise 1 gram of water 1o Celsius)
Additional information is contributed by olfactory receptors when food is in the mouth because volatile compounds travel upward from the mouth to the nasal cavity where they are detected which provides signals to the brain. Swallowing foods which creates a partial vacuum that draws the volatiles into the nose from the oral cavity.
We can detect odors when volatile molecules travel through the air and reach the olfactory epithelium (which is an area the size of a quarter located inside the upper part of the nasal cavity)
ODOR- aroma is more important than taste for food evaluation- humans can sense odor molecules at pp billion
We can distinguish 16 million odors
Heat is a form of energy associated with the motion of atoms or molecules.
When a substance absorbs heat, its molecules move faster -In liquids and gases, the molecules move more quickly from place to place and bounce off each other more frequently -In solids, the molecules stay mostly in place, but they vibrate with more energy
Acculturation
When people from one ethnicity move to an area with different cultural norms, adaptation to the new majority society begins Culturally based food habits are one of the last traditions people change -As enculturation can be used to describe the process of first-culture learning, acculturation can be thought of as second-culture learning
Simplest browning reaction is the Caramelization of SUGAR- SUGAR and SUGAR- Sugar into syrup
When you heat plain sugar, it first melts into a thick syrup then slowly it changes color, becoming light yellow and progressively to a dark brown
Whole peppercorns are from the Berries of a tropical climbing shrub- -Black pepper is from the dried, unripe berry:
Whole or crushed- seasoning in stocks, sauces, and sometimes red meats ground black pepper is what is found in the dining room by the customer
Fullness is a feeling of being satisfied.
Your stomach tells your brain that it is full. Normally, this feeling causes you to stop eating and not think about food again for several hours. Fullness is partly controlled by the hypothalamus, your blood sugar, and having food in your stomach and intestines.
Functions of Water in Food: pH Scale
pH scale measures the acidity or alkalinity of a substance, with 1 the most acidic, 14 the most alkaline or basic, and 7 neutral pH scale is logarithmic- each step down the scale from 7 is 10 time more acid.