Modules 7-12, Culinary Chemistry Exam 2!!
Hydrogenation
- Adds hydrogens across the double bond, transforming an unsaturated fatty acid to a saturated one - NOT truly saturated, forms trans fats that are very firm and can cause health problems
Herve This
- Began molecular gastronomy - Physical chemist who had a souffle disaster in his kitchen
Metabolizing alcohol
- Broken down in the stomach and liver - Women generally retain alcohol more than men - Genetics plays affect to alcohol handling
Maillard reaction
- Browning reaction - Carbohydrate and amino acid form unstable intermediate, then hundreds of by-products result - Due to amino acids in proteins
Spherification
- Calcium chloride ions cause the alginate polymers to become cross linked, creating a gel
Properties of alcohols
- Clear liquid at room temperature - Less dense than water - Boils at a lower temperature than water - Dissolves in water - Flammable
Supersaturated
- Contain more dissolved sugar than it could normally at this temperature - The smallest disturbance will induce sugar crystals to form and grow
Sous Vide cooking
- Cooking through air that is set at constant temperature - Repeatable, and can leave food in appliance and it won't overcook
Best material to use for cooking
- Copper - Excellent heat conductor - Highly reactive with acidic or basic foods, usually lined with tin or stainless steel to make it non reactive
Conduction
- Direct transfer of heat - Heat conducts in food towards the center - Food behaves more like an insulator than a conductor
Ethanol
- Drinking alcohol, CH3CH2OH - All other alcohols are toxic including methanol (CH3OH) which causes blindness
Flash Freezing
- Food exposed to extremely low temperatures - Causes outside to become frozen with liquid center - Liquid nitrogen
Distillation
- Goes from liquid to vapor to liquid again - Purifies and separates liquids
Radiation
- Heat in the form of waves - Considered thermal radiation, does not require contact between food and heat source
Convection
- Heat transfer through fluids - Can be water, oil, or air - Combines conduction and mixing
Induction
- Heat transfer through magnetism - Alternating current causes rapidly changing electromagnetic field - Most efficient way to convert energy to heat on a cooktop
Free Radicals
- Highly reactive compounds - Formed naturally and are important for normal cellular processes; however cause cell damage in high concentrations - Contain a single electron
Health benefits of alcohol
- Lower chance of death from heart disease or stroke - Helps limit blood clots and high colestorol - Antioxidant source (red wine) - Lowers the chances of arthritis and certain cancers
Cooking with alcohol
- Marinating proteins in wine help lock in moisture - Alcohol contributes distinct flavors - Hydrophobic ends dissolve compounds water cannot
Rancidity
- Saturated fats are more stable and slower to become rancid than unsaturated fats - This is because the double bond on a carbon opens up a small space for molecules such as oxygen to invade and break the chain
Saturated vs Unsaturated
- Saturated means it is filled to the capacity with hydrogen bonds, meaning there are no double bonds - Unsaturated compounds have one or more double bonds between carbons
Carmelization of Sugar
- Simplest browning reaction - When sucrose (sugar) is heated - Will deepen to dark brown because of sour organic acids and brown-colored polymers
Vegetable Texture
- Sodium and Potassium ions give rise to softer veggies - Calcium and Magnesium cross link with pectin molecules to produce firmer veggies
Cold water test
- Test used before thermometers - Thin syrups will form a thread in the air - Concentrated syrups form a soft, malleable ball - As the concentration increases, the cooled ball becomes harder
Searing meats
- The sizzle comes from a droplet of water making contact with a very hot metal - Searing meats actually causes the meats to lose more moisture than not searing - The moisture comes from the meat
Vegetable Carbohydrate sources
- beans, peas, corn, and potatoes - Veggies in general are a good source of fiber, minerals, and vitamins
Antioxidants
- neutralize free radicals by donating an electron - Come from vitamins
Specific heat capacity
- the amount of energy needed to raise the temperature of one gram of a substance one Kelving - Cheese > Sauce > Crust
Yeasts
- unicellular fungi - Convert sugar into alcohol, CO2, and other flavors
You consume an antioxidant capacity of 1967 when eating a red delicious apple. How much of the apple did you consume?
1/3 of the apple
Veggie pH
5-5.6
Calculate the antioxidant capacity of a salad made from ½ cup cranberries and ¼ oz pecans.
5765
Gay-Lussac's Law
As temperature increases, pressure increases
Charle's law
As temperature increases, volume increases
Other than fruits, vegetables, and nuts, what are some other sources of antioxidants?
Coffee, Green tea, Red wine, Dark chocolate, Certain spices
When one substance is evenly dispersed in another substance, you have a:
Colloid
Water, ammonia, and salt are all ______________ that are combined in definite proportions
Compounds
When grilling, what types of heat transfer can occur?
Convection and radiant
Interfering agents
Corn syrup also provides body and chewiness, is less sweet than sugars, and has the advantage for manufacturers of being less expensive than crystalline sugar
Conduction Cooking Style
Correct match:direct contact with heat
Order each of the following from strongest intermolecular force to weakest Strongest
Covalent Ionic Hydrogen bonding Van der Waals
Cause of free radicals
Environmental toxins such as cigarette smoke, radiation, pollution Also produced from oxidation
Discoloration Cause
Enzyme activity
Radiation
Heat in the form of waves
Conduction
Heat is transferred through direct contact with the heat source
Induction
Heat is transferred through magnetism
Convection
Heat is transferred through the movement of fluids
Vitamin C
Helps build connective tissue
Heat vs Temp
Temperature measures the average energy of each atom; heat is the total for all the atoms Average income of US household vs. total wages in the US
Since fats melt at a higher temperature than oils, what do you know about the total strength of the bonds in fats vs. oils?
The bonds are stronger between fat molecules than between oil molecules.
Sugar concentration vs boiling point
The higher the sugar concentration, the higher the boiling point
Sugar concentration vs texture
The lower the sugar concentration, the softer the final product will be
Resonance
The movement of electrons in double bonds to stabilize free radicals
Sweetness vs alcohol content
The sweeter the wine, the lower the alcohol content This is because the sugar from the grape converts itself to alcohol
Smoke point
The temperature at which a fat breaks down into visible gaseous products
All of the following is true about the bonds that hold fats together except:
These types of bonds are always weak, no matter how many there are
All of the following is true about the bonds that hold fats together except:
These types of bonds are always weak, no matter how many there are.
What properties do antioxidants have? Choose all that apply.
They have multiple double bonds, They can come from nuts, They are stable when in the radical form due to resonance.
A confectioner can boil a sugar syrup solution until a desired temperature is reached, which indicates the concentration of the syrup.
True
Acids are added to carbonated beverages to help keep CO2 in solution.
True
All candies are essentially a mixture of two ingredients: sugar and water.
True
Although ceramics are poor conductors, they are a versatile type of cookware.
True
Antioxidant free radicals are more stable than the radical that formed them.
True
Antioxidants donate an electron to make an unhealthy cell healthy again.
True
As a water boils (goes from liquid to gas) the temperature does not change.
True
Based on Henry's law, the higher the pressure of the gas above a solution, the higher the concentration of gas in solution.
True
Boiling foods occurs at a temperature lower than needed for browning reactions to occur.
True
Brittles are different than other hard candies because they contain butter and milk solids
True
Candies can be coated in a pan-hard panning-by spraying a sucrose syrup on the candy and allowing the water to evaporate.
True
Candy canes have bubbles and sugar to give them a crisp texture.
True
Candy texture is influenced by the concentration of the sugar in the syrup.
True
Cast iron materials work great in high temperature cooking.
True
Ceramics are poor conductors; both carbon steel and cast iron are reactive with acid and basic foods; copper provides the best conductor, while stainless steel is unreactive.
True
Certain foods have additives that behave as antioxidants, keeping the food fresher longer.
True
Certain types of cooking, such as boiling, do not allow browning reactions to occur because they do not get hot enough.
True
Complex disperse systems are simply mixtures of more than two phases.
True
Convection occurs between any type of fluid: water, oil, air, smoke.
True
Cooking a material through the use of a fluid is called convection.
True
Cooling with help preserve the freshness of most vegetables.
True
Copper is an excellent conductor and is non-reactive with food only when coated with tin or stainless steel.
True
Disrupting the tubulars of potatoes can cause discoloration due to enzyme activity.
True
Distillation is the separation of liquids based on the differences in boiling point.
True
Electrons are loosely held in metals, allowing them to conduct heat.
True
Even though radiation occurs in all types of cooking, only radiation at high temperatures is a useful type of heat transfer.
True
Free radicals attack healthy, living cells.
True
Free radicals represent a single electron and are formed from breaking weak bonds.
True
French fries are vegetables!
True
Fudge is a more complex crystalline candy because they syrup also carries milk solids and fat droplets.
True
Gases readily mix together regardless of the composition of the gas.
True
If the amount of gas increases the volume of gas increases.
True
Maillard reactions occur between a carbohydrate and an amino acid.
True
Microwaves cause water molecules to move faster, heating up the food.
True
Nonmetallic solids are great insulators, but are not good conductors.
True
Oxidative stress is caused by the cascading of free radical formation.
True
Pan frying works best with leafy green vegetables.
True
Pan-frying allows for browning reactions to occur due to the high temperature cooking.
True
Pressure cookers increase the pressure, allowing food to cook at a higher temperature.
True
Radicals are more stable if they have more carbon groups attached to them.
True
Rancid fats come from the decomposition of fatty acid chains of triglycerides.
True
Resonance is the movement of electrons in double bonds and it helps stabilize unstable free radicals.
True
Rock candies are made by slowly growing crystals out of a supersaturated solution
True
Saturate fats and hydrocarbons that are saturated with hydrogens.
True
Solutions can be created by mixing gas in to a liquid.
True
Spherification is used to create liquid spheres that "explode in your mouth."
True
Sugar molecules will bond together in orderly arrays.
True
Temperature and pressure are directly related.
True
The "hardness" of your cooking water can effect the flavor, texture and color of your vegetables.
True
The fruit in wine is concentrated when cooking to provide more flavor to the dish.
True
The main difference between beer and wine is what the yeast consumes to produce the alcohol.
True
The smoke point of oils can limit the temperature at which foods can be cook in certain fats and oils.
True
The solubility of gases in liquids increases as the temperature decreases.
True
Trans fatty acids are double bonds that have the chains extending from either side of the double bond, forming a "z" type shape.
True
Unsaturated fats contain at least one multi (double or triple) bond.
True
Vegetables are a better source of vitamins and minerals then fruit.
True
Vegetables cook right after harvest have more flavor then store bought vegetables.
True
Water hardness is the presence of Mg, Ca and other metal ions in your water.
True
When a free radical is produced, it causes the production of other free radicals due to the instability of the radical.
True
When alcohols are distilled, they turn into a vapor, then condense into another container.
True
When something boils at a lower temperature, it takes longer for the food to cook completely.
True
When sugar is caramelized, the taste, smell, and color changes.
True
While non-stick aluminum is both conductive and non-reactive with food, it can only be used up to certain temperatures.
True
Wooden spoons can help prevent premature crystallization.
True
How to prevent crystallizatoin
Use wooden spoons, avoid agitating the syrup once it is finished cooking and is cooling, remove dry spatter from walls of pot with a moist brush
Equipment for a molecular gastronomist
Vacuum machine, hypodermic syringe, liquid nitrogen, anti-griddle, and the gastrovac
Strength of bonds
Van der Waals< hydrogen bonds< ionic bonds< covalent bonds
What influences the texture of candy
Varying the proportions of water and sugar and how the candy is cooled
Steak sizzle
Water and proteins coming out of the meat and hitting the pan
Omnipresent steam
Water vapor coming off a steak
Beer ingredients
Yeast, barley, hops, and water - Barley is the seed of grain - hops are a pine-cone like flower, a member of the hemp family
How alcohol is made
Yielded from microscopic yeasts Sugars break down into alcohol molecules
Milk proteins are added to candies: to thicken the candy body, to add a rich flavor
a and b
Antioxidants do the following to free radicals: Stopping the cascading of free radical formation, become a radical themselves
a and c
All of the following is true about cooking food except:
all cooking uses the same kind of heat transfer
Boyle's law
as volume decreases, pressure increases
Properties of metals
conductors, loose flow of electrons, heat up and cool down quickly
A saturated solution:
contains all the solute the solvent can handle
In regards to heating food to an edible temperature:
continuously cook food until the desired temperature is reached
Folic Acid
creates the amino acid methionine to help maintain healthy blood vessels witch reduces the chances of stroke or heart disease.
Convection occurs because:
energetic particles collide, transferring energy to the surface of the food
Convection occurs because:
energetic particles collide, transferring energy to the surface of the food The most common example of convection is cooking in your oven. Food in your oven is cooked by energetic molecules circulating around the oven, and coming into contact with your food, transferring the energy. There is no direct contact with the heat source (like on your stove); the energy transferred to the foods through the walls of the oven is a radiant heat; energy transferred within food is heat transfer through conduction.
Water _______________ the boiling syrup solution, __________________ the concentration of sugar and __________________ the boiling point.
evaporates from; increasing; increasing
When boiling:
food is cooked at a constant temperature
Radiation
heat in the form of waves
Radiation Cooking style
heat in the form of waves
Convection
heat is transferred by the movement of currents within a fluid
conduction
heat is transferred through direct contact with the heat source
Induction
heat is transferred through magnetism
Convection Cooking style
heat transfer through fluid
Induction cooking style
heat transfer through magnetism
Interfering agents:
help with the preparation of non-crystalline candies
Browning reactions:
include Maillard reactions develop new flavors occur during the heating of sugar all of the above******
Will the solubility of the solute increase or decrease if sucrose is dissolved in water at 95 °C instead of 20 °C?
increase
Mark all of the true statements about metals below:
metals will heat up and cool down quickly, metals are good conductors, metals have loose electrons that behave as a fluid
All of the following is true about oxidation except:
oxidation produces lone pairs
Maillard reactions:
produce complex flavors due to amino acids in the proteins
Lycopene
reduces DNA damage (ie helps prevent cancer)
How can premature sugar crystallization be avoided?
remove dried spatter from the pan walls with a moist brush
Brown pan
residues from proteins and sugars released from the meat during cooking
What kind of fatty acids are the most stable?
saturated lipids
Cotton candy:
solidifies into threads when exposed to air
When cooking with alcohol: (choose all that apply)
some of the alcohol is left behind, no matter the cooking method, acidity, sweetness, and savoriness are added to the dish, moisture loss can be reduced if alcohol was used as a marinate
What type of cooking material gets "the closest" to being both chemically unreactive and a good conductor?
stainless steel with a copper plate
In candies such as fudge, it is important to:
stir the mixture continuously in order to have finer sugar crystals
Candy ingredients
sugar and water
All of the following is true about the cold water test except:
the higher the concentration of syrup, the softer the ball
Carryover Cooking
the phenomenon in which food continues to cook after it has been removed from the heat source as the heat is distributed more evenly from the outer to the inner portion of the food
What is true about how our bodies metabolize alcohol? Choose all that apply.
the stomach and liver break down alcohol, women are more affected by alcohol than men because they can't break down as much of the alcohol before it passes to the bloodstream, the amount of muscle and body fat a person has affects how their bodies metabolize alcohol
In a solution, the solvent is:
the substance in the greatest amount
In a solution, the solute is:
the substance that is dissolved
Caramelized sugar has all of the following characteristics except:
the sugar is now sweet and odorless
Since yeasts feed on the sugars to convert them into alcohol, what can you assume about the sweetness versus alcohol content in wines?
the sweeter the wine, the lower the alcohol content
The smoke point is:
the temperature at which fats boil.
All of the following is true about heat and temperature except:
the terms can be used interchangeably in cooking
Compounds have different melting and boiling points based on the forces holding the molecules together. Different forces are present that give water and fats vastly different melting and boiling points. What forces hold molecules of fat together?
van der Waals interactions
The specific heat capacity:
varies between materials is the energy needed to heat 1 g of substance 1 K ***all of the above*** explains why melted cheese on pizza can burn your mouth but the crust will not
Juices on Plate
Juices leaking out of the steak after being cooked while the meat "rests"
All of the following are ways to prevent you carbonated beverage from going flat. (Check all that apply.)
Keep it cool / refrigerated, Reduce the volume of air above the solution.
Combinations of substances that aren't held together chemically are called:
Mixtures
Strong bonds.. Weak bonds..
Need heat to change; harder to break Can change at room temperature
Will eicosapentaenoic acid dissolve in water (eicosapentaenoic acid)
No
Vegetable that is main source of starch
Potatoes
When baking: Food is cooked by the air, Food is cooked by the heat from the walls of the oven
Both a and b
When steaming food: water vapor condenses onto food, transferring energy, more conduction occurs within the food than in an oven.
Both a and b
When grilling, what types of heat transfer can occur? Radiant, Convection
Both of the above
Which ions tend to cross-link with pectin to provide firmer vegetables?
Calcium
Carbon steel is a great cooking material because it is both non-reactive and has great conducting power.
False
Cis fatty acids are more stable.
False
Deep frying uses the same type of heat transfer as pan-frying.
False
Even though foods cooked by varying methods have multiple forms of heat transfer, the predominant source of heat is always radiant.
False
Fat soluble minerals are easily leached from vegetables while cooking.
False
Food must be cooked for a certain time, and the temperature of the cooked food doesn't matter.
False
Foods prepared by molecular gastronomy methods should be consumed with caution.
False
Free radicals represent a pair of electrons and are formed from breaking weak bonds.
False
Gelatin and pectin are used to make hard candies.
False
Hydrogenation converts a saturated fat into an unsaturated fat.
False
If the volume of a gas goes down the temperature go up.
False
Induction occurs due to a steady electromagnetic field.
False
Marshmallows use an acid base reaction to produce the bubbles inside of them.
False
Nonmetallic solids are the best conductors.
False
Pressure and Volume are directly related.
False
Pressure cookers work because they lower the pressure, allowing food to cook at a higher temperature.
False
Pressure is area / force
False
Smokers use a direct heat source to cook food.
False
Sodium and potassium metals will give rise firmer vegetables.
False
Supersaturated solutions contain less dissolved solute than they can contain
False
The more often a gas collides with the boundary the lower the resulting pressure.
False
The only fluid that undergoes convection is air.
False
You can get all of the antioxidants you need from consuming just blueberries.
False
Smokers use a direct heat source to cook food.
False- Use indirect
The boiling point of a syrup _______________ with increasing concentration of sugar.
Increases
Mark all of the true statements about metals below:
-metals will heat up and cool down quickly -metals have loose electrons that behave as a fluid -metals are good conductors * Metals are good conductors; good conductors are usually not also good insulators. Metals have electrons that are held loosely, so they behave as a fluid to transfer energy. Good conductors will heat up fast, but will also cool down quickly.
When steaming food:
-water vapor condenses onto food, transferring energy -more conduction occurs within the food than in an oven
Vegetable Cooking Methods
-Baking: Using skin to contain heat; conduction -Boiling: Convection method - Steaming: Takes longer than boiling but holds more of the nutritional value - Pan fry: Cooked with steam from the water of the cut vegetables, best for leafy greens
Versatility of alcohol structure
-One end has a CH3, which resembles oils. This makes it able to mix with fatty substances - The other end has an -OH, making it able to mix with water
Pressure Cookers
-This speeds up cooking times by trapping the steam that escapes from boiling water, increasing the pressure on the liquid, thus increasing the boiling point to around 250 °F - With a higher boiling point of water, this cooks the food faster
Pan-frying:
-allows more flavor development with the addition of oil and browning reactions -requires a balance between cooking the inside of the food enough without burning the outside -allows uniform heat contact when an oil is used *****ALL OF THE ABOVE*****
When baking:
-food is cooked by the air -food is cooked by the heat from the walls of the oven
Mark all of the true statements about metals below:
-metals have loose electrons that behave as a fluid -metals are good conductors -metals will heat up and cool down quickly
Candies are rarely spoiled by the growth of bacteria due to: the high sugar content, the low moisture content.
A and C
Juices on top of steak
After searing one side of the steak, while searing the other side, juice builds up on the surface of the meat.
Sugar bonds
Bond to eachother in orderly arrays and form dense, solid masses, or crystals Form saturated solutions
When Herve This started studying molecular gastronomy, he prepared rules for cooking food, wanted to develop a systematic study of food preparation, partnered with a physicist to launch the new discipline.
All of the about
Antioxidants: are large molecules, are molecules with multiple double bonds, come from a variety of foods
All of the above
Browning reactions: develop new flavors, occur during the heating of sugar, include Maillard reactions
All of the above
Free radicals: Are produced from environmental toxins, are highly reactive, cause damage to DNA
All of the above
Hard candies: have a very high sugar concentration, have corn syrup added to the syrup to prevent premature crystal formation, are non-crystalline candies.
All of the above
Sugar molecules have a tendency to: bond together in orderly arrays, form a dense mass, form crystals.
All of the above
The chewiness in caramels, toffees, and taffies is due to: the higher moisture content, corn syrup, milk casein proteins.
All of the above
The mixture for spherification: Creates a gel between alginate and calcium chloride, creates cross-linked polymers, is mixed with sodium alginate.
All of the above
The specific heat capacity: varies between materials, explains why melted cheese on pizza can burn your mouth but the crust will not, is the energy needed to heat 1g of substance 1 K
All of the above
What causes free radical formation? The sun, cigarette smoke, pollution
All of the above
Yeasts: convert sugars into alcohol, are single celled micoorganisms, produce carbon dioxide when breaking down sugars.
All of the above
Pan-frying: allows more flavor development with the addition of oil and browning reactions, allows uniform heat contact when an oil is used, requires a balance between cooking the inside of the food enough without burning the outside
All of the above.
Supersaturated solutions: contain more dissolved sugar that it normally could at that temperature, will induce crystal sugars with a small disturbance, are formed when a hot sugar solution begins to cool.
All of the above.
Veggie colors
Betalains- red-violet and yellow Clorophyll- Green Carotenoids- yellow, orange, and red fat soluble pigments Anthoaxnthins- Colorless in acid but yellow or white in basic Anthocyanins- Colorful pH indicator Fat soluble vitamins are A, D, E, and K
Why don't candies go bad
Candies have a low moisture content and concentrated sugars
All of the following are good methods of cooking vegetables EXCEPT:
Canning
Sugar syrup that is cooked at a lower temperature, have the most moisture, and are the softest of the non-crystalline candies usually produce:
Caramels
Carbon, hydrogen, and nitrogen are all ______________ that cannot be broken down into other substances.
Elements
Acidic ingredients are sometimes added to candies to balance the texture.
False
Adding additional water to your vegetables will help maintain the nutritional content especially for vitamin B and C.
False
Alcohol has a higher boiling point than water.
False
Alcohols are able to be distilled because they have a higher boiling point than water.
False
Anti-oxidation is the same as oxidation.
False
Antioxidant free radicals are less stable and more reactive than the radical that formed them.
False
Berries are not good sources for antioxidants.
False
Both healthy and unhealthy cells have pairs of electrons.
False
Broccoli is part of the lily family.
False
Brown residue on your pan is a sign that searing in juices of a steak is not all it cracked up to be.
False
Browning reactions occur under 100 F.
False
Browning reactions occur under 100 oF.
False
Browning reactions usually occur when food is boiled.
False
Vitamin A
Regulates the growth of cells and our eyes detect light
Temperature during phase change
Stays constant during phase change until all the substance has been converted
Which method is recommended for cooking vegetables to avoid loosing the vitamins and minerals?
Steaming
Are the individual bonds/interactions that hold water molecules together stronger or weaker than the individual bonds/interactions that hold molecules of fats together?
Stronger
__________ containing compound gives rise to strong flavor / odor vegetables.
Sulfur
Is the bond indicated bond 1 a cis or trans bond?
Trans
Which is more stable: a cis or trans fatty acid?
Trans
