CHAPTER 10: FATS, OILS, AND EMULSIFIERS Flashcards
High quality bakes goods require a glance between what?
Tougheners and tenderizers, moisteners and driers.
Any proper formula will already contain a proper balance of ingredients, but what is still helpful to know?
An understanding of the ingredients that contribute to this balance.
What are some indispensable moisteners and tenderizers?
Fats, oils and emulsifiers.
Despite recommendations for a healthful diet, what can baked goods not be made without?
Most cannot be made without fat.
Lipids are loosely defined as what?
Substances that do not dissolve in water.
Fats, oils, emulsifiers, and flavor oils (peppermint oil and orange oil) are all classified as what?
Lipids
Fats are, strictly speaking, lipids that are ______ at room temperature.
solid
Is the term fat also commonly used to refer to any lipid? Example?
Yes, whether fat, oil, or emulsifier. The amount of fat listed on food labels includes the amount of solid fat, liquid oil, and emulsifiers present in the food product.
Triglyceride chain.
C - FA I C - FA I C - FA
Oils are lipids that are _____ at room temperature.
liquid
Oils are typically from what source?
Vegetable sources, such as soybean, cottonseed, canola, and corn.
Are tropical oils sold or liquid at room temperature?
Solid at 70ºF (21ºC) but melt quickly in a warm room.
Name three tropical oils.
Coconut, palm kernel, palm
Chemically speaking, fats and oils are what?
Triglycerides.
Triglycerides consist of what?
Three (tri) fatty acids attached to a three-carbon glycerol (glycerin) molecule.
Fatty acids are composed of what?
Carbon chains that typically contain anywhere from four to twenty-two carbon atoms.
Why is it important to understand the chemistry of fatty acids in more detail?
They are important to the makeup of fats and oils.
Can fatty acids be saturated or unsaturated?
Yes
Carbon atoms on saturated fatty acids are saturated with what?
Hydrogen atoms. That is, they cannot hold more hydrogen, and all bonds between carbon atoms are single.
Unsaturated fatty acids contain how many how many carbon atoms?
Two or more carbon atoms that are not fully saturated with hydrogen atoms.
Carbon atoms that are not fully saturated form what?
Double bonds.
Why don’t fats melt like ice?
Unlike pure water, which consists of identical molecules of H2O, fats contain a mix of different fatty acids. While identical water molecules melt at the same temperature (32ºF; 0ºC), each fatty acid melts at its own distinct temperature.
Explain how the structure of solid fats is like ice.
Solid fats contain many tiny fat crystals. Fat crystals consist of fat molecules arranged in an orderly fashion, bonded one to the next. For solid fat to melt, these bonds must break, just as ice crystals must break apart for ice to melt.
When fat softens, it is because some fat crystals have what?
Some fat crystals have melted while others have not.
Butter softens noticeably around what temperature? Why isn’t it completely melted? When does it completely melt?
Softens around 80ºF (27ºC) because many of the bonds between shorter fatty acids have broken. It is not until 90ºF (32ºC) and above that bonds break between longer fatty acids in butter, and it liquefies completely.
Why do fats like butter have a pleasant mouthfeel? What about shortening?
Fats, such as butter, melt quickly and completely from body heat. Fats that melt slowly or incompletely, such as all-purpose shortening, tend to have a less pleasant, often waxy mouthfeel.
Unsaturated fatty acids are either _______________ or ______________. Why?
Monounsaturated (having one double bond), polyunsaturated (having more than one double bond between carbon atoms).
All common food fats contain what?
A distinct mix of saturated, monounsaturated, and polyunsaturated fatty acids.
Typically, the higher a fat is in saturated fatty acids, the more _______ the fat.
solid
Name three fats that are all high in saturated fat.
Animal fat, cocoa butter, tropical oils.
Why are most vegetable oils liquid at room temp?
Because they’re low in saturated fatty acids.
Whats are trans fatty acids?
Unsaturated fatty acids where the two hydrogen atoms of a double bond are on opposite sides of each other.
Most naturally occurring unsaturated fatty acids__“cis” fatty acids–have the two hydrogen atoms on the same side of what?
The double bond.
Have many fats and oils used in the bakeshop been hydrogenated?
Yes
How are fats and oils hydrogenated?
By exposing them to hydrogen gas in the presence of high heat, pressure, and a catalyst, such as nickel.
What do catalysts do?
Speed up chemical reactions without actually being used up in the reaction.
Name a biological catalyst.
Enzymes
Name a metal catalyst.
Nickel
What happens to nickel in hydrogenated fats?
It is removed before the fats are packaged and sold.
Hydrogenation of fats is a process where hydrogen is added to to what?
Unsaturated fatty acids their double bonds.
Hydrogenation saturates carbon atoms with hydrogen, converting unsaturated fatty acids to what?
Saturated fatty acids
Why are parts only partially hydrogenated?
Fully saturated fats are so solid they’re hard to work with.
Leaving some unsaturated fatty acids makes the mass what?
Soft and plastic.
Is hydrogenation the same as adding air to fats? What’s the difference?
No, hydrogenation is a chemical process that changes the fatty acid molecule by forcing hydrogen into it. Aeration occurs when air is whipped into solid fat, as when fat is creamed. For this to occur, fats must be soft and plastic. Hydrogenation is one way to create this.
Why hydrogenate?
To increase their solidity and increase stability against oxidative rancidity.
When would solidity be desired in fat?
Flakiness and volume in pastry or to decrease the greasiness in doughnuts and cookies.
What is oxidative rancidity?
The breakdown of fatty acids that leads to rancid off flavors.
What goes rancid faster, unsaturated or saturated fatty acids?
The more unsaturated a fatty acid, the faster it undergoes oxidative rancidity.
What oxidizes faster, mono or polyunsaturated fatty acids?
Poly
What are plastic fats?
Plastic fats aren’t made from plastic. Rather, they are edible fats that have a plastic consistency, meaning that they are soft, moldable solids, such as Play-Doh.
Are plastic fats part liquid and part solid? What does this mean?
Yes, it means they consist of liquid oil trapped in a network of solid fat crystals.
Examples of fats that are plastic at room temp.
All-purpose shortening, lard, and butter.
Fats that are not plastic include what?
Vegetable oils, which are liquid at room temp, and cocoa butter, which is a hard solid.
Does plasticity depend on temperature?
Yes
All-purpose shortening is plastic when _______ and is still plastic when the bakeshop ________.
refrigerated, warms
What is one of the advantages of shortening?
It keeps its soft, workable consistency over a wide range over temperatures.
Highly unsaturated fats can oxidize how much faster than highly saturated ones?
100 times faster
Hydrogenation reduces oxidative rancidity by converting unsaturated fatty acids into what?
saturated ones
Hydrogenation reduces oxidative rancidity by converting polyunsaturated fatty acids into what?
Less unsaturated ones.
Does even a small amount of hydrogenation help reduce oxidative rancidity?
Yes, that is why vegetable oils, which remain liquid and therefore don’t appear hydrogenated, sometimes are.
Is regular soybean oil highly polyunsaturated when extracted from the soybean?
Yes, but partially hydrogenating it make the oil less likely to oxidize.
Describe the smell of oxidized oil.
Beany, fishy, or painty smell.
What is the most common vegetable oil in the bakeshop? Why?
Soybean because of its use in shortenings, margarines, and vegetable fat.
What are the two largest crops in the US?
Corn, then soybeans.
Standard mature dry soybean contains how much oil?
20% and over half is polyunsaturated.
Unfortunate downside of hydrogenation?
It generates saturated fatty acids, which can increase blood cholesterol and risk of coronary disease. The greater downside is creating trans fatty acids.
Do natural amounts of of trans fats occur in butter?
Yes
Greatest source of trans fats in North America.
Partial, but not totally hydrogenated oil.
Since January 2006, manufacturers must disclose what?
Amount of trans fats on their labels.
Why are trans fatty acids a concern?
They tend to increase LDL while also decreasing HDL. In doing so, increasing risk of coronary heart disease even more than naturally saturated fatty acids. Also been implicated in certain cancers.
What was created in response to trans fatty acids?
New versions of vegetable fats and oils that are trans-free yet have the stability and functions approaching that of regular fats and oils.
How have some of these new fats and oils been created?
Soybeans and other oil sources can be specially bred to be naturally low in polyunsaturated fatty acids without having to undergo hydrogenation.
These new liquid oils are often called what? Why?
Low-life oils because they are naturally low in alpha linolenic acid (ALA), a polyunsaturated fat that is highly susceptible to rancidity.
Name three plants that are made with this new approach.
Soybean, canola, sunflower.
Is it possible to produce trans-free plastic fats? Example.
Yes, trans-free shortenings and margarines can be made from fats that are naturally saturated, such as palm oil and coconut oil. Because they are naturally saturated, these tropical oils do not need partial hydrogenation. to achieve a soft plastic consistency and therefore are trans-free.
Why does blending fully hydrogenated fats with liquid oils also make trans-free plastic shortenings and margarines?
Full hydrogenation, unlike partial, does not generate trans-fats.
Have baked goods and fried food been implicated as two major sources of saturated and trans fats in our diets?
Yes, because bakers and pastry chefs cannot replace all saturated fats with unsaturated ones.
Fats (and oils) differ from each other in what ways?
Cost, flavor, consistency, amount of fat, amount of air, amount of water, and melting point.
Do additives, salt, colors, flavors, antimicrobial agents, milk solids and more affect how each fat functions in the bakeshop?
Yes
Butter is made from what?
Heavy cream, an emulsion of butterfat suspended in milk.
While some of the fat in chilled cream is in the form of liquid globules, a large amount consists of what?
Tiny solid fat crystals, so tiny that cream, while thickened by these solid crystals, seems totally liquid in the mouth.
Butter manufacturing is the separation of what?
Both solid fat crystals and liquid globules, from much of the remaining liquid, or buttermilk.
As with other fats, butter provides what important functions?
Moistness, tenderness, flakiness, and volume. But this does not explain the widespread use of butter in bakeshops since it does not excel at any of these functions.
Butter’s two main functions.
Mouthfeel and flavor. No other fat can match these two attributes.
Margarine may contain natural butter flavor and have a low final melting point, but it still doesn’t have what?
Superior flavor and texture of butter.
Final melting point is defines as what?
The temperature at which no solid fat crystals are visible; fat is completely clear liquid.
Butter is too hard to work with at what temp?
50ºF (10ºC)
Butter is too soft to work with at what temp?
80ºF (27ºC)
The best temp range for working with butter.
65ºF-70ºF (18-21ºC)
With laminated doughs why should butter be as solid as possible?
Because flakiness and volume are very important.
Butter’s final melting point is often stated around what?
94ºF (34ºC)
Give a description and common use in fats and oils: ANNATTO
Natural coloring from the seed of the annatto (anchiote) shrub.
Color for butter.
Give a description and common use in fats and oils: BETA CAROTENE
A form of vitamin A
Color for margarine
Give a description and common use in fats and oils: BHA
Synthetic antioxidant; butylated hydroxyanisole
Minimizes oxidative rancidity.
Give a description and common use in fats and oils: BHT
Synthetic antioxidant; butylated hydroxytoluene
Minimizes oxidative rancidity
Give a description and common use in fats and oils: CITRIC ACID
Organic acid, especially high in citrus fruits.
Minimizes oxidative rancidity, especially in lard.
Give a description and common use in fats and oils: COTTON SEED OIL, PARTIALLY HYDROGENATED
From seed of cotton plant.
Added to plastic shortening to encourage formation of proper crystal structure for creaming.
Give a description and common use in fats and oils: DIMETHYLPOLYSILOXANE
Silicone derivative
Added to frying fats to reduce foaming.
Give a description and common use in fats and oils: LECITHIN
Emulsifier
Added to margarine to minimize spattering during pan sautéing.
Give a description and common use in fats and oils: MONO- AND DIGLYCERIDES
Emulsifiers
Added to high ratio shortenings to increase moistness, tenderness, prevent staling of baked goods.
Give a description and common use in fats and oils: PALM OIL, PARTIALLY HYDROGENATED
From flesh of palm fruits
Added to plastic shortening to encourage formation of proper crystal formation for creaming.
Give a description and common use in fats and oils: POLYGLYCEROL ESTERS
Emulsifiers
Prevents clouding is salad oil
Give a description and common use in fats and oils: POTASSIUM SORBATE
Potassium salt of sorbic acid, a natural organic acid
Added to margarine to prevent microbial growth
Give a description and common use in fats and oils: PROPYL GALLATE
Synthetic antioxidant
Minimizes oxidative rancidity, especially in lard
Give a description and common use in fats and oils: PROPYLENE GLYCOL MONOSTEARATE
Emulsifier
Highly effective emulsifier in high-ratio liquid shortenings
Give a description and common use in fats and oils: SALT
Sodium chloride
Flavoring and preservative in butter and margarine.
Give a description and common use in fats and oils: SODIUM BENZOATE
Sodium salt and benzoic acid, a natural organic compound
Added to margarine to prevent microbial growth
Give a description and common use in fats and oils: STEARIC ACID
Naturally saturated fatty acid
Added to high ratio liquid shortening as an emulsifier
Give a description and common use in fats and oils: TBHQ
Synthetic antioxidant; tert-butylhydroquinone
Minimizes oxidative rancidity especially in lard
Give a description and common use in fats and oils: TOCOPHEROLS
Mixture of vitamin E and related molecules; Antioxidant
Minimizes oxidative rancidity
Give a description and common use in fats and oils: VITAMIN A PALMITATE
Added to margarine as a vitamin
Give a description and common use in fats and oils: VITAMIN D
Added to margarine as a vitamin.
Disadvantages of butter.
It’s expensive and fluctuates with the seasons and supply. Butterfat is undesirable from a health standpoint.
Highest of common bakeshop fats in saturated fat; even higher than lard.
Butterfat
Why is butter one of the hardest fats to work with?
Its narrow plastic range.
First step of butter manufacturer.
Pasteurize cream, then cool it to 60ºF (16ºC).
If desired, what may be added before the cream is vigorously agitated, or churned.
Natural yellow annatto color.
At first, churning action produces what? Describe what happens next during churning.
Whipped cream, as air is whipped in. Solid fat crystals surround and stabilize the air cells, but soon, warm temperatures soften the fat crystals. Continued violent agitation causes fat crystals and fat globules to clump. Eventually, large pools of liquid buttermilk seep out and chunks of butter form, as whipped cream collapses.
After churning, what happens to the butter chunks?
They’re washed with cold water, salted if desired, then worked or kneaded, to shape and to remove excess water.
Because kneading also softens butter, it is sometimes called what?
Work softening.
What remains at the end of the butter making process?
Smooth mixture of solid fat crystals, water droplets, air bubbles, milk solids, and liquid butterfat trapped throughout.
Why must pastries that rely on butter for leavening be chilled before baking?
Because butter is temperamental and melts quickly. If it isn’t cold enough or oven isn’t set properly, the dough will sag or not rise properly.
Does butter spoil faster than other fats?
Yes, especially if it isn’t salted.
Butter is susceptible to bacterial spoilage if it is not what?
Refrigerated for the short term or frozen for the long term.
Butter that has undergone bacterial spoilage taste like what?
Sour milk or rancid off flavor.
Butter can be classified by the type of what used in production?
Cream
Two types of butter.
Cultured butter and sweet cream butter.
Cultured butter is made from what?
Sour cream, where bacteria have converted lactose to lactic acid.
Cultured butter is also called what?
Ripened butter.
Flavor of cultured butter.
Distinct sour flavor, similar to sour cream.
Is cultured butter ever salted?
Rarely, if ever.
Is sweet cream butter more mild than cultured?
Yes
Why is it called sweet cream?
The cream has not been soured, not because it contains sweetener.
Are both types of butter available worldwide?
Yes, but there are regional preferences.
Sweet cream is traditional where?
North America and Great Britain.
Cultured butter is traditional where?
Certain countries in Europe, particularly France, Germany, and Switzerland.
European-style butter made and sold in North America is what?
Either cultured butter or sweet cream butter with an added cultured cream flavor.
Example of European style butter made with an added cultured cream flavor.
Plugrá
Minimum amount of butterfat required in the US and Canada.
80%
European butters require how much butterfat?
Slightly lower than 82%. However, it’s not uncommon for them to have as much as 86%.
Butter containing a higher amount of butterfat typically has what texture?
Smoother, creamier texture and mouthfeel.
Butterfat consists mostly of what?
Triglycerides with a small amount of natural emulsifiers.
Emulsifiers make up what % of butterfat?
2-3%, including mono- and diglycerides and lecithin.
The remaining 20% of butters makeup includes what?
Water (typically 16%), milk solids, and salt, if added.
Milk solids consist of water?
Proteins, lactose and minerals.
Three grades of butter in the US.
Grades AA, A, and B.
US grades most often seen.
AA and A, but grade B is available.
Is the grading of butter a voluntary system by the USDA?
Yes
Most important attribute of butter.
Flavor
Of the three grades, which is made from the freshest cream? Describe its flavor.
AA, it has a mild flavor with minimal flavor defects.
Describe USDA grade A butter.
Has a stronger, slightly sour but still pleasant flavor.