Chapter 5 Flashcards
The Structures of Sugars: Composed of ___, ____, and ____.
carbon, hydrogen and oxygen
Simple sugars:
- ______
- _____
Monosaccharides
Disaccharides
Sugar Alcohols:
- Sugars with ____ of one corner of their molecule.
- Cause ___ ___ in ___ ___ levels.
- Don’t participate in ____ reactions- lacking ___ ___.
modification corner molecule slow rise blood insulin chemical aldehyde group
Food Lipids: Fat and Oils
- The predominate chemical structure of lipids is the ____.
- Glycerol is a __-carbon molecule containing __ -___ (___) groups.
-Fatty acids are chains of ____ with a ___ at one end and a ___ at the other end.
triglyceride 3 3 -OH (alcohol) carbon carboxyl methyl
Saturated and Unsaturated Fats:
- ____– does not contain any C=C.
- ______– have one or more C=C.
Saturated
unsaturated
The omega naming system names fatty acids by where the __ ___ bond occurs counting from the ___ group ____.
first
double
methyl
backward
The pattern of the double bonds is also important because it determines ___ ___.
When the double bonds occur between every other carbon it is referred to as ____ double bonds.
chemical reactivity
conjugated
When a carbon without a double bond occurs between two sets of double bonds it is called ____.
More ____ and more ____.
interrupted
typical
reactive
Cis and Trans Fats:
- Refers to ___ ___ around the double bond of unsaturated ___.
- When the hydrogen are on the same side it is ___.
- When the hydrogen are on opposite sides it is ___.
geometric configuration
FA
cis
trans
___ is more common in nature, but ___ configuration occurs when vegetable oil is hydrogenated.
Cis
trans
___ ___- The temperature where a solid is converted to a liquid.
Melting Point
Lipids that are ___ at room temperature are referred to as fats and they possess ____ structure.
- The composition of the fat affects its __ ___.
- The more similar the triglycerides in a given fat the ____ the melting range.
- ___ chain fatty acids have higher melting points than ____ chain, ____ higher than ___, ___ higher than ___.
solid crystalline melting point narrower Longer shorter saturated unsaturated trans cis
**___ ____: Characteristic temperature at which fats begin to break down.
- Most fats begin to decompose ___ their boiling point.
- May spontaneously ___ on the stove if their fumes come in contact with flame.
- Depends on initial __ __ ___ content.
Smoke Point
before
ignite
free fatty acid
Flavor Compounds:
- Fats are highly important to ___, both good and bad flavors.
- _____ Oils
- ___ ___ products
flavor
Essential
Lipid degradation
Polar Lipids:
-Represented primarily by ____, these lipids have both ___ and ___ regions (___).
phospholipids
polar
nonpolar
amphiphilic
Pigments: Many of the pigments that provide color to plants and animals are __ ___.
fat soluble
Waxes:
- Waxes are ___ melting point lipids composed of a long chain __ ___ and a long chain ___ ___, esterified to each other.
- They primarily occur in the ___ layer of ___ and provide ___.
high fatty acid fatty alcohol outer plants protection
_____ – splits lipids into higher and lower melting point component parts.
-Can produce a good __ ___ and plastic fat for shortening from same ___ material.
Fractionation
frying oil
starting
_____ – the forced addition of hydrogen to unsaturated lipids.
-This will raise the ___ ___ and increase ____, but produces ___ ___ ___, which may have health disadvantages.
Hydrogenation
melting point
stability
trans fatty acids
_____ – a reaction requiring heat plus the addition of water molecules to separate fatty acids from glycerol.
- Produces an __ ___ referred to as ___ ___, which is caused by the release of short chain fatty acids.
- When all three fatty acids are lost during heating, the glycerol molecule can be further degraded to ___, which is responsible for the __ ___ of oils that are at their ___ point.
Hydrolysis off flavor hydrolytic rancidity acrolein noxious aroma smoke
- _______: This is the rearrangement of fatty acids on the glycerol molecule to create less homogenous triglycerides molecules.
- The primary function of interesterification is to cause __ ___ such as lard to have a ___ texture.
Interesterification
plastic fats
smoother
Oxidation:
-Oxygen reacts at the double bonds of unsaturated fatty acids and causes the production of __ __ compounds that are responsible for “___” odors.
Unsaturated FA react with oxygen to produce ____ and eventually the degradation of the ___ to ___ compounds (__, ___, __, ___).
small organic "rancid" hydroperoxides peroxide volatile ketones, aldehydes, alcohols, acids
Oxidation:
- The reaction sequence can be caused by __, __, __, ___, etc.
- ____ can prevent the reaction by donating hydrogen which basically terminates the reaction.
heat, light, metals, oxygen
Antioxidants
______ - Primarily occurs in heated oils where fatty acids that are cleaved from the glycerol molecules link together to produce polymers.
-Contribute to the ____ of overheated oil and the ____ of foods cooked in overheated oils.
Polymerization
smoking
darkening
____ – also called “creaming the fat” when baking cakes.
- This step incorporates ___ through agitation of a batter which is held in place by the ___ molecule arrangement of the fat.
- Ultimately responsible for the ___, or ___ of many baked products.
Aeration air crystal crumb texture
_____– all food fats contain very small crystals of fat which are composed of the fat’s triglycerides.
Crystallization
Because of differences in the fatty acids that make up the triglycerides, different ____ arrangements (_____) are possible.
- Include the classifications __, __, __-__,
- __-__ (___ __) is the most desirable from a functionality standpoint because they provide a smooth texture.
- __ ___ (__) coarser.
crystalline polymorphism α, β, β-prime B-prime (Beta prime) B crystals (Beta)
Crystallization: More ____ triglycerides result in __ ___.
- Fats are interesterified to reduce the ____ and produce _-____ crystals.
- Also, the more homogeneous the more ____ the melting range.
homogeneous B crystals homogeneity B-prime narrow
Emulsification– ____ are an important component of all food emulsions.
Ex: Cake Batter – __ in ___ emulsion
lipids
Oil in water
Flavor – ____ are believed to have the greatest impact on flavor.
-Their contribution to flavor is due to their inherent ____ properties.
lipids
flavor
Lipids:
Also carry flavor compounds that are lipid soluble such as ____.
-Terpenoids are responsible for __ ___, among many other flavors, which are contained in what is referred to as ___ __.
terpenoids
citrus flavor
essential oils
Heat transfer:
___ can be heated to higher temperature than ___.
Lipids
water
____: Lipids provide a smooth, creamy sensation during the mastication of food.
-Difficult to ___.
Mouthfeel
replace
______- Refers to the physical property of a fat which describes its softness at room temperature.
-Plastic fat will ___ when spread but __ its __ __.
Plasticity
deform
hold
new shape
Plasticity:
- This is due to the ____ nature of ___ lipids.
- ____ crystals have a smoother texture, which can be achieved by proper ____.
-Fats composed mainly of β crystals are less __ and more ___ to the touch.
crystalline solid β-prime tempering plastic grainy
______: Because of the lubrication properties of lipids, they also promote _____ of foods that contain them.
- Meat that has higher fat content (___) is more ___ than meat that has __ ___ __.
- In baked goods, ___ interferes with ___ formation.
Tenderization tenderization marbling tender less intramuscular fat lipid gluten
Food Proteins:
- Proteins are polymers of __ __.
- Called ____ because the bond between __ __ is the ___ bond.
-Connects the ____ group of one ___ acid to the ___ acid group of another ___ acid.
amino acids polypeptides amino acids peptide amino amino carboxylic amino
Amino acids all have an ___ group and a ____ group along with a ___ group.
-Functional group dictates classification as __, ___, ___, ___, or ____ containing amino acids.
amino
carboxylic
functional
neutral, basic, acidic, aromatic or sulfur
Proteins exist as either:
- ______: Contain only amino acids
- ______: Combined with other nonprotein substances.
Nonconjugated
conjugated
Conjugated: Examples: \_\_\_\_: \_\_\_, e.g. \_\_ \_\_\_ Lipid: Metals: metalloproteins, e.g. hemoglobin Phosphorus: phosphoproteins,
carbs, glycoproteins
egg white
There are \_\_ levels of protein structure: 1. 2. 3. 4.
4 primary secondary tertiary quaternary
_____ is the linear arrangement of amino acids.
Example: ____ (shorthand for primary structure)
Primary
N-C-C-N-C-C
_____ is the structural arrangement of the amino acids such as __-__, __-___ sheet.
Secondary
alpha-helix
beta-pleated
_____ is the overall three dimensional structure.
tertiary
_____ is the arrangement of more than one peptide chain within a single protein molecule.
Quaternary
_____ – preventing a pH change by undergoing an ionization reaction.
_____ – can behave as both acids and bases.
- ___ groups can act as acids.
- ___ groups can act as bases .
Buffering
Amphoteric
Carboxyl
amino
_____ can serve as buffers (maintain pH) because of this and can be either ___ or ____ depending on the pH of the food.
Proteins
acidic
basic
_______- the loss of three dimensional structure without breaking the primary structure.
- When proteins denature they lose ____ properties.
- Denaturation occurs due to __, ___ ___.
- __ __ __ may cause the protein to coagulate, which is more ___ than mere denaturation.
Denaturation functional heat, acid, agitation Excessive energy input severe
Enzymes – all enzymes are ____.
Many enzymes impact ___ ___, both naturally occurring & industrial enzymes that are purposefully used in food processing.
Natural enzymes that influence food quality include ____ in meat and ____ in fruits.
-Enzyme activity is affected by ____ (optimum is generally between __-__degreesC), __ (optimum generally between __-__) and __ __.
proteins food quality proteases phenoloxidases temperature 30-40 ph water activity
Emulsification – proteins can stabilize emusions by acting at the __-__ interface.
oil-water
Fat Reduction – proteins are often used as __ __.
fat replacers
Monosaccharides:
-Are the basic ___ ___ around which ___ carbohydrate units are built.
-Nomenclature is based on the number of ___.
-____ – 3 carbons.
-____ – 5 carbons.
-___ – 6 carbons.
__, ___, ___ – C6H12O6
building blocks larger carbons trioses pentoses hexoses glucose, fructose, galactose
Monosaccharides:
-Structural features, which are dependent on the location of ____ groups, have an influence on ____ properties.
-Glucose has a __ membered ring (___)
Fructose has a __ membered ring (___)
-This difference is partially responsible for the fact that fructose is ___ and more ___ than glucose.
functional functional 6 aldose 5 ketose sweeter soluble
Disaccharides:
-___ monosaccharides bonded together by a ___ bond.
two
glycosidic
The three most common disaccharides in food are:
- _____ (____ + ____) - common table sugar
- ____ (___ + ___) - milk sugar
- _____ (___ + ____) - common breakdown product from starch.
sucrose glucose fructose lactose glucose galactose maltose glucose glucose
Two important functional groups of Sugars:
- ___ (-___) group– important for solubility & sweetness.
- ___ (___) group– important for reducing activity and Maillard browning for color/flavor development.
Alcohol -OH
Carbonyl (-C=O)
Sugar functional groups:
These functional groups are either a ___ (on the ___ of the molecule) or an ____ (on the ___ of the molecule).
ketone
interior
aldehyde
end
Reducing sugars- contain a ____ group (___ or _____).
-All ______ are reducing sugars.
carbonyl
(aldehyde or ketone)
monosaccharides
There are two important browning reactions that occur in sugar:
- _____ reactions
- _______
Both are categorized as ______.
Maillard
Caramelization
nonenzymatic
____ _____ – a complex series of reactions that requires a reducing sugar and amino acids in foods.
Maillard reaction
____ ____ – the browning of foods as a result of the Maillard reaction.
-Intermediate products: _____, which tend to have pleasant aromas and flavor.
- End products: brown pigments called ____.
- _____ and result in ____ of food.
Maillard browning pyrazines melanoidins Irreversible darkening
The Maillard reaction is responsible for both ___ and ____ quality attributes, depending on the product.
positive and negative
The Maillard reaction takes place at relatively __ temperatures and can be accelerated by ___ molecular weight sugars, low __ __ (<15%) and in the pH range of __-__.
low
lower
moisture content
5-8
Caramelization – takes place at ___ temperature (200 C)
- Due to the _____ of the sugar molecule.
- ___ ___ refers to a brown coloring used in the food industry.
- Caramel refers to sauces or candies made from carbohydrates that have been allowed to ____.
high
dehydration
Caramel coloring
caramelize
Crystallization:
- ___ ___ can exist as syrups or the crystallized state.
- Crystallization– implies organized __-_ arrays of unit cells into solid form.
- In candy manufacture, control of the ____ process is highly critical to the ultimate quality of the candy.
Simple sugars
3-D
crystallization
____– a substance that has an affinity for moisture, also referred to as hygroscopic substances.
-This is ultimately related to their ability to form ____ bonds with ____.
Humectant
hydrogen
water
Inversion refers to the process where ___ is hydrolyzed to ___ and ____, which are then called ___ ___.
-Inversion can be induced by __, ___, or a special enzymes called ___.
sucrose fructose glucose invert sugars heat, acid invertase
Sugars undergo __ ___ reactions that promote important functional characteristics
Oxidation of the aldehyde group in sugars causes a loss of ___ and converts it to an ___.
Reduction of the ___ group of reducing sugars causes the formation of __ ___, which are moderately sweet.
Ex: ___ and ___
oxidation reduction sweetness acid carbonyl sugar alcohols mannitol and sorbitol
Sweetness is probably the most notable functional characteristic of __ ___, although ___ varies between different sugars.
-___ is usually used as the reference with other sugars.
____>___>____>___>___>___
simple sugars sweetness Sucrose Fructose>sucrose> glucose>maltose> galactose>lactose
Effect on texture through their interaction with ___.
-Sugar can provide ___, ____ (e.g. in baked goods) and can influence other texture promoting compounds such as __.
water
bulk
tenderization
starch
Polysaccharides:
Also called ___ ___ because of their large size.
-Polymers of monosaccharides and classified as either:
_____ (3-10 units)
_____ (>10 units)
complex carbohydrates
Oligosaccharides
polysaccharides
Oligosaccharides
Ex: ____ and ____.
- Present in ___ ___.
- Not digested in the __ ___ but are fermented by microorganisms in the ___ ___.
raffinose stachyose dried beans small intestine large intestine
Polysaccharides are much more ____ in foods than oligosaccharides and are commonly used as ___ to food for specific aspects of functionality.
abundant
additives
Beta-glucans:
-___ of glucose.
-Considered a ___ __ ____.
-Found primarily in __, __, and ___
-Have been found to lower ___ __(FDA allows this claim).
-Used as a __ __ in many different manufactured food products.
___ – used in baked goods, fillings and frostings, frozen desserts, salad dressings, etc.
Polymers soluble dietary fiber oats, barley, and yeast serum cholesterol fat replacer Oatrim
Cellulose:
-Most ___ of all carbohydrate polymers.
-Structural component of all __ __.
-The main source of __ __ __.
-Microparticulate form of cellulose:
Used as a __ __ and to increase dietary fiber in foods.
abundant
plant cells
insoluble dietary fiber
bulking agent
Dextrins & Maltodextrins:
- Both are derived from the breakdown of ___.
- Have ___ glucose chains than starch but are still considered polysaccharides.
-The term dextrin is generally applied to any __ molecule that has undergone ___, usually by __.
starch shorter starch degradation heat
_____ are more specifically related to commercially generated products, usually from cornstarch.
-Used in sauces, baked goods, processed meats as fat replacer and bulking agent.
Maltodextrins
Fructooligosaccharides:
- Polymers containing primarily ___, usually in association with ___.
- Found in a variety of ___ including garlic, onions, bananas, etc.
-Considered ____ because they are not broken down in the __ __ and make it to the large intestine where they nourish good bacteria (___).
fructose sucrose plants prebiotics small intestine probiotics
Inulin: Dietary Fiber
- ___ is a type of fructooligosaccharide found in onions, asparagus and especially chicory root.
- Serves as a ___ to stimulate the growth of good bacteria.
- Can be used to adjust ___ attributes.
Inulin
prebiotic
textural
Pectic Substances:
- ___ molecular weight polysaccharides found in plant cell walls, primarily for ___.
- Composed of ____ acid units some of which are methylated, which determines functionality.
High
support
galacturonic
Pectic Substances:
-___ chemically distinct substances:
- ____ – nonmethylated and found in immature fruit
- __ __ – methylated and produced during ripening
- __ ___– demethylated derivative of pectinic acid and associated with overripe fruit
three
Protopectin
pectinic acid
pectic acid
Pectic substances:
Degree of ____ (_____) deterimines functionality. High methoxyl (HM) pectin have > __% methylation, whereas low methoxyl (LM) pectin generally has < __% methylation.
esterification
methoxylation
50
30
Pectic Substances:
-Pectin ____
Pectins are able to form ___ ___ (sols and gels).
Gelation
colloidal dispersions
To convert a HM pectin sol to a gel it is necessary to reduce the association of pectin with ___ by incorporating ___ and reduce the __ __ between pectin molecules.
water
sugar repulsive forces
LM pectin can be converted into a gel without ___ by adding ___ ___ such as calcium.
Thus, LM pectin is used in the manufacture of __ __ ___.
sugar
divalent cations
sugar free jelly
Starch is the predominate source of __ __ in the world’s food supply.
It is a ___ of glucose molecules, found in two forms:
____– a straight chain.
_____ – numerous branches.
dietary energy
polymer
amylose
amylopectin
Starch:
Packaged in the plant as __ __.
Starches that are high in ___ can form gels.
Starches high in amylopectin can’t but do increase in ___.
\
starch granules
amylose
viscosity
Starch is often modified to change its ____.
An example of a modified starch is ___ ___, which is used in instant pudding and pie filling.
functionality
pregelatinized starch
Starch Gelatinization:
Starch is not soluble in __ water, but if __ and ___ it undergoes a conversion that is referred to as ____
During gelatinization, the heated starch granules absorb ___ and ___.
- ___ reaction.
- Increased ___.
cold agitated and heated gelatinization water and swell Irreversible viscosity
Starch Pasting and Gel Formation:
__ ___ – a starch/water system the has both thick liquid and solid-like properties.
____ can be thought of as a continuation of gelatinization where the thickening of the slurry occurs.
Starch paste
Pasting
Starch Pasting and Gel Formation:
In a paste, majority of starch granules have ___, producing __ and ___ granules.
____ – the formation of a gel from a cooled paste.
____ ___ – a thick starch/water mixture that has properties of a solid.
gelatinized
swollen and disrupted
Gelation
Starch gel
Starch Retrogradation:
_____ is the contraction of starch gels due to interactions between amylose molecules.
As the gel tightens it can __ water, which is referred to as ____.
Retrogradation
lose
syneresis
Vegetable Gums:
Vegetable gums are a broad category of ___ ___ that contain a variety of sugars including __ and ___.
complex polysaccharides
pentoses and hexoses
Gums are derived from a variety of sources including __ __ (__), seaweed (___), and microorganisms (___).
plant seeds (guar)
carageenans
xanthan
_____– proteins are good foaming agents because they can reduce interfacial tension and allow air to be incorporated into liquids.
Egg white meringues.
Foaming
____– some proteins can form three dimensional networks that allow incorporation of water and form gels.
Collagen that is used in Jell-O™ products.
Gelation
______– functionality is often dictated by solubility, which is affected by pH, temperature, etc.
Certain applications such as edible film manufacture require highly __ ___.
Solubility
soluble proteins
___-____ ___– This is the ability for a protein to bind water and is due to its hydrophilic components.
Water holding capacity is lowest, which means ___ is lowest at the ____ (__), where the charge on the molecule is neutral, which reduces the water protein interactions and maximizes the protein-protein interactions (causes protein to precipitate out of solution).
Water-holding Capacity
solubility
isoelectric pH (pi)
