Chapter 4 Flashcards
Foods are made of _____ which is composed of ___ ___, as either _____ or _____.
matter
pure substances
elements
compounds
Elements are the ____ form of matter - ____ be broken down further.
simplest
cannot
Compounds are made of ___ or ___ ____, _____ bonded in definite proportions by ____.
two more elements chemically weight
Compounds are represented as _____ that depict their _____ _____.
formulas
element
composition
Important compounds in food science are _____ compounds.
-All contain _____ (___), _____ (__), ____ (__) and sometimes ___ (__), ____ (__)or ____ (__).
organic carbon (C) Hydrogen (H) Oxygen (O) sulfur (S) Nitrogen (N) Phosphorus (P)
Matter can also exist as ____ in which two or more _____ are combined ____.
-___, ____, _____
mixtures
substances
physically
Solutions, dispersions, emulsions
_____ – one or two letter designations for elements depicted in the periodic table.
Symbols
Formulas – depicts all of the ____ in a ____, including ____ as ____ numbers.
elements
compound
proportions
subscribed
Equations– a ____ description of a ____ ___ using ___ ___ and ____.
Example:
C6H12O6 + 6 O2 6 CO2 + 6 H20 (breakdown of ____)
written chemical chemical symbols formulas glucose
Chemical reactions - ___/___ interact with each other through ___ ___.
-Results in a ___ ___ with different ___ from the ____.
atoms/molecules chemical bonding new substance properties reactants
Elements interact with one another via ___ ___, which requires ____.
-Only ____ are involved in chemical bonds.
chemical
bonds
energy
electrons
Electrons are ____ charged and are attracted to ____ charged ___.
___ can be seen as having a series of electron orbits.
negatively
positively
nucleus
atom
To determine maximum number of electrons in each energy level, use \_\_\_\_. 1st level – \_\_\_ 2nd level – \_\_ 3rd level – \_\_\_ 4th level – \_\_\_
X=2n^2 2 8 18 32
Most atoms become chemically stable when they have ___ electrons in their ____ shell (____ shell ).
Valence shell is the ____ electron ___.
8 outermost valence outer orbital
During chemical bonding, ____ elements are ____ according to the ___ given in their ___.
-____ Acid – C3H6O2
-Can be written as a ____ formula in order to ___ the bonding that takes place.
Exmaple: CH3 – CH2 – COOH
reacting combined proportions formula Propionic structural visualize
Covalent Bonds– occur when ____ are ___.
___, ___, or ___ pairs of elections can be shared resulting in ___, ___, ___ bonds.
electrons
shared
One, two or three
single, double, triple
__, ___, ___, and ___ have covalently bonded carbon atoms.
-Form the ____ of these molecules
Fats, proteins, carbs, vitamins
backbone
Ionic Bonds– the ___ of ___ between ___.
- Resulting in a ___ ____ shell of both ___.
- Elements that ____ electrons become ___ charged and are called ____ (____)
- Elements that ___ electrons are ___ charged and called ____ (___).
____ (NaCl) is an example of a compound with ionic bonding.
transfer electrons reactants full valence elements donate positively cations (sodium) receive negatively anions (chlorine) salt
- Hydrogen Bonds– a type of ____ bond with ___ rather than ___ sharing of ___, resulting in a ___ ___.
- Intermolecular bonds– ___ between ___ ___ molecules.
covalent unequal equal electrons weak force bonds two different
___ ___ (H bonding) They don’t ___, they just ___ with each other.
Static clinging
share
interact
Chemical reactions in foods: Generally classified as either ____ or ____ reactions.
-Either type may be either ____ or _____.
composition
decomposition
enzymatic
nonenzymatic
Composition reactions– __ or ___ substances combine resulting in a ____ ____ (____).
-Synthesis of ____ from ___ ___.
two more single product (A+B=AB) protein amino acids
Decomposition reactions– ___ substance becomes ___ ____ (____).
-____ of ____ yields two ____ molecules.
One substance two products (AB=A+B) hydrolysis maltose glucose
In food the effect of enzymes can be either:
- Positive- _____ of ____.
- Negative- ____ of ___ ___ and ____.
tenderization meat browning cut fruits vegetables
Enzymes are _____ ____ and serve as ____ ____ (cause ____ to speed ___) of chemical reactions.
specialized proteins biological catalyst reactions speed up
Active site–location where the ____ joins with the ____ to form the ____ ___ ___.
-____ ___ region that contains __ ___ that bind, __-____, to the substrate.
substrate enzyme enzyme substrate complex Three dimensional amino acids non-covalently
Activation energy– the amount of ___ required for a ___ to take ___.
-Enzymes ____ the activation energy thus ___ ___ the reaction.
energy reaction place reduce activation energy speeding up
Enzymatic Hydrolysis - the ____ of large components into ___ ones (___ ___).
Ex: ___, ____, ____.
breakdown large smaller protein hydrolysis carbohydrases, lipases, proteases
Enzymatic Oxidation-Reduction– ___ is the loss of ___ and ____ is the addition of ____.
- Ex: the ___ of ___ and ____ via ___ ___.
- In nature, they are ____.
oxidation electrons reduction electrons browning fruits vegetables polyphenol oxidase coupled
Enzymatic Polymerization– occur through ____ reactions (i.e. the ___ of ___ compounds).
-When many condensations occur within the same molecule, a ____ is formed.
condensation
joining
two
polymer
Nonenzymatic reactions: as the name implies, these reactions occur in ___ in the absence of an ___ ___.
Types include:
- ____
- ____-___
- ____
- ___
nature enzyme catalyst Addition Oxidation-reduction Hydrolysis Condensation
Addition– the ____ of an ____ to a ___.
-____ of __ ___ ___ where ___ is added to the ____ bonds.
addition element compound Hydrogenation unsaturated fatty acids hydrogen double
Oxidation-Reduction– electrons are ___ between ____.
-Can affect ___, ___, and ___ of foods.
-Oxidation – the addition of ____.
Reduction – the gain of ___.
-Can be caused by ___ ___, ___, high ___ ____, ___ ___, etc.
transferred substances color quality acceptability foods oxygen hydrogen UV Light heat oxygen environment metal catalyst
Condensation and Hydrolysis– these can be viewed as _____ reactions.
These reactions are generally catalyzed by __ or ___.
complimentary
heat or acid
Condensation reaction– occurs when ___ ___ are ___ together with the formation of a ___ ___ and ___.
two molecules joined new product water
Hydrolysis reaction– occurs when a molecule is ___ apart in the presence of ___, which is incorporated into the __ ___ products.
broken
water
two
new
Functional groups– ____ of ___ that create certain ____ of ____.
arrangements
atoms
properties
molecules
Functional groups Include:
\_\_\_\_ group \_\_\_\_ group \_\_\_\_\_ group \_\_\_\_ acid group \_\_\_\_ group \_\_\_\_ group \_\_\_ group \_\_\_\_ group \_\_\_\_ group \_\_\_\_ groups
Alcohol group Aldehyde group Amino group Carboxylic acid group Ester group Ketone group Methyl group Phosphate group Sulfhydryl group Ionic groups
Alcohol group– ___ or ____.
-Important food alcohols include ____ and ____.
OH or hydroxyl
ethanol
glycerol
Aldehyde group–___ at the end of the ____ which is ___ bonded to ____.
-Important in ____ and ___ of foods.
carbon molecule double oxygen odors flavor
Amino group– contains an ___ ( ___ ) ___ group.
-____, ___ and ____ are amines
amino (NH2) functional histamine serotonin dopamine
Carboxylic Acid– a ___ on the end of a molecule bonded to a ___ and double bonded to an ____.
Ex: ___ ____, ___ ___ (____).
carbon
hydroxyl oxygen
citric acid, acetic acid (vinegar)
Ester group– a carbon double bonded to an ____ and single bonded to a second ___ which is bonded to another ____.
-Associated with characteristic ___ of foods.
carbon oxygen oxygen carbon aroma
Ketones– ___ ___ atom is double bonded to an ____.
-Associated with ___ of food (cooking of ___, brewing of ___).
interior carbon
oxygen
flavor
meats, beer
Methyl Group– a ____ bonded to ___ ___.
- One of the important building blocks of ___ ___.
- Found in ___ and ___.
carbon three hydrogen organic molecules pectins gums
Phosphate group – a ___ bonded to ___ ___ and double bonded to one ____ and single bonded to one ____.
-Added to ____ to improve ____, ___ and ___-___capacity.
phosphorus two hydroxyl oxygen oxygen meat texture, juiciness, water-holding
Sulfhydryl Group– a ___ bonded to a ___.
- Compounds containing sulfhydryl groups are called ___.
- Important to ___ of foods (e.g. in ___ ___).
- Smell rotten eggs- you are smelling ____
sulfur hydrogen thiols structure bread dough sulfhydryl
Functional properties of food are the ___ and ____ factors that impact the ____ of food during ___, ___, and ___.
chemical and physical behavior formulation processing storage
Functional groups_in component molecules play an important role in ____ of the food itself.
functionality
Because most food contains a large proportion of ____, its functionality is a highly ____ ___ relative to the ____ of food.
water
critical factor
quality
A wide range of functions attributed to water include:
- Diluent and carrier of ____ components
- ___ for ___ reactions
- ___
- ___ of ___ transfer
- Participates in ___ ___
hydrophilic medium chemical solvent medium heat chemical reactions
Water molecule and structure:
___ ___ atoms bonded to ___ hydrogen
Each H atom shares an __ ___ with the ___.
Two hydrogen one hydrogen electron pair O
Oxygen ___ the ___ __ ___ more strongly than the ___.
A ___ is established where the oxygen is more ___ charged and the hydrogen is more ____ charged.
attracts shared electron pair hydrogen dipole negatively positively
This results in hydrogen bonding :
- High __ ___ and freezing point
- High __ ___
- High ___ ___.
boiling point
freezing point
vapor pressure
interfacial tension
Solubility- the ability to be ___ into solution.
-____ compounds disperse readily in water.
dispersed
hydrophilic
Hydration– water molecules ___ and ___ ___ molecules by acting as a ___.
-___ molecules
contact surround polar solvent Polar
Amphilphilic - contain both ___ and ____ regions.
-When water interacts with these compounds, ____ are formed.
Ex: ___, ___, ____.
polar
nonpolar
micelles
proteins, phospholipids, sterols
Moisture- the amount of ____ in a food.
water
Water activity- the amount of ____ ____ for ____ reactions or to support ____ ___, ___/____ reactions.
water available chemical microbial growth enzymatic chemical
Water is present in food in ____ states: ___ water, ____ water, and ___ water.
three
free
structural
bound
Free water - participates in ____ reactions and support ____ ____.
chemical
microbial growth
Structural water - participates in ___ reactions and support ___ ___.
chemical
microbial growth
Bound water - tightly associated with ____ ____ and does not act as ___ ___ molecules do.
Not available for _____ or ____ ___.
food components typical water reactions microbial growth
Food acids are primarily ___ ___ based (i.e. ___ acids).
carboxylic acid
organic
Differences in ___, ___ of ____ ___ and ___ of ___ ____ within the molecular structure, all influence the characteristics of the acids.
size number carboxylic units location carboxylic acid
