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FSTC
Chapter 4
31
Science
Undergraduate 4
02/15/2010

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Term
chemistry
Definition
basic science describing foods and reactions
Term
Matter
Definition
composed of ELEMENTS described in the periodic table
Term
compounds
Definition
2 or more elements chemically bonded together
Term
mixtures
Definition
2 or more substances combined physically rather than chemically
Term
chemical bonds
Definition
are the forces that hold atoms together and store energy
Term
covalent bonds
Definition
strong and form the back bone offood molecules
Term
ionic bonds
Definition
transfer elecgtrons between reactants forming chared ions
Term
hydrogen bonds
Definition
unequal sharing of the electrons between 2 diff molecules and are relatively weak
Term
composition(condensation)
Definition
reactions form larger molecules from smaller ones and yield a molecule of water
Term
d
Definition
Term
decompositon(hydrolysis or digestion)
Definition
reactions form smaller moleules from largerones by inserting water across a bond
Term
enzymes
Definition
are BIOLOGICAL CATALYSTS with ACTIVE SITES that make reactions occur by REDUCING ACTIVATION ENERGY. theyrequire precise temperature, ph and substrate concentration to work well and proceed through the reaction unhcnaged themselves.
Term
oxidation reduction
Definition
reactions are COUPLED to facilitate movement of electrons or oxygen
Term
polymerization
Definition
reactions join many molecules together into compounds of high molecular weight, good for forming films
Term
addition
Definition
reactions add molecules across doubleor triple bonds which are more reactive than single bonds
Term
functional groups
Definition
in food molecules create specific propeties
Term
funcional properties
Definition
are physical and chemical properties of food molecules that affect behavior of foods
Term
solubility
Definition
hydrogen bonding helps dissolve and disperse ingredients
Term
hydration
Definition
water surrounds and interacts with solutes acting as a carrier and diluent
Term
amphiphylic molecules
Definition
are attracted to water and fat.in water they form MICELLES which are clusters with hydrophobic ends toward center away from water.
Term
hydropylic
Definition
attracted to water
Term
hydrophobic
Definition
attracted to fats
Term
water activity
Definition
indicates availability of water to enter microbial, enzymatic or chemical reactions. it affects the shelf life and texture of food.
Term
moisture sorption isotherms
Definition
graphs that measure water activity against % moisture,allow prediction of storage stability and packaging requirements of a food.
Term
heat transfer
Definition
water conducts thermal(kinetic) energy to molecules.
Term
glass transition temperature
Definition
temp where change in mobility of water and other molecules occurs
Term
food acids
Definition
come in many and have many functionalproperties
Term
hygroscopicity
Definition
attraction for moisture (acids are low in this property)
Term
weak acids
Definition
have a small amount og H+ ions dissociated from them
Term
strong acids
Definition
have a large amount of H+ ions dissociated from them
Term
ionization constant (Ka)
Definition
expresses the degree of dissociation
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