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Food Science 4170
n/a
88
Science
Undergraduate 4
03/02/2014

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Term
Colloid
Definition
Substance microscopically dispersed throughout another
Term
Emulsion
Definition

dispersion liquids

colloidal dispersion discreet droplets one liquid in continuous phase of another

Term
Gel
Definition

continuous phase interconnected particles or macromolecules intermingled with continuous liquid phase soft elastic consistancy 

elastic solid like behavior

deforms recoverably 

Term
Sol
Definition
colloid suspension very small particles in contin. liquid medium
Term
Foam
Definition

colloid dispersion gas bubbles

in continuous liquid phase 

Term
Aerosol
Definition
Colloid dispersion solid or liquid drops in gas
Term
Coalescence
Definition

2+ particles fuse single larger particle

surface area reduced

Term
Flocculation
Definition

clumping of small particles no fusing into larger particle

surface area not reduced

some surface sites blocked touching other

Term
surface tension
Definition

resulting force, right angles directed inward

work involved increasing interfacial surface area between 2 phases

Term
peptization
Definition

redispersing of coagulated particles

in cases where possible

Term
coagulation
Definition

aggregation 

interparticle distances on order atomic dimentions

Forces between coagulated particles strong

coag often irreversible

Term
Lyphobic colloid
Definition

colloidal dispersion in which the dispersed phase has little or no affinity for the continuous phase.  Unstable

Term
Solution
Definition

homogenous mixture composed of only one phase

Term
Emulsifer
Definition

materials which can be added to an emulsion which prevents flocculation of the emulsion particles and thus makes the emulsion more stable

Term

Monodisperse colloid

Definition

a colloidal dispersion in which all of the particles are the same size and shape

Term

Polydisperse colloid 

Definition

a colloidal dispersion in which there is a distribution of particle sizes or shapes

Term

Ostwald ripening

Definition

observed phenomenon in solid solutions or liquid sols that describes the

change of an inhomogenous structure over time

Term

Surface excess concentration

Definition
Term

Homogenizer

Definition

lab equipment used to homogenize and break down particle size

Term

Colloid mill

Definition

machine used to reduce the particle size of a solid in suspension in a liquid

Term

Electrical double layer

Definition

depletion and enrichment of the solution layers near a surface

Term

DLVO theory 

Definition

theory that explains the aggregation of aqueous dispersions quantitatively and

describes the force between charged surfaces interacting through a liquid medium

Term

Steric stabilization

Definition

as two particles approach one another, their absorbed coatings of polymers interact and impart stability to both flocculation and coalescence by several mechanisms

Term

Depletion flocculation

Definition

the overall attraction of the two particles at very close separations as a result of water being drawn out of the pool of pure water between them by osmosis

Term

HLB numbers 

Definition

scale that assigns groups a number in terms of relative lipophilic and hydrophobic groups to determine if it’s an o/w or w/o emulsion

Term

Sedimentation/creaming 

Definition

if there is a density difference between the two liquid components of an emulsion,

then the dispersed droplets will either sediment ot the bottom or cream out

Term

Lecithin

Definition

natural emulsifier

Term

Amylopectin

Definition

component of starch that is a polysaccharide and highly branched polymer of glucose

Term

Alditol 

Definition

sugar alcohol

Term

Aldaric acid 

Definition

With a stronger acid such as nitric acid, one can oxidize both ends of the sugar molecule giving aldaric acids

Term

Lactase 

Definition

enzyme used in the digestion of milk protein, lactose

Term

Maillard browning 

Definition

chemical reaction of amino acids and reducing sugars that give brown notes and flavors

Term
Epimer
Definition
 stereoisomers that differ in configuration of only onestereogenic center other than last asymmetric carbon atom and anomeric carbon atom
Term

Anomeric carbon

Definition

carbon that defines the thing

Term

Furan 

Definition

furanose is a five membered ring

Term
Definition
[image]
Term

Glycoside 

Definition

a molecule in which a sugar is bound to another functional group via glycosidic bond

Term

Limit dextrin 

Definition

remaining polysaccharide after degradation stops since neither anylases can hydrolyze 1-6 linkages nor proceed past them

Term

Cellulose

Definition

liner Beta 1-4 linked polymer of d-glucose.

Primary structural component of plant cell walls. 

Almost completely insoluble in water, more soluble in shorter chain length.

Term

Uronic acid

Definition

if only the primary alcohol is oxidized, uronic acid is produced

Term

Maltase

Definition

hydrolizes maltose

Term

Enolization

Definition

the chemical equilibrium between ketone and alcohol

Term

Dietary fiber

Definition

indigestible portion of food derived form plants

Term
stereoisomer
Definition
 isomeric molecules that have the same molecular formula and sequence of bonded atoms (constitution), but that differ only in the three-dimensional orientations of their atoms in space
Term
Anomer
Definition
one of twostereoisomers of a cyclic saccharide that differs only in its configuration at thehemiacetal or hemiketal carbon, also called the anomeric carbon
Term

Pyran  

Definition

pyranose is a 6 membered ring with double bonds

Term

HFCS

Definition

corn syrups that has undergone enzymatic processing to convert some of its glucose to fructose to produce a desired sweetness

Term

Cyclodextrin

Definition

short, cyclic amylosic oligomers that are natural products of the bacterial degradation of starch

Term

Amylose

Definition

component of starch that is made up of D-glucose units

Term
glucose isomerase
Definition

is anenzyme that catalyzes thechemical reaction

D-xylose [image] D-xylulose
Term

Caramelization

Definition

direct heating of carbohydrates produces a complex set of reactions called caramelization, and is assisted by addition of small amounts of acid and salts.

Term

Aldonic acid

Definition

when treated with a weak acid such as HOCl, the aldehyde groups of sugars can be oxidized to acids, giving aldonic acids

Term

Invert sugar

Definition

mixture of glucose and fructose

obtained from splitting sucrose up

Term

Oligosaccharide

Definition

2-10 linked rings that are biologically synthesized by enzymes and have specific anomeric configurations

Term

Waxy starch

Definition

pure amylopectin starch with amylose

Term

Exoglycosidase

Definition

cleave off maltose disaccharides processively from the non-reducing end of the polysaccharide chain

Term

Retrogradation

Definition

when amylase precipitates out into a relatively regular solid because its not very soluble at low temperatures

Term

molecular gastronomy

Definition

approach to cooking that appreciates the value of scientific knowledge in the preparation of meals

Term

Helmholtz free energy 

Definition

A=U-TS, measures the ‘useful’ work obtainable from a closed system, used less often but applies to pressure cookers

Term

Gibbs free energy 

Definition

G=H-TS, measures the usefulness of work obtainable from a thermodynamic system at a constant temperature and pressure.

Term

chemical potential 

Definition

ui , the partial molar Gibbs free energy, or change in G with the composition, expressed as the amount of component i

Term

activity

Definition

partial pressure of a component

divided by the equilibrium 

Term

calorie

Definition

amount of energy needed to raise the temp of 1 gram of water by 1 degree celcius

Term

hydrophobic molecule  

Definition
no likey water
Term

electronegativity

Definition

the tendency of an atom to attract electrons toward itself

Term

calorimetry 

Definition

device used to measure heat exchanges

Term

triple point 

Definition

the temp and pressure where solid liquid and gas all coexist

Term

heat capacity 

Definition

measure of how much energy has to be added to a system to increase its temperature by a certain amount, or removed from the system to cool it

Term

glass transition temperature 

Definition

temperature at which an amorphous material becomes brittle

Term

heat of fusion 

Definition

change in enthalpy resulting in heat needed to melt something

Term

entropy

Definition

measure of disorder

Term

freeze concentration  

Definition

process of freezing and removing frozen material (water)

Term

 heat of vaporization 

Definition

change in enthalpy resulting in heat needed to turn liquid to gas

Term

enthalpy 

Definition

H, total heat of the system = internal energy + pressure and volume

Term

freezing point depression 

Definition

the process in which adding a solute to a solvent decreases the freezing point of the solvent

Term

hydrogen bond 

Definition

strong, attractive, non-covalent interactions between certain molecules containing hydrogen atoms and other functional groups that contain electronegative atoms. HOFBrINCl

Term

food glass 

Definition

brittle version of foods

Term

dendrite 

Definition

branched crystals, charataristic of runaway freezing in undercooled water

Term

entropy of mixing 

Definition

increase in total entropy when several initially separate systems are mixed without chemical reaction

Term

ultrafiltration

Definition

process of using semi-permeable membranes with large pore sizes, which can separate out colloidal-size particles and larger suspended materials from solvent water

Term

First law of thermodynamics 

Definition

energy of an isolated system is constant

Term

second law of thermodynamics 

Definition

the entropy of an isolated system increases during any natural process

Term

osmotic dehydration 

Definition

process of placing item like apple slices into a solution of highly concentrated solution to extract the water from the apple

Term

ideal solution 

Definition

the partial pressure of component A divided by the equilibrium vapor pressure of the pure component, is equal to its mole fraction Xa

Term

sorption isotherm hysteresis 

Definition

curves that measure the tendency of the water to be absorbed by the food product at a constant temperature as a function of overall water content, often exhibits hysteresis, which is when a different activity is recorded for a given moisture content depending on whether the food sample is being dried out or rehydrated. 

Term

Lyophilization

Definition

freeze drying,

food is dehydrated by first freezing, after which the water is removed by sublimation

Term

Cryoscopes

Definition

devices used to measure the freezing points of liquids, used a lot in dairy science

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