dispersion liquids

colloidal dispersion discreet droplets one liquid in continuous phase of another

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

elastic solid like behavior

deforms recoverably 

colloid dispersion gas bubbles

in continuous liquid phase 

2+ particles fuse single larger particle

surface area reduced

clumping of small particles no fusing into larger particle

surface area not reduced

some surface sites blocked touching other

resulting force, right angles directed inward

work involved increasing interfacial surface area between 2 phases

redispersing of coagulated particles

in cases where possible

aggregation 

interparticle distances on order atomic dimentions

Forces between coagulated particles strong

coag often irreversible

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

homogenous mixture composed of only one phase

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

Monodisperse colloid

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

Polydisperse colloid 

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

Ostwald ripening

observed phenomenon in solid solutions or liquid sols that describes the

change of an inhomogenous structure over time

Surface excess concentration

Homogenizer

lab equipment used to homogenize and break down particle size

Colloid mill

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

Electrical double layer

depletion and enrichment of the solution layers near a surface

DLVO theory 

theory that explains the aggregation of aqueous dispersions quantitatively and

describes the force between charged surfaces interacting through a liquid medium

Steric stabilization

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

Depletion flocculation

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

HLB numbers 

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

Sedimentation/creaming 

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

Lecithin

natural emulsifier

Amylopectin

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

Alditol 

sugar alcohol

Aldaric acid 

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

Lactase 

enzyme used in the digestion of milk protein, lactose

Maillard browning 

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

Anomeric carbon

carbon that defines the thing

Furan 

furanose is a five membered ring

Glycoside 

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

Limit dextrin 

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

Cellulose

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.

Uronic acid

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

Maltase

hydrolizes maltose

Enolization

the chemical equilibrium between ketone and alcohol

Dietary fiber

indigestible portion of food derived form plants

Pyran  

pyranose is a 6 membered ring with double bonds

HFCS

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

Cyclodextrin

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

Amylose

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

is anenzyme that catalyzes thechemical reaction

D-xylose [image] D-xylulose

Caramelization

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

Aldonic acid

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

Invert sugar

mixture of glucose and fructose

obtained from splitting sucrose up

Oligosaccharide

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

Waxy starch

pure amylopectin starch with amylose

Exoglycosidase

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

Retrogradation

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

molecular gastronomy

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

Helmholtz free energy 

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

Gibbs free energy 

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

chemical potential 

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

activity

partial pressure of a component

divided by the equilibrium 

calorie

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

hydrophobic molecule  

electronegativity

the tendency of an atom to attract electrons toward itself

calorimetry 

device used to measure heat exchanges

triple point 

the temp and pressure where solid liquid and gas all coexist

heat capacity 

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

glass transition temperature 

temperature at which an amorphous material becomes brittle

heat of fusion 

change in enthalpy resulting in heat needed to melt something

entropy

measure of disorder

freeze concentration  

process of freezing and removing frozen material (water)

 heat of vaporization 

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

enthalpy 

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

freezing point depression 

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

hydrogen bond 

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

food glass 

brittle version of foods

dendrite 

branched crystals, charataristic of runaway freezing in undercooled water

entropy of mixing 

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

ultrafiltration

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

First law of thermodynamics 

energy of an isolated system is constant

second law of thermodynamics 

the entropy of an isolated system increases during any natural process

osmotic dehydration 

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

ideal solution 

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

sorption isotherm hysteresis 

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. 

Lyophilization

freeze drying,

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

Cryoscopes

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