Surface treatment Flashcards
what can be regarded as surface treatment (5)
Irridiation
UV treatment
pulsed light
chemical treatments/ decontamination
physical sanding
how can antioxidants be used for surface treatment
reduce browning
salts like calcium can…
delay ripening
increase firmness
improve appearance
enhance resistance against disease
describe the functions of edible films
controls in and out of
organic vapours
water
solutes
light/UV
Gases
describe the requirements of edible coatings
free of toxins/ safe
good sensory qualities
high barrier and mechanical efficiencies
enough biochemical, physicochemical, and microbial stability
simple
non-polluting
low cost
what law is used to address the permeability of coatings
ficks law of diffusion
compenents of ficks law of diffusion
J- Mass flux
D- diffusivity
C change in conc
x change in distance
what is the flux
movement of objects from on point to another in a given time
why can permeability be hard to predict
lack of homogenous structure and hydrophilic nature of formulations
factors that affect permeability
material composition
functional group
addition of low molecular weight components
structure
molecular weight and crystalline structure of a polymer
temeprature
how does material composition affect permeability
polar are bad moisture barrier
nonpolar are good moisture barriers
how does a functional group affect permeability
chain interactions and motion: whether they are hydro philic or phobic
ionic: strong interactions = good O2 barrier
Hydrogen: absorbs water = high water vapour permeability
how does the addition of low moleuclar weight components effect permeability
disrupt the molecular interaction and increase permeability
how does structure effect permeability
polymer chain packing, loose or tight
how does moleuclar weight and crystline structe affect permeability
increased crystaliation =n increased permeability
