Surface treatment Flashcards

1
Q

what can be regarded as surface treatment (5)

A

Irridiation
UV treatment
pulsed light
chemical treatments/ decontamination
physical sanding

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2
Q

how can antioxidants be used for surface treatment

A

reduce browning

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3
Q

salts like calcium can…

A

delay ripening
increase firmness
improve appearance
enhance resistance against disease

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4
Q

describe the functions of edible films

A

controls in and out of
organic vapours
water
solutes
light/UV
Gases

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5
Q

describe the requirements of edible coatings

A

free of toxins/ safe
good sensory qualities
high barrier and mechanical efficiencies
enough biochemical, physicochemical, and microbial stability
simple
non-polluting
low cost

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6
Q

what law is used to address the permeability of coatings

A

ficks law of diffusion

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7
Q

compenents of ficks law of diffusion

A

J- Mass flux
D- diffusivity
C change in conc
x change in distance

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8
Q

what is the flux

A

movement of objects from on point to another in a given time

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9
Q

why can permeability be hard to predict

A

lack of homogenous structure and hydrophilic nature of formulations

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10
Q

factors that affect permeability

A

material composition
functional group
addition of low molecular weight components
structure
molecular weight and crystalline structure of a polymer
temeprature

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11
Q

how does material composition affect permeability

A

polar are bad moisture barrier
nonpolar are good moisture barriers

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12
Q

how does a functional group affect permeability

A

chain interactions and motion: whether they are hydro philic or phobic
ionic: strong interactions = good O2 barrier
Hydrogen: absorbs water = high water vapour permeability

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13
Q

how does the addition of low moleuclar weight components effect permeability

A

disrupt the molecular interaction and increase permeability

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14
Q

how does structure effect permeability

A

polymer chain packing, loose or tight

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15
Q

how does moleuclar weight and crystline structe affect permeability

A

increased crystaliation =n increased permeability

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16
Q

how does temp affect permeability

A

polymer have more mobility at higher temps so high perm

17
Q

what can permeability regulate

A

water loss
gas exchange

18
Q

what are the active properties of edible films and coatings

A

encapsulation
improvement of mechanical resistance
individual protection of small pieces of food

19
Q

what/how can edible films and coating encapsulate

A

flavours
anti-microbial/antioxidants
pigments
salts

20
Q

how can it improve mechanical resistance (edible films)

A

improve appearance
colour, shine
roughness
stickiness

21
Q

typical application of edible coatings

A

spray fluidisation
falling and pan coatings
spraying
dipping
brushing

22
Q

what does the application method depend on

A

film thickness and solution viscosity