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Food Packaging > Lecture 10: Nanotechnology > Flashcards

Lecture 10: Nanotechnology Flashcards

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1
Q

nanostructures occurs _____ in many foods

A

naturally

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2
Q

what is the size range of most food proteins?

A

10-100nm

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3
Q

most polysaccharides and lipids are what shape?

what thickness?

A

linear polymers

several nm in thickness

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4
Q

what are stabilized foams and emulsions?

A

2D nanostructures

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5
Q

how is custard produced?

A

heat starch to “melt” nanocrystals, then cool

this forms a paste due to the recrystallisation and hydration process

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6
Q

what is the size of casein particles in milk?

A

100nm

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7
Q

how is casein produced in milk?

A

lactic acid is released by microbial action which cleaves kappa chain

allows particles to grow to give a gel structure

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8
Q

what are properties of nano materials?

A
  • high mobility
  • new optical properties
  • molecular recognition (binding/disruption) in DNA and hormone systems
  • supermagnetism
  • superconductivity
  • increased reactivity
  • attractive/repulsive surface charge
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9
Q

what is nanotechnology?

A
  • controlling matter at 0.1-100nm

- includes H atom, DNA, ATPsnthases, viruses, etc…

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10
Q

what is the size of human hair?

A

100,000nm

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11
Q

what is the zetasizer?

A

used to observe nanothings

gives you graph of intesntiy vs radius of molecule

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12
Q

what is the mastersizer?

A
  • applies shear stress which causes velocity gradients

- creates particle-wall collisions and particle-particle collisions

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13
Q

what is SEM?

A

scanning electron microscopy

  1. electron beam comes from electron gun
  2. electron passes through two condensor lenses, deflection coils and backscatter detector
  3. enters secondary electron detector and then x-ray detector
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14
Q

what is AFM?

A

atomic force microscopy

  1. laser shoots photodiode to detector
  2. single polymer chains are recorder under aqueous media w/ different pH
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15
Q

what is TEM?

A

transmission electron microscopy

  1. E beam goes through sample to graphite block.
  2. gold reflectors reflect e-beam to SED
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16
Q

what are applications of nanotechnology?

A 
material science
engineering
surface treatment
life science
diagnostics
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17
Q

what are food products that use nanotechnology?

A 
diet supplements
nutritional additives
color additives
food processing aids
long-life packaging
anti-bacterial kitchenware
fertiliser
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18
Q

what are applications of nanotech in the health and nutrition?

A

nanoencapsulation (flavour and nutrient control)

engineered nanoparticulate additives

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19
Q

what are applications of nanotech in novel materials?

A

antibacterial packaging

controlled gas permeability

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20
Q

what are applications of nanotech in food safety?

A

small environmental sensorys (humidity, frost, temp, etc…)

self evident shelf life labels

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21
Q

what is nanoencapsulation

A

coating and entrapment of a pure material or mixture into another material

the coated or entrapped material is usually a liquid, but can also be a solid or gas

examples of materials used: birds egg shells, plant seeds, bacterial spores, skin, seashells

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22
Q

what is the size of an emulsion droplet?

A

<100nm

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23
Q

what are the two components in nanoemulsion?

A

emulsion droplet and surfactant

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24
Q

what are reasons for encapsulation of flavours?

A
  1. stability: stable against heat, pH, oxidation in food processing
  2. taste and color: no unpleasant taste or color
  3. safety: mild on stomach b/c of its insolubility in gastric juices
  4. bioavailability: sustained release, high absorption and bioavailability
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25
Q

what are 3 methods of nanoencapsulation of flavors? what does each consist of?

A
  1. extreme emulsification (extreme flow)
  2. phase inversion composition
  3. phase inversion temp (low flow and quenching temp)
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26
Q

what equipment is used to make nanoencapsulation of flavours? describe the steps of this

A

spray drying

  1. drying gas flow enters through heater to the drying chamber
  2. goes through a collecting electrode to a grounded electrode
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27
Q

what is the state of flavours before and after spray drying?

A

before: flavor emulsion is in liquid state
after: encapsulated flavor powder is in a solid state

28
Q

what is NSSL?

A

nano sized self assembled liquid structures

emulsions of 30nm

used for nanoencapsulation

29
Q

what molecules are used in nanoencapsulation?

A 
coenzyme Q10 (ubiquinone)
lutein
lycopene
phytosterol (sitosteroil)
vit D
30
Q

describe coenzyme Q10 in nanoencapsulation

A
  • not soluble in water
  • bioavailability of CoQ10 can be reduced with a diet high in fiber
  • fortifying a nano-vehicle with CoQ10 enables its fortification into water or oil based food products
31
Q

describe phytosteroils in nanoencapsulation

A
  • more effective in competition w/ cholesterol
  • high effectiveness of solubility and transfer of phytosterol to the bile salt micelles in place of cholesterol
  • improves solubility
  • allows transportation without breaking up
  • can identify large micelle membrane and compete for transportation
32
Q

what are components of omega 3 bread that uses nanoencapsulation?

why is nanoencapsulation needed for this?

A

tuna fish oil

this allows mixing omega 3 into foods that can’t normally hide the fish flavor in which the oils more readily break down

33
Q

what are types of chemical cross-linked nanoparticles

A

common cross linker:
- glutaraldehyde (toxic)

novel crosslinkers:

  • genipin
  • natural di and tri carboxylic acids
34
Q

what is the difference between chemical and physical cross linked nanoparticles?

A

chemical: has chemical bonds between particles
physical: has electrostatic interactions within the particle

35
Q

what are types of physical cross linked nanoparticles?

A
  1. anion crosslinker: tripolyphoshate (TPP)

2. cation crosslinker: bivalent Ca2+

36
Q

alginate nanoparticles crosslinked by Ca2+ is an example of what?

A

a physical-cross linked nanoparticle

37
Q

what are 2 methods of loading bioactive compounds?

A

during preparation (incorporation)

after preparation (incubation)

38
Q

wood cellulose based polyelectrolyte nanoparticles are made from what?

A

carboxymethyl cellulose and quaternized cellulose

39
Q

what are advantages of physical cross linked nanoparticles?

A
  • no chemical crosslinking reagents
  • mild aqueous conditions
  • simple procedures
  • suitable for bioactive agents
40
Q

what are examples of nano-sized ingredients and additives?

A
  • colors, flavouring agents, preservative, antioxidants
  • lycopene
  • nano-salt
  • mineral supplements (Ca, Mg, Fe, Zn, etc…)
  • nano-tea (“slim-shake chocolate”)
41
Q

what are the benefits of using nanosized ingredients and additives?

A
  • better texture, flavor, taste
  • reduction in amont of salt, fat, sugar
  • enhanced bioavailability and health benefits
42
Q

how is nanotechnology used in a nutritional supplement drink for toddlers?

A

uses nano iron

increases bioavailability of the iron

43
Q

how is nanotechnology used in nano chicken feed?

A

nano selenium may stop bird flu b/c polystyrene nanoparticles bind w/ bacteria as alternative to chemical antibiotics

44
Q

describe the nano powdered catalytic device

A
  • coated with 20nm width zeolite nanoparticles
  • better taste and crisper deep fried foods
  • better consistency of pdt
  • lower costs
45
Q

describe the use of nano filters for food coloring and flavoring

A
  • gentle process
  • doesn’t involve phase change, heating or chemical extraction
  • produces fresher flavors
  • cheaper because it uses less energy
46
Q

what particles are usually incorporated into films?

what is the result of this?

A

inorganic particles (silver, TiO2, nanoclay)

changes functionalities of packaging materials (antibacterial packaging, improves barriers to O2 and moisture)

47
Q

what are effects of adding nanoparticles in packaging?

A
  • damages cell membranes to reduce E.coli growth and viability
  • affects particle size, surface charge, etc…
48
Q

what are characteristics of nanoclay particle based beer bottles?

A
  • lighter and stronger

- minimizes loss of CO2 from beer

49
Q

describe the organization of clay platelets and polymers in

a) microcomposites
b) nanocomposites

A

microcomposites:
- clay platelets are clustered with polymer around it

nano:
- polymer is between each clay platelets

50
Q

what are applications of smart dust?

A
  1. monitors humidity, temp, environment
  2. detects onset of food spoilage and food freshness
  3. monitor soil conditions and crop growth for precision farming
51
Q

what are types of nanosensors?

A
  • CO2
  • acoustic
  • odour
  • pressure
  • temp
  • humidity and dust
52
Q

what is the use of nanoelectric tongue?

A

for quality control fo beverages by electronic tongue

53
Q

what are gas indicators for shelf-life labels?

A

O2
ethanol
water vapour

54
Q

describe the use of CO2 as a gas indicator in self evident shelf life labels

A

critical conc of CO2 causes colour change due to

  • microbial respiration and fermentation
  • produce respiration
55
Q

describe the use of hydrogen sulfide as a gas indicator in self evident shelf life labels

A
  • used as a poultry freshness indicator
  • metmyoglobin based, which is normally brown
  • when metmyoglobin reacts with H2S produced by bacteria, it produces sulfmyoglobin (green)
  • brown to green color change: indicates loss of freshness due to bacterial growth
56
Q

what does green color due to hydrogen sulfide with poultry indicate?

A

indicates loss of freshness due to bacterial growth

57
Q

what is ripesense?

how does it work?

A

a ripeness indicator (self-evident shelf-life label)

as ripeness increases, volatiles cause a change in indicator from red to yellow

58
Q

what is toxin guard? how does it work?

A

type of self-evident shelf life label used to detect specific molecules (eg. toxins) produced by spoilage bacteria

  1. when toxins are produced by pathogens, detector antibodies are incorporated into a polymer
  2. detector Ab binds to toxin
  3. detector antibody-toxin complex binds to capture area on label
  4. binding to label causes color change or fluorescence which indicates product is not safe
59
Q

describe the temperature indicator

A
  • type of self-evident shelf life label
  • thermo-chromic dye is incorporated in the plastic
  • coffee brown colour changes to red when heated
  • red colour indicates that (1) contents are hot (2) lid has been properly attached (3) coffee has not become too cold to drink
  • overall, when red, the end-point temp has been reached. This occurs b/c at the end-point temp, a wax melts and irreversibly mixes with red dye
60
Q

what are some product safety concerns of nanotechnology?

A
  • dermal, inhalation and ingestion
  • crossing biological membranes, cells, tissue, organs
  • organ bio-concentration
  • increased SA which provides increased reactivity
61
Q

what are some environment safety concerns of nanotechnology?

A

risks involving mobility, transportation, reactivity, durability and bioaccumulation during manufacture, transport, use, disposal that is not fully assessed yet

62
Q

describe the use of nano silver in food and its effects on the environment

A
  • inserted for nano-enhanced germ-killing properties
  • has antimicrobial properties
  • but the same properties can also seriously harm aquatic organism, microorganism, ecosystems
63
Q

describe the use of carbon fulereness in food and its effects on the environment and human health

A
  • used in face and anti-aging creams
  • environmental impacts: brain damage in fish, kills water fleas, has bactericidal properties
  • human health impacts: low levels can be toxic to human liver cells
64
Q

describe the use of nano-sunscreen and effects on human health

A
  • nanoparticles of titanium dioxide and zinc oxide which are photoactive
  • but produces free radicals and causes DNA damage to human skin cells when exposed to UV light
65
Q

what are general consumer safety concerns of nanotechnology?

A
  • need to ensure nanostructures are solubilized/digested in the gut
  • need to ensure that greater bioavailability does not lead to increased health risks
  • toxicological properties of most nanoparticles are not yet known
66
Q

how can we move forward with use of nanoparticles?

A

industry should only use nano products when benefits > risks. The risks must be acceptable

assure product quality and promote research to ensure compliance, give case-by-case assessment of potential risks, give consumer information in regard to benefits and risks

Food Packaging (11 decks)

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