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LECTURE 2.
WHEY PROTEIN EDIBLE COATINGS WITH ANTIMICROBIAL ACTIVITY IN RIPENED CHEESE
Marta Henriques
2017
ESAC – IPC
College of Agriculture – Polytechnic Institute of Coimbra
Department of Food Science and Technology
Poznan University – PolandFaculty of Food Science and TechnologyErasmus mission
Part D. nonconventional applications
WPC films active coatings
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Films & Coatings
• Food Safety• Ensure microbiological safety and food protection from the
influence of external factors
• Edible coatings• Natural
• Biodegradable
• May incorporate active ingredients and additives
• May present similar properties to the synthetic coatings
Whey protein coatings applications
• Proved Characteristics…• Small water retention capacity (hidrophyllic)
• High oil and oxygen barrier capacity (similar to some synthetic polymers)
• Improve food characteristics with the incorporation of antioxidants and antimicrobials.
Applications
Fruits
Fresh/processed meat
Cheese
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Motivation
• Replacement of conventional/synthetic coatings (PVA) by naturalcoatings with antimicrobial activity
• Whey protein valorization (WPC) from dairy industry by-products
• Use of natural bioactive compounds as antimicrobials
• Evaluate how whey protein polymerization method influences the performance of cheese coatings
• Assess the effectiveness of antimicrobial whey protein edible coatings on cheese
uncoated
commercial coatingUV
modification (UV)
heat denaturation
(HD)(HD+UV)
WPC, glycerol, guar gum, tween 20, sunflower oil, lactic acid, natamycin
(Ramos, 2011)
physicochemical, microbiological and sensorial properties
ripened cheese
antimicrobial WPC coatings
natamycin
Part D. WPC-based coatings with antimicrobial activity
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Commercial HDHeat denaturation
UVUV polymerization
HD+UV
PVAPolyvinyl alcohol
Coating types
WPCwhey protein concentrate: 10% (w prot/w coat)
Glycerol (plasticizer): 50% (w gly/w prot)Guar gum (thickener): 0.7% (w thick/w coat)
Sun flower oil (hydrophobic compound): 10% (w oil/w coat)
Tween 20 (surfactant): 0.2% (w surf/w coat)
AntimicrobialNatamycin
2.5 g/L
AntimicrobialsLactic acid: 6 g/L
Natamycin: 0.125 g/L
PhotoinitiatorIrgacure 2969: 3.5% w phot/w prot
Positive control
Negative control
Uncoated cheese
Coating application
Commercial HDHeat denaturation
UVUV polymerization
HD+UV
Polymerization methods
Dry Dry DryDry
Heat treatment
Coating application
UV treatment
Heat treatment
Coating application
Coating application
UV treatment
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Coating performance on cheeseCheese properties
Physicochemical
Weight loss
MoistureFat
Protein
Sodium
aw
pH
Total Acidity
Texture
Hardness
Microbiological
Staphylococcusspp.
Pseudomonasspp.
Enterobactereacea
Yeasts & molds
Sensorial
Visual Appearance
Colour
Exterior:
whole cheese
Interior:
sliced cheese
Cheese - physicochemical properties
Weight loss
time (days)
0 5 10 15 20 25 30 35 40 45
Wei
ght
loss
(%
)
0
20
40
60
80
100
Uncoated HD UV HD+UV Commercial
Uncoated57% weight loss
Coated46-52% weight loss
- small cheese size- large ripening period
The coating type and polymerization method influence the weight loss profile
Part D. WPC-based coatings with antimicrobial activity
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Cheese - physicochemical properties
Moisture content
time (days)
0 5 10 15 20 25 30 35 40 45
Moi
stur
e (%
)
10
20
30
40
50
60
70
Uncoated HD UV HD+UV Commercial
Uncoated43% water loss
Coated33-39% water loss
UV and HD+UV coatings are more effective then commercial coating
Part D. WPC-based coatings with antimicrobial activity
time (days)
0 5 10 15 20 25 30 35 40 45
Ha
rdn
ess
(g)
0
2000
4000
6000
8000Uncoated HD UV HD+UV Commercial
nd> 6000 g
HD and Uncoated cheese have the lower hardness profiles
HD+UV and Commercialcoatings have the higher hardness profiles
Higher hardness
Higher effectiveness preventing water loss
Cheese - texture propertiesHardness
Part D. WPC-based coatings with antimicrobial activity
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Physicochemical properties
time (days)
0 5 10 15 20 25 30 35 40 45
Fa
t (%
)
10
20
30
40
50
Uncoated HD UV HD+UV Commercial
time (days)
1 15 30 45
Pro
tein
(%
)5
10
15
20
25
30
35
Uncoated HD UV HD+UV Commercial
aa
a
a a
b b bc
cc
Fat content Protein content
Part D. WPC-based coatings with antimicrobial activity
cheese - microbiological profile
Pseudomonas spp.
Enterobacteriaceae
time (days)
0 5 10 15 20 25 30 35 40 45
Log
(cf
u g
-1)
3
4
5
6
7
8
9
10
11
12
Uncoated HD UV HD+UV Commercial
Yeasts & Molds
time (days)
0 5 10 15 20 25 30 35 40 45
Staphylococcus spp.
Log
(cf
u g
-1)
3
4
5
6
7
8
9
10
11
12
Uncoated cheese- microbiological
development
Coated cheeses- microbiological
control or inhibition
Commercial is the most effective against yeasts and molds
HD+UV have the overall best microbiological performance
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Uncoated HD UV HD+UV Commercial
t0
t15
t30
t45
visual identification of molds after 30 days
No visual differences were identified between HD+UV and Commercialcoated cheeses
Part D. WPC-based coatings with antimicrobial activity
cheese - sensorial profile
Interior: sliced cheeseExterior: whole cheese
0
1
2
3
4
5shape
rind color
colour homogeneity
hardness
Uncoated
HD
UV
HD+UV
Commercial
1
2
3
4rind color
odor
consistency
general acceptability
flavor
holes
No significant differences (p<0.05) were obtained between treated cheesesThe HD+UV and the commercial are the most accepted cheeses.
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Conclusions in more detail…
• It was possible to produce natural whey protein edible films with antimicrobial activity
• The protein polymerization method influences the coating performance on cheese• Using only heat denaturation did not improve significantly the coating
efficiency• UV polymerization improved the coating efficiency
• Antimicrobial Whey Protein HD+UV coating• prevents more efficiently water loss• leads to physicochemical cheese composition similar to the commercial
coating• prevents and inhibits microbial growth• brings a good visual appearance to cheese
• Antimicrobial whey protein-based edible film produced by HD+UV polymerization is an effective alternative to commercial coatings
team
Carlos Pereira David Gomes
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Currently...
Mucor
Tempo (dias)
0 1 2 3 4 5
Diâ
metr
o (c
m)
0
2
4
6
8
10
CN EE CP
Penicillium
Tempo (dias)
0 1 2 3 4 5 6 7
Diâ
met
ro (
cm)
0
1
2
3
4
5
CN EE CP
Negative control
Positive control
Thymusmastichina
extract
TANKS FOR YOUR ATTENTION
Marta Henriques [email protected]