6. Active and intelligent packaging

How does packaging help prevent food waste?

• Packaging is only a minor contribution to total GHG emission

• Food loss should be prevented

• Which packaging can help reduce it

Oxygen absorber

• Packaging that actively affects the internal environment of the product

• Objective: increase shelf life

• Oxygen is absorbed by packet

Definition and principle of active packaging

• Active when the packaging actively change the condition of the packed food to extend shelf-life or improve safety or sensory properties, while maintaining quality of packaged food

• The active components may be part of the packaging material or could be inserted or attached to the inside of the packaging

Active film

• When active components are incorporated into the film

• However these may degrade overtime when packaging is not yet used

• Therefore this packaging can be activated using for example UV light.

Passive protection

• The scavenger layer is strategically put in between other layers so it only catches the oxygen passing through the packaging

Advantages of oxygen absorbers

• Prevent oxidation: rancidity, change of colours, loss of nutrients

• Prevent growth of aerobic microbes

• Reduce or eliminate the need for preservatives and antioxidants

• Slow don metabolism

• Alternative for MAP and vacuum

Combination of MAP and vacuum packaging

• MAP or vacuum packaging may not facilitate complete oxygen removal → residual O₂ may be removed using oxygen scavenging technology

Modelling active packaging design

• can help optimize packaging

Carbon dioxide emitters and scavengers

• CO₂ to inhibit microbial growth

• Removal of O₂ and dissolution of CO₂ in the product creates a partial vacuum → collapse of flexible packaging

  • Dual action CO₂ generators/O₂ scavengers

• Safety risks of CO₂ in packaging

  • E.g. C. botulinum type B

• Mechanisms: ferrous carbonate or a mixture of ascorbic acid and sodium bicarbonate

Moisture absorber

• Used to absorb drip from meat, poultry and fish (or for vegetables that condense)

• This then prevents microbes from growing in the moisture and it looks more attractive to consumers

Advantages of moisture absorber

• Enhanced product appearance and freshness: shelf life

• Removes and retains spoilage bacteria

• Reduces costly rewraps and product downgrades

• Reduces product and packaging waste

Which factors of the food, the package and the environment do you need to consider when selecting a type of moisture absorber

Food:

• Sensitivity

• Size

• Weight

• Initial a_w

• Shelf life

Package:

• WVTR

Environment:

• T

• RH

Antimicrobial packaging

• Antimicrobial agents (e.g. organic acids or bacteriocins’ or metals or metal oxides) may be incorporated in or on (coating) package materials

• Extends shelf life: especially for fresh foods

Forms of antimicrobial packaging

• Additions of sachets/pads containing volatiles

• Incorporation of volatile and non-volatiles directly into polymers

• Coating or adsorbing antimicrobials onto polymer surface

• Immobilization of antimicrobials to polymers by ion or covalent linkages

• Use of polymers that are inherently antimicrobial

Direct vs indirect contact

• if only part of the food comes in contact with the food, then it might be good to allow the volatiles to diffuse into the packaging atmosphere.

• These are known as release antimicrobials

Release antimicrobials

• Synthetic antimicrobials

• Natural antimicrobials: e.g. essential oils

• Naturally in situ formed antimicrobials

  • e.g. mustard seeds must be broken and combined with water to get antimicrobial effect.

• Allows for controlled release

Effect of AITC on fat

More fat = reduction in antimicrobial effect of AITC

Controlled formation and release of AITC (antimicrobial compound in musterd)

• Activate Myrosinase:

  • Hydrolysis of sinigrin glucosinolate

  • Formation of AITC

• Release AITC:

  • Diffusion

  • Partitioning

• Control by:

  • Particle size

  • Water content

  • Oil content

Advantages of active packaging

Extension of shelf life

• Enables longer transport, batch production

Less expensive packaging material

• packaging for limited shelf life products may require enhancement of only one property for a fixed period

Simpler processing

• Additional microbiological “hurdles” can allow MAP to be achieved without use of expensive equipment

Difficult to handle products

• oxygen can be removed form tightly packed products such as cheeses that are subject to mold growth

• Prevents use of antimicrobials in foods: clean label

Perceived quality

• Perceived quality = analyses product quality from the viewpoint of the consumer

• Quality of food changes

• Variation in intrinsic quality attributes

  • Variation in initial quality

  • Variable conditions

Why is intelligent packaging necessary?

What is intelligent packaging?

Smart freshness indicator

What are the two types of intelligent packaging?

Packaging systems with sensor for measuring:

• Quality attributes (indicator compound for quality, like volatiles)

• Advantage: direct quality indicator

• Disadvantage: specific sensors for each product group

• External conditions (T, humidity, pressure, integrity)

• Advantage: sensor has broad application

• Disadvantage: indirect quality indicator

Application of IP

Expensive, highly perishable foods

• rapid quality deterioration

• variable initial quality

• High wastage

What intelligent packaging could be used for milk?

• Can be indirect, by measuring temperature with a sensor we can predict quality of food

• Quality sensor would be too expensive as milk is pretty cheap

TTI

• Time temperature indicator

• Provide visual indications of the cumulative effects of the temperature history and are used as freshness indicators for estimating remaining shelf life

• See picture: on day four there was an increase in temp to it can be assumed that that decreased the quality

Formula TTI

• Temperature sensitivity should have similar sensitivity to temperature as the product.

Mechanisms of TTI

• Polymerization that occurs upon increase in temperature

• Enzymatic reaction: drop in pH from enzymatic lipid hydrolysis

  • Lipolytic enzymes and pH indicator dye

  • Lipid substrate

  • Close to reactions in fatty foods

• Diffusion reactions: diffusion is dependent on temperature, dependent on Ficks first law

Fresh fish quality sensor

• Initial quality: unknown and highly variable

• Development of freshness sensor

• Important quality attribute of fresh fish:

  • Smell that indicates freshness

  • TMA levels correlate with sensory evaluation of freshness

Development of non-destructive method

• Non-destructive method monitors changes in the freshness status

  • Electrodes in aqueous sensor phase

  • Volatile compounds dissolve in aqueous phase

• In the picture you can see that the results correlate with the freshness of the fish

Modelling TMA formation

• The graph also shows the differences in quality per fish

Approach development: intelligent packaging

Quality-controlled logistics

• Instead of first in first out, FIFO can be determined depending on simply quality if using sensor

Dynamic pricing based on DED

• Currently, only discount on last selling day

• Dynamic pricing

  • Based on dynamic expiration date

  • Consumers can choose for products with longer/shorter remaining shelf life