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Development of Novel Smart Packaging to Use in the Food Industry.

Roberts, Luke A. (2010) Development of Novel Smart Packaging to Use in the Food Industry. Doctoral thesis, University of Surrey (United Kingdom)..

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Abstract

Oxygen indicators are one of the most common forms of intelligent packaging but despite considerable literature and commercial examples, current technologies are often unsuited for the desired applications owing to storage problems, reversibility, or high sensitivity to oxygen. Polyviologens were synthesised and their electrochemistry analysed by cyclic voltammetry. Polyviologens show single electron reduction to a stable radical cation that has an intense violet colour. This radical reacts readily with molecular oxygen to regenerate the oxidised polyviologen. The polyviologens are therefore of interest as the electrochrome in an oxygen indicator. Polyviologens were formulated into oxygen indicators that were triggered by UV light. The oxygen indicators based on polyviologen electrochromes were more efficient in the trigger step compared to methylene blue. The reduced forms of polyviologens and methylene blue are highly reactive to oxygen and these oxygen indicators become completely oxidised at oxygen concentrations below 0.05%. There are applications where higher residual oxygen levels are acceptable and therefore these indicators would be too sensitive. Furthermore, where an oxygen scavenger is used the time required for the scavenger to remove residual oxygen could trigger the indicator prematurely. To decrease the sensitivity of the oxygen indicator to oxygen, electrochromes with more anodic redox potentials were trialled. Thionine and dicyanodimethylviologen dimeylsate were incorporated into oxygen indicator formulations and their sensitivity to oxygen investigated. These electrochromes showed a decreased sensitivity to oxygen; thionine detected oxygen above 0.9-2.45% and dicyanodimethylviologen dimeylsate above 4.00%. Oxygen indicators based on these electrochromes could therefore be used when higher oxygen concentrations are permissible. As another intelligent packaging application, a high pressure pasteurisation indicator was discussed. An indicator is required to visually display that the package has been pasteurised to the correct high pressure conditions. Initial research into the production of an indicator compound based on the pigment perylenetetracarboxylic anhydride was investigated.

Item Type: Thesis (Doctoral)
Divisions : Theses
Authors : Roberts, Luke A.
Date : 2010
Additional Information : Thesis (Eng.D.)--University of Surrey (United Kingdom), 2010.
Depositing User : EPrints Services
Date Deposited : 06 May 2020 14:37
Last Modified : 06 May 2020 14:44
URI: http://epubs.surrey.ac.uk/id/eprint/856314

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