טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentMeltzman Shai
SubjectDetection of Oxygen in Modified Atmosphere Food Packaging
DepartmentDepartment of Chemistry
Supervisor Professor Yoav Eichen
Full Thesis text - in Hebrew Full thesis text - Hebrew Version


Abstract

Modified atmosphere packages (MAP) are packages in which the inside atmosphere does not contain the normal air mixture. In this type of packages the atmosphere is changed in order to extend the shelf life of the packaged food product. In 2007, more then 50 billion modified atmosphere packages have been used in the food industry in the USA, Western Europe and Japan. Monitoring and detection of inadequate sealing or incorrect air mixtures inside the package is very important due to microbial growth which can start along with the introduction of oxygen to the package (which is assumed to be oxygen-free). This microbial growth can compromise the quality of the packaged product up to the point of a serious health hazard and will most probably shorten the initial shelf life which the food product should have. A similar phenomenon of shortened shelf life of a food product can occur in packages with high levels of oxygen, as a result of an oxygen leak into/from the package. The goal of this research was to examine non-destructive methods that will be able to quantitatively report oxygen levels at a given atmosphere. The technology should provide the food manufactures the ability to monitor the quality of each modified atmosphere package along the supply chain, and by that to reduce the waste and the production line interferences to a minimal level. In this research we examined two different approaches for detecting oxygen in a closed vessel. The first approach is a visual detection of oxygen, using the naked eye. The second approach is based on a machine-readable based oxygen detection in which the detection is carried out by external reading/measuring equipment. The visual detection in this study is based on the colorigenic reaction of catechin, a polyphenol which is abundant in fruits and vegetables when exposed to oxygen. Ctaechin undergoes oxidation processes during which its color changes from colorless for the reduced form, to brown/black for the oxidized form. The machine-readable detection in this research is based on the change of the intensity and/or lifetime of photoluminescent materials as a function of oxygen levels in their surrounding atmosphere. We focused on three different photo luminescent materials: Iridium based complexes, erythrosine B which is a photoluminescent food colorant and riboflavin (vitamin B2), which is also a photoluminescent food additive.