Continued development of accelerated shelf-life tests for Tetra Recart®

Abstract

Different types of food are packed in Tetra Recart (TRC) ®. The package itself is
made out of several of layers, including paperboard, aluminum and a polymer
coating. There are some types of food such as some types of picklesthat are regarded
as “aggressive”. These products have a high salt content (1%) and a low pH (pH<4)
and have an impact on the packaging material, and cannot today be packed in Tetra
Recart.

For this thesis, a robust accelerated test method was developed for these “aggressive
products”. Much of the work has been based on the results in a master thesis
performed 2013 by Cecilia Jansson, Chalmers University. The purpose was to have
a test method that mimics these “aggressive products” but in a much faster rate. This
accelerated test method will be used when testing development packaging materials
for Tetra Recart without having to wait the shelf-life time of two years to study the
food package interactions.
The work also included finding a suitable wetting agent to use in the fill product.
Tween 80 was found to be the most suitable one, a non-ionic food classified
surfactant. It can be used in Tetra Recart filling machines and works as a wetting
agent and emulsifier.

The recommended aggressive fill product was found to be formulation 1.
Formulation 1 has a water matrix with a salt content of 7.5%, a pH of 2.56 and 70
ppm of FFAs. Moreover, the Tween 80 and FFA ratio is 1:1.

Popular Abstract

Development of aggressive fill product with to be used for testing paperboard packaging material

Acidic food such as pickles and very salted food such as olives can have a negative impact and cause corrosion on packages that have aluminum inside them. By having a fill product that has similar properties as these types of foods, packaging materials that are newly developed can be tested at a faster rate.
Tetra Recart® (TRC) is a paperboard package that consists of several layers, the inside layers consist of plastic and aluminum. There are some types of foods are regarded as “aggressive” and cannot be packed in TRC packages today. That includes products that have a pH below 4 and a salt concentration of 1%. Usually, corrosion is developed on the aluminum foil layer when the package is exposed to these “aggressive” products. Corrosion is the breakdown of metals due to chemical reactions. For example, steel that has stood outside in the rain gets corroded. When new packaging materials are developed for TRC, the impact of these foods needs to be tested. That would take up to two years (the shelf-life for TRC packages). Shelf-life is how long a food product can be stored while also being safe for consumption.

In this thesis with the title of “Continued development of accelerated shelf-life tests for Tetra Recart®”, a fill product that has similar properties as these “aggressive” foods has been developed so the packaging material can be tested at a faster rate. Instead of storing the packages for two years at room temperature, they were stored for 12 weeks at 35 °C and 24 days at 60 °C. For 35 °C, the storage time and temperature were based on recommendations from a master thesis with the title of “Development of fill product with aggressive properties for accelerated storage tests in Tetra Recart” by Cecilia Jansson at Chalmers University. For 60 °C, the storage time and temperature were based on recommendations from the EU regulation No 10/2011 regarding plastics materials and articles intended to come in contact with food.

The recommended fill product in this thesis had a pH of 2.5 and a salt concentration of 7.5%. It contained water, acids, fat, and salt. Oleic acid, which is a type of fat, was one of the ingredients. Fat is a common ingredient in food and causes the inside plastic and the aluminum foil loses stickiness from each other. When this happens, corrosion can develop at an even faster rate. Another ingredient was Tween 80. Tween 80 is a wetting agent that helps the acid and salt reach the aluminum much easier so that even more corrosion can develop. It was found that when Tween 80 was not present in the fill product, no corrosion was developed. So, Tween was therefore seen as a crucial ingredient for corrosion development.

When storing this fill product at 35 °C for 12 weeks, corrosion had developed on the inside of the package. The corrosion development was similar to real products and did increase in proportion over time. The results for 60 °C were considered as too aggressive for real-life conditions and it is recommended to use a lower storage temperature. The results at 35 °C were comparable with real products and are recommended to be used in the future.

Author: Daniela Varfi

• author: Varfi, Daniela
• supervisor: Katrin Molina-Besch
• organization: Packaging Logistics
• course: MTTM10 20192
• year: 2020
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: Adhesion, Packaging, Corrosion, Test-method, Accelerated, Aggressive Foods
• language: English
• id: 9005200
• date added to LUP: 2020-02-18 10:46:54
• date last changed: 2020-02-18 10:46:54