Retort Heat-Treatment of Fiber-Based Packaging
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Solution Overview
Problem
Retort systems for fiber-based packaging materials face issues with water/steam penetration during heat-treatment, leading to compromised mechanical properties and appearance, especially at open edges and during agitation.
Innovation Solution
A method and apparatus that adjust the pressure and temperature ratio in the treatment environment over time to decrease the P/T ratio during the heat-treatment process, creating a molecular driving force that reduces water/steam penetration into the packaging material, by either lowering pressure or increasing temperature, starting from the cooking onset and extending into the cooling phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional retort heat-treatment is applied to fiber-based packaging materials, then shelf life of the product is extended, but water/steam penetration into the packaging material occurs causing degraded mechanical properties and appearance
Solution Approach 1:
The invention changes the pressure and temperature parameters during retort processing. Specifically, it maintains a pressure of 1-2 bar absolute and a temperature of 121-130°C for 30-90 minutes, which prevents water/steam penetration while still achieving shelf life extension. This parameter optimization resolves the contradiction between extending shelf life and maintaining packaging mechanical properties.
2Reliability
If conventional retort heat-treatment with high temperature and pressure is applied, then sterilization effect is achieved, but packaging material absorbs liquid causing compromised physical appearance
Solution Approach 1:
The invention optimizes the temperature and pressure parameters to 121-130°C and 1-2 bar absolute respectively. This specific parameter combination achieves effective sterilization while preventing excessive liquid absorption that would compromise the physical appearance of the packaging, particularly at open edges.
3Reliability
If rigid foldable paperboard packaging with thermoplastic coatings is used, then tightness properties against gases are achieved, but water/steam penetration occurs during retorting process
Solution Approach 1:
The invention changes the retort processing parameters to maintain pressure at 1-2 bar absolute and temperature at 121-130°C. This parameter adjustment creates conditions where the packaging material's gas barrier properties are preserved while preventing harmful water/steam penetration during the heat-treatment process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach minimizes water/steam penetration, maintains mechanical integrity, and allows for a wider variety of packaging materials to be used in retort processes without degradation, while improving the physical appearance and handling of containers, especially during agitation.
Implementation Method 1
adjusting the temperature and/or pressure in the treatment environment to decrease said ratio over a duration in a time period... creating a molecular driving force that reduces water/steam penetration into the packaging material
Implementation Method 2
heated therein with the aid of a circulating medium, e.g. hot steam
Implementation Method 3
heated therein with the aid of a circulating medium, e.g. hot steam, and/or water
Implementation Method 4
cooled with a circulating medium, for example cold water
Implementation Method 5
cooled with a circulating medium, for example cold water
Data Source
AI summary
A method of heat-treatment of a product in a sealed container of a packaging material is described. The method includes placing the container in a treatment environment having a pressure (P) and a temperature (T), the pressure and the temperature having a ratio (P/T), and adjusting the temperature and/or pressure in the treatment environment to decrease the ratio over a duration in a time period. The time period starts at a time of cooking onset of the product and extends over a time of cooling onset at which time a temperature decrease is started, the time of cooking onset being preceded by a first time period of temperature ramping during which the temperature is increased. An apparatus for controlling heat-treatment of a product in a sealed container of a packaging material is also described.