Sterilization of Moisture-Sensitive Packages Using Pressurized Gas
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Solution Overview
Problem
Current continuous processing systems for sterilization and pasteurization of food products packaged in flexible or semi-rigid, humidity-sensitive packaging are inadequate due to limitations in thermal control, pressure management, and agitation, leading to inefficient treatment times and potential packaging damage.
Innovation Solution
A continuous treatment process utilizing a single enclosed system with controlled pressure, where food products are heated and cooled using microdroplets of water in a pulsating air or steam flow, and subjected to agitation, ensuring rapid and controlled thermal processing without delamination or pressure-induced damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If continuous treatment systems with water immersion or steam are used, then thermal activation speed is improved, but packaging absorbs too much water and loses structural integrity
Solution Approach 1:
The patent uses pressurized gas (nitrogen or carbon dioxide) instead of liquid water or steam for thermal treatment. The gas is introduced at controlled pressure (0.2-2.0 bar gauge) to heat the packaging and product simultaneously, eliminating water absorption while maintaining thermal activation speed. The pneumatic system allows continuous processing without the harmful effects of liquid immersion.
Solution Approach 2:
The invention changes the physical state parameter of the treatment medium from liquid/steam to pressurized gas. By controlling gas pressure and flow rate, the system achieves effective thermal treatment without the packaging absorbing moisture. The pressure parameter is specifically controlled to be higher than atmospheric but within a range that prevents packaging deformation while enabling efficient heat transfer.
2Temperature
If multiple successive enclosures with airlock systems are used, then thermal control is improved, but device complexity increases
Solution Approach 1:
The patent combines heating, cooling, and thermal treatment functions into a single continuous enclosure rather than using multiple successive enclosures with airlocks. The pressurized gas system allows the same chamber to perform multiple thermal functions by controlling gas flow and pressure, thereby simplifying the overall device structure while maintaining effective thermal control throughout the continuous processing line.
3Device complexity
If discontinuous treatment installations are used, then pressure control is simplified, but treatment time increases due to batch processing
Solution Approach 1:
The invention implements continuous processing where packaging moves constantly through the treatment zone on conveyors while being exposed to pressurized gas. This eliminates the batch processing interruptions and waiting times inherent in discontinuous systems. The continuous action of gas flow and conveyor movement ensures uninterrupted thermal treatment, reducing overall treatment time while the pressure control system manages the continuous gas supply efficiently.
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 significantly reduces treatment time, enhances thermal control, and maintains packaging integrity by preventing water accumulation and managing pressure, resulting in improved sterilization and pasteurization efficiency with reduced cycle times and better product quality.
Implementation Method 1
heated by contact with microdroplets, with a diameter of around 50 to 200 μm, of hot water in a flow of air and/or of pulsed steam
Implementation Method 2
pulsed steam
Implementation Method 3
microdroplets, with a diameter of around 50 to 200 μm, of hot water in a flow of air and/or of pulsed steam
Implementation Method 4
said pressure inside the treatment enclosure being set higher or equal to the pressure inside said packaging
Data Source
Figure 1~2c
AI summary
The process for sterilization and/or pasteurization of food products conditioned in a flexible or semi-rigid moisture sensitive package (1), comprises heating and then cooling the package, directly or indirectly transporting the package in a continuous manner to different treatment phases under controlled pressure in single treatment enclosure (2), and heating the package with hot micro-droplets in the presence of air and/or pulsed vapor at 120-130[deg] C. The package is alternatively or sequentially subjected to agitation during a specific treatment phase. The process for sterilization and/or pasteurization of food products conditioned in a flexible or semi-rigid moisture sensitive package (1), comprises heating and then cooling the package, directly or indirectly transporting the package in a continuous manner to different treatment phases under controlled pressure in single treatment enclosure (2), and heating the package with hot micro-droplets in the presence of air and/or pulsed vapor at 120-130[deg] C. The package is alternatively or sequentially subjected to agitation during a specific treatment phase in a continuous or discontinuous manner. The pressure inside the treatment enclosure is regulated to a value, which is greater than or equal to a pressure inside the package. The micro-droplets have a diameter of 50-200 mu m. The air is flown at a speed of 0.5-2 m/s. The package is further cooled by sprinkling with atmospheric pressure. The internal pressure of the enclosure is 300-1200 mbar, which is greater than the vapor pressure. An independent claim is included for an installation for sterilization and/or pasteurization of food products.