Vacuum Packaging Tray Asymmetry for Microwave Heating
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Solution Overview
Problem
Existing methods for pasteurizing and vacuum-packing ready-to-eat food face challenges such as uneven heating during microwave reheating and limited food freshness due to inadequate packaging, which increases production costs and complexity.
Innovation Solution
A method involving a tray with a flexible bottom and stiff lateral walls, covered with a flexible layer containing a one-way valve, where food is pasteurized under microwave energy and then vacuum-packed, creating a vacuum that ensures even heating and reduces contamination, with the valve opening to indicate completion and allowing vapour to spread heat evenly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If food is transferred to packages before pasteurisation, then the food is exposed to surrounding air during transfer, but this shortens the period of freshness of the food
Solution Approach 1:
The patent applies preliminary action by performing the pasteurisation process before final packaging and sealing. The food is pasteurised in an open tray first, then packaged and sealed afterward. This sequence eliminates exposure to surrounding air during the critical packaging transfer phase, thereby preventing contamination and extending freshness while maintaining food safety through prior pasteurisation
2Stability of the object's composition
If a rigid package structure is used, then the package maintains its shape, but the distance between cover layer and bottom is equal throughout, causing uneven microwave heating
Solution Approach 1:
The patent applies asymmetry by designing the package with a flexible bottom that creates an asymmetric distance between the cover layer and bottom surface. The center portion has a shorter distance while peripheral edges have longer distances. This asymmetric geometry compensates for microwave heating patterns by positioning food in regions with appropriate heating characteristics, achieving uniform overall heating while maintaining package stability through the flexible structure
3Reliability
If vacuum-packing is applied to ready-cooked food, then the package is sealed, but the food has already been exposed to air during transfer, reducing keeping qualities
Solution Approach 1:
The patent applies preliminary action by performing pasteurisation before packaging and sealing. The food is pasteurised in an open tray first, then packaged and sealed afterward. This sequence eliminates exposure to surrounding air during the critical packaging transfer phase, thereby preventing contamination and extending freshness while maintaining food safety through prior pasteurisation
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 method results in even microwave heating and extended food freshness by reducing contamination risks and optimizing heating efficiency, while simplifying the manufacturing process and reducing production costs.
Implementation Method 1
pasteurising the contents inside the package thus formed by means of microwaves
Implementation Method 2
cooling the package, whereby a vacuum is created in the package due to condensation
Data Source
AI summary
A method of pasteurising and vacuum packing food (2), comprising the steps of placing the food (2) on a tray 81) having a flexible bottom (7) and stiff lateral walls (8) extending in the vertical direction of the tray (1), up to a filling degree of 410-60% of the maximum volume of the tray (1), covering the tray (1) with a flexible cover layer (3) to form a package, providing a one-way valve (4) for one-directional communication from the interior of the package (5) to the exterior thereof, pasteurising the contents inside the package (5) thus formed by means of microwaves, closing the valve (4) upon completed pasteurisation of the package and cooling the package (5), whereby a vacuum is created in the package (5) in such a manner that the package (5) with the vacuum-packaged food (2) therein presents a centre portion where the distance between said flexible cover layer (3) and said bottom (7) is shorter than the distance between said flexible cover layer (3) and said bottom (7) at the peripheral edges of the package.