Ohmic Heating Food Composition Sterilization
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Solution Overview
Problem
Conventional food sterilization methods, such as retort processes, result in non-uniform heat distribution, particularly for heterogeneous mixtures and foods with large particles, leading to incomplete sterilization due to high heat exposure at the product package interface and low heat exposure at the cold spot, which hinders rapid and uniform heating of all food components.
Innovation Solution
The use of ohmic heating, where an electric current is passed through the food composition to generate heat uniformly, allowing for rapid and immediate product heating from the inside-out, maintaining a power-to-mass flow rate range of 125 kJoules/kg to 750 kJoules/kg, and adjusting the flow rate to maintain temperatures between 75°C and 175°C, ensuring comprehensive sterilization of both large and small particles, heterogeneous, and homogeneous materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional retort sterilization is used, then sterilization is achieved, but heat distribution becomes non-uniform with high heat exposure at package interface and low heat exposure at cold spot
Solution Approach 1:
The patent replaces conventional thermal conduction heating with ohmic heating, where electrical energy is converted to thermal energy directly within the food material through its electrical resistance. This substitution of heating mechanism enables uniform heat generation throughout the food matrix, eliminating the non-uniform heat distribution characteristic of conventional retort sterilization.
Solution Approach 2:
The patent employs high-frequency alternating electrical current (typically 27 MHz) that induces rapid molecular vibration and rotation within the food material. This vibrational energy converts to heat through molecular friction, creating uniform internal heating that penetrates all particles simultaneously regardless of size or position in the package.
2Reliability
If conventional heating is used, then sterilization is achieved, but heating time increases for large particles
Solution Approach 1:
The patent replaces slow thermal conduction heating with rapid ohmic heating, where electrical energy directly converts to thermal energy within the food material. This eliminates the time-consuming heat penetration process through large particles, reducing sterilization time from hours to minutes while ensuring complete sterilization of all particles simultaneously.
Solution Approach 2:
The patent uses high-frequency alternating current (27 MHz) that continuously cycles the direction of electron flow, creating periodic heating cycles that rapidly elevate the temperature of all food particles. This periodic electrical action ensures uniform and rapid heating throughout the entire food composition, including all large and small particles.
3Productivity
If rapid heating is applied, then sterilization speed increases, but food properties may be compromised
Solution Approach 1:
The patent carefully controls the ohmic heating parameters, including electrical field strength, frequency (27 MHz), and processing time, to achieve rapid sterilization while maintaining food quality. By optimizing these parameters, the process achieves commercial sterility within minutes while minimizing degradation of heat-sensitive nutrients, colors, and textures compared to conventional prolonged heating.
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
Ohmic heating enables rapid and uniform heating of all food components, achieving commercial sterility by ensuring all particles reach the sterilization temperature quickly, thereby overcoming the limitations of conventional methods and preserving food properties.
Implementation Method 1
Ohmic heating is a food processing method in which an alternating electrical current is passed through a food sample. This results in heat generation to a food ample.
Data Source
AI summary
The present invention relates to a food composition prepared by a method of sterilizing. More specifically to a sterilizing process designed to be used in an aseptic process that comprises the steps of transferring said food composition into a heating unit; passing an electric current through said composition; maintaining a power to mass flow rate range through said heating unit from about 125 kJoules/kg to about 750 kJoules/kg; adjusting a flow rate to maintain said food composition temperature exiting the heating unit from about 75° C. to about 175° C.; and cooling said food composition to a final temperature from about 5° C. to 100° C.