Two-Stage Microwave–Infrared Heating for Enzyme Deactivation in Produce

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Solution Overview

Problem

Existing methods for preventing enzymatic browning in fruits and vegetables often involve chemicals, affecting taste and texture, and there is a need for a more effective, chemical-free method to inhibit browning while preserving quality.

Innovation Solution

A two-stage computer-controlled microwave and infrared heating system is used to deactivate enzymes, where produce is first heated in a microwave oven at low humidity and then in an infrared oven at higher humidity, adjusting temperatures and depths to ensure efficient enzyme deactivation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If chemical methods are used to prevent enzymatic browning, then browning inhibition is effective, but taste and texture quality deteriorate

Engineering Contradiction:

Improvebrowning inhibition effectivenessVSAvoidtaste and texture quality

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces chemical methods with a physical heating system combining microwave and infrared energy. The microwave oven provides volumetric heating while the infrared oven provides surface heating, together achieving complete enzyme deactivation without chemical additives that would compromise taste and texture.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The heating process is divided into two sequential stages: microwave heating followed by infrared heating. Each stage targets different aspects of enzyme deactivation, with the microwave providing initial heating and the infrared completing the deactivation process, achieving better results than either method alone.

Inventive Principle:

Principle #1Segmentation

2Reliability

If conventional heating methods are used, then enzyme deactivation is achieved, but processing time and energy consumption increase

Engineering Contradiction:

Improveenzyme deactivation effectivenessVSAvoidprocessing time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system uses periodic alternating action between microwave and infrared heating modes. The microwave operates first to rapidly heat the produce internally, then the infrared operates to complete surface deactivation. This periodic sequence achieves complete enzyme deactivation faster than continuous conventional heating.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent utilizes different heating phases: microwave radiation causes internal molecular vibration and heating, while infrared radiation provides surface heating. By sequencing these different heating phases, the system achieves rapid and complete enzyme deactivation.

Inventive Principle:

Principle #36Phase transitions

3Productivity

If monolayer depth is increased for high throughput, then processing capacity improves, but heating uniformity and enzyme deactivation effectiveness worsen

Engineering Contradiction:

Improveprocessing throughputVSAvoidheating uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies different heating methods to different depths of the monolayer. Microwave energy penetrates deeper to heat the bulk material uniformly, while infrared energy concentrates on the surface layer. This local differentiation of heating quality ensures uniform enzyme deactivation throughout the entire monolayer depth while maintaining high throughput.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system combines two different heating technologies (microwave and infrared) into a composite heating approach. Each technology complements the other's limitations, with microwave providing deep penetration and infrared providing surface effectiveness, together achieving uniform heating through thicker monolayers at high throughput.

Inventive Principle:

Principle #40Composite materials

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

The system effectively deactivates enzymes without chemicals, maintaining the taste and texture of fruits and vegetables while achieving high throughput rates.

Implementation Method 1

conveying a monolayer of the produce through a microwave heating system configured to emit electromagnetic waves in the microwave frequency range

Methodology Applied

Scientific EffectMicrowave heating: Dielectric Heating

Implementation Method 2

conveying the produce through an infrared heating system configured to emit electromagnetic waves in the infrared range

Methodology Applied

Scientific EffectInfrared heating: Infrared Radiation

Data Source

PatentUS20250295130A1Microwave and infrared heating system and method for fruit and vegetable enzyme deactivation

Publication Date: 2025.09.25 DEAKTIV INC

AI summary

A method for enzyme deactivation in raw produce involves a computer-controlled two-step heating process using microwave and infrared systems. Initially, a monolayer of raw produce is conveyed through a microwave oven, maintaining relative humidity below a threshold, to achieve a first average temperature. Subsequently, the produce is transferred to an infrared oven, where the relative humidity is kept above the threshold, resulting in a second average temperature that is equal to or greater than the first. The method ensures efficient enzyme deactivation by adjusting the respective depth of produce monolayers, the intensity and duration of microwave and infrared exposure, and controlling temperature and humidity levels during the heating process.