Persimmon Ripening Chamber With Respiration-Based CO2 Control

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Solution Overview

Problem

Conventional methods for ripening astringent fruits, such as persimmons, often result in excessive or insufficient tannin reduction, leading to impaired flavor, fruit damage, and reduced shelf life, due to uncontrolled carbon dioxide concentration and duration during the ripening process.

Innovation Solution

A method and chamber that measures fruit respiration to dynamically control carbon dioxide, oxygen, and ethylene concentrations, adjusting these parameters based on the fruit's respiration rate to achieve optimal ripening conditions, reducing tannin concentration gently and uniformly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If fixed CO2 concentration fumigation is applied for 24 hours, then tannin breakdown is achieved, but excessive or insufficient ripening occurs leading to impaired flavor and fruit damage

Engineering Contradiction:
Improvetannin reduction consistencyVSAvoidfruit quality stability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent implements dynamic control of CO2 concentration based on real-time respiration rate measurements. The system continuously monitors fruit respiration and adjusts CO2 concentration accordingly, transitioning from static fixed-time fumigation to dynamic adaptive control. This resolves the contradiction by allowing precise tannin reduction while preventing fruit damage through real-time feedback adjustment.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent introduces a feedback mechanism where respiration rate measurements guide CO2 concentration adjustments. The system measures respiration rates, compares them to target ranges, and modifies CO2 dosing accordingly. This closed-loop feedback control ensures consistent tannin breakdown while maintaining fruit quality, directly addressing the reliability issue with fixed fumigation protocols.

Inventive Principle:
Principle #23Feedback

2Reliability

If lower CO2 concentration or shorter duration is used, then fruit damage is reduced, but remaining tannins require extended conventional storage reducing shelf life

Engineering Contradiction:
Improvefruit quality stabilityVSAvoidshelf life
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The feedback mechanism ensures that CO2 fumigation continues until respiration rate reaches the target range indicating sufficient tannin breakdown, preventing under-treatment that would require extended storage. This optimizes the balance between avoiding fruit damage and maximizing shelf life by precisely determining when ripening is complete.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically changes CO2 concentration parameters based on real-time respiration measurements rather than using fixed low concentrations. This allows achieving complete tannin reduction in optimized timeframes, eliminating the need for extended conventional storage and maximizing shelf life while maintaining fruit quality.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If CO2 concentration is increased to accelerate ripening, then ripening reliability and uniformity improve, but risk of excessive ripening and fruit damage increases

Engineering Contradiction:
Improveripening uniformityVSAvoidfruit damage risk
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The real-time respiration monitoring and feedback control system prevents excessive ripening by continuously adjusting CO2 concentration based on measured respiration rates. This ensures uniform ripening across all fruit while preventing damage from over-exposure to high CO2 concentrations, resolving the contradiction between ripening precision and damage risk.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts CO2 concentration parameters based on real-time respiration data, increasing CO2 when needed for uniformity and reducing it when approaching optimal ripening. This adaptive parameter control achieves consistent ripening results while minimizing fruit damage risk compared to fixed high-concentration protocols.

Inventive Principle:
Principle #35Parameter changes

4Manufacturing precision

If conventional storage is used after partial detannation, then remaining tannins are broken down, but shelf life is significantly reduced

Engineering Contradiction:
Improvetannin reduction completenessVSAvoidshelf life
Core Design Contradiction:
Manufacturing precisionVSDuration of action of stationary object

Solution Approach 1:

The system uses dynamic CO2 concentration adjustments based on respiration rates to achieve complete tannin reduction in optimized timeframes, eliminating the need for extended conventional storage. This parameter optimization ensures complete detannation while maximizing shelf life by minimizing the duration of post-ripening storage required.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The feedback mechanism detects when respiration rate indicates complete tannin breakdown, allowing immediate termination of the process without requiring extended conventional storage. This real-time monitoring ensures complete tannin reduction while preserving shelf life by eliminating unnecessary storage time.

Inventive Principle:
Principle #23Feedback

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 method ensures consistent, high-quality ripening with reduced tannin concentration within a few days, eliminating the need for subsequent storage, enhancing shelf life and flavor, and allowing for flexible ripening adjustments to meet sales demands.

Implementation Method 1

When persimmons are fumigated with carbon dioxide, the tannins are rapidly broken down. Various studies exist regarding CO2 concentration and fumigation duration

Methodology Applied
Scientific EffectCarbon dioxide fumigation:

Implementation Method 2

Ethylene ripening can be used to increase the reliability and uniformity of ripening, and the process can be considerably accelerated by adding ethylene gas to the atmosphere in which the fruit is stored

Methodology Applied
Scientific EffectEthylene ripening:

Implementation Method 3

Such deaeration processes are sometimes initiated by subjecting the fruit to cold or frost. The resulting cell damage stimulates the release of ethylene, which promotes cell wall degradation

Methodology Applied
Scientific EffectFreezing: Freezing

Implementation Method 4

the application of ethyl alcohol vapor, which activates the enzyme alcohol dehydrogenase with subsequent accumulation of acetaldehyde

Methodology Applied
Scientific EffectEnzyme catalysis: Enzyme

Implementation Method 5

Acetaldehyde is the compound responsible for the polymerization of tannin molecules

Methodology Applied
Scientific EffectPolymerization:

Implementation Method 6

the promotion of anaerobiosis, which induces the conversion of pyruvate to acetaldehyde in a reaction catalyzed by the enzyme pyruvate decarboxylase

Methodology Applied
Scientific EffectAnaerobic fermentation: Anaerobic Digestion

Data Source

PatentEP3797597B1Maturing chamber and method for maturing astringent fruits
Publication Date: 2025.12.24 WIRTH ROLAND
  • EP3797597B1 patent drawingFigure 1

AI summary

The present invention relates to a ripening chamber and a method for ripening astringent fruits. The invention particularly relates to a ripening chamber and a method for reducing the tannin concentration in persimmons, wherein the ripening process is artificially and selectively controlled by varying the carbon dioxide concentration in the ripening chamber.