Fruit Marking via Laser Incision and Metal Cation Contrast Agent
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Solution Overview
Problem
Current methods for marking fruits, especially citrus, are inefficient and costly due to the need for high dynamic energy density laser beams, which can cause structural damage and require high concentrations of chromophore substances, leading to unintended color changes and material wastage.
Innovation Solution
A method involving a superficial laser incision on fruits followed by the deposition of a contrast agent with metal cations at low concentrations (0.001-1%) that react with phenolic and polyphenolic compounds to create high-contrast, permanent markings without structural damage, using a CO2 laser with lower energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high dynamic energy density laser beam is used for marking citrus fruits, then visible markings are produced, but structural collapse of the irradiated area occurs
Solution Approach 1:
The patent applies preliminary action by first creating a superficial incision with the laser beam to expose phenolic compounds, then subsequently applying the metal cation contrast agent. This two-step approach allows the marking process to proceed at lower energy densities that preserve structural integrity, as the incision itself prepares the surface for contrast agent deposition without requiring high-power calcination
Solution Approach 2:
The patent introduces a contrast agent containing metal cations (Fe2+, Fe3+, Cu+, Cu2+) as an intermediary substance. This contrast agent reacts with phenolic compounds exposed by the laser incision to produce visible color changes, eliminating the need for high-energy density laser beams that would directly calcinate and damage the fruit surface
2Manufacturing precision
If high concentrations of chromophore substances are used for fruit marking, then high-contrast markings are achieved, but unintended color changes in adjacent zones occur
Solution Approach 1:
The patent applies local quality by concentrating the chromophore substance (metal cation contrast agent) specifically at the incision site where phenolic compounds are exposed. The laser incision creates a localized reaction zone, and the contrast agent is deposited precisely in this area, ensuring high contrast markings without spreading to adjacent zones and causing unintended color changes
Solution Approach 2:
The patent changes the concentration parameter of chromophore substances from high (40-60% in prior art) to very low (0.001-1%). This parameter change is effective because the contrast agent is applied locally to the incision where phenolic compounds are concentrated, allowing low concentrations to produce high-contrast markings without the side effects of high concentrations
3Illumination intensity
If CO2 laser with very high dynamic energy density is used for citrus marking, then markings are visible to naked eye, but calcination of organic surface matter occurs
Solution Approach 1:
The patent replaces the mechanical/thermal system (high-power CO2 laser directly calcining the surface) with a chemical system (low-power laser creating incisions that react with metal cation contrast agents). The visible marking is achieved through chemical color reactions rather than thermal calcination, eliminating surface damage while maintaining visibility
Solution Approach 2:
The metal cation contrast agent serves as an intermediary that converts the invisible laser incision into a visible colored marking. The laser creates the incision at low energy density, and the contrast agent subsequently reacts with exposed phenolic compounds to produce the visible color change, replacing the need for high-energy density calcination
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 allows for cost-effective, high-contrast, and structurally stable markings on fruits by utilizing low concentrations of chromogen additives, eliminating unintended color changes and ensuring the structural integrity of the fruit surface.
Implementation Method 1
a superficial incision with a laser beam
Implementation Method 2
a metal ion interacts with flavonoids through complexation reactions
Implementation Method 3
After complexation occurs, the redox reaction starts between the flavonoid and the metal to produce the corresponding quinone derivative
Data Source
Figure 1~2
Figure 3
AI summary
The present invention describes a method of marking fruits which comprises an incision in a fruit piece surface with a laser beam and the deposition in such superficial incision of a contrast agent comprising salts or oxides of iron or copper at a concentration between 0.001% and 1 % of the total weight. This salts or oxides are capable of reacting with any of the phenolic and/or polyphenolic compounds present in the superficial tissues of the fruit. This contrast agent may also comprise other additives: acidity regulators, emulsifiers, antioxidants and complexing.