Fruit Quality Detection Using Dual-Wavelength Absorbance
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Solution Overview
Problem
Existing methods for determining the quality of fruit and vegetable products are complex, not portable, and often provide unreliable results, being specific to certain types and affected by temperature, requiring lengthy calibration and destructive tests.
Innovation Solution
A method and apparatus using absorbance measurements at specific wavelengths (670 nm and 720 nm) to determine the quality of fruits, independent of temperature and surface color, utilizing a portable device with LED diodes and a sensor system to calculate the absorbance difference (AD index) for assessing ripeness and quality features like ethylene concentration and pulp hardness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing methods use complex apparatuses with multiple light sources and spectrographs, then measurement precision can be improved, but device complexity increases and portability is lost
Solution Approach 1:
The patent divides the spectral measurement into discrete wavelength segments (670nm and 720nm) rather than using continuous spectroscopy. This segmentation allows simple LED light sources at specific wavelengths to replace complex spectrographs, maintaining measurement precision while dramatically reducing device complexity and enabling portability.
Solution Approach 2:
The patent creates a universal measurement approach that works across different fruit types by measuring absorbance at two specific wavelengths (670nm for chlorophyll and 720nm for carotenoid content). This multi-functional method can assess multiple quality parameters (ripeness, chlorophyll content, carotenoid content) using a single portable device, eliminating the need for type-specific complex apparatuses.
2Measurement precision
If existing methods require extensive calibration and destructive testing, then measurement precision improves, but loss of time and loss of substance increase
Solution Approach 1:
The patent enables the device to measure quality parameters directly without requiring external calibration curves or destructive reference tests. The absorbance measurements at 670nm and 720nm directly correlate with chlorophyll and carotenoid content, allowing the system to self-calibrate and provide immediate results without time-consuming calibration procedures or loss of test samples.
3Ease of operation
If existing methods measure surface color to assess ripeness, then ease of operation improves, but reliability deteriorates for fruits where surface color is not indicative of ripeness
Solution Approach 1:
The patent replaces visual color assessment with optical absorbance measurement at specific wavelengths. By measuring light absorption at 670nm (chlorophyll) and 720nm (carotenoid) wavelengths, the system objectively quantifies internal pigment content regardless of surface coloration, maintaining ease of operation while significantly improving reliability for fruits like peaches and apples where surface color does not indicate ripeness.
4Measurement precision
If existing methods are affected by temperature variations, then measurement precision improves, but reliability deteriorates due to temperature-dependent measurements
Solution Approach 1:
The patent measures absorbance at two specific wavelengths (670nm and 720nm) where the temperature-dependent effects cancel out when calculating the ratio or difference between measurements. This parameter selection allows the measurement to remain reliable across different temperature conditions, as the relative absorbance values at these wavelengths are less sensitive to temperature variations compared to single-wavelength measurements.
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 solution simplifies and enhances the reliability of quality assessments, providing precise and portable measurements independent of temperature and surface color, reducing the need for extensive calibration and destructive testing, and enabling objective evaluation of fruit quality.
Implementation Method 1
a source of light radiation with a wavelength centred on a wavelength value of 670 nm with a range of more or less 50 nm; a source of light radiation with a wavelength centred on a wavelength value of 720 nm with a range of more or less 50 nm
Implementation Method 2
measurement of the radiation reflected by the product (2) at the wavelengths (670 nm and 720 nm)
Implementation Method 3
calculation of the difference in the absorbance value between the values of the wavelengths at 670 nm and at 720 nm
Data Source
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AI summary
The invention relates to a method and an apparatus (1) for determining the quality of fruit and vegetable products (2) . The method comprises the following steps: irradiation of a product (2) with light radiation with at least a wavelength centred on the values 670 nm ± 50 nm; measuring of the absorbance of the radiation with wavelength of 670 nm and 720 nm return wavelength from the product (2) ; calculation of the absorbance difference between the values of the wavelengths at 670 nm and at 720 nm; obtaining from said difference an index (AD) the value of which is correlated with various parameters of the quality of the product: hardness of the pulp, Brix grades, ethylene concentration, etc. The apparatus (1) , which can be portable, comprises: a radiating light source (3) with at least a wavelength of 670 nm ± 50 nm,- a sensor (4) suitable for collecting part of the radiation reflected by the product (2) and connected, by means of an optic fibre beam (5) , to a detector unit (6) comprising possible optic filter means (7) and a detector (8) , a central control and processing unit (10) of the detected signals and a display (11) for displaying the result of the reprocessed signals.