Determination of vegetable freshness by measuring chlorophyll content with colorimeter

In the era of digital information, both our daily life and industrial production are increasingly inseparable from various data. In order to better study the content of plant chlorophyll, the laboratory uses a colorimeter and a scanner to quantify the content of chlorophyll digitally, making analysis and processing easier and more convenient.

We study the chlorophyll content in order to evaluate the relationship between the color and chlorophyll content of vegetables, so as to determine the freshness of vegetables. We know that the colorimeter is an advanced instrument for analyzing and detecting product color information. Its measuring principle is to simulate the process of human eyes looking at color, analyze the incident and reflected light, and finally convert the abstract color information into digital information that can be analyzed.

The color of vegetables is an important evaluation index for people to choose and buy. Therefore, it is necessary to determine the chlorophyll content in the research of vegetable preservation. However, the sample needs to be destroyed when determining this index, and the detection speed is relatively slow. In recent years, Australian researchers have studied the color of vegetables with a colorimeter, which is generally expressed by the hue angle. In terms of color theory, the tristimulus values X, Y and Z are the three main calculation parameter values in the calculation of color difference meter. However, in order to measure more accurately, we also use CIE Lab chromaticity space with more uniform color. This advanced color difference meter is generally called a spectrophotometer, which is more accurate and reliable for chlorophyll analysis and measurement. The spectrophotometer generally uses L, a, b, C, H equivalent to represent color information. The meanings represented by these values have been introduced in CIE Standard Chromaticity System of Color Difference Meter.

By analyzing the amount of chlorophyll in vegetables to determine the freshness of vegetables, we can quickly and accurately analyze the freshness of materials and grade them on this basis without destroying the vegetables themselves. This method not only does not destroy vegetables but also is fast and accurate. It is one of the widely used methods in the market at present.

Detection of transparent film by colorimeter:
The color detection and evaluation of transparent substances may be more difficult than that of ordinary substances, because they are transparent, so light can easily leak in. I also know that the color of transparent substances is too big for the naked eye to control during measurement for various reasons. The material detected by the colorimeter requires that the measuring aperture cover the material surface without light leakage, but the transparent film itself will leak light due to its special properties, which is more troublesome than other materials, but it is not an unsolved problem. When measuring transparent film products, the colorimeter provides two measurement schemes. Many of our users solve the color quality control of film products in this way.

First, multilayer film superposition measurement
This method can reduce the light transmittance of the film, and increase the color depth of the film to make it more accurate and convenient for the color detection of the colorimeter. In this way, attention must be paid to the superposition amount and batch of films, and the superposition amount of films must be consistent. This method may be more reliable in detecting the color difference between two batches and the color of the product itself. However, the color difference measurement between the same batch is more complex, so another detection method is given.

Second, the same A4 printing paper as the background
An A4 paper is used as the background during the measurement, so that the consistency of the surrounding measurement environment can be ensured. This method is very effective in measuring the color difference between the same batch and the color difference meter between different batches, but it is not very good for detecting the color formula of the product itself.

In actual production, the measurement method of color difference meter shall be selected according to the inspection requirements of the factory for film products, and the two methods shall be combined to achieve the color quality control of film products.

Determination of white silk by colorimeter
Silk is a traditional product in China, more than 90% of which are still exported as semi-finished products due to insufficient deep processing and limited printing and dyeing technology. Whiteness is one of the important physical indicators to measure its quality.

In the world of colors around people, white is the most common. People often use whiteness to describe the “degree of white”, but so far, there is no exact definition of whiteness. Like other colors, white is one of the senses reflected by the brain when the reflected light enters the human eye and acts on the visual organs after the object is irradiated. In the chromatic color space, the wavelength of white is in the range of 470nm~570nm and forms a three-dimensional space color. Whiteness is a measure of “whiteness”. White itself has the color attributes of high reflectance and low purity. Whiteness can be roughly divided into non whitening and fluorescent whitening. The fluorescent effect is not necessary for the sample without whitening, while the fluorescent whitening sample has not only reflected light but also fluorescence generated by the fluorescent agent itself under the light irradiation, so the fluorescent factor of the fabric itself should be considered.

In the process of white refining and thickening for export, most of them are not subject to fluorescent whitening treatment, which belongs to this kind of white products. Now we say that the whiteness of white refining silk is measured by the color difference meter, and the fluorescent factor is not necessary to be considered.

Whiteness is not only an important physical quantity to measure the quality of refined products, but also an important assessment item for appearance quality inspection. The determination of this value can not only provide measured data for product quality control, but also be used to adjust and control the degumming rate of silk consistency and other process parameters, which has a positive significance for product quality control and improvement. Based on the analysis of the current whiteness inspection status of the production enterprises and the whiteness control of the refined white silk by the Commodity Inspection Bureau, the whiteness measurement methods of the refined white silk can be summarized into two categories.

Visual inspection and evaluation method:
This method, also called direct comparison method, is a traditional method. It has the advantages of convenience, simplicity and intuition, but the disadvantages are that it is easily affected by light sources and lighting conditions, has no quantitative concept, and often has subjectivity.

Colorimeter measurement:
This method is also called physical (objective) evaluation method, which is expressed by numerical value Lab. It is characterized by instrument measurement, with quantitative concept and excluding subjective factors, but the value of Lab is related to the instrument type, performance, sample placement angle, etc.

LISUN lauched Portable Colorimeter/Chroma Meter is an innovation color measuring tool with powerful configuration to make color measurement easier and more professional; It support Bluetooth to connect with Android and ISO devices, Portable Colorimeter/Chroma Meter will take you into a new world of color management; It can be widely used to measure color value, color difference value and find similar color from color cards for printing industry, paint industry, textile industry, etc.

CD-320PRO_Portable Colorimeter/Chroma Meter

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