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3nh
2025-03-04
The gloss of the fruit surface can directly reflect the freshness of fresh citrus fruits and is one of the important indicators for evaluating the appearance quality of citrus fruits. The traditional citrus peel gloss test mainly uses the visual method, which is affected by many factors. This article introduces the application of three-angle gloss measurement in citrus peel gloss measurement.
Tangerine
Citrus is one of the important economic crops in my country, and its cultivated area and output rank first in the national fruit industry. In recent years, with the rapid development of the citrus industry and the improvement of people's living standards, consumers have also put forward higher requirements for the appearance quality of fruits. The gloss of the fruit surface can directly reflect the freshness of fresh citrus fruits and is one of the important indicators for evaluating the appearance quality of citrus. Glossy citrus is more attractive to consumers. Therefore, maintaining and improving the gloss of the fruit surface is an important part of the research on post-harvest preservation of citrus.
Waxing is currently the main way to improve the gloss of citrus fruit surface in post-harvest production, but brightening fruit waxes can easily cause the accumulation of odorous substances inside the fruit, reducing the flavor and taste of the fruit. Due to the lack of a scientific system for quantitative evaluation of fruit surface gloss, the gloss of the fruit surface is mainly graded through sensory evaluation in production, but this method has the disadvantages of strong human subjectivity, low efficiency and large evaluation errors; in scientific research, researchers usually use the L* value of a colorimeter to quantitatively describe the gloss of citrus, but studies have found that there is no obvious difference in the L* value of citrus with significant gloss differences, so the L* value cannot accurately characterize the gloss of the fruit surface. Therefore, in order to accurately quantify the gloss of citrus peel and provide a digital reference for its grading, a professional gloss measurement instrument, a gloss meter, can be used.
Three-angle gloss meter
Gloss is the reflective property of an object's surface to light. In layman's terms, the stronger the ability of an object's surface to reflect light, the higher the gloss. The ability of an object's surface to reflect light depends on the smoothness of the surface, that is, the ability of the surface to reflect light in a certain direction varies with the smoothness of the surface. The smoother the surface, the greater the reflective ability and the higher the gloss; conversely, the rougher the surface, the worse the reflective ability and the lower the gloss. The measure of gloss is called gloss. Gloss is obtained by measuring the ability of an object's surface to reflect light. The instrument for measuring gloss is a gloss meter.
The existing gloss test instruments are 20°, 60°, and 85°. The 60° gloss meter is suitable for all samples, but for samples with very high gloss, the 20° gloss meter can give better identification, and for samples that are close to matte, the 85° gloss meter can give better identification. Therefore, if the user wants to conduct a comprehensive test, he must carry three gloss instruments, which not only increases the purchase cost of the equipment, but also is inconvenient for on-site use. Therefore, a three-angle gloss meter is derived, which integrates the functions of three gloss meters into one machine. The structure of this three-angle gloss tester is that three measuring angle components are assembled on a mechanical device according to the standard. The output end of the sensor at each angle is connected to the input switching end of the amplifier, and the light source is connected to the output switching end of the corresponding light source power supply. They share an amplifier and light source power supply, and can give the gloss value of the sample at three angles.
There are many brands and models of three-angle gloss meters on the market. Here we recommend the Tri-Enshi HG268 three-angle gloss meter. The instrument is designed and manufactured in accordance with the international standard ISO2813 and the Chinese national standard GB/T9754, and meets the working gloss requirements of JJG696. The instrument has three measuring angles of 20°, 60° and 85°, and the measuring mileage is up to 1000GU. It can measure the gloss values of 20°, 60° and 85° at the same time. The instrument is equipped with powerful PC-side data management software, supports online measurement, can print test reports, transfer data, and realize more functional expansion.
When measuring the glossiness of citrus peel, place the instrument on the sample and press the operating button to obtain the measurement data of three angles of 20°, 60° and 85° at the same position, and the average value and standard deviation can be measured. The data generally read is the arithmetic mean of the five test points, and the difference between the readings of each test point and the average value is not greater than 5% of the average value. Introducing the gloss meter into the agricultural product industry is to digitize the original abstract physical phenomenon, namely gloss. The digitization of gloss means to identify the gloss with specific values , which is convenient for fast and accurate product grading.
