Použití kolorimetru při hodnocení barvy plodů lilku

This article uses a portable spectrophotometer to detect color differences in the peel and calyx colors of five different eggplant materials, including photosensitive and photosensitive. The results showed that the Colorimeter detection results could truly reflect the differences in the apparent color characteristics of eggplants, which are more accurate than the naked eye observation results. It can reflect the subtle differences in the color of different materials. The difference in fruit color between green and purple eggplants is mainly distributed in the 650-700nm wavelength range. The research results provide a new approach for detecting eggplant color appearance and data support for eggplant variety selection and research on the mechanism of fruit color production.

Solanume longena L., also known as Luosu, Kunlun melon, eggplant melon, purple melon, etc., is an annual or perennial plant of the Solanaceae genus. China is the world’s largest producer and consumer of eggplants, which play an important role in China’s vegetable production. The color of eggplant peel is an important quality and commercial trait of eggplant. According to the color of the fruit peel, eggplants can be classified into different types, such as purple-black eggplants, purple-red eggplants, red eggplants, green eggplants, and white eggplants. Consumers in different regions have different preferences for fruit color. At present, the market is mainly dominated by purple-black eggplant varieties. There are two different types of purple-black eggplants. One is a photosensitive variety, which lightens the skin color under low light conditions and even turns green or white under dark conditions; The second type is the light dull variety, which has little change in skin color under low light conditions. Even in dark conditions, the skin color is still a deep purple-red. There has been some progress in the research on the fruit color mechanism in photosensitive and photosensitive eggplants. The effect of light on eggplant skin color is mainly achieved by regulating the biosynthesis of anthocyanins and chlorophyll. Photosensitive eggplant skin anthocyanin synthesis is a light-dependent pathway, while photosensitive eggplant skin anthocyanin synthesis may have two pathways: light dependent and non-light dependent. However, the existing research on eggplant fruit color mainly relies on visual observation to identify and detect eggplant skin color. There needs to be more research on precise detection using instruments and equipment.

The chromatic aberration meter is an instrument that directly measures the colorimetry index of the surface of an object using the photoelectric integrating element with specific spectral sensitivity and the CIELAB chromaticity space, which is commonly used internationally. For industries that only need to control the color of an object but do not need color matching, it has the advantages of fast measurement speed and high accuracy. Colorimeters have been widely used for color detection in agricultural fields such as meat, flour, fruits, and tea. They have yet to be widely used in vegetable production and product detection and are only for related research. The color and appearance of vegetable products, especially eggplant products, rely on direct sensory judgment. To identify the subtle differences in the color of eggplant peel between photosensitive and photosensitive types, this paper used a color difference instrument to measure the fruit color of five eggplant materials to provide a basis for the study of eggplant fruit color mechanism and provide new ideas for vegetable color appearance detection and breeding of new eggplant varieties.

1. Materiály a metody

1.1 Materials and Equipment

There are 5 different types of eggplants, as shown in Table 1.
CS-600 portable spectrophotometer, produced by Hangzhou CHNSpec Technology Co., Ltd. This kolorimetr obtains chromaticity data by detecting the reflectance of 31 wavelengths of light at intervals of 400-700nm and 10nm on the surface of an object, including reflectance, overall color difference E, brightness (black and white) L, red-green a, and yellow, blue b.

Table.1 Comparison of Fruit Color, Calyx Color, and Undercalyx Color of Five Different Types of Eggplant

Item varieties Source Typ Fruit peel color Sepal Color Calyx Color
1 Green Delicious Buy Blunt Type Purple black Purple Black Zelená
2 TK99 Self Education Blunt Type Purple black Purple Black Zelená
3 98 Self Education Mixed Type Purple black Lavender  Purple
4 9798 Self Education Mixed Type Purple black Lavender  Purple
5 10012 Self Education Photosensitive Type Purple black Zelená Purple

1.2 Test methods

Use a colorimeter to measure the color difference data of different eggplant varieties. Select 5 eggplants for each variety, which is repeated 5 times. First, correct the Colorimeter for black and white. Then, select 1 ‘green handlebar’ and peel it at a uniform color point in the middle of the eggplant, with a length of 5cm and a width of 4cm. Place the outer skin tightly against the test hole, completely covering the test hole. Press the test button, and the test result will be used as the standard value, denoted as S1; Afterwards, the same method was used to determine the color difference values of the remaining eggplants, S2-S25. The method for measuring the color difference value of the lower sepal color is the same as that of the fruit skin color. Peel the skin at the position covered by the sepals, with a length of 3cm and a width of 3cm. The measurement results are sequentially recorded as P1-P25.

1.3 Data statistical analysis

Perform analysis of variance on the test data using the Duncan method using DPS software, and perform chart analysis using Microsoft Office Excel 2007 software.

2. Results and Analysis

2.1 Analysis of peel color difference

As shown in Table 2, the total color difference of the five materials did not show significant differences; Δ E is between 1.15 and 1.63. Among them, ’98’ is the smallest, at 1.15‘TK99 ‘maximum, 1.63; The difference between the two is only 0.48; The ‘Green Jiao Zi’ is closest to ‘TK99’. The brightness L ranges from 25.94 to 28.02. A significant difference between ‘Green Bajiao Zi’ and ‘10012’ indicates that ‘Green Bajiao Zi’ has the brightest epidermis and ‘10012’ has the darkest epidermis. The red-green value a shows significant differences between ‘9798’ and ‘TK99’. The yellow and blue values of ‘10012’ are the lowest, showing significant differences from other varieties. As shown in Figure 1, on the spectral reflectance curves of different materials, ‘Green Bajiao’ and ‘TK99’ form a group, while the other three materials form a group; In terms of different spectral reflectance, 400-650nm is a group, 660-670nm is a group, and 680-700nm is a group; Overall, before 650nm, there was no significant difference in spectral reflectance among the five varieties. After 650nm, the difference gradually became apparent and was significantly divided into two groups.

Table.2 Comparison of Results of Fruit Peel Colorimeter Measurement

Item Ukázka L a b AE 400 nm 410 nm 420 nm 640 nm 650 nm 660 nm 670 nm 680 nm 690 nm 700 nm
1 Green Delicious 28.02a -0.44ab 2.71a 1.55a 5.02a 4.72a 4.65a 5.85a 6.16a 6.90a 8.05a 10.61a 17.19a 25.64a
2 TK99 26.76ab -0.21b 2.63a 1.63a 4.79a 4.43a 4.31a 5.29a 5.59ab 6.55ab 8.24a 11.59a 18.54a 25.77a
3 98 27.21ab -0.41ab 2.62a 1.15a 4.89a 4.58a 4.51a 5.50a 5.52ab 5.73bc 6.13b 7.38b 10.62b 15.24b
4 9798 27.07ab -0.51a 2.32ab 1.16a 4.86a 4.58a 4.53a 5.37a 5.33ab 5.51c 5.84b 6.84b 9.50b 13.44b
5 10012 25.94b -0.34ab 1.98b 1.31a 4.68a 4.45a 4.30a 5.14a 5.13b 5.29c 5.56b 6.57b 9.66b 14.61b

Note: Δ E represents the overall color difference, L represents the brightness (black and white), a represents red and green, and b represents yellow and blue.

Table.3 Comparison of Measurement Results of Colorimeter under Calyx

Item Ukázka L a b AE 400 nm 410 nm 420 nm 480 nm 4 90 nm 650 nm 660 nm 680 nm 690 nm 700 nm
1 Green Delicious 26.93a 7.60c 3.73b 2.89a 5.16a 4.65a 4.32a 4.50a 4.48a 10.91ab 12.97ab 19.15ab 27.49a 34.00a
2 TK99 26.30a 5.60c 2.17ab 3.46a 5.24a 4.77a 4.41a 4.57a 4.54a 9.38a 11.83a 19.44ab 27.82a 34.54a
3 98 36.11b 14.26b 2.22ab 12.71b 9.37b 8.92bc 8.53bc 8.04b 7.31a 15.79bc 15.42ab 17.88ab 25.73a 32.76a
4 9798 36.40b 16.99a -1.16a 15.34b 10.75b 10.37c 9.95c 8.39b 7.43a 17.08c 17.19b 21.38b 30.44a 38.53a
5 10012 57.62c -9.06d 38.81c 50.63c 8.72b 7.77b 7.02b 10.27b 11.32b 18.84c 15.89ab 15.89a 25.56a 36.39a

20230502215818 47425 - The Application of Colorimeter in the Evaluation of Eggplant Fruit Color

Fig.1 Line chart Diagram of Skin Color Spectral Reflectance

2.2 Analysis of color difference under the calyx

As shown in Table 3, the total color difference under the calyx of the five materials showed significant differences; Δ E is between 2.89 and 50.63. Among them, ‘Green Hand Jiaozi’ is the smallest, at 2.89‘10012 ‘maximum, 50.63; The difference between the two is 47.74; It is generally divided into three groups, with ‘Green Baby’ and ‘TK99’ being one group, both of which have smaller values‘98 ‘and’ 9798 ‘form a group, with moderate values‘ 10012 ‘is a separate group with the highest value. The brightness L is between 26.93 and 57.62. The numerical pattern is consistent with Δ E is consistent and also divided into 3 groups, with the highest being ‘10012’, indicating its lightest color, the colors of ‘Lvbajiao Zi’ and ‘TK99′ is the darkest, while ’98’ and ‘9798’ are in the middle, consistent with their apparent traits. The red-green value a is also divided into the same three groups, with the difference being that ‘10012’ leans green, while the other four materials lean red. The yellow-blue value b, different from the apparent traits, ‘9798’ has the smallest value of -1.16, indicating a bluish color ‘10012 ‘maximum, 38.81, indicating a very yellow color; There is no significant difference between the other three materials. As shown in Figure 2, on the spectral reflectance curves of different materials, the overall and apparent properties are consistent and divided into three groups ‘Green Jiaozi ‘and’ TK99 ‘are grouped,’ 98 ‘and’ 9798 ‘are grouped, and’ 10012 ‘is grouped separately. In terms of different spectral reflectance, at 400-470nm, the difference between the values of ‘Green Bajiao Zi’ and ‘TK99’ is very small and low, while the values of the other three materials are relatively close, around 9; At 480-650nm, five materials showed significant differences, with ‘10012’ having the highest reflectivity, while the other four materials were less than 10; At 660-700nm, the difference is not significant, but the overall value is relatively high and increases with the wavelength. Overall, the spectral reflectance of the five materials exhibited completely different characteristics between the three bands of 400-470, 480-650, and 660-700nm, only consistent with their apparent properties between 480-650nm.

20230502220209 27985 - The Application of Colorimeter in the Evaluation of Eggplant Fruit Color

Fig.2 Line chart of Spectral Reflectance under Calyx

3. Discussion and Conclusion

3.1 The detection results of the color difference instrument can truly reflect the differences in the apparent color traits of eggplants

The experimental results show that the detection results of the Colorimeter are consistent with the sensory results (eggplant color appearance traits) at the macro level, and it is feasible to use the Colorimeter to detect whether the eggplant color can meet the requirements. The skin color of the 5 eggplant materials in this experiment is all deep purple, with slight differences in color and brightness; When viewed with the naked eye, the difference is insignificant; Colorimeter test results, Δ E also did not reach a significant level. In terms of the color under the calyx, it can be divided into three types when viewed with the naked eye, namely purple-black, light purple, and green, with significant differences; Colorimeter detection results, Δ E also showed significant differences, with values identical to those observed with the naked eye. From this, it can be seen that the detection results of the Colorimeter are highly consistent with the sensory results, and the Colorimeter can be used for detecting the color of eggplants.

3.2 Colorimeter detection results are more accurate than those observed with the naked eye

Colorimeter except for overall color difference Δ in addition to E, there are three data, namely L, a, and b, representing the chromaticity value of the object’s color, which is the color space coordinate of that color. Any color has a unique coordinate value. Among them, L represents brightness (black and white), a represents red and green, and b represents yellow to blue; Δ The L + value indicates a brighter color, Δ the L-value indicates darkness, Δ A + value indicates a reddish color, Δ the a-value indicates a greenish color, Δ the value of b + indicates a yellowish color, Δ the b-value indicates a bluish color. As shown in Table 2, although 5 materials Δ The difference in E is not significant, the values of L, a, and b show certain differences‘ There is a significant difference in brightness between ‘Lvbajiao Zi’ and ‘10012’, with ‘TK99’ and ‘9798’ showing a significant difference in red and green, and ‘10012’ and ‘Lvbajiao Zi,’ ‘TK99′ and ’98’ showing a significant difference in yellow and blue. These differences are difficult to distinguish through the eyes; Δ E cannot show this difference either. From this, it can be seen that the detection data of the color difference instrument is more comprehensive and accurate.

3.3 The detection results of the Colorimeter can reflect the subtle differences in colors of different materials

By comparing the reflectivity of different materials for different wavelengths of light, more refined results can be obtained, and more subtle differences can be discovered. As shown in Figure 2, the full spectrum values show no significant difference in the reflectivity of the five materials before 650nm. After 650nm, the difference becomes more and more significant and is ultimately divided into two groups. ‘Green Bajiao’ and ‘TK99′ form one group (photosensitive type), while ’98’, ‘9798’, and ‘10012’ form one group (photosensitive type, photosensitive combination type). Therefore, the difference in skin color between green and purple eggplants is mainly in the long wavelength range of 650-700nm. As shown in Figure 3, there is a significant difference in the reflectivity of different wavelengths of light under different material calyxes, mainly concentrated in the mid-wavelength range of 500-650nm. It can be divided into three groups: purple-purple eggplant (photosensitive light passively combined type), purple-purple eggplant (photosensitive type), and green-purple eggplant (photosensitive type). In summary, the 650nm wavelength is an important node. The color generation mechanism of photosensitive and photosensitive eggplants may be generated by the action of light with wavelengths above 650nm and below 650nm, respectively. The subtle differences in spectral reflectance of these five different materials provide a new approach to studying the mechanism of eggplant color production.
Author: Guo Shoupeng

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