Green raisin browning quantitative evaluation method

Abstract

The invention provides a green raisin browning quantitative evaluation method, and belongs to the technical field of forest fruit product detection. The method comprises the following steps: flatly laying raisins subjected to spot check on a flat plate with a white ground color, measuring a plurality of positions of a batch to be checked by adopting a colorimeter to obtain a yellow-blue coefficient value b and a color angle h degree, and substituting the average value of the color angle h degree and the average value of the yellow-blue coefficient value b into a formula Y = 153.21-3.06 X1-1.14 X2 to obtain the overall browning rate of the raisins in the batch to be checked, wherein in the formula, Y is the browning rate, X1 is the yellow-blue coefficient value b, and X2 is the color angle h degree. According to the method, the overall browning condition of a batch of raisins can be effectively and quantitatively evaluated at a time, the raisin browning evaluation efficiency is improved, and the problems that manual evaluation is low in efficiency and high in cost are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of forest fruit product detection, and particularly relates to a method for quantitatively evaluating the browning of green raisins. Background Art

[0002] Seedless white grapes are also known as Thompson seedless and seedless grapes. The fruit is oval or short oval, yellow-green in color, crystal clear, like emeralds. Seedless white is the main grape variety used for drying, mainly green seedless raisins, which are favored by consumers because of their fresh and attractive color. Using air-drying rooms to produce green raisins is the biggest difference and competitive advantage between my country and other raisin producing areas in the world. With the continuous development of plant growth regulator types and application technologies, plant growth regulators such as gibberellins are used for fruit swelling treatment to increase grain weight and increase yield. With the continuous increase in grain weight and ear weight, and the influence of adverse meteorological factors such as cooling and rainfall during the drying process, the browning rate of seedless white raisins increases, which has a greater impact on product quality. Color is an important appearance quality indicator of raisins, and the browning rate is an important indicator for evaluating the quality of raisins, especially green grapes such as seedless white.

[0003] However, the browning rate is usually evaluated by sensory means in current production. There is a lack of effective quantitative evaluation methods, and it is difficult to obtain accurate browning rate evaluation data, which restricts the evaluation of raisin production, sales, processing, and storage effects. At present, the colorimeter can only measure the color difference of a single object separately, and cannot show the overall browning of the sample. Therefore, a quantitative evaluation method for the browning of seedless white raisins is a technical problem that needs to be solved at this stage. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a quantitative evaluation method for browning of green raisins, which can efficiently determine the browning rate of a large number of seedless white raisins at one time and reduce labor costs.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] The invention provides a method for quantitatively evaluating the browning of green raisins, comprising the following steps: laying raisins on a flat plate with a white background, measuring a yellow-blue coefficient value b and a color angle h° by using a colorimeter, substituting the color angle h° and the yellow-blue coefficient value b into a formula Y=153.21-3.06X1-1.14X2 to obtain a browning rate; wherein in the formula, Y is the browning rate, X1 is the yellow-blue coefficient value b, and X2 is the color angle h°.

[0007] Preferably, the raisins are sampled using a 5-point method.

[0008] Preferably, the usage amount of the raisins is 300-500g.

[0009] Preferably, the colorimeter has 20-25 measuring points.

[0010] Preferably, when the colorimeter cannot measure the color angle h°, the red-green coefficient value a and the yellow-blue coefficient value b are measured, and the color angle h° is calculated based on a and b.

[0011] Preferably, the calculation formula of the outstanding angle h° is: In the formula, h 。 is the color angle h°, a is the red-green coefficient value a, and b is the yellow-blue coefficient value b.

[0012] Preferably, the hue angle h° and the yellow-blue coefficient value b are average values ​​of multiple measurements.

[0013] Preferably, the process of obtaining the formula Y=153.21-3.06X1-1.14X2 is as follows: 64 batches of seedless white raisin samples are taken, and sampling is performed using the 5-point method. 200-300g of raisin samples are sampled from each batch, and the browning rate is measured manually and the color difference data is measured using a colorimeter; the color difference data obtained by the measurement and the manually measured browning rate are fitted using the stepwise regression method to obtain the fitting formula: Y=153.21-3.06X1-1.14X2, where Y is the browning rate, X1 is the yellow-blue coefficient value b, and X2 is the color angle h°.

[0014] Preferably, the method for manually measuring the browning rate comprises: separating the browned raisins in the sample, counting them separately, and calculating the browning rate of the batch of raisins, browning rate=(number of browned raisins / total number of raisins)×100%.

[0015] Preferably, the color difference data measured by a colorimeter includes a color difference value E, a brightness value L, a red-green coefficient value a, a yellow-blue coefficient value b, a chroma C, and a color angle h°.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The present invention analyzes the relationship between the color difference index and the browning rate of seedless white raisins, and uses stepwise regression analysis to establish a model and quantitative evaluation method for the browning rate of seedless white raisins based on colorimeter measurement and analysis. This method can effectively and accurately evaluate the browning of a large number of green raisins at one time, improves the efficiency of browning evaluation of green raisins, and solves the problem of low efficiency and high cost of manual evaluation.

[0018] Furthermore, through experiments and verification, it was found that the quantitative evaluation method for browning of seedless white raisins set by the present invention can achieve similar evaluation results as manual evaluation, which indicates that the evaluation method prepared by the present invention can replace manual evaluation and improve the evaluation efficiency of browning of green raisins. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The figure is a linear regression analysis result diagram of manual evaluation data and model prediction data, wherein the X-axis is the manual evaluation browning rate data of the validation group of 20 seedless white raisins, and the Y-axis is the sample browning rate calculated by the method of the present invention. DETAILED DESCRIPTION

[0020] The present invention provides a method for quantitatively evaluating the browning of green raisins, comprising the following steps: spreading the raisins on a flat plate with a white background, measuring the yellow-blue coefficient value b and the color angle h° using a colorimeter, substituting the color angle h° and the yellow-blue coefficient value b into the formula Y=153.21-3.06X1-1.14X2 to obtain the browning rate; wherein Y in the formula is the browning rate, X1 is the yellow-blue coefficient value b, and X2 is the color angle h°. The present invention uses the L, a, b color quantization mode on the colorimeter, uses a blackboard for zeroing, measures and records indicators such as the color difference value E, the brightness value L, the red-green coefficient value a, the yellow-blue coefficient value b, the chroma C, and the color angle h°; when some colorimeter cannot measure the color angle h°, the red-green coefficient value a and the yellow-blue coefficient value b are measured, and the calculation formula is as follows: Calculate the color angle h°, where h in the formula 。 is the color angle h°, a is the red-green coefficient value a, and b is the yellow-blue coefficient value b. The grape variety of the present invention is preferably a seedless white grape. The raisins of the present invention are green raisins.

[0021] In the present invention, 300-500g of raisin samples are randomly selected from each batch of raisin samples by the 5-point method, mixed, and then measured by a colorimeter. The present invention randomly selects 20-25 measuring points in the sample, and uses a colorimeter to measure and record the color difference value E, brightness value L, red-green coefficient value a, yellow-blue coefficient value b, chroma C, and color angle h°. The measured values ​​of each index described in the present invention are averaged to perform the next step.

[0022] In the present invention, the process of obtaining the formula Y=153.21-3.06X1-1.14X2 is as follows: 64 batches of seedless white raisin samples are taken, and the 5-point method is used for sampling. 200-300g of raisin samples are drawn from each batch, and the browning rate is measured manually and the color difference data is measured by a colorimeter; the color difference data obtained by the measurement and the manually measured browning rate are fitted by a stepwise regression method to obtain a fitting formula: Y=153.21-3.06X1-1.14X2, where Y is the browning rate, X1 is the yellow-blue coefficient value b, and X2 is the color angle h°. The method for manually measuring the browning rate of the present invention includes: separating the browned raisins in the sample, counting them separately, and calculating the browning rate of the batch of raisins, where the browning rate=(the number of browned raisins / the total number of raisins)×100%. The color difference data measured by the colorimeter in the present invention include color difference value E, brightness value L, red-green coefficient value a, yellow-blue coefficient value b, chroma C and color angle h°.

[0023] In the present invention, unless otherwise specified, the raw materials or instruments used are commercially available products well known to those skilled in the art.

[0024] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Example 1

[0026] 64 batches of seedless white raisin samples were obtained, and the 5-point method was used for sampling. 200-300g of raisin samples were taken from each batch, and the browning rate was measured manually and the color difference data was measured by colorimeter. The color difference data obtained by measurement and the browning rate measured manually were used. The browning rate was measured manually as Y, and the six colorimeter measurement indicators, including E (color difference value with zero blackboard), L (brightness value), a (red-green value), b (yellow-blue value), C (chroma), and h° (color angle) measured by the colorimeter, were used. SAS software was used for fitting by stepwise regression method, and a quantitative evaluation model of the browning rate of seedless white raisins based on colorimeter measurement and analysis was established: Y = 153.21-3.06X1-1.14X2, Y is the browning rate, X1 is the yellow-blue coefficient value b, and X2 is the color angle h°. The measurement data are shown in Table 1.

[0027] The method of manually measuring the browning rate is as follows: separate the browning raisins in the sample, count them separately, and calculate the browning rate of the batch of raisins, browning rate = (number of browning raisins / total number of raisins) × 100%. The method of measuring the color difference data using a colorimeter is as follows: use a colorimeter, use the L, a, b color quantization mode, use a blackboard to zero, measure and record the color difference value E, brightness value L, red-green coefficient value a, yellow-blue coefficient value b, chroma C and color angle h° index.

[0028] Table 164 Batch manual determination of browning rate and color difference data

[0029]

[0030]

[0031] Example 2

[0032] A quantitative evaluation method for browning of seedless white raisins, comprising the following steps:

[0033] (1) Using the 5-point method, randomly select 300 g of raisin samples from each batch of green raisin samples, mix them evenly, and spread them on a flat plate with a white background.

[0034] (2) Randomly select 25 measuring points and use a colorimeter (HIGH-QUALITY COLORIMETER NH310, Suzhou Kebosheng Mechanical Equipment Co., Ltd.) to measure and record the color difference value E, brightness value L, red-green coefficient value a, yellow-blue coefficient value b, chroma C and color angle h° using the L, a, b color quantization mode and a blackboard for zeroing.

[0035] (3) The average value of multiple measurement data is used as the test data, and the browning rate calculation formula Y=153.21-3.06X1-1.14X2 is used to obtain the browning rate of the sample for this test. In the formula, Y is the browning rate, X1 is the yellow-green coefficient value b obtained by measurement, and X2 is the color angle h° obtained by measurement.

[0036] Example 3

[0037] The difference from Example 2 is that 300 g of green raisin sample is taken, 20 measuring points are randomly selected, and the remaining steps are the same as those in Example 2.

[0038] Example 4

[0039] The difference from Example 2 is that 500 g of green raisin sample is taken, 25 measuring points are randomly selected, and the remaining steps are the same as those in Example 2.

[0040] Test Example 1

[0041] Seedless white-green raisins were purchased from the market, and three groups of raisins were randomly selected, each weighing 200g. The evaluation was carried out by human evaluation and the evaluation method described in Example 2, respectively. The steps of the manual evaluation method are as follows: First, the raisins were classified according to the browning and non-browning rates, the number of raisins of each type was counted, and the browning rate was calculated, where the browning rate = the number of browning / (the number of browning + the number of non-browning). A colorimeter (HIGH-QUALITY COLORIMETER NH310, Suzhou Kebosheng Mechanical Equipment Co., Ltd.) was used, and the L, a, b color quantification mode was used, and the blackboard was used for zeroing. 25 positions of the sample were measured, and the yellow-blue coefficient value b and the color angle h° index were recorded. The average value of each index was substituted into Y = 153.21-3.06X1-1.14X2, where X1 is the color angle h° obtained by the measurement, and X2 is the yellow-blue coefficient value b obtained by the measurement, and the browning rate Y was calculated.

[0042] The results are shown in Table 2. The results show that for the browning evaluation of seedless white-green raisins purchased from the market, the quantitative evaluation method of the present invention achieves results similar to those of manual evaluation, and can be used as a simple and fast quantitative evaluation method.

[0043] Table 2 Browning evaluation results of seedless white-green raisins purchased from the market

[0044]

[0045] Test Example 2

[0046] The Institute of Horticultural Crops of Xinjiang Academy of Agricultural Sciences used seedless white grapes that were conventionally expanded in production to air-dry raisins in the Turpan production area, and randomly selected 3 groups of raisins, each weighing 200g, and measured them using manual evaluation and the evaluation method described in Example 2. The manual evaluation method is the same as that in Test Example 1. The results are shown in Table 3, which shows that the quantitative evaluation method of the present invention achieves the same results as manual evaluation for the browning evaluation of air-dried raisins after expansion treatment in the Turpan production area, and can replace manual evaluation.

[0047] Table 3 Browning evaluation results of seedless white raisins after enlargement treatment in Turpan production area

[0048]

[0049]

[0050] Test Example 3

[0051] The Xinjiang Academy of Agricultural Sciences used seedless white grapes without swelling treatment to dry raisins in the Turpan production area, and randomly selected 3 groups of raisins, each weighing 100g, and measured them by human evaluation and the evaluation method described in Example 2. The manual evaluation method is the same as that in Test Example 1. The results are shown in Table 4, which shows that the quantitative evaluation method of the present invention achieves the same results as manual evaluation for the browning evaluation of raisins dried in the Turpan production area without swelling treatment, and can replace manual evaluation.

[0052] Table 4 Evaluation results of browning of seedless white raisins without expansion in Turpan production area

[0053]

[0054] Test Example 4

[0055] The Institute of Horticultural Crops of Xinjiang Academy of Agricultural Sciences used seedless white grapes with normal expansion management to air-dry raisins in the Urumqi production area, and randomly selected 3 groups of raisins, each weighing 200g, and measured them by human evaluation and the evaluation method described in Example 2. The manual evaluation method is the same as that in Test Example 1. The results are shown in Table 5, and the results show that for the browning evaluation of air-dried raisins in the Urumqi production area without expansion treatment, the quantitative evaluation method of the present invention achieves the same results as manual evaluation and can replace manual evaluation.

[0056] Table 5 Evaluation results of browning of seedless white raisins after enlargement treatment in Urumqi production area

[0057]

[0058] Test Example 5

[0059] 20 batches of seedless white-green raisin samples were obtained by various methods such as market purchase and experimental drying; 3 groups of replicates were taken for each batch of samples using a 5-point sampling method, each group weighing 200g, and the samples were measured using manual evaluation and the evaluation method described in Example 2. The steps of the manual evaluation method are as follows: first, the raisins were classified according to the browning and non-browning rates, the number of raisins of each type was counted, and the browning rate was calculated, where the browning rate = the number of browning / (the number of browning + the number of non-browning). The model prediction method of Example 2 of the present invention uses a colorimeter (HIGH-QUALITY COLORIMETER NH310, Suzhou Kebosheng Mechanical Equipment Co., Ltd.) L, a, b color quantification mode, and a blackboard is used for zeroing to measure 25 positions of the sample, and the yellow-blue coefficient value b and the color angle h° index are recorded. The average value of each index is substituted into Y = 153.21-3.06X1-1.14X2, where X1 is the color angle h° obtained by measurement, and X2 is the yellow-blue coefficient value b obtained by measurement, and the browning rate Y is calculated. The average value of three repetitions in each batch was taken as the test result. The test results are shown in Table 6. A scatter plot was made with the model prediction result as the Y axis and the manual evaluation result as the X axis. A univariate linear regression was performed on the scatter plot. R 2 >0.9, such as Figure 1 As shown, it is shown that the prediction results of the model of the present invention are significantly positively correlated with the manual evaluation data, and the browning rate of the formula sample can be determined quickly and effectively.

[0060] Table 6 Manual evaluation data and model prediction data

[0061] serial number Manual evaluation of browning rate (%) Model predicted browning rate (%) T1 25.68 25.87 T2 30.95 29.18 T3 39.81 41.18 T4 50.00 38.53 T5 40.48 43.11 T6 40.35 40.48 T7 53.55 51.41 T8 30.05 30.23 T9 65.17 58.02 T10 35.50 32.46 T11 25.33 24.40 T12 30.74 27.45 T13 3.15 3.59 T14 11.84 11.69 T15 6.54 7.31 T16 14.36 17.51 T17 25.25 27.37 T18 23.13 24.04 T19 33.75 35.33 T20 23.81 25.20

[0062] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for quantitatively evaluating the browning of green raisins, characterized in that: The method comprises the following steps: laying raisins on a flat plate with a white background, measuring the sample for inspection by using a colorimeter to obtain a yellow-blue coefficient value b and a color angle h°, substituting the color angle h and the yellow-blue coefficient value b into a formula Y=153.21-3.06X1-1.14X2 to obtain the overall browning rate of the batch of raisins for inspection; In the formula, Y is the browning rate, X1 is the yellow-blue coefficient value b, and X2 is the color angle h°.

2. The method for quantitatively evaluating browning of green raisins according to claim 1, characterized in that: The raisins were sampled using a 5-point method.

3. The method for quantitatively evaluating browning of green raisins according to claim 1, characterized in that: The usage amount of the raisins is 100-500g.

4. The method for quantitatively evaluating browning of green raisins according to claim 1, characterized in that: The colorimeter has 20-25 measuring points.

5. The method for quantitatively evaluating browning of green raisins according to claim 1, characterized in that: When the colorimeter cannot directly measure the color angle h°, measure the red-green coefficient value a and the yellow-blue coefficient value b, and calculate the color angle h° based on a and b.

6. The method for quantitatively evaluating browning of green raisins according to claim 5, characterized in that: The calculation formula of the color angle h° is: In the formula, h 。 is the color angle h°, a is the red-green coefficient value a, and b is the yellow-blue coefficient value b.

7. The method for quantitatively evaluating browning of green raisins according to claim 1, characterized in that: The hue angle h° and the yellow-blue coefficient value b are average values ​​of multiple measurements.

8. The method for quantitatively evaluating browning of green raisins according to claim 1, characterized in that: The process of obtaining the formula Y=153.21-3.06X1-1.14X2 is as follows: 64 batches of seedless white raisin samples are taken, and sampling is performed using the 5-point method. 200-300g of raisin samples are taken from each batch, and the browning rate is measured manually and the color difference data is measured using a colorimeter; the color difference data obtained by the measurement and the manually measured browning rate are fitted using a stepwise regression method to obtain a fitting formula: Y=153.21-3.06X1-1.14X2, where Y is the browning rate, X1 is the yellow-blue coefficient value b, and X2 is the color angle h°.

9. The method for quantitatively evaluating browning of green raisins according to claim 8, characterized in that: The method for manually measuring the browning rate includes: separating the browned raisins in the sample, counting them separately, and calculating the browning rate of the batch of raisins, where the browning rate=(the number of browned raisins / the total number of raisins)×100%.

10. The method for quantitatively evaluating browning of green raisins according to claim 8, characterized in that: The color difference data measured by the colorimeter include color difference value E, brightness value L, red-green coefficient value a, yellow-blue coefficient value b, chroma C and color angle h°.

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