Visual detection label for fruit diseases and application of visual detection label in fruit packaging

Abstract

The invention relates to the field of food packaging / monitoring / fruit preservation, in particular to a visual detection label responding to fruit diseases through color change and application of the visual detection label in fruit packaging. The visual detection label for the fruit diseases comprises an adsorption carrier and a plant pigment component adsorbed on the adsorption carrier, and the plant pigment component comprises one or more of an anthocyanin compound and a betacyanin compound. The label provided by the invention can represent fruit infectious diseases, so that fruit disease information is visually fed back to producers and consumers through naked eye monitoring or instrument monitoring under the condition that packaging is not damaged, and the label is suitable for the situation of non-transparent paper single fruit packaging.

Description

Technical Field

[0001] The invention relates to the field of food packaging / monitoring / fruit preservation, and in particular to a visual detection label for responding to fruit diseases through color changes and application of the label in fruit packaging. Background Art

[0002] Packaging is one of the main methods to protect fruits during storage and transportation, and is also an important means to improve the commercial quality of fruit products. At present, there are various packaging methods for citrus fruits, among which paper packaging has good water permeability and air permeability, but poor transparency. Once a disease occurs, it is not easy to be observed, which brings certain difficulties to merchants and consumers. Adding visual labels can determine the disease of fruit products by monitoring the color change of the indicator label with the naked eye or instruments without destroying the packaging, helping merchants and consumers to identify diseased products and ensure the quality of the supplied products.

[0003] Anthocyanin is a common natural plant pigment, widely found in the roots, stems, leaves, flowers, fruits and other tissues and organs of plants. It is a coloring substance for many horticultural products such as fruits, flowers, and vegetables. Under acidic conditions, anthocyanin is red, and as the pH value increases to neutral, it gradually becomes colorless. When the pH is in the alkaline range, it will turn purple or blue and finally degrade. Betacyanin is another common type of pigment in plants, and its content is particularly rich in pitaya peel. Under acidic conditions, betacyanin is red or purple-red, and as the pH value increases to alkaline conditions of pH greater than 11, it becomes light yellow.

[0004] At present, plant pigment indicator labels are mostly used to indicate the quality deterioration of livestock and poultry meat and aquatic products. The principle is that under the condition of quality deterioration of aquatic products and livestock meat products, volatile N-containing compounds are released, which increases the pH of the environment, and plant pigments such as anthocyanins change color under alkaline pH conditions, thus indicating the quality deterioration of the product.

[0005] Regarding the use of pigments to indicate the freshness of fruits and vegetables, there have been studies on the use of chemical indicators such as methyl red and bromothymol blue. In comparison, anthocyanin natural pigments have been listed as food additives that do not require certification in the United States, Japan, and other countries, and are allowed to be used in food, beverages, and pastries. Compared with indicators such as methyl red and bromothymol blue, they are more suitable for scenarios where they come into direct contact with fruits. However, there is currently no application of plant pigment indicator labels for fruit disease indications. The development of disease response labels that use paper as a carrier and can come into direct contact with fruits can monitor the degree of color change of the indicator label through the naked eye or instruments without damaging the packaging, and determine the occurrence of diseases in fruit products, helping merchants and consumers identify diseased products and ensure the quality of supplied products. It is suitable for scenarios such as non-transparent paper single fruit packaging. Summary of the invention

[0006] In order to solve the above-mentioned technical problems, the purpose of the present invention is to provide a visual detection label for fruit diseases. The label provided by the invention can characterize infectious diseases of fruits, so that the information of fruit diseases can be intuitively fed back to producers and consumers through naked eyes or instrument monitoring without destroying the packaging. The label is suitable for the case of non-transparent paper single fruit packaging.

[0007] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions: A fruit disease visualization detection label comprises an adsorption carrier and a plant pigment component adsorbed on the adsorption carrier, wherein the plant pigment comprises one or more of anthocyanin compounds and betacyanin compounds.

[0008] Preferably, the source of the plant pigment is blueberry, purple sweet potato, dragon fruit or black bean.

[0009] Preferably, the adsorption carrier is a paper carrier.

[0010] Furthermore, the present invention also provides a method for preparing a fruit disease visualization detection label, which is prepared by soaking a paper carrier in a plant pigment solution for 10-15 minutes, taking it out and drying it; the plant pigment component content in the plant pigment solution is greater than 10 mg / mL.

[0011] Furthermore, the present invention also provides a method for detecting fruit diseases, which uses the detection label to contact the diseased fruit and respond to the occurrence of the fruit disease through color changes.

[0012] Preferably, the result is determined by naked eye or instrumental determination. Naked eye determination can be made by the color difference between the label color and the standard color band to determine that the disease has occurred. Instrumental determination is made by measuring the color difference between the label color and the standard color band using a color difference detection instrument and determining the color according to the ΔE value. ΔE=((L * 1-L * 0) 2 + (a * 1-a * 0) 2 + (b * 1-b * 0) 2 ) 0.5 , where L * 1.a * 1 and b * 1 is the label reading, L * 0.a * 0 and b * 0 is the reading of the standard color card.

[0013] Preferably, the standard color band is made from the color parameters of the label after contact with healthy fruit.

[0014] Furthermore, the present invention also provides the detection label or the method for detecting fruit diseases in direct contact with fruit packaging.

[0015] The present invention uses anthocyanin and betacyanin pigments as raw materials and paper materials as adsorption carriers. The label provided by the present invention can characterize fruit infectious diseases, so that the information of fruit disease can be fed back to producers and consumers intuitively through naked eyes or instrument monitoring without destroying the packaging, and is suitable for non-transparent paper single fruit packaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the label.

[0017] Figure 2 Flowchart of label preparation and application.

[0018] Figure 3 This is a graph showing the chromaticity value changes of the visualization label in Example 1 during monitoring of citrus green rot fruit; A, pitaya pigment; B, purple potato pigment; C, black bean pigment; D, blueberry pigment; CK represents healthy fruit; BR represents green rot fruit.

[0019] Figure 4 This is a graph showing the chromaticity value changes of the visualization label in Example 2 in monitoring stem rot in citrus fruits; A, pitaya pigment; B, purple potato pigment; C, black bean pigment; D, blueberry pigment; CK represents healthy fruit; STR represents stem rot-affected fruit.

[0020] Figure 5 This is a graph showing the chromaticity value changes of the visualization label in Example 3 in monitoring green rot in citrus fruit; A, pitaya pigment; B, purple potato pigment; C, black bean pigment; D, blueberry pigment; CK represents healthy fruit; GR represents green rot fruit.

[0021] Figure 6 This is a graph showing the chromaticity value changes of the visualization label in Example 4 in monitoring mixed diseases in citrus fruit; A, pitaya pigment; B, purple potato pigment; C, black bean pigment; D, blueberry pigment; CK represents healthy fruit; MX represents citrus fruit with mixed diseases. DETAILED DESCRIPTION

[0022] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0023] Example 1: Application of visual tags in monitoring citrus green rot fruit 1) Test methods Extraction of plant pigments: Purple sweet potato, black bean skin, and blueberry skin were dried in an oven at 50°C (dragon fruit skin was dried in an oven at 65°C), then ground into powder using a pulverizer at high speed, and the obtained powder was mixed with 70% methanol (containing 1% formic acid) at a solid-liquid ratio of 1:10 (m:v), and ultrasonic-assisted water bath extraction was performed for 30 min. The obtained extract was filtered using a Buchner funnel, and the residue was extracted 1 to 2 more times. The supernatant was combined, and the methanol in the filtrate was removed by rotary evaporation at 35°C under light-proof conditions to obtain anthocyanin concentrate.

[0024] Label preparation: Cut the filter paper into rectangular labels with a width of 1.5 cm and a length of 8 cm, immerse the lower half in 10 mg / mL anthocyanin concentrate for 30 s, and dry in the dark to obtain anthocyanin labels.

[0025] Interaction between the label and the diseased fruit: The label is directly contacted with the diseased part of the fruit but not covered by spores and maintained for 30 seconds, and then the label is removed for color measurement.

[0026] Determination of label color: Use a colorimeter to record the color of the standard color card and the label. The color difference between the standard color bands is ΔL*=L * 1-L * 0, Δa*=a * 1-a * 0, Δb*=b * 1-b * 0, ΔE=((L * 1-L * 0) 2 + (a * 1-a * 0) 2 + (b * 1-b * 0) 2 ) 0.5 , where L * 1.a * 1 and b * 1 is the label reading, L * 0.a * 0 and b * 0 is the reading of the standard color card.

[0027] 2) Test results The L* and b* values ​​of purple sweet potato, pitaya, black bean, blueberry and other plant pigment labels after contact with healthy citrus fruits were not significantly different from those before contact ( P >0.05), while the a* value increased ( P<0.05). The specific values ​​are shown in Table 1. Therefore, a standard color card was prepared based on the L*, a* and b* values ​​of the labels after contact with healthy citrus fruits.

[0028] The changes in chromaticity values ​​are shown in Table 2. The L* values ​​of purple sweet potato, dragon fruit, black bean, blueberry and other plant pigment labels all increased significantly ( P <0.05), b* value decreased significantly ( P <0.05), while the a* value of blueberry pigment and purple potato pigment labels showed a significant increase ( P <0.05). The comprehensive evaluation results show that the ΔE values ​​of all labels have increased significantly, ranging from 14.93 to 24.68, and the ranking is pitaya pigment label < purple potato pigment label < black bean pigment label < blueberry pigment label ( Figure 3 ).

[0029] Table 1 L*, a* and b* values ​​of plant pigment labels before and after contact with healthy citrus fruits Λmax(pH 2) L* a* b* Blueberry pigment Before contact 512 nm 64.03±1.45 19.92±0.60 -5.88±0.19 After contact 64.80±0.56 26.19±0.87 -4.69±0.15 Purple potato pigment Before contact 524 nm 76.68±0.63 16.98±1.21 -6.49±0.04 After contact 74.38±1.38 22.23±0.95 -6.22±0.20 Black bean pigment Before contact 513 nm 85.48±1.30 1.59±0.40 0.54±0.21 After contact 85.78±1.29 5.42±0.56 0.10±0.28 Dragon fruit pigment Before contact 532 nm 80.85±0.84 10.36±0.41 5.03±0.23 After contact 79.32±1.72 10.46±0.45 4.40±0.40 Table 2 Label chromaticity difference after exposure to green rot citrus fruit ΔL* Δa* Δb* ΔE Blueberry pigment -10.41±0.17 -5.54±2.14 -2.95±3.65 24.68±2.73 Purple potato pigment -8.86±2.57 -10.63±0.71 17.49±3.63 22.55±1.97 Black bean pigment -13.17±4.16 1.10±0.94 0.00±3.89 22.56±5.22 Dragon fruit pigment -8.65±3.01 -2.59±4.02 11.43±4.02 14.93±5.06 Example 2: Application of visual tags in monitoring citrus fruit stem rot 1) Test methods The extraction of plant pigments, preparation of labels, and determination of label color are the same as those in Example 1.

[0030] Interaction between the label and the diseased fruit: The label is directly contacted with the diseased part of the fruit and maintained for 30 seconds, and then the label is removed for colorimetry.

[0031] 2) Test results The changes in chromaticity values ​​of plant pigment labels after contact with green rot fruit are shown in Table 3. The L* values ​​of plant pigment labels such as purple sweet potato, pitaya, black bean, and blueberry all decreased significantly (P < 0.05), and the b* values ​​increased significantly (P < 0.05), while the a* values ​​of blueberry pigment and purple sweet potato pigment labels increased significantly (P < 0.05). The comprehensive evaluation results showed that the ΔE values ​​of all labels increased significantly, ranging from 10.68 to 17.63, and the ranking was purple sweet potato pigment label < pitaya pigment label < black bean pigment label < blueberry pigment label ( Figure 4 ).

[0032] Table 3 Label color changes after exposure to citrus fruits with stem rot ΔL* Δa* Δb* ΔE Blueberry pigment -0.75±3.13 -3.76±1.03 14.07±1.65 17.63±2.84 Purple potato pigment -2.21±2.84 -6.64±1.14 17.86±1.01 10.68±1.38 Black bean pigment -7.22±0.68 1.60±0.34 16.31±2.20 15.10±1.62 Dragon fruit pigment -2.59±1.43 -2.7±1.10 10.42±0.79 13.11±0.40 Example 3: Application of visual tags in monitoring green rot of citrus fruits 1) Test methods The extraction of plant pigments, preparation of labels, interaction between labels and diseased fruits, and determination of label color are the same as those in Example 1.

[0033] 2) Test results The changes in chromaticity values ​​after the plant pigment label came into contact with the green rot fruit are shown in Table 4. The L* value of the dragon fruit pigment label increased significantly ( P <0.05), while the L* value of black bean pigment label decreased, the L* value of blueberry and purple sweet potato pigment labels did not change significantly, and the b* value of purple sweet potato, dragon fruit, black bean, blueberry and other plant pigment labels increased significantly ( P <0.05), while the a* value of blueberry pigment and purple potato pigment labels showed a significant increase ( P <0.05). The comprehensive evaluation results show that the ΔE values ​​of all labels have increased, with an increase range of 7.52~19.89, and the ranking is purple potato pigment label < dragon fruit pigment label < black bean pigment label < blueberry pigment label ( Figure 5 ).

[0034] Table 4 Label color changes after exposure to green rot diseased citrus fruits ΔL* Δa* Δb* ΔE Blueberry pigment 0.26±1.46 4.56±1.51 5.73±1.02 19.89±2.19 Purple potato pigment -0.11±0.88 -0.23±1.02 8.45±4.02 7.52±1.96 Black bean pigment -1.93±0.76 -1.38±1.08 11.41±5.90 14.12±3.63 Dragon fruit pigment 2.24±0.67 -3.65±1.30 6.04±0.67 9.65±1.45 Example 4: Application of visual tags in monitoring mixed diseases of citrus fruits 1) Test methods The extraction of plant pigments, preparation of labels, interaction between labels and diseased fruits, and determination of label color are the same as those in Example 1.

[0035] 3) Test results The changes in chromaticity values ​​after the plant pigment label was exposed to the mixed diseased fruit are shown in Table 5. The L* value of the label exposed to blueberry pigment increased significantly ( P <0.05), while the L* values ​​of the other three pigment labels decreased significantly, and the b* values ​​of the purple potato and pitaya pigment labels increased significantly ( P <0.05), while the b* values ​​of blueberry and black bean decreased significantly ( P <0.05); while the a* values ​​of blueberry pigment, purple potato pigment and pitaya pigment labels increased significantly ( P <0.05), while the a* value of black bean pigment label did not change significantly ( P＞ 0.05). The comprehensive evaluation results show that the ΔE values ​​of all labels have increased, with an increase range of 12.30~24.69, and the ranking is pitaya pigment label < purple potato pigment label < black bean pigment label < blueberry pigment label ( Figure 6 ).

[0036] Table 5 Label color changes after exposure to mixed diseased citrus fruits ΔL* Δa* Δb* ΔE Blueberry pigment 10.41±0.17 -5.54±2.14 -2.95±3.65 24.69±2.73 Purple potato pigment -9.54±1.80 -9.06±1.68 9.64±4.22 16.59±3.12 Black bean pigment -8.89±3.65 1.54±1.53 -2.58±2.14 18.15±3.60 Dragon fruit pigment -8.39±1.49 -2.36±1.52 8.51±3.36 12.30±3.41 The above is a description of the embodiments of the present invention. Through the above description of the disclosed embodiments, professionals and technicians in the field can implement or use the present invention. Various modifications to these embodiments will be apparent to professionals and technicians in the field. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown in this article, but will conform to the widest range consistent with the principles and novelties disclosed herein.

Claims

1. A visual detection label for fruit diseases, It is characterized in that The detection label comprises an adsorption carrier and a plant pigment component adsorbed on the adsorption carrier, wherein the plant pigment comprises one or more of anthocyanin compounds and betacyanin compounds.

2. A fruit disease visual detection label according to claim 1, It is characterized in that Sources of plant pigments include blueberries, purple sweet potatoes, dragon fruit or black beans.

3. A fruit disease visual detection label according to claim 1, It is characterized in that The adsorption carrier is a paper carrier.

4. The method for preparing a fruit disease visualization detection label according to claim 3, It is characterized in that The method is prepared by soaking a paper carrier in a plant pigment solution for 10-15 minutes, taking it out and drying it; the plant pigment component content in the plant pigment solution is greater than 10 mg / mL.

5. A method for detecting fruit diseases, It is characterized in that The method uses the detection label described in any one of claims 1 to 3 to contact the diseased fruit, and responds to the occurrence of the fruit disease through color change.

6. The method according to claim 5, It is characterized in that The results are determined by visual judgment or instrumental judgment. The visual judgment can be judged as disease occurrence by the color difference between the label color and the standard color band; the instrumental judgment is determined by the color difference between the label color and the standard color band measured by the color difference detection instrument and the ΔE value; ΔE=((L * 1 -L * 0 ) 2 + (a * 1 -a * 0 ) 2 + (b * 1 -b * 0 ) 2 ) 0.5 , where L * 1 、a * 1 and b * 1 is the tag reading, L * 0 、a * 0 and b * 0 It is the reading of the standard color card.

7. The method according to claim 6, It is characterized in that The standard color band is made from the color parameters of the label after contact with healthy fruit.

8. The detection label according to any one of claims 1 to 3 or the method according to any one of claims 5 to 7 is used for detecting fruit diseases in direct contact with fruit packaging.

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