A response surface optimization method for preserving soft-seeded pomegranates using brassinolide and γ-aminobutyric acid

Abstract

The invention discloses a method for optimizing brassinolide and gamma-aminobutyric acid for preserving soft-seeded pomegranates by response surface method. On the basis of single factor test results, the concentration of brassinolide, the concentration of gamma-aminobutyric acid and the processing time are used as response variables, each variable is coded according to three levels of low, medium and high, i.e., 1, 0 and 1, and a Box-Beken experiment with three factors and three levels of N=17 is designed by using software designexpert10. The freshness of the soft-seeded pomegranates after refrigeration for 120 days and room temperature storage for 5 days is used as a response value, and each factor is fitted and regressed to obtain a model equation. The optimal conditions for treating the soft-seeded pomegranates with brassinolide and gamma-aminobutyric acid are determined by using the response surface method, so that the precise control of the freshness-preserving treatment and the stability of the freshness-preserving effect are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of soft-seeded pomegranate preservation, and particularly relates to a method for preserving soft-seeded pomegranates by optimizing brassinolide and gamma-aminobutyric acid using a response surface. Background Art

[0002] In recent years, soft-seeded pomegranates have been increasingly recognized by producers, operators and consumers. However, soft-seeded pomegranates are not resistant to storage, especially cold damage, and have a short shelf life. 2 Treatment of Heyin Tunisian soft-seeded pomegranates can effectively reduce the decay rate of Heyin Tunisian soft-seeded pomegranates, allowing the pomegranates to be stored intact for 37 days at room temperature. Yang Zongqu et al.'s research showed that after 1% chitosan coating was treated with Heyin pomegranates, the fruit preservation effect was good after 120 days of storage. Yan Xinpeng et al. used low temperature combined with 1-MCP to treat Tunisian soft-seeded pomegranates. The results showed that the use of 1.0 mg / L 1-MCP to treat soft-seeded pomegranates can effectively maintain good sensory quality.

[0003] Brassinolide is a new endogenous plant hormone that can improve the cold resistance, disease resistance, and salt resistance of crops. Liu Pei et al.'s research shows that the combined preservation of brassinolide and kojic acid has a significant effect on the post-harvest storage of litchi fruit. γ-Aminobutyric acid (GABA) can effectively reduce the accumulation of reactive oxygen in plants, alleviate the damage of adversity to organisms, and enhance the enzyme activity of the body. Existing technical research also shows that exogenous GABA has a certain promoting effect on the accumulation of endogenous GABA in fruits and vegetables such as melons and bananas, and improves the stress resistance of fruits. Chen Xiu et al.'s research shows that after the treatment of ponkan fruit with exogenous GABA, the weight loss rate of the fruit can be significantly reduced, the brightness of the peel can be increased, and the quality of the fruit can be maintained.

[0004] Brassinolide and γ-aminobutyric acid have a good preservative effect on fruits and vegetables, but their preservative effect on soft-seeded pomegranates is still unknown. Summary of the invention

[0005] The invention provides a method for optimizing brassinolide and gamma-aminobutyric acid for preserving soft-seeded pomegranates by response surface method. The method adopts the response surface method to optimize the processing conditions of brassinolide and gamma-aminobutyric acid for the soft-seeded pomegranates, evaluates the storage taste, color and flavor of the soft-seeded pomegranates after refrigeration for 120 days and room temperature storage for 5 days, and measures the hardness, mass loss rate, soluble sugar content, proline content, titratable acid content, soluble protein content and malondialdehyde content, aiming to optimize the best solution for preserving the soft-seeded pomegranates and reveal the preservation mechanism thereof, so as to provide support for extending the storage period of the soft-seeded pomegranates and increasing economic benefits.

[0006] The following technical solutions are specifically adopted:

[0007] A method for optimizing brassinolide and γ-aminobutyric acid for preserving soft-seeded pomegranates using a response surface method, specifically comprising the following steps:

[0008] (1) Fruit treatment: Select soft-seeded pomegranates that are full, free of pests and diseases, free of rot, smooth in surface, intact and undamaged, of uniform size, and well-grown; treat the soft-seeded pomegranates with brassinolide and γ-aminobutyric acid, and after treatment, refrigerate and store the soft-seeded pomegranates at room temperature, and evaluate the freshness of the soft-seeded pomegranates;

[0009] (2) Response surface optimization analysis: Based on the results of the single-factor experiment, the concentration of brassinolide, γ-aminobutyric acid concentration, and treatment time were used as response variables. Each variable was coded as low, medium, and high at three levels: -1, 0, and 1. The software designexpert10 was used to design a Box-Beken experiment with 3 factors and 3 levels of N=17. The freshness of soft-seeded pomegranates after refrigeration for 120 days and room temperature storage for 5 days was used as the response value. The factors were fitted and regressed to obtain the model equation: freshness of soft-seeded pomegranates = 98.71-4.98A + 0.75B-1.91C + 3.74AB + 0.49AC + 3.53BC-5.27A 2 -5.31B 2 -0.043C 2 , where A is the concentration of brassinolide, B is the concentration of γ-aminobutyric acid, and C is the treatment time.

[0010] The optimal treatment conditions in the response surface optimization method for preserving soft-seeded pomegranates with brassinolide and γ-aminobutyric acid are: 0.34 μmol / L of brassinolide, 2.14 mmol / L of γ-aminobutyric acid, and 6.86 min for each treatment time; the freshness of the treated soft-seeded pomegranates after refrigeration for 120 days and storage at room temperature for 5 days is 100.5;

[0011] The optimal treatment conditions in the response surface optimization method for preserving soft-seeded pomegranates with brassinolide and γ-aminobutyric acid are: 0.29-0.37 μmol / L of brassinolide, 2.09-2.19 mmol / L of γ-aminobutyric acid, and 6.4-7.4 min for each treatment time; the freshness of the treated soft-seeded pomegranates is 100 after refrigeration for 120 days and storage at room temperature for 5 days;

[0012] The specific processing method is to soak the soft-seeded pomegranate in a mixed solution of brassinolide and gamma-aminobutyric acid for soaking treatment.

[0013] Beneficial Effects

[0014] The invention optimizes the preservation method of soft-seeded pomegranate by using brassinolide and γ-aminobutyric acid through response surface methodology. The preservation method is simple and easy to implement, and has a good preservation effect; the response surface methodology is used to optimize the optimal conditions for the preservation of soft-seeded pomegranate by using brassinolide and γ-aminobutyric acid, and the precise control of the preservation treatment and the stability of the preservation effect are achieved; and through the analysis of the hardness, soluble solid content, proline content, titratable acid content, soluble protein content, malondialdehyde content, soluble sugar content, rotten fruit rate, browning index and other related indicators of the soft-seeded pomegranate after corresponding treatment, a theoretical basis and experimental basis are provided for the study of the preservation mechanism of brassinolide and γ-aminobutyric acid on soft-seeded pomegranate; and theoretical support is provided for extending the storage period of soft-seeded pomegranate and increasing economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The color changes of soft-seeded pomegranates treated with brassinolide and γ-aminobutyric acid after refrigeration (4±0.5℃) for 120 days and storage at room temperature for 5 days; wherein 1-17 are treatments 1-17 shown in Table 2 respectively;

[0016] Figure 2 This is the response surface diagram of sensory evaluation of soft-seeded pomegranates after storage under the interaction of brassinolide, γ-aminobutyric acid and treatment time;

[0017] Figure 3 This is the response surface diagram of the soluble solid content of soft-seeded pomegranate after storage under the interaction of brassinolide, γ-aminobutyric acid and treatment time. DETAILED DESCRIPTION

[0018] The technical solution of the present invention is described in detail below with reference to the accompanying drawings and specific embodiments. The raw materials described in the present invention can be obtained from the market unless otherwise specified, and the methods described are conventional methods unless otherwise specified.

[0019] Reagents used in the experiment: 3% sulfosalicylic acid, glacial acetic acid, toluene, 2.5% acidic ninhydrin, 50 μg / mL proline, bovine serum albumin, Coomassie brilliant blue G250, anhydrous ethanol, phosphoric acid, phenolphthalein, trichloroacetic acid, thiobarbituric acid solution, anthrone, sulfuric acid, brassinolide, γ-aminobutyric acid. All of the reagents can be obtained from commercial sources.

[0020] Instruments used in the experiment: high-speed desktop centrifuge (Neofuge13R, Shanghai Lishen Scientific Instrument Co., Ltd.), UV-visible spectrophotometer (TU-1810, Beijing Puxi General Instrument Co., Ltd.), digital saccharimeter (SW-32D, Suwei Electronic Technology Co., Ltd.), constant temperature water bath (HH-2, Jintan Baita Xinbao Instrument Factory), digital fruit hardness tester (GY-4, Aipu Measuring Instrument Co., Ltd.), balance (Yuyao Jinnuo Balance Instrument Co., Ltd.)

[0021] Preparation of brassinolide and γ-aminobutyric acid solution

[0022] Prepare 0.5 μmol / L, 1.0 μmol / L, and 1.5 μmol / L brassinolide solutions;

[0023] Prepare 3mmol / L, 5mmol / L, and 7mmol / L γ-aminobutyric acid solutions;

[0024] Example 1

[0025] A response surface optimization method for preserving soft-seeded pomegranates using brassinolide and γ-aminobutyric acid

[0026] (1) Fruit processing

[0027] Select soft-seeded pomegranates with full fruits, no pests and diseases, no rot, smooth surface, intact and undamaged, uniform size, and good growth and development as experimental supplies. The software design expert10 was used to design a 3-factor 3-level Box-Beken experiment with N=17 (see Table 1), and the independent variables were brassinolide concentration (X1), γ-aminobutyric acid concentration (X2) and time (X3). The soft-seeded pomegranates selected as experimental supplies were soaked in a solution containing a certain concentration of brassinolide and γ-aminobutyric acid for treatment, with 40 fruits in each treatment. After the treatment, the soft-seeded pomegranates were covered with fresh-keeping bags and placed in boxes, with 10 fruits in each box. The refrigeration temperature was 4±0.5℃. The specific experimental design is shown in Table 2.

[0028] Table 1 Levels of each factor in the response surface of soft-seeded pomegranate treatments

[0029]

[0030] Table 2 Experiments of response surface design

[0031]

[0032] (2) Response surface optimization analysis

[0033] Effects of brassinolide + γ-aminobutyric acid on the color of soft-seeded pomegranate

[0034] Effect of brassinolide + γ-aminobutyric acid on the color of soft-seeded pomegranates stored for 120 days in cold storage + 5 days at room temperature Figure 1 .Depend on Figure 1 The results show that the fruit skin of treatments 1, 3, 7, 8, and 17 was shiny, the seeds were full, crystal clear, bright in color, and basically free of disease spots and browning; the fruit skin of other treatments was bright, but the seeds were browning. The average rotten fruit rate was 4.90%, and the average quality loss rate was 4.35%.

[0035] Effects of brassinolide + γ-aminobutyric acid on the taste, color and flavor of soft-seeded pomegranate

[0036] The sensory evaluation of soft-seeded pomegranates after refrigeration for 120 days + 5 days (room temperature storage) is shown in Table 4. The response surface regression model variance analysis of the effect of brassinolide + γ-aminobutyric acid on the freshness (taste, color, flavor) of soft-seeded pomegranates is shown in Table 4. As shown in Table 4, the model F value is 4.86, indicating that the model is significant. Only 2.45% of the probability will be caused by noise. Model equation: sensory evaluation = 98.71-4.98A + 0.75B-1.91C + 3.74AB + 0.49AC + 3.53BC-5.27A 2 -5.31B 2 -0.043C 2 (A: brassinolide, B: γ-aminobutyric acid, C: treatment time).

[0037] Depend on Figure 2 From a, 2b, and 2c, we can see that when the independent variables take appropriate values, the taste, color, and flavor can reach the optimal level. Figure 2 aIt can be seen that brassinolide and γ-aminobutyric acid have a significant effect on the taste, color and flavor of soft-seeded pomegranate.

[0038] The recommended optimal storage method for taste, color and flavor is: 0.34μmol / L brassinolide, 2.14mmol / L γ-aminobutyric acid, 6.86min treatment time, the predicted taste, color and flavor is 100.533 points, and the accuracy is 95.45%. Considering the feasibility of the experiment, the concentration of brassinolide is set to 0.29-0.39μmol / L, the concentration of γ-aminobutyric acid is set to 2.09-2.19mmol / L, and the soft-seeded pomegranate is treated for 6.4-7.4min. After 120 days of refrigeration and 5 days of room temperature storage, the sensory (taste, color, flavor) score of the soft-seeded pomegranate reaches 100 points; the actual score can reach 100 points, and the difference between the predicted value and the actual value is small, which proves that the response surface methodology is reliable to optimize the storage taste, color and flavor of soft-seeded pomegranate and has certain practical application value.

[0039] The determination of relevant indicators refers to the following methods:

[0040] The mass loss rate was calculated according to formula (1); the peel browning degree classification is shown in Table 2, the peel browning index was calculated according to formula (2), the hardness was measured by a hardness meter, the soluble solids were measured by a saccharimeter, and the titratable acid content was measured by acid-base titration; the proline content, malondialdehyde content, soluble protein content, and soluble sugar content were determined in accordance with the relevant contents of "Plant Physiology Experiment"; 8 professional evaluators conducted sensory scoring on soft-seeded pomegranates, and the scoring criteria are shown in Table 3.

[0041] Mass loss rate = (mass before storage - mass before storage) / mass before storage x 100 Formula (1) Browning index = [∑ (browning score of each level × percentage of browning area of ​​each level)] / (highest level score) × 100% Formula (2)

[0042] Table 2 Browning grade table

[0043]

[0044] Table 3 Sensory evaluation table

[0045]

[0046] The present invention also studies and analyzes the effects of brassinolide + γ-aminobutyric acid on other related indicators of soft-seeded pomegranate

[0047] The variance analysis of the response surface regression model on the hardness, soluble solids content, proline content, titratable acid content, soluble protein content, malondialdehyde content, soluble sugar content, rotten fruit rate, browning index, etc. of soft-seeded pomegranate after 120 days of refrigeration + 5 days (room temperature storage) is shown in Table 4.

[0048]

[0049] As shown in Table 4, the model F value of soluble solid content is 7.88, indicating that the model is significant, and only 0.3% of the probability is due to noise. The lack of fit term is not significant, and this model is closer to reality. Model equation: soluble solid content = 13.78-0.46A-0.086B-0.27C (A: brassinolide, B: γ-aminobutyric acid, C: time).

[0050] The response surface curve of the effect of brassinolide + γ-aminobutyric acid on the soluble solid content of soft-seeded pomegranate is shown in Figure 3 .Depend on Figure 3 a It can be seen that when brassinolide increases, the soluble solid content increases; Figure 3b It can be seen that when the treatment time increases, the soluble solid content increases. However, it is clear that the increase in soluble solid content has not reached the maximum value, which suggests that if the maximum soluble solid content is to be achieved, the brassinolide content needs to be reset and the treatment time needs to be extended.

[0051] As shown in Table 4, the Modle (model) of hardness, proline content, titratable acid content, soluble protein content, malondialdehyde content, soluble sugar content, browning index, etc. is not significant, and the Lack of Fit (lack of fit term) is not significant, indicating that among the 17 treatments, there are no significant differences in hardness, proline content, titratable acid content, soluble protein content, malondialdehyde content, soluble sugar content, and browning index. The treatment with different concentrations of brassinolide + γ-aminobutyric acid has little effect on the hardness, proline content, titratable acid content, soluble protein content, malondialdehyde content, soluble sugar content, and browning index of soft-seeded pomegranate.

[0052] From the above, it can be seen that after 120 days of cold storage + 5 days (room temperature storage) of brassinolide + γ-aminobutyric acid response surface optimization treatment of soft-seeded pomegranate, there were no significant differences in 17 treatments such as weight loss rate, soluble sugar content, hardness, proline content, titratable acid content, malondialdehyde content, etc., and the model was not significant, suggesting that the preservation mechanism of brassinolide + γ-aminobutyric acid on soft-seeded pomegranate may not be to improve the above indicators and enhance its cold resistance; however, the model of soluble solids content is significant, and the lack of fit term is not significant. It is also possible that soft-seeded pomegranate increases its tolerance to cold by increasing the content of soluble solids; of course, it is also possible to improve its resistance to stress by increasing the activity of peroxidase, etc. Therefore, its mechanism of tolerance to cold damage needs further experimental proof.

[0053] Market value assessment: The brassinolide + γ-aminobutyric acid response surface optimization treatment of soft-seeded pomegranates was used. After refrigeration for 120 days + 5 (room temperature) days, during the preservation process, the average bad fruit rate was 4.90%, the average quality loss rate of good fruit was 4.35%, and the total loss rate was 9.25%. The average good fruit rate of treatments 1, 7, 8, and 17, which were close to the optimal combination, was 99.6%. If a 20m 3 The small cold storage in the factory stores 6 tons of soft-seeded pomegranates. According to the market price, the seasonal selling price of soft-seeded pomegranates is 40 yuan / kg, and the total purchase price is 240,000 yuan. However, after being treated with the optimized solution and kept fresh at 4°C for 120 days, the selling price is conservatively estimated to be 80 to 100 yuan / kg. Excluding power consumption (1,000 yuan / month), labor costs (500 / month), maximum quality loss (10%), and reagent consumables costs (about 1,000 yuan), the sales amount is 420,000 to 530,000 yuan, which is a considerable profit, which is 175% to 220.8% of the seasonal profit of fresh fruit.

[0054] The above embodiments are only preferred specific implementation methods of the present invention, and the protection scope of the present invention is not limited thereto. Any simple changes or equivalent replacements of the technical solutions that can be obviously obtained by any technician familiar with the technical field within the technical scope disclosed in the present invention all fall within the protection scope of the present invention.

Claims

1. A method for optimizing brassinolide and γ-aminobutyric acid for preserving soft-seeded pomegranates using response surface, characterized in that: The specific steps include: (1) Fruit treatment: Select soft-seeded pomegranates that are full, free of pests and diseases, free of rot, smooth in surface, intact and undamaged, of uniform size, and well-grown; treat the soft-seeded pomegranates with brassinolide and γ-aminobutyric acid, and after treatment, refrigerate and store the soft-seeded pomegranates at room temperature, and evaluate the freshness of the soft-seeded pomegranates; (2) Response surface optimization analysis: Based on the results of the single-factor experiment, the concentration of brassinolide, γ-aminobutyric acid concentration, and treatment time were used as response variables. Each variable was coded as low, medium, and high at three levels: -1, 0, and 1. The software designexpert10 was used to design a Box-Beken experiment with 3 factors and 3 levels of N=17. The freshness of soft-seeded pomegranates after refrigeration for 120 days and room temperature storage for 5 days was used as the response value. The factors were fitted and regressed to obtain the model equation: freshness of soft-seeded pomegranates = 98.71-4.98A + 0.75B-1.91C + 3.74AB + 0.49AC + 3.53BC-5.27A 2 -5.31B 2 -0.043C 2 , where A is the concentration of brassinolide, B is the concentration of γ-aminobutyric acid, and C is the treatment time; The optimal treatment conditions in the response surface optimization method for preserving soft-seeded pomegranates with brassinolide and γ-aminobutyric acid are: 0.29-0.37 μmol / L of brassinolide, 2.09-2.19 mmol / L of γ-aminobutyric acid, and 6.4-7.4 min for each treatment time; the freshness of the treated soft-seeded pomegranates is 100 after refrigeration for 120 days and storage at room temperature for 5 days; The treatment method described in step (1) is to soak the soft-seeded pomegranate in a mixed solution of brassinolide and γ-aminobutyric acid for soaking treatment.

2. The method for optimizing brassinolide and γ-aminobutyric acid for preserving soft-seeded pomegranates using response surface method according to claim 1, characterized in that: The optimal treatment conditions in the response surface optimization method for preserving soft-seeded pomegranates using brassinolide and γ-aminobutyric acid are: 0.34 μmol / L brassinolide, 2.14 mmol / L γ-aminobutyric acid, and 6.86 min for each treatment time; the freshness of the treated soft-seeded pomegranates is 100.533 after being refrigerated for 120 days and stored at room temperature for 5 days.

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