Fresh-keeping agent and application thereof in fruit and vegetable preservation

Abstract

The present application belongs to the technical field of fruit and vegetable preservation, and particularly relates to a preservative and application thereof in fruit and vegetable preservation. The active ingredients of the preservative provided by the present application include melatonin and calcium chloride, and the preservative has the characteristics of safety, non-toxicity, no residue, small environmental pressure, and no harm to non-target organisms such as humans and livestock. Through verification of the examples, the picked peppers are treated by using the preservative provided by the present application, the melatonin and calcium chloride have synergistic effect, compared with the control, the hardness and the brightness L* value of the pepper fruits decrease at a significantly reduced speed during the storage period, and the preservation effect is further improved.

Description

Technical Field

[0001] This invention belongs to the field of fruit and vegetable preservation technology, specifically relating to a preservative and its application in fruit and vegetable preservation. Background Technology

[0002] Chili peppers are rich in vitamins such as vitamin C, B, and A, as well as various minerals like magnesium, phosphorus, and iron. They possess high nutritional and health benefits, and both their fruit and roots can be used medicinally, offering benefits such as stomachic, digestive, blood-activating, swelling-reducing, anthelmintic, and diaphoretic effects. They have become an essential vegetable and condiment in daily life. However, because chili peppers are non-climacteric tropical fruits and vegetables and are sensitive to low temperatures, they are prone to wilting, aging, turning red, and rotting when stored at room temperature after harvest due to moisture evaporation. Conversely, cold storage can easily cause chilling injury, severely affecting their appearance, internal physiological changes, and shelf life, resulting in economic losses for producers and distributors. Therefore, strengthening research on chili pepper storage, transportation, and preservation, and accelerating research into chili pepper storage and transportation technologies, is of great significance.

[0003] Currently, chemical preservatives are used to preserve chili peppers on the market. However, commonly used chemical preservatives such as biguanide salts, miconazole, triazole fungicides, fenpropathrin, and aluminum fosetyl-aluminum have certain toxicity, leading to a series of problems such as environmental pollution, disruption of ecological balance, and pesticide residues. Therefore, developing a safe, efficient, and natural preservative is urgently needed. Summary of the Invention

[0004] The purpose of this invention is to develop a safe, efficient, and natural preservative to improve the preservation effect of fruits and vegetables, especially chili peppers, and effectively extend their storage period.

[0005] The present invention provides a preservative, wherein the active ingredients of the preservative include melatonin and calcium chloride.

[0006] Preferably, the preservative further includes a solvent, wherein the solvent is water.

[0007] Preferably, the concentration of melatonin in the preservative is 25–400 μmol / L; and the concentration of calcium chloride in the preservative is 0.2 mol / L.

[0008] Preferably, the concentration of melatonin in the preservative is 100 μmol / L.

[0009] This invention also provides the application of the preservatives described in the above technical solutions in the preservation of fruits and vegetables.

[0010] Preferably, the fruit and vegetable preservation includes extending the storage period of harvested fruits and vegetables and maintaining their firmness and brightness.

[0011] Preferably, the fruit or vegetable includes chili peppers.

[0012] This invention also provides a method for extending the post-harvest storage period of chili peppers, comprising the following steps:

[0013] After harvesting, the chili peppers are soaked in the preservative described in the above technical solution.

[0014] Preferably, the harvested chili peppers are chili pepper fruits in the green-ripe stage.

[0015] Preferably, the soaking time is 15 to 25 minutes.

[0016] Beneficial effects

[0017] The preservative provided by this invention comprises melatonin and calcium chloride as its active ingredients. It is safe, non-toxic, residue-free, has low environmental impact, and is harmless to non-target organisms such as humans and livestock, effectively extending the storage period of fruits and vegetables. Verification through examples shows that when freshly harvested chili peppers are treated with the preservative provided by this invention, the synergistic effect of melatonin and calcium chloride significantly reduces the rate of decline in the firmness and brightness (L*) value of the chili peppers during storage compared to the control, further improving the preservation effect. Detailed Implementation

[0018] The present invention provides a preservative, wherein the active ingredients of the preservative include melatonin and calcium chloride.

[0019] In this invention, the concentration of melatonin in the preservative is preferably 25–400 μmol / L, more preferably 100–400 μmol / L, and even more preferably 100 μmol / L. The concentration of calcium chloride in the preservative is preferably 0.2 mol / L. The preservative preferably also includes a solvent, preferably water. Melatonin plays an important regulatory role in plant growth, development, maturation, senescence, and stress resistance. Calcium chloride can regulate enzyme activity and affect metabolic processes in plants, reduce the damage of pathogens to the cell walls and cell membranes of fruits and vegetables, inhibit water loss from fruits and vegetables, and maintain the storage quality of fruits and vegetables. This invention uses melatonin and calcium chloride as active ingredients in the preservative, which can produce a synergistic effect and further improve the preservation effect.

[0020] This invention also provides the application of the preservatives described in the above technical solutions in the preservation of fruits and vegetables.

[0021] In this invention, the preservation of fruits and vegetables preferably includes extending the storage period of harvested fruits and vegetables and maintaining their firmness and brightness. The fruits and vegetables preferred in this invention are chili peppers.

[0022] This invention also provides a method for extending the post-harvest storage period of chili peppers, comprising the following steps:

[0023] After harvesting, the chili peppers are soaked in the preservative described in the above technical solution.

[0024] In this invention, the post-harvest chili peppers are preferably green-ripe chili peppers; the soaking time is preferably 15-25 minutes, more preferably 20 minutes. Preferably, the soaked post-harvest chili peppers are stored in an environment with a humidity of 90%-95% and a temperature of 18-22°C. Prolonged soaking of chili peppers in a solution accelerates decay; this invention, by adjusting the soaking time, effectively extends the shelf life of the chili peppers.

[0025] To further illustrate the present invention, the following detailed description, in conjunction with embodiments, of a preservative provided by the present invention and its application in fruit and vegetable preservation, should not be construed as limiting the scope of protection of the present invention.

[0026] Example 1

[0027] A preservative is composed of melatonin, calcium chloride and water; wherein the final concentration of melatonin in the preservative is 25 μmol / L and the final concentration of calcium chloride is 0.2 mol / L.

[0028] Example 2

[0029] A preservative, the only difference from Example 1, is that the final concentration of melatonin in the prepared preservative is 50 μmol / L and the final concentration of calcium chloride is 0.2 mol / L.

[0030] Example 3

[0031] A preservative, the only difference from Example 1, is that the final concentration of melatonin in the prepared preservative is 100 μmol / L and the final concentration of calcium chloride is 0.2 mol / L.

[0032] Example 4

[0033] A preservative, the only difference from Example 1, is that the final concentration of melatonin in the prepared preservative is 200 μmol / L and the final concentration of calcium chloride is 0.2 mol / L.

[0034] Example 5

[0035] A preservative, the only difference from Example 1, is that the final concentration of melatonin in the prepared preservative is 400 μmol / L and the final concentration of calcium chloride is 0.2 mol / L.

[0036] Comparative Example 1

[0037] A preservative, the only difference from Example 1, is that the final concentration of melatonin in the preservative prepared in step (1) is 50 μmol / L, and calcium chloride is not used.

[0038] Comparative Example 2

[0039] A preservative, the only difference from Example 1, is that the final concentration of melatonin in the preservative prepared in step (1) is 0 μmol / L and the final concentration of calcium chloride is 0.2 mol / L.

[0040] Test Example 1

[0041] The chili pepper "Dianjiao No. 5" (GPD chili pepper (2021) 530743, Announcement No. 456 of the Ministry of Agriculture and Rural Affairs of the People's Republic of China) from the Tomato and Chili Pepper Laboratory of the College of Horticulture and Landscape Architecture, Yunnan Agricultural University, was used as the experimental material. Sowing took place in early January 2022, and the peppers were transplanted into greenhouses in late April of the same year, followed by routine management. Mature fruits were harvested, and fruits free from pests and diseases, mechanical damage, uniform size, and consistent maturity were selected as experimental materials. These fruits were sterilized with 1 wt.% NaClO for 2 minutes, dried, and randomly divided into 7 treatment groups. Each group was soaked in the preservatives specified in Examples 1-5 and Comparative Example 1, and in water (CK) for 20 minutes, respectively, and then dried. S182 fruits were placed in PE preservation bags, one fruit per bag, for a total of 15 bags per treatment group.

[0042] The treated samples were placed in a 20℃ incubator and stored in the dark at a humidity of 90%–95%. Three bags of samples were taken on each of the 0, 3, 6, 9 and 12 days of storage for relevant quality determination.

[0043] 1. Measurement of luminance L* value

[0044] The brightness L* of the pepper pericarp was measured using a 3nh NR110 fully automatic colorimeter (Shenzhen Sanenshi Technology Co., Ltd.) (Li Pingping, Zhang Xiang, Liu Yuting, et al., Study on the relationship between coloring substances and fruit color in pepper fruit. Journal of Horticulture, 2022, 49(7): 1589–1601). The values ​​of three points (top, middle, and bottom) on the light-facing surface of the central part of the fruit were measured and averaged. The results are shown in Table 1.

[0045] Table 1. Results of L* value determination for chili pepper fruits

[0046]

[0047] As shown in Table 1, after treatment with different concentrations of melatonin and calcium chloride, the L* value of pepper fruits generally showed a slow decreasing trend during the 12-day storage period. There was no significant difference in L* value among the treatment groups after 3 days of storage (P>0.05). After 6 days of storage, the L* value of peppers treated with preservatives from Examples 3, 4, and 5 was significantly higher than that of CK (water) and peppers treated with preservatives from Examples 1 and 2 (P<0.05). After 9 to 12 days of storage, the L* value of peppers treated with preservative from Example 3 was the highest.

[0048] 2. Determination of pepper fruit firmness

[0049] The firmness of the fruit sample at the equatorial region (the point of maximum transverse diameter) was determined using a texture analyzer. Three fruits were measured for each treatment, and three points were measured for each fruit. The average value was then taken. The results are shown in Table 2.

[0050] Table 2 Results of chili fruit firmness determination

[0051]

[0052]

[0053] As shown in Table 2, after 3, 6, and 12 days of storage, the hardness of the chili peppers treated with the preservatives in Examples 1 to 5 was significantly higher than that of the control (water) (P<0.05). During the 12-day storage period, the hardness of the chili peppers treated with the preservative in Example 3 was significantly higher than that of the other examples (P<0.05). After 6 days of storage, the hardness of the chili peppers treated with the preservatives in Examples 2 and 5 was significantly higher than that of Examples 1, 4, and the control (water) (P<0.05). After 9 days of storage, the hardness of the chili peppers treated with the preservatives in Examples 2 and 5 was significantly higher than that of the control (water) and Example 1 (P<0.05). After 12 days of storage, the hardness of the chili peppers treated with the preservative in Example 2 was significantly lower than that of Example 3 but significantly higher than that of the other examples and the control (water) (P<0.05), while the hardness of the chili peppers treated with the preservative in Example 5 was significantly higher than that of the control (water) but significantly lower than that of the other examples (P<0.05).

[0054] 3. The effect of preservatives on the shelf life of chili peppers

[0055] The day after soaking was completed was recorded as day 1. The shelf life of chili peppers in different treatment groups was statistically analyzed, and the results are shown in Table 3.

[0056] Table 3 Shelf life of chili peppers

[0057]

[0058] As shown in Table 3, the shelf life of the chili peppers treated with the preservatives in Examples 1 to 5 was longer than that of the control (water). Among them, Example 3 showed the best effect, with a shelf life of 18 days, which was significantly longer than the other examples (P<0.05). The shelf life of the other examples ranged from 13 to 16 days.

[0059] Test Example 2

[0060] The 'Dianjiao No. 5' chili pepper from the Tomato and Pepper Laboratory of the College of Horticulture and Landscape Architecture, Yunnan Agricultural University, was used as the experimental material. Sowing took place in early January 2022, and the peppers were transplanted into greenhouses in late April of the same year, followed by routine management. Green-ripe fruits were harvested, and fruits free from pests and diseases, mechanical damage, uniform size, and consistent maturity were selected as experimental materials. These fruits were sterilized with 1 wt.% NaClO for 2 minutes, dried, and randomly divided into 7 treatment groups. Each group was soaked in the preservatives specified in Examples 1-5 and Comparative Example 1, and in water (CK) for 20, 30, 40, 50, and 60 minutes, respectively, and then dried. S182 fruits were placed in PE preservation bags, one fruit per bag, for a total of 15 bags per treatment group.

[0061] The treated samples were placed in a 20℃ incubator and stored in the dark at a humidity of 90%–95%. Their shelf life was determined, and the results are shown in Table 4 below.

[0062] Table 4. Effects of different soaking times (in water) on the shelf life of chili peppers (control group).

[0063]

[0064] As shown in Table 4, soaking time that is too long will actually accelerate the rotting of chili peppers and reduce their shelf life.

[0065] As can be seen from the above examples, the preservative prepared with melatonin and calcium chloride as active ingredients can effectively improve the preservation effect, maintain the firmness and brightness of peppers after harvest, and extend the shelf life. The preservation effect is best when the final concentration of melatonin in the preservative is 100 μmol / L and the final concentration of calcium chloride is 0.2 mol / L.

[0066] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. The application of a preservative in fruit and vegetable preservation, characterized in that, The active ingredients of the preservative are melatonin and calcium chloride; the preservative also includes a solvent, which is water; the concentration of melatonin in the preservative is 100 μmol / L; the concentration of calcium chloride in the preservative is 0.2 mol / L. The preservative is applied after the chili peppers are harvested; the preservation of fruits and vegetables is to extend the storage period of harvested fruits and vegetables and maintain their firmness and brightness; the fruits and vegetables are chili peppers, and the chili peppers are green-ripe chili peppers.

2. A method for extending the post-harvest storage period of chili peppers, characterized in that, Includes the following steps: The harvested chili peppers are soaked in the preservative as described in claim 1.

3. The method according to claim 2, characterized in that, The harvested chili peppers refer to chili pepper fruits at the green-ripe stage.

4. The method according to claim 2, characterized in that, The soaking time is 15-25 minutes.

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