Mineral water composite fresh-keeping coating film and application thereof

Abstract

The invention discloses a mineral water composite fresh-keeping coating film and application thereof. The fruit and vegetable composite fresh-keeping coating liquid is prepared from polyvinyl alcohol, mineral water and deionized water. Every 100 mL of the fruit and vegetable composite fresh-keeping coating liquid is prepared from the following components: 0.75 g to 3.75 g of polyvinyl alcohol; 25 mL of mineral water; and 75 mL of deionized water. The deep sea mineral water fresh-keeping coating film can supplement medium trace elements to fruit cell walls. The used polyvinyl alcohol has good film-forming property and adhesiveness on the skins of various fruits and vegetables, and can achieve the effects of blocking outside air, resisting bacteria and keeping freshness by being combined with deep sea mineral water. The deep sea mineral water composite coating has good storage and fresh-keeping effects on fruits and vegetables, and has good improvement effects on indexes such as hardness, weight loss rate and soluble solids of the fruits and vegetables.

Description

Technical Field

[0001] The invention relates to a mineral water composite fresh-keeping coating film and application thereof, belonging to the field of fruit and vegetable fresh-keeping. Background Art

[0002] Nowadays, fruits are popular among consumers for their rich aroma and high nutritional value, but they are prone to rot and deterioration, and their storage period is short. Coating treatment provides a new idea for green preservation technology to extend the storage period of fruits, because they can be used as O 2 , CO 2 The semi-permeable barrier of the fruit cell wall and water vapor prevents water loss, hardness change or oxidation; by supplementing trace elements to the fruit cell wall, maintaining the stability of the cell wall, and in the metabolism of fruit texture and plant hormones, reducing the respiration rate and maintaining quality attributes (color, flavor, etc.) to preserve the fruit, improve the fruit quality, solve the problem of post-harvest preservation, and protect the fruit cell wall and plasma membrane. Therefore, the present invention is proposed. Summary of the invention

[0003] The purpose of the present invention is to provide a mineral water composite fresh-keeping coating film, which is prepared with basic raw materials such as deep-sea mineral water and polyvinyl alcohol. The coating film can effectively reduce the weight loss rate of fruits, maintain the hardness of fruits, reduce the consumption of soluble solids in fruits, and improve the storage quality of fruits.

[0004] The composite fresh-keeping coating liquid for fruits and vegetables provided by the invention is made of polyvinyl alcohol, mineral water and deionized water.

[0005] The composition of each 100 mL of the fruit and vegetable composite fresh-keeping coating liquid is as follows:

[0006] 0.75g-3.75g polyvinyl alcohol; 25-30mL mineral water; 75mL deionized water.

[0007] In the present invention, the mineral water is preferably deep sea mineral water;

[0008] The deep sea mineral water is water from 700 meters below the sea surface, containing high concentrations of trace elements (such as calcium, magnesium, potassium, etc.). These elements are important nutrients for cell division and fruit growth and development, and play an important role in maintaining the stability of the cell wall and in the metabolism of fruit texture and plant hormones. The deep sea mineral water is combined with the coating preservative liquid to supplement the trace elements to the epidermal cell wall by coating on the surface of fruits and vegetables, so as to achieve the purpose of preserving fruits and vegetables and extending the shelf life.

[0009] The contents of various elements in the deep sea mineral water are as follows:

[0010] Boron 732ppm, sodium 14600ppm, magnesium 48000ppm, aluminum 0.475ppm, phosphorus 4.763ppm, potassium 8000ppm, calcium 650ppm, scandium 0.211ppm, vanadium 0.296ppm, chromium 0.028ppm, manganese 0.021ppm, iron 0.07ppm, cobalt 0.014ppm, nickel 0.312ppm, copper 0.105ppm, zinc 0.491ppm, arsenic 0.09ppm, selenium 0.027ppm, rubidium 15.313ppm, strontium 0.294ppm;

[0011] The content of major elements in different batches of deep sea mineral water fluctuates within 20%, and the major elements refer to elements with a content greater than 100 ppm.

[0012] In the present invention, the molecular weight of the polyvinyl alcohol may be 30,000-70,000.

[0013] The preparation method of the composite fresh-keeping coating liquid for fruits and vegetables of the present invention comprises the following steps:

[0014] S1, dispersing the polyvinyl alcohol in the deionized water, heating and stirring to obtain a polyvinyl alcohol solution;

[0015] S2, adding the mineral water into the polyvinyl alcohol solution, heating and stirring to obtain.

[0016] In step S1, stirring is performed at a temperature of >80°C;

[0017] In step S2, stirring is performed at a temperature of >80°C and a stirring speed of >500 r / min.

[0018] Under the condition that every 100 mL of the composite fresh-keeping coating liquid for fruits and vegetables contains 25 mL of deep-sea mineral water, increasing the content of polyvinyl alcohol helps to improve the film-forming property and adhesion of the fresh-keeping liquid on the epidermis of fruits and vegetables, especially the waxy and smooth epidermis, thereby promoting the diffusion of elements in the deep-sea mineral water to the epidermal cells. However, the content of polyvinyl alcohol should not exceed 3.75% to ensure that the polyvinyl alcohol will not precipitate.

[0019] The composite fresh-keeping coating liquid for fruits and vegetables of the present invention can be used for preserving fruits and vegetables, and is used after being diluted 25-100 times, preferably 25 times, 50 times or 100 times.

[0020] When the composite fresh-keeping coating liquid for fruits and vegetables of the present invention is used for fresh-keeping of fruits and vegetables, the fruits and vegetables are immersed in the diluted composite fresh-keeping coating liquid for fruits and vegetables;

[0021] The dilution multiple is 25-100 times;

[0022] The immersion time is 30-120s.

[0023] Applicable fruits and vegetables include lychee, mango, etc.

[0024] The present invention has the following beneficial technical effects:

[0025] The deep sea mineral water fresh-keeping coating film of the present invention can supplement trace elements to the fruit cell walls.

[0026] The polyvinyl alcohol used in the present invention has good film-forming property and adhesion on the skin of various fruits and vegetables, and can achieve the effects of blocking external air, resisting bacteria and preserving freshness when combined with deep-sea mineral water.

[0027] The deep-sea mineral water composite coating of the present invention has a good storage and preservation effect on fruits and vegetables, and has a good improvement effect on the hardness, weight loss rate, soluble solids and other indicators of fruits and vegetables. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The invention discloses an effect of the deep sea mineral water composite coating on the hardness of mangoes.

[0029] Figure 2 This is the effect of the deep sea mineral water composite coating of the present invention on the weight loss rate of mango.

[0030] Figure 3 The invention discloses an effect of the deep sea mineral water composite coating on the respiration rate of mango.

[0031] Figure 4 The invention relates to the influence of the deep sea mineral water composite coating on the ethylene release rate of mango.

[0032] Figure 5 The invention discloses an effect of the deep sea mineral water composite coating on the soluble solids of mango.

[0033] Figure 6 The invention relates to the influence of the deep sea mineral water composite coating on the titratable acid of mango.

[0034] Figure 7 The invention discloses an effect of the deep sea mineral water composite coating on the hardness of litchi.

[0035] Figure 8 This is the effect of the deep sea mineral water composite coating of the present invention on the weight loss rate of litchi.

[0036] Fig. 9 The invention discloses an effect of the deep sea mineral water composite coating on soluble solids of litchi. DETAILED DESCRIPTION

[0037] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0038] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0039] The deep sea mineral water used in the following examples was purchased from Beijing Xianzhi Technology Co., Ltd.

[0040] Example 1: Determination of element content in deep sea mineral water by ICP-MS

[0041] The ICP-MS method was used to determine the contents of 20 elements such as boron, sodium, magnesium, aluminum, phosphorus, potassium, and calcium in deep-sea mineral water.

[0042] Table 1 shows the results of element determination in deep-sea mineral water by ICP-MS. Compared with the element content in the deionized water of the control group, deep-sea mineral water is rich in calcium, magnesium, potassium, boron and other elements, which can provide important nutrients for the surface of the fruit, thereby maintaining the stability of the cell wall on the surface of the fruit, and achieving the purpose of improving fruit quality and extending the storage period.

[0043] Table 1 Determination results of elements in deionized water and deep sea mineral water

[0044]

[0045]

[0046] Example 2: Preparation of deep sea mineral water composite fresh-keeping coating liquid

[0047] (1) dissolving 0.75-3.75 g of polyvinyl alcohol powder (molecular weight 30,000-70,000) in 75 ml of deionized water, stirring with a magnetic stirrer at >80° C. and a stirring speed of >500 r / min to obtain a PVA solution;

[0048] (2) While heating and stirring, continue to add 25 ml of mineral water to the solution in (1), then cool to room temperature and add deionized water to 100 ml to obtain a composite fresh-keeping coating solution.

[0049] When using, it is preferred to choose a composite preservative coating liquid containing 3.75g of polyvinyl alcohol per 100mL to enhance the film-forming and adhesion properties of the composite preservative coating liquid on the surface of fruits and vegetables.

[0050] When using, add deionized water to dilute the obtained composite fresh-keeping coating liquid by 25, 50 or 100 times, immerse mango, lychee and other fruits and vegetables in the coating liquid, take out and dry naturally, and the surface of the fruits and vegetables will be coated with deep-sea mineral water fresh-keeping coating.

[0051] Example 3: Effect of Deep Sea Mineral Water Fresh-keeping Coating on Mango Hardness

[0052] Mango fruit hardness is one of the important indicators to measure its maturity stage and storage quality.

[0053] A total of 400 "Xiaotai Mango" mangoes with uniform shape, size, uniform maturity and no obvious damage were selected. They were randomly and evenly divided into four groups: after cleaning and sterilization, they were immersed in the composite film solution of Example 2 for 60 seconds, so that the coating solution adhered to the entire surface of the fruit to form a uniform coating, and then taken out and dried naturally; and the control group was immersed in deionized water for 60 seconds.

[0054] Figure 1 The effect of deep-sea mineral water fresh-keeping coating on mango hardness. With the increase of storage time, the hardness of both the treatment group and the control group showed a gradual decrease, and the trend change of each group was roughly the same. The hardness of the fruit decreased fastest at the beginning of storage, which may be because the fruit dehydrated during the ripening and decomposition process, causing the cell structure to be destroyed, resulting in the softening of the fruit. Among them, the hardness of the deep-sea mineral water coating treatment group was significantly higher than that of the control group, and on the 4th and 6th days of storage, the hardness of the (×25) treatment group was significantly higher than that of the other treatment groups. This is because the high concentration of deep-sea mineral water provides the mango tissue cell wall and other structures and prevents the degradation of intracellular substances. The trace elements present in the cell wall, thus maintaining the hardness of the mango.

[0055] Example 4: Effect of Deep Sea Mineral Water Fresh-keeping Coating on Mango Weight Loss Rate

[0056] Weight loss is a direct reflection of the fullness and freshness of the mango, which manifests itself as shrunken fruit tissue, reduced nutrition and poor taste.

[0057] A total of 400 "Xiaotai Mango" mangoes with uniform shape, size, uniform maturity and no obvious damage were selected. They were randomly and evenly divided into four groups, and after cleaning and sterilization, they were immersed in the composite film solution of Example 2 for 60 seconds, so that the coating solution adhered to the entire surface of the fruit to form a uniform coating, and then taken out and dried naturally; the control group was immersed in deionized water for 60 seconds.

[0058] Figure 2 The effect of deep-sea mineral water fresh-keeping coating on the weight loss rate of mangoes showed an upward trend during the entire storage period, which may be due to the increased water loss caused by transpiration. During the storage period of 4 to 10 days, the weight loss rate of the control group changed the most, and the weight loss rate of the deep-sea mineral water coating treatment group was significantly lower than that of the control group. Moreover, on the 10th day of storage, the weight loss rate of the (×25) treatment group was significantly lower than that of the other treatment groups. This shows that the deep-sea mineral water coating treatment of the present invention can delay the weight loss of fruit to a certain extent.

[0059] Example 5: Effect of Deep Sea Mineral Water Fresh-keeping Coating on the Respiration Rate of Mango

[0060] Respiration refers to the process in which plants consume oxygen to oxidize and decompose organic components into simple molecules while releasing energy. Plants decompose various organic matter in this process, which is the main cause of physiological phenomena such as plant maturity and aging.

[0061] A total of 400 "Xiaotai Mango" mangoes with uniform shape, size, uniform maturity and no obvious damage were selected. They were randomly and evenly divided into four groups, and after cleaning and sterilization, they were immersed in the composite film solution of Example 2 for 60 seconds, so that the coating solution adhered to the entire surface of the fruit to form a uniform coating, and then taken out and dried naturally; the control group was immersed in deionized water for 60 seconds.

[0062] Figure 3 The effect of deep-sea mineral water fresh-keeping coating on the respiration rate of mangoes. Mangoes are respiratory climacteric fruits, and there will be a respiratory peak during storage. Mangoes showed a respiratory peak on the 4th day of storage. Compared with the control group, the deep-sea mineral water coating treatment group reduced the respiratory peak. During the entire storage period, the respiration rate of the deep-sea mineral water coating treatment group was lower than that of the control group. This shows that the deep-sea mineral water coating treatment of the present invention can inhibit the respiration of mangoes.

[0063] Example 6: Effect of Deep Sea Mineral Water Fresh-keeping Coating on Ethylene Release Rate of Mango

[0064] The rate of ethylene release is usually correlated with the degree of maturity of the fruit. During the ripening process of mangoes, ethylene production increases significantly and peaks at the beginning of ripening. Therefore, ethylene release can reflect the life process of the fruit and is closely related to its degree of maturity.

[0065] A total of 400 "Xiaotai Mango" mangoes with uniform shape, size, uniform maturity and no obvious damage were selected. They were randomly and evenly divided into four groups, and after cleaning and sterilization, they were immersed in the composite film solution of Example 2 for 60 seconds, so that the coating solution adhered to the entire surface of the fruit to form a uniform coating, and then taken out and dried naturally; the control group was immersed in deionized water for 60 seconds.

[0066] Figure 4 The effect of deep sea mineral water fresh-keeping coating on the ethylene release rate of mango. Ethylene production reached a peak at 4 days of fruit storage. Compared with the control group, the treatment group reduced the ethylene release rate of the fruit, and the ethylene release rate was lower than that of the control group during the entire storage process. The difference between the ethylene release rate and the control group on the 4th and 6th days was significant (P < 0.05). This shows that the deep sea mineral water coating treatment reduced the ethylene release rate of mango, thereby slowing down the ripening of the fruit.

[0067] Example 7: Effect of Deep Sea Mineral Water Fresh-keeping Coating on Soluble Solids in Mango

[0068] The soluble solids content is closely related to fruit maturity.

[0069] A total of 400 "Xiaotai Mango" mangoes with uniform shape, size, uniform maturity and no obvious damage were selected. They were randomly and evenly divided into four groups, and after cleaning and sterilization, they were immersed in the composite film solution of Example 2 for 60 seconds, so that the coating solution adhered to the entire surface of the fruit to form a uniform coating, and then taken out and dried naturally; the control group was immersed in deionized water for 60 seconds.

[0070] Figure 5 This is the effect of deep-sea mineral water fresh-keeping coating on the soluble solids of mango. The soluble solids content of mango increased in the early stage and began to decline rapidly in the later stage, with a large fluctuation. It may be due to the decomposition of macromolecules such as starch into small molecular monosaccharides during the respiration of mango, which leads to an increase in the soluble solids content. As respiration continues, nutrients are gradually exhausted, resulting in a decrease in the soluble solids content. On the 8th day of storage, the soluble solids content of the control group was significantly lower than that of the treatment group (P < 0.05), indicating that the deep-sea mineral water coating treatment effectively reduces the consumption of nutrients, thereby slowing down the decline in the soluble solids content.

[0071] Example 8: Effect of Deep Sea Mineral Water Fresh-keeping Coating on Titratable Acidity of Mango

[0072] Titratable acidity is the main determinant of fruit flavor and an important indicator of fruit ripeness.

[0073] A total of 400 "Xiaotai Mango" mangoes with uniform shape, size, uniform maturity and no obvious damage were selected. They were randomly and evenly divided into four groups, and after cleaning and sterilization, they were immersed in the composite film solution of Example 2 for 60 seconds, so that the coating solution adhered to the entire surface of the fruit to form a uniform coating, and then taken out and dried naturally; the control group was immersed in deionized water for 60 seconds.

[0074] Figure 6 This is the effect of deep sea mineral water fresh-keeping coating on mango titratable acid. The respiration of the fruit will consume part of the titratable acid. During the entire storage period, the titratable acid content of mango gradually decreased. On the second day of storage, the acid content in each treatment group decreased significantly, and the reduction in titratable acid in the control group was significantly lower than that in the treatment group (P < 0.05). This shows that deep sea mineral water coating treatment effectively delays the decline in titratable acid content and can effectively maintain the nutritional quality of mango.

[0075] Example 9: Effect of Deep Sea Mineral Water Fresh-keeping Coating on Litchi Hardness

[0076] Hardness is one of the important indicators to measure the storage quality of litchi fruit. The softer the hardness, the worse the quality of the litchi fruit.

[0077] A total of 200 "Feizixiao" lychees with uniform shape, size, uniform maturity and no obvious damage were selected. They were randomly and evenly divided into two groups: one was immersed in the (×25) composite film solution of Example 2 for 60 seconds, so that the coating solution adhered to the entire fruit surface to form a uniform coating, and then taken out and dried naturally; the other was immersed in deionized water for 60 seconds as a control group.

[0078] Figure 7 The effect of deep-sea mineral water fresh-keeping coating on the hardness of litchi. With the increase of storage time, the hardness of both the treatment group and the control group showed a downward trend. As shown in the figure, on the 6th and 8th days of storage, the hardness of litchi in the deep-sea mineral water coating treatment group was significantly higher than that in the control group. Analysis shows that the deep-sea mineral water fresh-keeping coating can provide calcium, potassium, magnesium and other important nutrients for cell division and fruit growth and development to the surface of fresh fruits, and maintain the stability of cell walls.

[0079] Example 10: Effect of deep sea mineral water fresh-keeping coating on litchi weight loss rate

[0080] The weight loss rate is on an upward trend, which means that the water and nutrients of litchi are constantly lost, and the quality of litchi is getting worse and worse.

[0081] A total of 200 "Feizixiao" lychees with uniform shape, size, uniform maturity and no obvious damage were selected. They were randomly and evenly divided into two groups: after washing and sterilization, they were immersed in the (×25) composite film solution of Example 2 for 60 seconds, so that the coating solution adhered to the entire fruit surface to form a uniform coating, and then taken out and dried naturally; and the control group was immersed in deionized water for 60 seconds.

[0082] Figure 8 This is the effect of deep-sea mineral water fresh-keeping coating on the weight loss rate of litchi. The weight loss rate of the deep-sea mineral water coating treatment group was significantly lower than that of the control group. Analysis shows that the deep-sea mineral water fresh-keeping coating is equivalent to forming a barrier on the surface of the litchi peel, which can not only reduce the evaporation of water through the peel, but also block the entry of oxygen and inhibit respiration, thereby reducing the water produced when the fruit breathes. The deep-sea mineral water fresh-keeping coating contains calcium ions, which can effectively maintain the hardness of fruits and vegetables, reduce the weight loss rate, delay the decline of nutrients such as vitamin C, delay the maturation and aging process of fruits and vegetables, and extend the storage period.

[0083] Example 11: Effect of Deep Sea Mineral Water Fresh-keeping Coating on Soluble Solids in Litchi

[0084] Soluble solids mainly refer to soluble sugars, which are important substances that constitute the flavor of fruits and are also important indicators reflecting the intrinsic quality and maturity of fruits.

[0085] A total of 200 "Feizixiao" lychees with uniform shape, size, uniform maturity and no obvious damage were selected. They were randomly and evenly divided into two groups: after washing and sterilization, they were immersed in the (×25) composite film solution of Example 2 for 60 seconds, so that the coating solution adhered to the entire fruit surface to form a uniform coating, and then taken out and dried naturally; and the control group was immersed in deionized water for 60 seconds.

[0086] Fig. 9 The effect of deep-sea mineral water preservative coating on the soluble solids content of litchi. On the 4th and 6th days of storage, the soluble solids content of the deep-sea mineral water coating treatment group was significantly lower than that of the control group, and in the later stage of storage, the deep-sea mineral water coating treatment group delayed the decrease of the soluble solids content of the fruit, effectively inhibited the decomposition of soluble solids, and thus maintained the taste and flavor of litchi.

Claims

1. A composite fresh-keeping coating liquid for fruits and vegetables, made from polyvinyl alcohol, mineral water and deionized water.

2. The composite fresh-keeping coating liquid for fruits and vegetables according to claim 1, characterized in that: The composition of each 100 mL of the fruit and vegetable composite fresh-keeping coating liquid is as follows: 0.75g-3.75g polyvinyl alcohol; 25mL mineral water; 75mL deionized water.

3. The composite fresh-keeping coating liquid for fruits and vegetables according to claim 1 or 2, characterized in that: The mineral water is deep sea mineral water.

4. The composite fresh-keeping coating liquid for fruits and vegetables according to claim 3, characterized in that: The contents of various elements in the deep sea mineral water are as follows: Boron 732ppm, sodium 14600ppm, magnesium 48000ppm, aluminum 0.475ppm, phosphorus 4.763ppm, potassium 8000ppm, calcium 650ppm, scandium 0.211ppm, vanadium 0.296ppm, chromium 0.028ppm, manganese 0.021ppm, iron 0.07ppm, cobalt 0.014ppm, nickel 0.312ppm, copper 0.105ppm, zinc 0.491ppm, arsenic 0.09ppm, selenium 0.027ppm, rubidium 15.313ppm, strontium 0.294ppm; The content of major elements in different batches of deep sea mineral water fluctuates within 20%, and the major elements refer to elements with a content greater than 100 ppm.

5. The composite fresh-keeping coating liquid for fruits and vegetables according to any one of claims 1 to 4, characterized in that: The molecular weight of the polyvinyl alcohol is 30,000-70,000.

6. The method for preparing the composite fresh-keeping coating liquid for fruits and vegetables according to any one of claims 1 to 5, comprising the following steps: S1, dispersing the polyvinyl alcohol in the deionized water, heating and stirring to obtain a polyvinyl alcohol solution; S2, adding the mineral water into the ethylene alcohol solution and stirring to obtain the product.

7. The preparation method according to claim 6, characterized in that: In step S1, stirring is performed at a temperature of >80°C; In step S2, stirring is performed at a temperature of >80°C and a stirring speed of >500 r / min.

8. Application of the composite fresh-keeping coating liquid for fruits and vegetables according to any one of claims 1 to 5 in the preservation of fruits and vegetables; The fruit and vegetable composite fresh-keeping coating liquid is diluted 25-100 times before application.

9. A method for preserving fruits and vegetables, comprising the step of immersing the fruits and vegetables in the diluted fruit and vegetable composite preservative coating liquid according to any one of claims 1 to 5; The dilution multiple is 25-100 times; The immersion time is 30-120s.

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