Soaking solution for apple storage and apple storage method

Abstract

The invention provides a soak solution for apple storage and application of the soak solution in apple storage, and belongs to the technical field of fruit preservation. The soaking solution is an organic calcium solution; the concentration of the organic calcium solution is 20g / L-40g / L. The organic calcium is used as the soaking solution, so that the total calcium content in the apple peel can be increased, no peculiar smell is left on the fruit, and the fruit flavor is not influenced.

Description

Technical Field

[0001] The invention relates to the technical field of fruit preservation, and more specifically to an immersion liquid for apple storage and application in apple storage. Background Art

[0002] Calcium is one of the most important mineral elements that determines the quality of fruit. Many physiological diseases are caused by calcium imbalance in the fruit. Calcium plays a core role in stabilizing cell wall structure and plant signal transduction. In the early stages of apple development, calcium is evenly distributed in the fruit. In the later stages of fruit development, the calcium content in different parts of the flesh varies. The calcium content in the peel is greater than that in the seeds and core, while the calcium content in the flesh is relatively low. The concentration of calcium gradually decreases from the fruit peduncle to the calyx pit. The peduncle is the main channel for the fruit to obtain nutrients and water from the tree. In the middle and late stages of fruit development, the increase in oxalic acid content in the peduncle can easily form calcium oxalate and block the vascular bundle, hindering the input of calcium and resulting in calcium absorption obstruction in the fruit.

[0003] Hanfu apple is a large-fruit apple variety mainly grown in the cold and cool fruit producing areas in northern my country. Due to the high yield, large fruit and relatively short growth period of Hanfu apple, physiological diseases induced by calcium imbalance in the fruit often occur in production, which seriously reduces the commercial value of the fruit and causes great economic losses. Calcium has poor mobility in plants, especially after the fruit is bagged, the fruit's absorption efficiency of calcium decreases, and physiological diseases caused by calcium imbalance become more serious.

[0004] The soaking liquid temperature is around 20°C, and the increase in the total calcium content of the peel after treatment with the inorganic calcium solution is relatively poor. In addition, the inorganic calcium solution will leave an odor on the fruit after treatment, reducing the flavor of the fruit. Summary of the invention

[0005] In view of the above problems, the present invention provides an apple storage soaking liquid and its application in apple storage. The present invention uses organic calcium as the soaking liquid to increase the total calcium content in the apple peel without leaving any peculiar smell on the fruit and affecting the flavor of the fruit.

[0006] The first object of the present invention is to provide an apple storage soaking solution, wherein the soaking solution is an organic calcium solution.

[0007] The concentration of the organic calcium solution is 20 g / L to 40 g / L. For example, the concentration of the organic calcium solution is 20 g / L, 22 g / L, 24 g / L, 26 g / L, 28 g / L, 30 g / L, 32 g / L, 34 g / L, 36 g / L, 38 g / L, 40 g / L, etc., but is not limited to the listed values. Other values ​​not listed within the above numerical range are also applicable, and will not be repeated here.

[0008] In a preferred embodiment of the present invention, the concentration of the organic calcium solution is 20 g / L.

[0009] In a preferred embodiment of the present invention, the organic calcium is calcium lactate.

[0010] In a preferred embodiment of the present invention, chitosan is further included, and the mass concentration of chitosan in the organic calcium solution is 0.9% to 1.1%. For example, the mass concentration of chitosan in the organic calcium solution is 0.9%, 1%, 1.1%, etc., but is not limited to the listed values. Other unlisted values ​​within the above numerical range are also applicable and will not be repeated here.

[0011] In a preferred embodiment of the present invention, the mass concentration of chitosan in the organic calcium solution is 1%.

[0012] A second object of the present invention is to provide an apple storage method, comprising the following steps:

[0013] The apples are immersed in the above-mentioned soaking liquid for apple storage. After the soaking is completed, the soaking liquid for apple storage is drained and stored.

[0014] In a preferred embodiment of the present invention, the soaking times are 3 to 4 times.

[0015] In a preferred embodiment of the present invention, the immersion time is 5s to 7s, for example, the immersion time is 5s, 6s, 7s, etc., but is not limited to the listed values. Other unlisted values ​​within the above numerical range are also applicable and will not be described one by one here.

[0016] In a preferred embodiment of the present invention, the soaking temperature is 19°C to 21°C, for example, the soaking temperature is 19°C, 20°C, 21°C, etc., but is not limited to the listed values. Other unlisted values ​​within the above numerical range are also applicable and will not be described one by one here.

[0017] In a preferred embodiment of the present invention, the storage temperature is 3°C to 5°C, for example, the storage temperature is 3°C, 4°C, 5°C, etc., but is not limited to the listed values. Other unlisted values ​​within the above numerical range are also applicable and will not be described one by one here.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] At around 20°C, organic calcium can more easily penetrate the wax layer on the surface of the apple peel and enter the peel cells, and can also be more easily transported in the flesh; a high calcium content is beneficial to reduce the degradation rate of cell wall components, increase the ratio of water-soluble calcium and pectin calcium, and thus improve the storage of the fruit. In addition, the use of organic calcium can prevent the fruit from leaving odors and maintain the flavor of the fruit.

[0020] The present invention uses calcium lactate solution as a calcium supplement, which has fast dissolution speed, high solubility, high biomass utilization rate, good taste and high safety. Calcium lactate can avoid leaving peculiar smell on fruits and maintain the flavor of fruits. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Effects of different calcium treatments on the calcium content of the peel.

[0022] Figure 2 Effects of different calcium treatments on calcium content in pulp.

[0023] Figure 3 Effect of calcium treatment on soluble sugar content of fruit during storage.

[0024] Figure 4 Effect of calcium treatment on titratable acid content of fruit during storage.

[0025] Figure 5 Effect of calcium treatment on hemicellulose content of fruit during storage.

[0026] Figure 6 Effect of calcium treatment on the soluble pectin calcium content of fruit during storage.

[0027] Figure 7 Effect of calcium treatment on calcium content in the flesh near the skin of fruit during storage.

[0028] Figure 8 Effect of calcium treatment on calcium content in the middle part of fruit pulp during storage.

[0029] Fig. 9 The effect of calcium treatment on the calcium content of the flesh near the center of the fruit during storage.

[0030] Fig.10 This is the effect of calcium treatment on the (N+K+Mg) / Ca ratio of the fruit near the skin during storage.

[0031] Fig.11 This is the effect of calcium treatment on the (N+K+Mg) / Ca ratio in the middle part of the fruit during storage.

[0032] Fig.12 This is the effect of calcium treatment on the (N+K+Mg) / Ca ratio of the fruit flesh during storage.

[0033] Fig.13 The effect of calcium treatment on the water-soluble calcium content in the flesh near the skin of the fruit during storage.

[0034] Fig.14 Effect of calcium treatment on the water-soluble calcium content in the middle part of the fruit pulp during storage.

[0035] Fig.15The effect of calcium treatment on the water-soluble calcium content in the pulp near the center of the fruit during storage.

[0036] Fig.16 The effect of calcium treatment on the pectin calcium content in the pulp near the skin of the fruit during storage.

[0037] Fig.17 This study is the effect of calcium treatment on the pectin calcium content in the middle part of the fruit pulp during storage.

[0038] Fig.18 The effect of calcium treatment on the pectin calcium content in the pulp near the center of the fruit during storage.

[0039] Fig.19 Effect of calcium treatment on Ca2+ in the pulp of fruit during storage 2+ -Effects on ATPase activity.

[0040] Fig. 20 Effect of calcium treatment on the Ca content of the middle part of the fruit during storage 2+ -Effects on ATPase activity.

[0041] Fig.21 Effect of calcium treatment on Ca content of fruit pulp during storage 2+ -Effects on ATPase activity.

[0042] Fig. 22 Effect of calcium treatment on H + -Effects on ATPase activity.

[0043] Fig.23 Effect of calcium treatment on H in the middle part of fruit during storage + -Effects on ATPase activity.

[0044] Fig.24 Effect of calcium treatment on H + -Effects on ATPase activity. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in 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.

[0046] In the present invention, calcium lactate is denoted as CL, and calcium chloride is denoted as CC. The apple variety used in the present invention is Hanfu apple. The chitosan used in the present invention is carboxymethyl chitosan, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., with a product number of C304738.

[0047] Example 1

[0048] In this embodiment, an apple storage soaking liquid is prepared. The apple storage soaking liquid is a calcium lactate solution with a concentration of 20 g / L prepared by dissolving calcium lactate pentahydrate in water.

[0049] Soak the apples in a 20 g / L calcium lactate solution at 4 ± 1 °C for 30 min. Wash and dry the treated fruits, and take samples immediately.

[0050] Example 2

[0051] In this embodiment, an apple storage soaking liquid is prepared. The apple storage soaking liquid is a calcium lactate solution with a concentration of 20 g / L prepared by dissolving calcium lactate pentahydrate in water.

[0052] Soak the apples in a 20 g / L calcium lactate solution at 4 ± 1 °C for 60 min. Wash and dry the treated fruits, and take samples immediately.

[0053] Example 3

[0054] In this embodiment, an apple storage soaking liquid is prepared. The apple storage soaking liquid is a calcium lactate solution with a concentration of 20 g / L prepared by dissolving calcium lactate pentahydrate in water.

[0055] Soak the apples in a 20 g / L calcium lactate solution at 20 ± 1 °C for 30 min. Wash and dry the treated fruits, and take samples immediately. This treatment is recorded as CL2.

[0056] Example 4

[0057] In this embodiment, an apple storage soaking liquid is prepared. The apple storage soaking liquid is a calcium lactate solution with a concentration of 20 g / L prepared by dissolving calcium lactate pentahydrate in water.

[0058] Soak the apples in a 20 g / L calcium lactate solution at 20 ± 1 °C for 60 min. Wash and dry the treated fruits, and take samples immediately.

[0059] Example 5

[0060] In this embodiment, an apple storage soaking liquid is prepared. The apple storage soaking liquid is a calcium lactate solution with a concentration of 40 g / L prepared by dissolving calcium lactate pentahydrate in water.

[0061] Soak the apples in a 40 g / L calcium lactate solution at 4 ± 1 °C for 30 min. Wash and dry the treated fruits, and take samples immediately.

[0062] Example 6

[0063] In this embodiment, an apple storage soaking liquid is prepared. The apple storage soaking liquid is a calcium lactate solution with a concentration of 40 g / L prepared by dissolving calcium lactate pentahydrate in water.

[0064] Soak the apples in a 40 g / L calcium lactate solution at 4 ± 1 °C for 60 min. Wash and dry the treated fruits, and take samples immediately.

[0065] Example 7

[0066] In this embodiment, an apple storage soaking liquid is prepared. The apple storage soaking liquid is a calcium lactate solution with a concentration of 40 g / L prepared by dissolving calcium lactate pentahydrate in water.

[0067] The apples were soaked in a 40 g / L calcium lactate solution at 20 ± 1 °C for 30 min. The treated fruits were washed and dried, and samples were taken immediately. This treatment was recorded as CL1.

[0068] Example 8

[0069] In this embodiment, an apple storage soaking liquid is prepared. The apple storage soaking liquid is a calcium lactate solution with a concentration of 40 g / L prepared by adding calcium lactate pentahydrate into water.

[0070] Soak the apples in a 40 g / L calcium lactate solution at 20 ± 1 °C for 60 min. Wash and dry the treated fruits, and take samples immediately.

[0071] Comparative Example 1

[0072] In this comparative example, an apple storage soaking solution is prepared. The apple storage soaking solution is a calcium chloride solution with a concentration of 20 g / L prepared by dissolving anhydrous calcium chloride in water.

[0073] Soak the apples in a 20 g / L calcium chloride solution at 4 ± 1 °C for 30 min. Wash and dry the treated fruits, and take samples immediately.

[0074] Comparative Example 2

[0075] In this comparative example, an apple storage soaking solution is prepared. The apple storage soaking solution is a calcium chloride solution with a concentration of 20 g / L prepared by dissolving anhydrous calcium chloride in water.

[0076] Soak the apples in a 20 g / L calcium chloride solution at 4 ± 1 °C for 60 min. Wash and dry the treated fruits, and take samples immediately.

[0077] Comparative Example 3

[0078] In this comparative example, an apple storage soaking solution is prepared. The apple storage soaking solution is a calcium chloride solution with a concentration of 20 g / L prepared by dissolving anhydrous calcium chloride in water.

[0079] Soak the apples in a 20g / L calcium chloride solution at 20±1℃ for 30min. Wash and dry the treated fruits and take samples immediately.

[0080] Comparative Example 4

[0081] In this comparative example, an apple storage soaking solution is prepared. The apple storage soaking solution is a calcium chloride solution with a concentration of 20 g / L prepared by dissolving anhydrous calcium chloride in water.

[0082] Soak the apples in a 20g / L calcium chloride solution at 20±1℃ for 60min. Wash and dry the treated fruits and take samples immediately.

[0083] Comparative Example 5

[0084] In this comparative example, an apple storage soaking solution is prepared. The apple storage soaking solution is a calcium chloride solution with a concentration of 40 g / L prepared by dissolving anhydrous calcium chloride in water.

[0085] Soak the apples in a 40 g / L calcium chloride solution at 4 ± 1 °C for 30 min. Wash and dry the treated fruits, and take samples immediately.

[0086] Comparative Example 6

[0087] In this comparative example, an apple storage soaking solution is prepared. The apple storage soaking solution is a calcium chloride solution with a concentration of 40 g / L prepared by dissolving anhydrous calcium chloride in water.

[0088] Soak the apples in a 40 g / L calcium chloride solution at 4 ± 1 °C for 60 min. Wash and dry the treated fruits, and take samples immediately.

[0089] Comparative Example 7

[0090] In this comparative example, an apple storage soaking solution is prepared. The apple storage soaking solution is a calcium chloride solution with a concentration of 40 g / L prepared by dissolving anhydrous calcium chloride in water.

[0091] Soak the apples in a 40g / L calcium chloride solution at 20±1℃ for 30min. Wash and dry the treated fruits and take samples immediately.

[0092] Comparative Example 8

[0093] In this comparative example, an apple storage soaking solution is prepared. The apple storage soaking solution is a calcium chloride solution with a concentration of 40 g / L prepared by dissolving anhydrous calcium chloride in water.

[0094] Soak the apples in a 40g / L calcium chloride solution at 20±1℃ for 60min. Wash and dry the treated fruits and take samples immediately.

[0095] Comparative Example 9

[0096] In this comparative example, apples were soaked in water at 4±1°C for 30 minutes. The treated fruits were washed and dried, and samples were taken immediately.

[0097] Comparative Example 10

[0098] In this comparative example, apples were soaked in water at 4±1°C for 60 minutes. The treated fruits were washed and dried, and samples were taken immediately.

[0099] Comparative Example 11

[0100] In this comparative example, apples were soaked in water at 20±1°C for 30 minutes. The treated fruits were washed and dried, and samples were taken immediately.

[0101] Comparative Example 12

[0102] In this comparative example, apples were soaked in water at 20±1°C for 60 minutes. The treated fruits were washed and dried, and samples were taken immediately.

[0103] The apples treated in Examples 1-8 and Comparative Examples 1-12 were stored in a cold storage at 4±1°C, and samples were taken at 0d, 30d, 60d, and 90d of storage; each sampling was repeated 5 times, with 5 fruits as one repeat, for a total of 25 fruits.

[0104] Sampling location: The sampling location is about 3 to 4 cm wide from the equator of the fruit to the end of the stem depression. The peel and pulp are taken. After sampling, the samples are treated with liquid nitrogen and ground, and stored in an ultra-low temperature refrigerator for later use. Peel sampling method: Use a peeler to sample, the thickness is about 1mm;

[0105] The method of sampling the pulp was as follows: Use a peeler to take samples from three parts of the fruit, namely, the pulp about 2 mm thick after peeling, the pulp about 2 mm thick in the middle of the pulp radius, and the pulp about 2 mm thick 5 mm near the core.

[0106] It should be noted that the lowercase letters in the table of the present invention represent the significant difference between the distilled water treatment and the calcium chloride and calcium lactate treatments (P<0.05).

[0107] Fruit hardness and soluble solids content are basic indicators for measuring fruit quality. Table 1 shows that different calcium preparations have significantly different effects on the basic quality of Hanfu apple fruit. When the treatment temperature was 4±1℃ and the soaking time was 30min, the fruit hardness and soluble solids content of 40g / L calcium chloride (CC) and 40g / L calcium lactate (CL) treatments were higher than those of the control (H 2 O). When the treatment temperature was 20±1℃ and the soaking time was 60min, the fruit hardness of the 40g / L CC treatment was lower than that of the control (H 2O), the fruit firmness of the 40g / L CL treatment was higher than that of the control (H 2 O), the soluble solids content of the two calcium treatments increased by 1.29% and 2.63% respectively compared with the control. The fruit hardness was the highest when the treatment temperature was 20±1℃, soaked for 30min, and the fruit treated with 40g / L CL had the highest soluble solids content. On the whole, organic calcium is more efficient in entering fruit cells, and organic calcium is easier to transport in the pulp, which increases the calcium level in the fruit, and is beneficial to delay pulp aging, promote the accumulation of soluble solids, and reduce the decomposition rate of substances during storage.

[0108] Table 1 Effects of different calcium reagent treatments on fruit firmness and soluble solids content of Hanfu apple

[0109]

[0110]

[0111] Figure 1 and Figure 2 The results showed that the calcium content of fruits treated with exogenous calcium was significantly higher than that of the control (H 2 O), with the increase of treatment temperature and calcium concentration, the calcium content of the fruit increased. This shows that calcium reagent treatment can effectively increase the calcium content of the peel.

[0112] Figure 1 In the experiment, the soaking liquid temperature was 4±1℃, the order of total calcium content in peel was 40g / L CC(60min)>20g / L CL(60min)>40g / L CC(30min)>20g / L CC(30min)>40g / L CL(60min)>20g / L CC(60min)>20g / L CL(30min)>40g / L CL(30min)>CK; the order of total calcium content in pulp was 40g / L CC(60min)>20g / LCC(60min)>20g / LCL(60min)>40g / L CL(60min)>CK>20g / L CC(30min)>20g / L CL(30min)>40g / L CC(30min)>40g / L CL(30min). This means that at 4±1℃, high-concentration calcium chloride treatment is relatively efficient in promoting calcium entry into the peel, and low-concentration calcium lactate treatment for a slightly longer time can also effectively promote the absorption of calcium by the peel.

[0113] Figure 2In the experiment, the soaking liquid temperature was 20±1℃, the order of total calcium content in peel was 40g / L CCL(30min)>20g / L CL(60min)>40g / L CC(60min)>40g / L CL(60min)>20g / L CC(30min)>40g / L CC(30min)>20g / L CL(30min)>20g / L CC(60min)>CK; the order of total calcium content in pulp was 40g / L CC(30min)>20g / LCL(30min)>40g / LCL(30min)>40g / L CC(60min)>20g / L CC(60min)>CK>40g / L CL(60min)>20g / L CC(30min)>20g / L CL(60min). This shows that at 20±1℃, short-time treatment with high concentration of calcium lactate has a better effect on increasing the calcium content in the peel, and the effect of short-time treatment with calcium lactate on increasing the calcium content in the pulp is only lower than that of high concentration of calcium chloride (30min).

[0114] Fruit flavor is an important component of fruit quality and can intuitively evaluate the quality of the fruit and its commercial value. As shown in Table 2, calcium chloride treatment has the most obvious effect on the taste of Hanfu apple fruit. Under the condition of a treatment temperature of 4±1℃, the fruit flavor of 40g / L CC treatment for 30min and 60min was significantly affected, indicating that calcium chloride treatment will reduce the fruit flavor when the soaking liquid temperature is low. Low-concentration calcium lactate treatment did not have a significant effect on the flavor of apples under the conditions of a treatment temperature of 4±1℃ or 20±1℃, but only under low temperature and high concentration conditions will it affect the flavor of the fruit. Overall, calcium lactate treatment is more beneficial to maintaining the natural flavor of apple fruit; long-term soaking treatment is more likely to damage the fruit flavor, and short-term treatment has a better effect on maintaining the fruit flavor.

[0115] Table 2 Effects of different calcium reagent treatments on the flavor of Hanfu apple fruit

[0116] deal with concentration temperature time Flavor Impact <![CDATA[H 2 The]]> 4℃ 30min - <![CDATA[H 2 The]]> 4℃ 60min - <![CDATA[H 2 The]]> 20℃ 30min - <![CDATA[H 2 The]]> 20℃ 60min - CC 20g / L 4℃ 30min - CC 20g / L 4℃ 60min - CC 20g / L 20℃ 30min - CC 20g / L 20℃ 60min - CC 40g / L 4℃ 30min ++ CC 40g / L 4℃ 60min +++ CC 40g / L 20℃ 30min + CC 40g / L 20℃ 60min + CL 20g / L 4℃ 30min - CL 20g / L 4℃ 60min - CL 20g / L 20℃ 30min - CL 20g / L 20℃ 60min - CL 40g / L 4℃ 30min + CL 40g / L 4℃ 60min - CL 40g / L 20℃ 30min - CL 40g / L 20℃ 60min +

[0117] - indicates that the flavor is not affected, and + indicates the degree to which the flavor is affected.

[0118] The flavor of the fruit can directly affect the commercial value of the fruit, so the present invention first takes maintaining the natural flavor of the fruit as the first screening principle, and then takes increasing the calcium content of the peel as the goal, and then comprehensively considers the fruit hardness and soluble solid content, and optimizes the type of calcium reagent and treatment conditions. Subsequent tests were carried out using Examples 3 and 7 as examples.

[0119] The apple fruits were soaked in distilled water at room temperature (20±1℃) for 30 minutes as CK. The apple fruits of CL1, CL2 and CK were stored in a cold storage at 4±1℃. Samples were taken at 0d, 30d, 60d and 90d of storage; each sampling was repeated 5 times, with 5 fruits in each repeat, for a total of 25 fruits.

[0120] The hardness and soluble solids of the fruit directly reflect the edible quality of the fruit. Table 3 shows that during storage, the hardness and soluble solids content of the control (CK) fruit gradually decreased; the hardness of the calcium lactate-treated fruit (CL1 and CL2) changed little, and the soluble solids content increased significantly, and was significantly higher than that of CK.

[0121] After 90 days of storage, the decrease in fruit firmness of CL1 and CL2 was significantly less than that of CK. Compared with CK, the soluble solids content of fruits treated with CL1 and CL2 increased significantly. CL1 treatment was better than CL2 treatment in maintaining fruit firmness and soluble solids.

[0122] Table 3 Effects of calcium treatment on the basic quality of Hanfu apple fruit during storage

[0123] deal with Storage days (d) <![CDATA[Hardness (kg / cm 2 )]]> Soluble solids (%) CK 0 7.96±0.12a 12.90±0.07a 30 7.55±0.06b 12.93±0.07a 60 7.35±0.14b 12.42±0.29b 90 6.75±0.14c 11.87±0.27c CL1 30 7.99±0.12ab 13.69±0.27a 60 7.90±0.15ab 13.42±0.36ab 90 7.55±0.12b 13.07±0.36b CL2 30 7.81±0.20a 13.61±0.42a 60 7.74±0.15a 13.41±0.24a 90 7.13±0.06b 12.97±0.18b

[0124] Lowercase letters indicate significant differences between different storage times within the same treatment (P < 0.05), the same below.

[0125] Figure 3 The results showed that exogenous calcium treatment had a significant effect on the soluble sugar content of Hanfu apple fruit during storage. During storage, the soluble sugar content of the fruit treated with CL1 and CL2 was significantly higher than that of the control (CK). At 90 days of storage, the soluble sugar content of the fruit treated with CL2 was 12.24%, slightly lower than that of the CL1 treatment, but significantly higher than that of the CK (9.69%).

[0126] Figure 4 The results showed that during storage, the titratable acid content of CK fruits showed an overall increasing trend, while the titratable acid content of fruits treated with calcium lactate (CL1 and CL2) first increased and then decreased, and was significantly lower than that of CK at 90 days.

[0127] Figure 5 The results showed that during storage (0-90d), the hemicellulose content of fruits treated with CK varied greatly, showing an increase-decrease-increase trend; the hemicellulose content of fruits treated with CL1 varied relatively little during storage, and was significantly lower than that of CK at 30d and 90d; the hemicellulose content of fruits treated with CL2 was significantly higher than that of CK and CL1 at 30-90d.

[0128] Figure 6The results showed that during storage, the soluble pectin content of CK fruits showed an overall increasing trend; the soluble pectin content of CL1-treated fruits was gradually higher than that of CK before 30 days; CL1 and CL2 decreased rapidly from 30 to 90 days, and were significantly lower than CK at 90 days.

[0129] like Figure 7 As shown in the figure, during the storage period, the total calcium content of the fruit flesh near the skin of the CK treatment decreased slowly as a whole, and was significantly lower than that of the CL1 and CL2 treatments; the calcium content of the fruit flesh near the skin of the CL1 and CL2 treatments significantly increased, and showed a downward trend after 30 days, and the total calcium content of the fruit flesh near the skin of the CL1 treatment was always higher than that of the CL2 treatments.

[0130] like Figure 8 As shown, during storage (0-90d), the calcium content in the middle of the pulp of CK was relatively stable; the calcium content in the middle of the pulp of CL1 and CL2 treatments was significantly higher than that of CK, and the calcium content in the middle of the pulp of CL1 was higher than that of CL2.

[0131] like Fig. 9 As shown in the figure, during storage, the calcium content of the flesh near the center of CK fruit slowly decreased. The calcium content of the flesh near the center of fruit treated with CL1 and CL2 was significantly higher than that of CK at 30 days, but only the CL1 treatment reached a significant difference with CK; at 90 days of storage, the calcium content near the center of fruit treated with CL1 and CL2 was significantly higher than that of CK.

[0132] like Fig.10 As shown, compared with CK, CL1 and CL2 treatments significantly reduced the (N+K+Mg) / Ca ratio of the flesh near the skin. At 30 and 90 days of storage, the (N+K+Mg) / Ca ratio of the flesh near the skin in CL2 treatment was significantly higher than that in CL1.

[0133] like Fig.11 As shown in the figure, during storage (0-90 days), the (N+K+Mg) / Ca ratio of the middle fruit of CL1 and CL2 treatments was significantly lower than that of CK. At 30-90 days, the (N+K+Mg) / Ca ratio of the middle fruit of CL1 and CL2 treatments increased slowly, and the (N+K+Mg) / Ca ratio of the middle fruit of CL1 was significantly lower than that of CL2.

[0134] like Fig.12 As shown, from 30 to 90 days, the (N+K+Mg) / Ca ratios of the fruit flesh near the center of the CL1 and CL2 treatments were similar; at 30 days and 90 days, the (N+K+Mg) / Ca ratios of the fruit flesh near the center of the CL1 and CL2 treatments were significantly lower than that of the CK.

[0135] like Fig.13As shown in the figure, the water-soluble calcium content of the pulp near the skin of CK fruit showed an overall downward trend during storage, and was significantly lower than that of CL1 and CL2 treatments; the water-soluble calcium content of the pulp near the skin of CL1 and CL2 treatments also continued to decrease, and the water-soluble calcium content of the pulp near the skin of CL1 was always higher than that of CL2 treatment.

[0136] like Fig.14 As shown in the figure, the water-soluble calcium content in the middle of the CK pulp decreased significantly at the beginning of storage (0-30 days), and then remained stable at a low level. The water-soluble calcium content in the middle of the CL1-treated fruit was relatively stable from 0 to 60 days, increased rapidly at 90 days, and was significantly higher than that of CK at 30 and 90 days; the water-soluble dry content of the middle of the CL2-treated fruit was significantly higher than that of CK and CL1 at 30-60 days, and was significantly lower than CL1 at 90 days but significantly higher than CK.

[0137] like Fig.15 As shown in the figure, during storage, the water-soluble calcium content of the fruit pulp near the center of the CL1 treatment was relatively stable, and was significantly higher than that of the CK at 30 days and 90 days; the water-soluble calcium content of the fruit pulp near the center of the CL2 treatment gradually decreased, was slightly higher than that of the CK at 30 days, and was significantly lower than that of the CK and CL1 at 60 days and 90 days.

[0138] like Fig.16 As shown, during the storage period, the pectin calcium content of the pulp near the peel of CK first increased and then decreased significantly; the pectin calcium content of the pulp near the peel of CL1 and CL2 treatments was significantly higher than that of CK, and the pectin calcium content of the pulp near the peel of CL1 treatment was always significantly higher than that of CL2.

[0139] like Fig.17 As shown, during the storage period, the pectin calcium content in the middle pulp of CK remained stable at a low level; the pectin calcium content in the middle pulp of CL1 treatment was significantly higher than that of CK at 30d and 90d; the pectin calcium content in the middle pulp of CL2 treatment was significantly higher than that of CK, significantly lower than CL1 at 30d and 90d, and significantly higher than CL1 at 60d.

[0140] like Fig.18 As shown in the data, during the storage period, the pectin calcium content in the pulp near the center of CK fruit was generally at a high level; compared with CK, the CL1 treatment further significantly increased the pectin calcium content in the pulp near the center of the fruit; the pectin calcium content in the pulp near the center of CL2 treatment was significantly higher than that of CK and CL1 only at 30 days, and then significantly lower than that of CK at 60 days and 90 days.

[0141] like Fig.19 As shown in Figure 2, compared with CK, CL1 treatment significantly reduced the Ca content of the flesh near the skin at 30 days. 2+ -ATPase activity, and then a significant increase in Ca 2+ -ATPase activity; Ca in the flesh near the skin treated with CL22+ -ATPase activity was similar to that of CK at 30 days, and then increased significantly, and was significantly higher than that of CK and CL1 treatments at 60 days and 90 days.

[0142] like Fig. 20 As shown, compared with CK, the Ca content of the middle fruit pulp treated with CL1 was 2+ -ATPase activity increased significantly at 60 and 90 days of storage; Ca in the middle pulp of CL2 treatment 2+ -ATPase activity increased significantly from 30 to 90 days, and was significantly higher than that of CL1 treatment at 30 and 60 days.

[0143] like Fig.21 As shown in Figure 2, compared with CK, CL1 treatment significantly increased the Ca content of the fruit pulp near the center. 2+ -ATPase activity, and reached significant levels at 60d and 90d; CL2 treatment also significantly increased the Ca 2+ -ATPase activity reached significant levels compared with the control at 30d and 90d, and was significantly higher than CL1 only at 30d.

[0144] like Fig. 22 As shown, compared with CK, the flesh H near the skin of CL1 treatment + -ATPase activity changed relatively greatly, which was significantly higher than CK at 30-60 days of storage and close to CK at 90 days. CL2 treatment also increased H + -ATPase activity, but it was significantly higher than CK only at 30d and 60d.

[0145] like Fig.23 As shown, compared with CK, the middle flesh H + -ATPase activity increased significantly at 30d and 90d; the middle flesh H + -ATPase activity was significantly higher than that of CK and CL1 at 30d and 90d.

[0146] like Fig.24 As shown, the H of the flesh near the center of the CL1 and CL2 treatments + -ATPase activity changes and the relationship between H + -ATPase activity is similar.

[0147] Example 9

[0148] This embodiment prepares an apple storage soaking liquid, and the preparation method of the apple storage soaking liquid is as follows:

[0149] Step 1: Calcium lactate pentahydrate is added into water to prepare a calcium lactate solution with a concentration of 20 g / L.

[0150] Step 2: Dissolve chitosan with a 20 g / L calcium lactate solution, and use the above-mentioned calcium lactate solution to make a chitosan soaking solution for apple storage with a mass concentration of 1%.

[0151] The apples were immersed in the apple storage soaking solution for 5 seconds, then taken out and dried. After the surface of the fruit was dry, the soaking process was repeated for a total of 3 times. This treatment was recorded as calcium coating.

[0152] Comparative Example 13

[0153] In this comparative example, a chitosan aqueous solution with a concentration of 1% was used as the soaking liquid for apple storage.

[0154] The apple fruits were immersed in the chitosan aqueous solution at 20±1℃ for 5s and then taken out to dry. After the surface of the fruit was dry, the immersion process was repeated for a total of 3 times. This treatment was recorded as calcium-free coating.

[0155] The fruits immersed in distilled water for three times and then dried were used as the CK2 group. The fruits of the calcium coating group, the calcium coating group, and the CK2 group were stored in a cold storage at 4±1℃. After 90 days of cold storage, the fruits were placed at room temperature (20±1℃) to simulate the shelf life. Samples were taken at 0d, 30d, 60d, 90d, 90+7d, and 90+14d of storage; 3 replicates, 3 fruits per replicate, a total of 9 fruits.

[0156] Table 4 shows that during storage 0-90 days and simulated shelf life, the fruit hardness of CK2, calcium coating and non-calcium coating treatments gradually decreased, and the fruit hardness was calcium coating > non-calcium coating > CK2, and the two coating treatments were significantly higher than CK2 at 90 days of storage and shelf life; the soluble solids content of fruits treated with calcium and non-calcium coating was significantly higher than that of CK2 from 60 days, and was significantly higher than that of CK2 at 90 days and shelf life; in addition, during storage 90 days and shelf life, the soluble solids content of fruits treated with non-calcium coating gradually decreased, while that of fruits treated with calcium coating remained stable at a higher level.

[0157] This shows that the coating treatment delays the aging process of the fruit, prolongs the storage period of the fruit, improves the quality of the fruit during the shelf life, and the effect of calcium coating treatment is better.

[0158] Table 4 Effects of coating treatment on basic fruit quality of Hanfu apple during storage

[0159]

[0160] Note: The number after + represents the shelf life in days. For example, 90+7 means that the product is stored in a cold storage for 90 days and then moved indoors to simulate a shelf life of 7 days.

[0161] Taste and flavor are key factors in the intrinsic quality of fruits, which directly affect the nutritional value and economic value of fruits. Therefore, the quality indicators of fruit soluble sugar content, titratable acid content, soluble solid content and fruit hardness were used as evaluation criteria for screening and optimizing the combination of calcium preparations. The above test results show that treatment with 20 g / L or 40 g / L calcium lactate for 30 min at 20±1℃ can better maintain the flavor of fruits and improve the quality of fruits; calcium immersion for 30 min and 60 min at 20±1℃ and 40 g / L calcium lactate can increase the calcium content of peel and the hardness of fruits; in addition, short-term calcium immersion has a better effect on maintaining the hardness of fruits. When the fruits were treated with 40 g / L calcium chloride for 60 min at 4±1℃, the calcium content of peel was significantly increased, but the hardness of fruits was low and the flavor of fruits was obviously deteriorated. Finally, 20±1℃, 40g / L calcium lactate solution soaking for 30min was selected as treatment formula CL1, and 20±1℃, 20g / L calcium lactate solution soaking for 30min was selected as treatment formula CL2. The present invention found that calcium lactate can significantly increase the soluble solids and soluble sugar content of Hanfu apples during storage, indicating that calcium lactate treatment can effectively delay the aging of Hanfu apples during storage and stabilize the fruit quality. The CL1 treatment in the present invention has the best effect of delaying the aging of Hanfu apple fruits and stabilizing the fruit quality during storage.

[0162] The cell wall material of the fruit is mainly composed of polysaccharides such as pectin, cellulose, and hemicellulose, which form a network structure through mutual cross-linking, giving the fruit a certain shape and elasticity. The ripening and softening of the fruit is mainly due to the degradation of the original pectin in the cell wall into pectin and the degradation of cellulose into hemicellulose. The aging of the fruit is caused by the rupture of the cell wall structure. The calcium ions in the fruit combine with pectin to form pectin calcium, which can enhance the stability of pectin, stabilize the cell wall structure, increase the toughness of the cell wall, and increase the fracture stress of the peel. Calcium deficiency will cause the concentration difference between the inside and outside of the cell wall in the fruit to change, the permeability of the cell wall to increase, the fruit to soften quickly, and it is not resistant to storage. The incidence of physiological diseases of calcium-deficient fruits increases. Exogenous calcium treatment combined with low-temperature storage can significantly alleviate the degradation of fruit cell wall materials, maintain the stability of the cell membrane and the toughness of the cell wall, and improve the quality of the fruit during storage.

[0163] In the present invention, calcium lactate significantly slows down the degradation of cellulose in the fruit of Hanfu apple during storage, stabilizes the change of hemicellulose content, and at the same time, calcium lactate treatment also significantly increases the content of pectin calcium in various parts of the fruit, thereby enhancing the mechanical strength of the cell wall. This is one of the physiological bases for calcium lactate treatment to maintain fruit hardness and fruit quality.

[0164] Mineral elements are essential nutrients for plant growth and have a complex and critical impact on fruit quality. This study determined the calcium, potassium, magnesium, and nitrogen contents in the fruit, which are closely related to the fruit quality. Among them, the ratio of calcium content to the above-mentioned mineral elements is crucial to the physiological effect of calcium. The present invention shows that calcium lactate treatment can effectively increase the calcium content in various parts of the pulp, promote the uniform distribution of calcium in different parts of the fruit, and increase the pectin calcium content in the pulp and reduce the (N+P+K) / Ca ratio. This helps to enhance the overall quality and storage resistance of the fruit and reduce physiological diseases of the fruit caused by uneven calcium distribution.

[0165] When the intracellular calcium concentration changes, Ca 2+ -ATPase is activated, pumping the elevated calcium ions in the cytoplasm to the extracellular space or storing them in organelles, thus maintaining the calcium ion concentration in the cytoplasm at a low level. 2+ -ATPase activity is reduced, which hinders Ca 2+ The results of the present invention show that calcium lactate treatment effectively improves the Ca content of fruits during long-term storage. 2+ -ATPase activity, especially in the middle part of the fruit, which is the main edible part of the fruit. 2+ -After the activity of ATPase increases, the stability of the cell membrane is strengthened, delaying the aging of fruit quality. + -ATPase regulates H inside and outside the plasma membrane by generating transmembrane potential gradient and transmembrane pH gradient + concentration, thereby affecting the intracellular pH value, maintaining the intracellular ion balance, and transporting Ca across the membrane 2+ / H+ antiporter provides driving force. The results of the present invention show that calcium lactate treatment significantly changes fruit H + -ATPase activity, H + -ATPase can affect the activity of pectinase, cellulase and other enzymes by regulating intracellular pH, thereby affecting the quality and aging of fruits during storage.

[0166] The present invention combines calcium lactate with coating treatment. The addition of calcium lactate will not affect the physical and chemical properties of the chitosan film, and the surface of the prepared chitosan film is relatively smooth and flat, while other calcium salts will reduce the transmittance of the chitosan film. The test results show that both calcium coating and calcium-free coating treatment can significantly slow down the decline in fruit hardness during storage and shelf life compared with CK2, but the fruit hardness of the calcium coating treatment is better maintained and the soluble solids content of the fruit is higher. Calcium coating treatment is an effective fruit preservation technology that can significantly improve the quality and storability of Hanfu apples during storage, extend the shelf life of the fruit, and meet the needs of consumers.

[0167] Hanfu apples can be stored until May or June of the following year, but during storage, bitter pits will gradually increase, the flesh will gradually become soft, and the fruit skin will easily have a strange smell. According to the method of the present invention, the quality will not deteriorate after at least three months of storage, and the soluble solids will even increase.

[0168] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0169] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A soaking liquid for apple storage, characterized in that: The soaking liquid is an organic calcium solution; The concentration of the organic calcium solution is 20 g / L to 40 g / L.

2. The soaking liquid for apple storage according to claim 1, characterized in that: The concentration of the organic calcium solution is 20 g / L.

3. The soaking liquid for apple storage according to claim 1, characterized in that: Organic calcium is calcium lactate.

4. The soaking liquid for apple storage according to claim 1, characterized in that: The organic calcium solution also includes chitosan, and the mass concentration of chitosan in the organic calcium solution is 0.9% to 1.1%.

5. The soaking liquid for apple storage according to claim 4, characterized in that: The mass concentration of chitosan in the organic calcium solution is 1%.

6. A method for storing apples, characterized in that: The following steps are involved: The apples are immersed in the apple storage soaking liquid according to any one of claims 1 to 5. After the soaking is completed, the apple storage soaking liquid is drained and stored.

7. The apple storage method according to claim 6, characterized in that: The soaking times are 3 to 4 times.

8. The apple storage method according to claim 6, characterized in that: The soaking time is 5s to 7s.

9. The apple storage method according to claim 6, characterized in that: The soaking temperature is 19℃~21℃.

10. The apple storage method according to claim 6, characterized in that: The storage temperature is 3℃~5℃.

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