Processing method of preserved plums and product thereof

Abstract

The invention discloses a processing method of preserved plums and a product thereof, and belongs to the technical field of food processing. According to the improved preserved plum processing method provided by the invention, the content of acrylamide in a preserved plum product can be greatly reduced by adding a pretreatment soaking mode, the processing technology is high in operability, and expensive complex equipment does not need to be added. And the method has important significance on processing of the preserved plums.

Description

Technical Field

[0001] This invention belongs to the field of food processing technology, and specifically discloses a processing method for preserved plums and its product. Background Technology

[0002] Plums are rich in organic acids, minerals, and vitamins. They can be eaten fresh or processed into dried fruit, canned goods, and other foods, giving them high commercial value. The sour taste of plums can promote intestinal peristalsis, improve appetite, and aid digestion, especially beneficial for those with reduced stomach acid, postprandial bloating, and constipation.

[0003] Preserved fruit is a fruit product made from fresh fruit through processes such as pickling with honey or sugar and salt (or not pickling). It is mainly divided into candied fruit, icing fruit, dried fruit, preserved fruit, candied fruit, fruit cake, and others. As a common snack, preserved fruit has always been popular with consumers.

[0004] Currently, the processing technology for preserved fruit is still mainly based on traditional methods, which are outdated and may result in the presence of certain harmful components in the products. Acrylamide is a byproduct of the Maillard reaction during the processing of preserved fruit. Acrylamide has reproductive toxicity, genotoxicity, and potential carcinogenicity, and is classified as a Group 2A carcinogen (possibly carcinogenic) by the International Agency for Research on Cancer. High levels of acrylamide (0-1502 μg / kg) have been detected in dried fruits, with some products even exceeding the levels found in fried potato products (20-1068 μg / kg), which are traditionally considered high-risk for acrylamide contamination. Therefore, the issue of high concentrations of acrylamide in preserved fruit is attracting significant public attention.

[0005] Natural, green, and healthy foods are gradually becoming a popular market trend. As people's living standards improve, their demand for the nutritional and health benefits of food is also increasing. Therefore, developing modern processing technologies that effectively preserve the nutritional components of food while reducing the acrylamide content in dried fruit, and producing nutritious and healthy natural green products, has a broader market prospect. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a processing method for dried plums and the resulting product. The specific technical solution is as follows:

[0007] A method for processing dried plums includes the following steps:

[0008] S1. Cleaning and processing: Select ripe plums and remove rotten and moldy fruits;

[0009] S2. Blanching: Blanch the plums in 80℃ water, then immediately cool them with ice water.

[0010] S3. Cutting: Cutting and breaking the skin of plum fruits to improve their sugar penetration rate and drying speed;

[0011] S4, color protection and hardening: Add hardener and color protection agent, and perform color protection and hardening for 3 hours simultaneously;

[0012] S5. Pretreatment: Immerse the plums after the color-protecting and hardening treatment in the pretreatment solution for 4 hours.

[0013] S6. Sugar infiltration: The process is carried out using microwave sugar infiltration. The sugar solution concentration is 40%. The sugar solution consists of 30% sucrose, 20% xylitol, 10% glucose, 5% sodium alginate, 5% guar gum, 2% citric acid, and 3% sodium chloride. The sugar infiltration time is 12 hours.

[0014] S7. Drying: Place in a hot air drying oven and dry at a temperature of 45℃-60℃ to achieve a moisture content of around 20%. During the drying process, turn the fruit over every two hours to ensure even drying.

[0015] In some embodiments, the pretreatment solution consists of the following components: 12g glycine, 5g potassium dihydrogen phosphate, 8g dipotassium hydrogen phosphate, 1g zinc sulfate, 8g salicylic acid, 2g mannitol, with water added to 1L and the pH adjusted to 5.0±0.5.

[0016] In some implementations, the scalding and rinsing step involves scalding for 20 seconds and then cooling in ice water for 30 seconds.

[0017] In some embodiments, the curing agent is 0.4% gluconate-δ-lactone; the color-protecting agent is 0.5%.

[0018] NaCl + 0.5% Vitamin C

[0019] In some implementations, the microwave power in the microwave percolation process is 300W, and the time is 30 minutes.

[0020] In another aspect, the present invention also provides a preserved plum product prepared by the above method.

[0021] Combining all the above technical solutions, the advantages and positive effects of this invention are:

[0022] 1) The plum preserve processing method provided by the present invention can reduce the acrylamide content in plum preserves through pretreatment soaking.

[0023] 2) The plum preserve processing method provided by the present invention is simple to operate and requires no additional processing equipment. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. Unless otherwise specified, the equipment and reagents used in the embodiments and experimental examples are commercially available. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0025] Based on the information contained in this application, various changes to the precise description of the invention can be readily made by those skilled in the art without departing from the spirit and scope of the appended claims. It should be understood that the scope of the invention is not limited to the defined processes, properties, or components, as these embodiments and other descriptions are merely illustrative of specific aspects of the invention. In fact, various modifications to embodiments of the invention that will be apparent to those skilled in the art or related fields are covered within the scope of the appended claims.

[0026] To better understand the invention and not to limit its scope, all figures indicating amounts, percentages, and other numerical values ​​used in this application should, in all cases, be understood to be modified by the word "about". Therefore, unless specifically stated otherwise, the numerical parameters listed in the specification and appended claims are approximate values ​​and may vary depending on the desired properties being sought. Each numerical parameter should at least be considered as obtained based on reported significant figures and through conventional rounding methods. In this invention, "about" means within 10%, preferably within 5%, of a given value or range.

[0027] Unless otherwise specified, all embodiments of the present invention are performed under normal temperature conditions. Normal temperature refers to the natural room temperature conditions in all four seasons, without additional cooling or heating treatment. Generally, the normal temperature is controlled between 10 and 30°C, preferably between 15 and 25°C.

[0028] Unless otherwise specified, the reagents and materials used in the embodiments of the present invention can all be obtained through commercial means.

[0029] The detailed implementation process and content are as follows:

[0030] Example 1

[0031] A method for processing dried plums includes the following steps:

[0032] S1. In July, remove rotten and moldy plums from the harvested plums and wash them three times with clean water.

[0033] S2. Blanching: Blanch the washed plums in 80℃ water for 20 seconds, then immediately cool them in ice water for 30 seconds.

[0034] S3. Cutting and slitting: Take out the plums after blanching and rinsing, and cut and slit the skin of the plums to improve their sugar penetration rate and drying speed.

[0035] S4. Color protection and hardening: Pour the cut plums into the hardening agent and color protection agent and simultaneously perform color protection and hardening for 3 hours. The hardening agent is 0.4% gluconate-δ-lactone, and the color protection agent is 0.5% NaCl + 0.5% Vc. The ratio of hardening agent to color protection agent is 3:7.

[0036] S5. Pretreatment: Soak the plums treated in S4 in the pretreatment solution for 4 hours. The pretreatment solution consists of: 12g glycine, 5g potassium dihydrogen phosphate, 8g dipotassium hydrogen phosphate, 1g zinc sulfate, 8g salicylic acid, and 2g mannitol. Add water to 1L and adjust the pH to 5.0±0.5.

[0037] S6. Sugar infiltration: The process is carried out using microwave infiltration. The microwave power is 300W, the time is 30min, the sugar concentration is 40%, and the sugar solution consists of 30% sucrose, 20% xylitol, 10% glucose, 5% sodium alginate, 5% guar gum, 2% citric acid, and 3% sodium chloride. The infiltration time is 12h.

[0038] S7. Drying: Place in a hot air drying oven and dry at a temperature of 45℃-60℃ to achieve a moisture content of around 20%. During the drying process, turn the fruit over every two hours to ensure even drying.

[0039] Example 2

[0040] A method for processing dried plums includes the following steps:

[0041] S1. In July, remove rotten and moldy plums from the harvested plums and wash them three times with clean water.

[0042] S2. Blanching: Blanch the washed plums in 80℃ water for 20 seconds, then immediately cool them in ice water for 30 seconds.

[0043] S3. Cutting and slitting: Take out the plums after blanching and rinsing, and cut and slit the skin of the plums to improve their sugar penetration rate and drying speed.

[0044] S4. Color protection and hardening: Pour the cut plums into the hardening agent and color protection agent and simultaneously perform color protection and hardening for 3 hours. The hardening agent is 0.4% gluconate-δ-lactone, and the color protection agent is 0.5% NaCl + 0.5% Vc. The ratio of hardening agent to color protection agent is 3:7.

[0045] S5. Pretreatment: Soak the plums treated in S4 in the pretreatment solution for 4 hours. The pretreatment solution consists of: 12g glycine, 5g potassium dihydrogen phosphate, 8g dipotassium hydrogen phosphate, and 1g zinc sulfate. Add water to 1L and adjust the pH to 5.0±0.5.

[0046] S6. Sugar infiltration: The process is carried out using microwave infiltration. The microwave power is 300W, the time is 30min, the sugar concentration is 40%, and the sugar solution consists of 30% sucrose, 20% xylitol, 10% glucose, 5% sodium alginate, 5% guar gum, 2% citric acid, and 3% sodium chloride. The infiltration time is 12h.

[0047] S7. Drying: Place in a hot air drying oven and dry at a temperature of 45℃-60℃ to achieve a moisture content of around 20%. During the drying process, turn the fruit over every two hours to ensure even drying.

[0048] Example 3

[0049] A method for processing dried plums includes the following steps:

[0050] S1. In July, pick out the rotten and moldy plums from the harvested plums and wash them three times with clean water.

[0051] S2. Blanching: Blanch the washed plums in 80℃ water for 20 seconds, then immediately cool them in ice water for 30 seconds.

[0052] S3. Cutting and slitting: Take out the plums after blanching and rinsing, and cut and slit the skin of the plums to improve their sugar penetration rate and drying speed.

[0053] S4. Color protection and hardening: Pour the cut plums into the hardening agent and color protection agent and simultaneously perform color protection and hardening for 3 hours. The hardening agent is 0.4% gluconate-δ-lactone, and the color protection agent is 0.5% NaCl + 0.5% Vc. The ratio of hardening agent to color protection agent is 3:7.

[0054] S5. Sugar infiltration: The process is carried out using microwave infiltration. The microwave power is 300W, the time is 30min, the sugar concentration is 40%, and the sugar solution consists of 30% sucrose, 20% xylitol, 10% glucose, 5% sodium alginate, 5% guar gum, 2% citric acid, and 3% sodium chloride. The infiltration time is 12h.

[0055] S6. Drying: Place in a hot air drying oven and dry at a temperature of 45℃-60℃ to achieve a moisture content of around 20%. During the drying process, turn the fruit over every two hours to ensure even drying.

[0056] Test Example 1

[0057] Ten evaluators scored Examples 1-3 respectively. As shown in Table 1, there was no significant difference in color and texture scores between the traditional preserved fruit of Example 3 and the preserved fruit of Examples 1-2. However, the preserved fruit of Examples 1 and 2 had significantly better taste and aroma than the traditional preserved fruit. Overall, the total sensory scores of the preserved fruit of Examples 1 and 2 were significantly higher than those of the traditional preserved fruit.

[0058] Table 1

[0059] Example 1 Example 2 Example 3 Color 23.7 24.1 23.8 form 26.7 28.2 27.3 Taste and smell 25.6 43.1 36.8 Total Score 76 95.4 87.9

[0060] Test Example 2

[0061] The acrylamide content in the plum preserves prepared in Examples 1-3 was determined by liquid chromatography.

[0062] Sample pretreatment: Weigh 5g of dried plum fruit, homogenize it using a pulverizer, place it in a 50mL centrifuge tube, add 10mL of water, vortex for 5min, then add 10mL of acetonitrile, vortex for 3min, and sonicate for 15min; add 4g of anhydrous magnesium sulfate and 1g of sodium chloride to the sonicated solution, vortex for 2min; centrifuge at 10000rpm for 15min, collect the supernatant in a 15mL centrifuge tube and treat with nitrogen blowing; reconstitute with 1mL of ultrapure water, vortex for 1min; filter through a 0.22μm aqueous filter membrane for liquid chromatography detection.

[0063] Liquid chromatography method: Chromatographic separation conditions: Acquity UPLC HSS T3 column (2.1×100mm, 1.8μm, Waters, USA); mobile phase (A) 0.1% formic acid aqueous solution, (B) acetonitrile, flow rate 0.5mL / min; column temperature 40℃; injection volume 1μL.

[0064] The gradient elution program is as follows: 100% A 0.5 min, 90% A 0.5 min, 50% A 1 min, 30% A 3 min, 20% A 2 min.

[0065] The results of acrylamide content testing are shown in Table 2:

[0066] Table 2

[0067]

[0068]

[0069] High-performance liquid chromatography (HPLC) analysis showed that the acrylamide content in the plum preserves was significantly reduced after pretreatment, especially with the processing method of Example 1, which produced almost no acrylamide.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for processing preserved plums, characterized in that: The following steps are involved: S1. Cleaning and processing: Select ripe plum fruits, remove rotten and moldy fruits, and wash them with clean water for 3 times; S2, blanching: blanch the plum fruit in 80℃ water, and then immediately cool it with ice water; S3, cutting: cutting and breaking the skin of plum fruit to improve its sugar penetration rate and drying speed; S4, color protection and hardening: add hardener and color protection agent, and carry out color protection and hardening for 3 hours at the same time; S5, pretreatment: soak the plum fruits treated in S4 in the pretreatment solution for 4 hours; S6, sugar infiltration: microwave sugar infiltration is used, the sugar solution concentration is 40%, the sugar solution consists of 30% sucrose, 20% xylitol, 10% glucose, 5% sodium alginate, 5% guar gum, 2% citric acid and 3% sodium chloride, and the sugar is soaked for 12 hours; S7. Drying: Dry in a hot air drying oven at a temperature of 45°C-60°C to keep the moisture content at about 20%. During the drying period, turn the preserved fruits over every two hours to ensure uniform drying of the preserved fruits.

2. The method for processing preserved plums according to claim 1, characterized in that: The pretreatment solution consists of the following components: Glycine 12g, potassium dihydrogen phosphate 5g, dipotassium hydrogen phosphate 8g, zinc sulfate 1g, salicylic acid 8g, mannitol 2g, add water to 1L, and adjust the pH to 5.0±0.

5.

3. The method for processing preserved plums according to claim 1, characterized in that: In the blanching step, the blanching step is performed for 20 seconds and then cooled with ice water for 30 seconds.

4. The method for processing preserved plums according to claim 1, characterized in that: The hardener is: 0.4% glucono-δ-lactone.

5. The method for processing preserved plums according to claim 1, characterized in that: The color protecting agent is: 0.5% NaCl+0.5% Vc.

6. The method for processing preserved plums according to claim 1, characterized in that: The microwave power in the microwave infiltration sugar is 300W and the time is 30min.

7. The product prepared by the method according to any one of claims 1 to 6.

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