阅读说明：本技术 一种松软饱满黄桃干的加工方法 (Processing method of soft and full dried yellow peaches ) 是由 李安平 唐玉妹 李冬阳 谭翠萍 邓石茂 邓运成 于 2021-08-26 设计创作，主要内容包括：一种松软饱满黄桃干的加工方法,包括以下步骤：(1)原料预处理；(2)热烫灭酶；(3)冻融；(4)超高压渗糖；(5)低温干燥；(6)超声波辅助加碱注胶；(7)微波干燥；(8)二次冻融；(9)低温干燥；(10)真空包装。本发明加工过程中不添加有毒有害化学试剂,对环境友好,产品具有营养价值高,外观饱满,软硬适中,色泽金黄,酸甜适口等优点。(A processing method of soft and full dried yellow peaches comprises the following steps: (1) pretreating raw materials; (2) blanching to inactivate enzyme; (3) freezing and thawing; (4) carrying out ultrahigh pressure sugar permeation; (5) drying at low temperature; (6) adding alkali and injecting glue under the assistance of ultrasonic waves; (7) drying by microwave; (8) secondary freeze thawing; (9) drying at low temperature; (10) and (7) vacuum packaging. The processing method does not add toxic and harmful chemical reagents in the processing process, is environment-friendly, and the product has the advantages of high nutritional value, full appearance, moderate hardness, golden color, proper sour and sweet taste and the like.)

1. The processing method of the soft and full dried yellow peaches is characterized by comprising the following steps:

(1) pretreatment of raw materials: selecting fresh yellow peach raw materials, cleaning, peeling, removing kernels, and slicing to obtain fresh yellow peach slices;

(2) blanching to inactivate enzyme: adding the fresh yellow peach slices obtained in the step (1) into a citric acid solution for blanching, enzyme deactivation and color protection, then taking out the yellow peach slices, placing the yellow peach slices in clear water for cooling, taking out the yellow peach slices, and draining;

(3) freezing and thawing: carrying out freeze-thawing treatment on the drained yellow peach slices in the step (2);

(4) sugar permeation under ultrahigh pressure: immersing the yellow peach slices subjected to freeze thawing treatment in the step (3) in a mixed solution containing high fructose corn syrup, and then performing high-pressure sugar permeation treatment to obtain sugar-permeated yellow peach slices;

(5) and (3) low-temperature drying: carrying out low-temperature vacuum drying on the sugar-permeated yellow peach slices obtained in the step (4);

(6) ultrasonic-assisted alkali adding and glue injecting: immersing the yellow peach slices dried in the step (5) in a mixed solution of pectin and alkali liquor, and then adding alkali and injecting glue with the assistance of ultrasonic waves to obtain glue-injected yellow peach slices;

(7) microwave drying: microwave drying the glue-injected yellow peach slices obtained in the step (6);

(8) secondary freeze thawing: performing second freeze thawing on the yellow peach slices subjected to microwave drying in the step (7);

(9) and (3) low-temperature drying: carrying out low-temperature vacuum drying on the yellow peach slices subjected to freeze thawing in the step (8) for the second time again to obtain dried yellow peach slices;

(10) and (3) vacuum packaging: and (4) carrying out vacuum sealing packaging on the dried yellow peach slices obtained in the step (9) to obtain a soft and full yellow peach dry product.

2. The processing method of the soft and full dried yellow peaches as claimed in claim 1, wherein in the step (1), the thickness of the fresh yellow peach slices is 15-20 mm.

3. The processing method of the soft and full dried yellow peaches according to claim 1 or 2, wherein in the step (2), the concentration of the citric acid solution is 0.1-0.2 wt%; the temperature for blanching, enzyme killing and color protection is 85-95 ℃; the time for blanching, enzyme deactivation and color protection is 2-3 min.

4. The processing method of the soft and full yellow dried peaches as claimed in any one of claims 1 to 3, wherein in the step (4), the mixed solution containing the high fructose corn syrup comprises the following components in percentage by mass: 20-30% of high fructose corn syrup, 0.2-0.4% of citric acid, 0.2-0.3% of high methoxyl pectin and the balance of purified water, wherein the sum of the content percentages of the components is 100%.

5. The method for processing the soft and full dried yellow peaches according to any one of claims 1 to 4, wherein the ultra-high pressure sugar-permeating treatment is carried out by taking air as a medium, the pressure is 100 to 150MPa, and the treatment time is 30 to 40 min.

6. The method for processing the soft and full yellow dried peach slices as claimed in any one of claims 1 to 5, wherein in the step (5), the temperature of the low-temperature vacuum drying is 50 to 55 ℃; the vacuum degree of the low-temperature vacuum drying is-0.092 to-0.095 Mpa; and the low-temperature vacuum drying time is 3-4 h.

7. The processing method of the soft and full yellow dried peaches as claimed in any one of claims 1 to 6, wherein in the step (6), the pectin and alkali solution mixed solution comprises the following components in percentage by mass:high fructose corn syrup 30-40%, high methoxyl pectin 0.2-0.4%, NaHCO₃0.1-0.5 percent of the total weight of the components, and the balance of purified water, wherein the sum of the content percentages of the components is 100 percent; the frequency of the ultrasonic assistance is 15-20 kHz; the power of the ultrasonic wave assistance is 100-150W; the ultrasonic wave assisting time is 30-40 min.

8. The method for processing the soft and full yellow peach slices as claimed in any one of claims 1 to 7, wherein in the step (7), the microwave drying power is 500-600W; the microwave drying time is 10-15 min.

9. The method for processing the soft and full yellow peach dried slices according to any one of claims 1 to 8, wherein in the step (8), the temperature of the second freeze-thaw is-35 to-45 ℃; and the time of the second freeze thawing is 60-90 min.

10. The method for processing the soft and full yellow dried peaches according to any one of claims 1 to 9, wherein the low temperature vacuum drying condition in the step (9) is the same as the low temperature vacuum drying condition in the step (5).

Technical Field

The invention relates to a processing method of dried yellow peaches, in particular to a processing method of soft and full dried yellow peaches.

Background

The yellow peach is rich in nutrition, has multiple tastes and beautiful juice, is fragrant and pleasant, and is deeply loved by consumers. However, with the enlargement of the planting area, the yield is increased day by day, and the yellow peaches are produced in the summer, the fresh sales are limited, and the processing and digestion are urgently needed. In addition, there are many mechanical injuries and irregular defective fruits that require processing. Therefore, part of fresh yellow peach fruits are processed into products such as juice beverages, cans and dried yellow peaches. The dried yellow peaches are one of common processed products due to simple and convenient processing and low investment.

Dried yellow peaches are processed by a plurality of methods, but many products have the problems of insufficient fullness, too high hardness, too high sugar degree, dark color and the like. For example, most of the yellow peach trunks sold on the market at present have the problems of high hardness, insufficient dryness and the like, and some people with poor teeth mouths are difficult to gnaw, so that the sale of the yellow peach trunks is seriously influenced. The hardness of the yellow peaches can be reduced by increasing the moisture content of the yellow peaches, but the yellow peaches are easy to cause a great amount of growth of microorganisms to cause the deterioration of products. The processed dried yellow peaches are convenient for long-term storage if the moisture content is low, but the hardness is high and the yellow peaches are difficult to chew; however, if the water content is high, the yellow peaches are dry and soft, and are difficult to store for a long time. Therefore, the technical problem that the processing of the dried yellow peaches needs to be solved is to reduce the dry hardness of the yellow peaches and prolong the storage period at the same time.

CN106473036A discloses a method for preparing dried peach by freezing fresh peach below freezing point and then removing water from the fruit by converting ice into steam under higher vacuum. The product obtained by the freeze drying method has good taste, but the processing cost is too high.

CN104719788B discloses a method for drying yellow peaches by pulse airflow puffing, which utilizes a cyclic pulse airflow puffing process to rapidly dehydrate and puff the yellow peaches, and the crispness of the product can be improved by the process. The resulting products are still not ideal for softness and fullness.

Disclosure of Invention

The invention aims to solve the technical problem of overcoming the defects in the prior art and provides a processing method of dried yellow peaches, which improves the softness and fullness of the dried yellow peaches and has better edible mouthfeel of products.

The technical scheme adopted for solving the technical problems is that the processing method of the soft and full dried yellow peaches comprises the following steps:

(1) pretreatment of raw materials: selecting fresh yellow peach raw materials, cleaning, peeling, removing kernels, and slicing to obtain fresh yellow peach slices;

(2) blanching to inactivate enzyme: adding the fresh yellow peach slices obtained in the step (1) into a citric acid solution for blanching, enzyme deactivation and color protection, taking out the yellow peach slices, placing the yellow peach slices in clear water for cooling, taking out the yellow peach slices, and draining;

(3) freezing and thawing: carrying out freeze-thawing treatment on the drained yellow peach slices in the step (2);

(4) sugar permeation under ultrahigh pressure: immersing the yellow peach slices subjected to freeze thawing treatment in the step (3) in a mixed solution containing high fructose corn syrup, and then performing high-pressure sugar permeation treatment to obtain sugar-permeated yellow peach slices;

(5) and (3) low-temperature drying: carrying out low-temperature vacuum drying on the sugar-permeated yellow peach slices obtained in the step (4);

(6) ultrasonic-assisted alkali adding and glue injecting: immersing the yellow peach slices dried in the step (5) in vacuum at low temperature into a mixed solution of pectin and alkali liquor, and then adding alkali and injecting glue with the assistance of ultrasonic waves to obtain glue-injected yellow peach slices;

(7) microwave drying: microwave drying the glue-injected yellow peach slices obtained in the step (6);

(8) secondary freeze thawing: performing second freeze thawing on the yellow peach slices subjected to microwave drying in the step (7);

(9) and (3) low-temperature drying: carrying out low-temperature vacuum drying on the yellow peach slices subjected to freeze thawing in the step (8) for the second time again to obtain dried yellow peach slices;

(10) and (3) vacuum packaging: and (4) carrying out vacuum sealing packaging on the dried yellow peach slices obtained in the step (9) to obtain a soft and full yellow peach dry product.

Further, in the step (1), the thickness of the yellow peach slices is 15-20 mm.

Further, in the step (2), the concentration of the citric acid solution is 0.1-0.2 wt%; the temperature for blanching, enzyme killing and color protection is 85-95 ℃; the time for blanching, enzyme deactivation and color protection is 2-3 min.

Further, in the step (4), the mixed solution containing high fructose corn syrup comprises the following components in percentage by mass: 20-30% of high fructose corn syrup, 0.2-0.4% of citric acid, 0.2-0.3% of high methoxyl pectin and the balance of purified water.

Further, in the step (4), the ultrahigh pressure sugar permeability treatment is carried out by taking air as a medium, the pressure is 100-150 MPa, and the treatment time is 30-40 min.

Further, in the step (5), the low-temperature vacuum drying temperature is 50-55 ℃; the vacuum degree of the low-temperature vacuum drying is-0.092 to-0.095 Mpa; and the low-temperature vacuum drying time is 3-4 h.

Further, in the step (5), the yellow peach slices are turned over for 1-2 times during low-temperature vacuum drying.

Further, in the step (6), the pectin and alkali liquor mixed solution comprises the following components in percentage by mass: high fructose corn syrup 30-40%, high methoxyl pectin 0.2-0.4%, NaHCO₃0.1-0.5 percent of the total weight of the components, and the balance of purified water, wherein the sum of the content percentages of the components is 100 percent.

Further, in the step (6), the frequency of the ultrasonic wave assistance is 15-20 kHz; the power of the ultrasonic wave assistance is 100-150W; the ultrasonic wave assisting time is 30-40 min.

Further, in the step (7), the power of the microwave drying is 500-600W; the microwave drying time is 10-15 min.

Further, in the step (8), the temperature of the second freezing and thawing is-35 to-45 ℃; and the time of the second freeze thawing is 60-90 min.

Further, in the step (9), the low-temperature vacuum drying conditions are the same as those of the step (5).

Compared with the prior art, the invention has the following beneficial effects:

(1) according to the invention, ultrahigh pressure sugar permeation treatment is adopted, macromolecular substances such as fructose and glucose syrup and pectin which are difficult to enter the yellow peach slices are rapidly permeated into tissues by virtue of ultrahigh pressure action, and the traditional slow sugar soaking process of preserved fruits is replaced, so that the fullness and the softness of the preserved fruits of the yellow peaches are improved;

(2) according to the invention, through freeze thawing treatment for 2 times and low-temperature vacuum drying treatment at intervals, on one hand, the low-temperature freeze thawing destroys the cell walls of the yellow peach fruits, so that high fructose corn syrup and pectin substances can more easily enter cells, the space for losing water is filled, and the plumpness of the yellow peach is improved; on the other hand, the alternate low-temperature vacuum drying can avoid high hardness caused by rapid migration of the content of the yellow peaches to the surface, thereby obtaining soft and delicious dried yellow peaches;

(3) the invention permeates citric acid into yellow peach slices in two working procedures of blanching enzyme inactivation in the early stage and high-pressure sugar permeation, and then NaHCO is added in the ultrasonic-assisted alkali-adding and glue-injecting working procedure₃The yellow peach pieces and the yellow peach pieces react to generate gas, and a plurality of fine pores are formed in the yellow peach pieces under the action of the gas, so that the yellow peach pieces are puffed like the yellow peach pieces, and the yellow peach pieces are soft;

(4) by means of the early-stage short-time blanching enzyme deactivation and color protection effects and the later-stage low-temperature vacuum drying, the yellow peach slices are enabled to have no major color change all the time, and the golden yellow color of the original yellow peach pulp is maintained;

(5) the invention does not use any toxic and harmful chemical reagent and has no pollution to the environment.

In summary, the invention maintains the golden color of the original yellow peach meat, reduces the hardness of yellow peach contents which are transferred to the appearance along with the drying process and increases the hardness of yellow peach contents, and permeates a large amount of sugar and pectin substances into the yellow peach stems by the synergistic effect of a plurality of processes of blanching enzyme inactivation, ultrahigh pressure sugar permeation, 2 times of freeze thawing treatment combined with interval low temperature vacuum drying treatment, ultrasonic wave assisted alkali adding and glue injecting and the like, so that the permeated citric acid and NaHCO are enabled to permeate₃The gas generated by the reaction forms pores, and a soft and full yellow peach dry product is obtained.

Detailed Description

The present invention will be described in further detail with reference to specific examples. These examples should not be construed as limiting the scope of the claims of the present application.

The starting materials used in the examples of the present invention were obtained by conventional commercial methods unless otherwise specified.

Example 1

The embodiment comprises the following steps:

(1) pretreatment of raw materials: selecting fresh yellow peach raw materials which are free of plant diseases and insect pests and are eighty percent ripe, cleaning, peeling, removing kernels, and cutting into fresh yellow peach slices with the thickness of 20mm and uniform thickness;

(2) blanching to inactivate enzyme: putting the fresh yellow peach slices obtained in the step (1) into a citric acid solution with the temperature of 90 ℃ and the concentration of 0.2%, blanching, deactivating enzyme and protecting color for 2min, taking out the yellow peach slices, putting the yellow peach slices into flowing clear water for cooling, quickly taking out the yellow peach slices, and draining for later use;

(3) freezing and thawing: putting the yellow peach slices obtained in the step (2) into a refrigeration house with the temperature of-30 ℃ for freeze thawing treatment for 2 h;

(4) sugar permeation under ultrahigh pressure: immersing the yellow peach slices obtained in the step (3) in a mixed solution containing high fructose corn syrup, and then putting the yellow peach slices into an ultrahigh pressure container to perform sugar permeation treatment for 30min by using air as a pressure medium and under the pressure of 120 MPa; the mass percent of each component of the mixed solution containing the high fructose corn syrup is as follows: 25% of high fructose corn syrup, 0.3% of citric acid, 0.2% of high methoxyl pectin and the balance of purified water, wherein the sum of the content percentages of the components is 100%;

(5) and (3) low-temperature drying: flatly paving the yellow peach slices obtained in the step (4) on a tray, then placing the tray in an oven at the temperature of 55 ℃ for low-temperature vacuum drying for 4 hours at the vacuum degree of-0.093 MPa, and turning over the yellow peach slices at intervals for 1 time;

(6) ultrasonic-assisted alkali adding and glue injecting: immersing the yellow peach slices obtained in the step (5) in a prepared pectin and alkali liquor mixed solution, and then adding alkali and injecting glue for 35min by means of ultrasonic assistance with the frequency of 15kHz and the power of 100W; the pectin and alkali liquor mixed solution comprises the following components in percentage by mass: high fructose syrup 35%, high methoxyl pectin 0.3%, NaHCO₃0.2 percent, and the balance of purified water, wherein the sum of the content percentages of the components is 100 percent;

(7) microwave drying: flatly paving the yellow peach slices obtained in the step (6) on a tray, and then placing the tray in a microwave oven with the power of 600W for drying for 10 min;

(8) secondary freeze thawing: putting the yellow peach slices obtained in the step (7) into a refrigeration house with the temperature of minus 40 ℃ for freeze thawing for 80 min;

(9) and (3) low-temperature drying: flatly paving the yellow peach slices obtained in the step (8) on a tray, then placing the tray in an oven at 55 ℃ for vacuum drying at low temperature of-0.093 MPa for 4h, and turning over the yellow peach slices at intervals for 1 time;

(10) and (3) vacuum packaging: carrying out vacuum sealing packaging on the dried yellow peach slices obtained in the step (9) to obtain soft and full yellow peach dry products;

example 2

Example 2 differs from example 1 only in that the time of the ultra-high pressure sugar-osmosing treatment in step (4) was increased from 30min to 40min, and all the experimental steps were carried out as described in example 1 above to obtain dried yellow peaches, which were then measured for sugar content, volume crinkle ratio and hardness, and the results are shown in table 1.

Comparative example 1

Comparative example 1 is different from example 1 only in that the yellow peach slices described in step (4) are not subjected to ultra-high pressure sugar permeation treatment, i.e., the ultra-high pressure sugar permeation treatment time is 0, and other preparation steps and conditions are the same as those of example 1, so that dried yellow peaches are obtained, and then the sugar content, the volume wrinkle ratio and the hardness of the obtained dried yellow peaches are measured, and the results are shown in table 1.

TABLE 1 Effect of ultra-high pressure sugar penetration on the volume wrinkle shrinkage ratio and hardness of yellow peach

Note: the upper right-hand corner of the data in the table indicates that there is a very significant difference between examples 1 and 2 compared to comparative example 1, P < 0.01.

As can be seen from Table 1, the sugar content of the dried yellow peaches obtained in example 1 and example 2 is very different (P is less than 0.01) compared with that of comparative example 1, the sugar content of the dried yellow peaches is remarkably improved by adopting ultrahigh pressure sugar permeation treatment, the total bacterial count of 3 dried yellow peaches in a sample after being stored for 120 days at normal temperature meets the national quality standard requirement, but the total bacterial count of the 3 dried yellow peaches in the sample does not have significant difference (P is more than 0.05).

The volume shrinkage ratio is the ratio of the volume of the product obtained by processing the yellow peaches to the volume before processing, and the more the shrinkage ratio is close to 1, the fuller the product is, which indicates that the volume appearance is changed less. As can be seen from Table 1, the volume shrinkage ratio of the yellow peaches in the examples 1 and 2 is significantly higher than that in the comparative example 1(P < 0.01), which shows that the yellow peaches treated by the ultra-high pressure sugar permeation have small volume shrinkage change and show full volume morphology.

The hardness of 3 dry yellow peach samples was measured using a TA-XT Plus type texture analyzer (TPA mode), and the results showed that the hardness of examples 1 and 2 was significantly lower than that of comparative example 1(P < 0.01), indicating that the hardness of the dry yellow peaches was reduced after the ultra-high pressure sugar-osmosizing treatment.

Comparative example 2

Comparative example 2 is different from example 1 only in that the secondary freeze-thaw process described in step (8) is not performed and other preparation steps and conditions are the same as those of example 1, thereby obtaining dried yellow peaches, and then the sugar content, volume shrinkage ratio and hardness of the obtained dried yellow peaches are measured, and the results are shown in table 2.

Comparative example 3

Comparative example 3 is different from example 1 only in that the freezing and thawing in step (3) and the secondary freezing and thawing in step (8) were not performed, and other preparation steps and conditions were the same as those of example 1, thereby obtaining dried yellow peaches, and then the sugar content, volume shrinkage ratio and hardness of the obtained dried yellow peaches were measured, and the results are shown in table 2.

TABLE 2 Effect of freeze-thaw times on dry volume wrinkle reduction ratio and hardness of yellow peach

Note: the different letters in the upper right corner of the data in the table indicate that there is significant difference in the comparison between the samples, P < 0.05.

As can be seen from Table 2, the sugar content and the volume shrinkage ratio of the dried yellow peaches obtained by twice freezing and thawing in example 1 are significantly higher than those of comparative example 2(P < 0.05) which is subjected to once freezing and thawing, while comparative example 2 is significantly higher than that of comparative example 3(P < 0.05) which is not subjected to freeze thawing treatment, and the total bacterial count of 3 dried yellow peaches after 120 days of normal-temperature storage meets the national quality standard requirements, but has no significant difference (P > 0.05). Example 1 the hardness of the dried yellow peaches obtained after two passes of freezing and thawing is significantly lower than that of comparative example 2(P < 0.05) which is subjected to freezing and thawing once, and comparative example 2 is also significantly lower than that of comparative example 3(P < 0.05) which is not subjected to freezing and thawing treatment. The freeze-thaw treatment can improve the sugar content and the volume wrinkle ratio in the dried yellow peaches, reduce the hardness and make the dried yellow peaches sweeter, fuller, softer and more delicious.

Example 3

Example 3 differs from example 1 only in that the pectin in step (6) is mixed with NaHCO in the lye mixture solution component₃Adjusted from 0.2% to 0.4%, and the other preparation steps and conditions were the same as in example 1, thereby obtaining dried yellow peaches, which were then measured for sugar content, volume shrinkage ratio and hardness, and the results are shown in Table 3.

Comparative example 4

Comparative example 3 differs from example 1 only in that no NaHCO was added to the pectin and lye mixed solution component in step (6)₃Other preparation steps and conditions were the same as in example 1, thereby obtaining dried yellow peaches, and then the sugar content, volume shrinkage ratio and hardness of the obtained dried yellow peaches were measured, and the results are shown in Table 3.

TABLE 3 NaHCO₃Influence of addition amount on wrinkle shrinkage ratio and hardness of dry yellow peach

Note: the upper right-hand corner of the data in the table indicates that there is a very significant difference between examples 1 and 3 compared to comparative example 4, P < 0.01.

As can be seen from Table 3, in comparison with comparative example 4, examples 1 and 3 were prepared by adding 0.2% and 0.4% NaHCO, respectively, in the ultrasonic-assisted alkali-adding and glue-injecting step₃The sugar content and the volume wrinkle ratio of the dried yellow peaches are remarkably improved, the hardness of the dried yellow peaches is remarkably reduced,after 120 days of normal temperature storage, the total bacterial count of 3 kinds of dry yellow peach samples all meet the requirements of national quality standard, but no significant difference exists between the samples (P is more than 0.05). Adding citric acid into yellow peach slices by blanching to inactivate enzyme and pressing sugar at ultrahigh pressure, adding NaHCO in the ultrasonic-assisted alkali-adding and glue-injecting process₃The yellow peach pieces and the pulp are reacted to generate gas, a plurality of fine pores are formed in the yellow peach pieces, and the yellow peach pieces have the function similar to puffing, so that the yellow peach pieces absorb more high fructose corn syrup and pectin, and become fuller and softer.