Preparation method of low-sweetness preserved polygonatum sibiricum

Abstract

The invention provides a preparation method of low-sweetness preserved polygonatum sibiricum. The preparation method comprises the following steps: preparing citric acid, preparing a sugar solution, peeling and slicing polygonatum sibiricum, freezing, pre-cooking and protecting color, boiling with sugar at high pressure, performing ultrasonic sugaring, baking and packaging. The low-sweetness preserved polygonatum kingianum is prepared by utilizing pharmacology property of polygonatum kingianum, through a high-pressure sugar boiling and ultrasonic sugaring method in combination with the advantages of low calorie and mild sweetness of trehalose, so that the taste of a polygonatum kingianum product is improved, the intake of heat by consumers is reduced, and the health level of citizens is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of edible polygonatum preserved fruits, and particularly relates to a preparation method of low-sweetness polygonatum preserved fruits. Background Art

[0002] Polygonatum sibiricum belongs to the Liliaceae family. It is a perennial herb and a special raw material with high health care functions and medicinal and edible properties. Modern pharmacology has also proven that Polygonatum sibiricum is rich in steroidal saponins, polysaccharides, flavonoids, amino acids and trace elements, and has multiple pharmacological effects such as strengthening immunity, anti-oxidation, anti-fatigue and regulating blood sugar. Polygonatum sibiricum is mild in nature and has the effects of replenishing qi and nourishing yin, strengthening the spleen and benefiting the kidneys. It can be eaten for a long time without side effects.

[0003] At present, the comprehensive utilization of Polygonatum sibiricum is mainly concentrated in Chinese patent medicines and health foods. In clinical practice, Polygonatum sibiricum is often used in combination with other drugs, such as Huangjing Pills, Huangjing Four Herbs Decoction, Huangjing Yiyin Decoction, Huangjing Xiaku Paste, Huangjing Zanyu Capsules, etc., with a wide range of indications and significant efficacy. In health foods, the application of Polygonatum sibiricum as a traditional Chinese medicine with both medicinal and edible properties in the field of health foods is mainly studied in anti-aging, cardiovascular protection and other aspects.

[0004] Polygonatum sibiricum has a compact texture, and usually the preserved fruit is cooked at normal pressure, which will cause great damage to the nutritional components of the preserved fruit and also destroy the sensory quality of the preserved fruit. In addition, the traditional normal pressure sugar infiltration process has the problems of high sugar content in the finished product and slow sugar infiltration speed. Summary of the invention

[0005] In view of the above problems, the present invention provides a method for preparing low-sweetness preserved polygonatum fruit, which utilizes the pharmacology of polygonatum, through high-pressure sugar cooking and ultrasonic sugaring methods, combined with the advantages of low calories and mild sweetness of trehalose, to prepare low-sweetness preserved polygonatum fruit, improve the taste of polygonatum products, reduce consumers' calorie intake, and improve the health level of the people, mainly through the following methods;

[0006] A method for preparing low-sweetness preserved polygonatum sibiricum, comprising the following steps:

[0007] (1) Preparation of citric acid: Weigh 4.5 g of citric acid using a balance and add the mixture to a 500 ml volumetric flask to prepare a 0.9% citric acid solution;

[0008] (2) Slice freezing: Use a reciprocating slicer to slice the peeled and cleaned Polygonatum into 5-7 mm slices, and then freeze them in a refrigerator;

[0009] (3) Pre-cooking: Place the frozen polygonatum slices in 0.9% citric acid and pre-cook on an induction cooker for 20 minutes. The mass ratio of polygonatum slices to citric acid is 1:5. This step plays a role in protecting the color.

[0010] (4) Preparation of sugar solution: trehalose and honey are mixed in a ratio of 0:1 to 6:4, pure water is added in a certain ratio, and then heated and mixed evenly to prepare a sugar solution with a sugar content of 30% to 50%;

[0011] (5) Sugar boiling: Put the color-protected polygonatum and the prepared sugar solution into a pressure cooker in a ratio of 1:4 and boil for 30 to 50 minutes;

[0012] (6) Ultrasonic sugaring: put the cooked Polygonatum sibiricum into an ultrasonic cleaner and sugar-suck for 60 to 100 minutes at a temperature of 40 to 80°C;

[0013] (7) Baking: Place the candied Polygonatum on a sieve to drain the excess sugar on the surface, and then place it in an electric heated air drying oven and dry it at 65°C;

[0014] (8) Packaging: Cool the dried Polygonatum sibiricum preserved fruit, put it into a packaging bag, seal it, and finally store it in a cool and dry place.

[0015] Furthermore, in step 4, the mass ratio of honey to white sugar is 1:1, and the sugar content of the sugar solution is 40%.

[0016] Furthermore, in step 5, the sugar boiling time is 40 minutes.

[0017] Furthermore, in step 6, the temperature of ultrasonic sugaring is 70° C., and the ultrasonic sugaring time is 80 minutes.

[0018] Beneficial technical effects of the present invention:

[0019] 1. The present invention adopts ultrasonic sugar infiltration method to replace the traditional normal pressure cooking method, which retains the original tissue morphology of polygonatum preserved fruit to the greatest extent and makes the effect of sugar infiltration better; the ultrasonic sugar infiltration method can make the pulp form micro channels, thereby accelerating the dehydration speed of polygonatum preserved fruit and assisting the diffusion of the osmotic agent, and the higher the concentration, the faster the diffusion, so ultrasonic sugar infiltration can greatly accelerate the sugar infiltration speed of the preserved fruit, improve the quality of the preserved fruit, and better preserve the nutrients therein. Therefore, the production of preserved fruit by ultrasound can keep the original structure and morphology of the preserved fruit tissue good.

[0020] 2. The present invention utilizes trehalose's unique physical and chemical characteristics and processing characteristics that are superior to other sugars. The low sweetness of trehalose is utilized to make the preserved polygonatum sibiricum have a light sweetness and are not greasy to eat. The all-round protective effect of trehalose is utilized to enable the preserved polygonatum sibiricum to maintain its freshness during processing and storage such as heating, drying, freezing, etc., and to maintain its original fresh flavor. Trehalose has strong storage resistance, which can improve the quality of the preserved polygonatum sibiricum and the added value of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a process flow chart of the present invention;

[0022] Figure 2 The effect of the sugar solution composition in the present invention on the sensory score of low-sweetness polygonatum preserved fruit;

[0023] Figure 3 The effect of high pressure sugar cooking time on the sensory quality of low sweetness polygonatum preserved fruit in the present invention;

[0024] Figure 4 The effect of ultrasonic sugaring time on the sensory quality of low-sweetness preserved polygonatum sibiricum in the present invention;

[0025] Figure 5 The effect of ultrasonic candied temperature on the sensory quality of low-sweetness preserved polygonatum fruit in the present invention;

[0026] Figure 6 The effect of the sugar solution concentration on the sensory quality of low-sweetness preserved polygonatum fruit in the present invention; Specific embodiments

[0027] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0028] Example

[0029] A method for preparing low-sweetness preserved polygonatum sibiricum, comprising the following steps:

[0030] (1) Preparation of citric acid: Weigh 4.5 g of citric acid using a balance and add the mixture to a 500 ml volumetric flask to prepare a 0.9% citric acid solution;

[0031] (2) Slice freezing: Use a reciprocating slicer to slice the peeled and cleaned Polygonatum into 5-7 mm slices, and then freeze them in a refrigerator;

[0032] (3) Pre-cooking: Place the frozen polygonatum slices in 0.9% citric acid and pre-cook on an induction cooker for 20 minutes. The mass ratio of polygonatum slices to citric acid is 1:5. This step plays a role in protecting the color.

[0033] (4) Preparation of sugar solution: trehalose and honey are mixed in a ratio of 0:1 to 6:4, pure water is added in a certain ratio, and then heated and mixed evenly to prepare a sugar solution with a sugar content of 30% to 50%;

[0034] (5) Sugar boiling: Put the color-protected polygonatum and the prepared sugar solution into a pressure cooker in a ratio of 1:4 and boil for 30 to 50 minutes;

[0035] (6) Ultrasonic sugaring: put the cooked Polygonatum sibiricum into an ultrasonic cleaner and sugar-suck for 60 to 100 minutes at a temperature of 40 to 80°C;

[0036] (7) Baking: Place the candied Polygonatum on a sieve to drain the excess sugar on the surface, and then place it in an electric heated air drying oven and dry it at 65°C;

[0037] (8) Packaging: Cool the dried Polygonatum sibiricum preserved fruit, put it into a packaging bag, seal it, and finally store it in a cool and dry place.

[0038] The present invention utilizes the medicinal value of polygonatum to improve the taste of raw polygonatum, utilizes the advantages of low calorie and mild sweetness of trehalose to prepare low-sweetness polygonatum preserved fruit, reduces the calorie intake of consumers, and produces preserved fruit through ultrasound, so that the original structure and morphology of the preserved fruit tissue can be kept good. The ultrasonic sugar infiltration method can make the pulp form micro channels, thereby accelerating the dehydration speed of the polygonatum preserved fruit and assisting the diffusion of the osmotic agent, and the higher the concentration, the faster the diffusion, so the ultrasonic sugar infiltration can greatly accelerate the sugar infiltration speed of the preserved fruit, improve the quality of the preserved fruit, better preserve the nutrients therein, and can keep the original structure and morphology of the preserved fruit tissue good.

[0039] Experimental Example 1

[0040] In this experimental example, the raw material of the fixed polygonatum preserved fruit is 50g of polygonatum slices, the mass fraction of citric acid solution is 0.9%, the oven temperature is 65℃, and the composition of the sugar solution (the mass ratio of honey to trehalose is 0:1, 2:8, 3:7, 4:6, 5:5, 6:4), high-pressure sugar cooking time (30min, 35min, 40min, 45min, 50min), ultrasonic sugaring time (60min, 70min, 80min, 90min, 100min), ultrasonic sugaring temperature (40℃, 50℃, 60℃, 70℃, 80℃) and sugar solution concentration (30%, 35%, 40%, 45%, 50%) are controlled in sequence. The TPA experimental results and sensory scores are used as evaluation indicators. One factor is optimized each time to examine the influence of each factor on the quality and moisture content indicators of low-sweetness polygonatum preserved fruit.

[0041] On the basis of single factor experiment, the composition of sugar solution, high pressure sugar cooking time, ultrasonic sugaring temperature and ultrasonic sugaring time were taken as the investigation factors, and the sensory score was taken as the evaluation index to optimize the formula process of low-sweetness Polygonatum cyrtonema preserved fruit. A 4-factor 3-level orthogonal experimental design was carried out. The orthogonal experimental factor level table is shown in Table 1.

[0042] Table 1 Orthogonal test factor level table

[0043]

[0044]

[0045] The sensory evaluation index of low-sweetness Polygonatum preserved fruit includes three parts: appearance, flavor, and taste, with a full score of 100. An evaluation team consisting of 10 students majoring in food science and engineering conducted a sensory evaluation of low-sweetness Polygonatum preserved fruit after training, and the average score of the 10 judges was calculated. The sensory evaluation standards of low-sweetness Polygonatum preserved fruit are shown in Table 3.

[0046] Table 3 Sensory evaluation of low sweetness Polygonatum sibiricum preserved fruit

[0047]

[0048] Sugar penetration rate determination:

[0049]

[0050] Moisture content determination:

[0051] The moisture content was determined using an MB25 moisture analyzer. The test steps were as follows: the heating temperature was set to 105°C; the heating time was set to automatic mode.

[0052] Texture determination and test parameters:

[0053] The texture characteristics of preserved fruits were determined using a TA-XT Plus texture analyzer (TPA form).

[0054] Specific operation: Preserved fruit → Select the force sensor of the texture analyzer with a range of 1000N → Install a 10mm cylindrical probe model → Pause for 2s → Set the displacement zero point → Surface height 10mm → Sample compression deformation level is 50% → Probe speed during testing is 10mm / min → Initial detection pressure 0.5N → Measure each sample twice in parallel and take the average value.

[0055] The indicators measured for the samples mainly include sample hardness, chewiness, elasticity, stickiness, cohesion and adhesion of preserved fruits.

[0056] Experimental Example 1.1

[0057] One of the factors affecting the sensory quality of low-sweetness Polygonatum preserved fruit is the composition of the sugar solution, that is, the ratio of honey and trehalose. This ratio will affect the quality of the Polygonatum preserved fruit. When too much trehalose is added and too little honey is added, the phenomenon of "returning to sand" is likely to occur, and the obtained preserved fruit is very hard and lacks the sweetness of honey, affecting the taste. However, when too little trehalose is added and more honey is added, the resulting product is very sweet and will produce a strong sticky feeling when eaten, affecting the senses. Therefore, trehalose and honey should be compounded and used in a moderate ratio to adjust the deficiencies of each other, so as to change the taste, appearance and flavor of low-sweetness Polygonatum preserved fruit. Figure 2 From the sensory evaluation results shown, it can be concluded that when the sugar solution composition is honey: trehalose = 5:5, the sensory score of the product is the best.

[0058] The results of the sensory quality and texture test of low-sweetness Polygonatum cyrtonema preserved fruit by using sugar solution made of different proportions of honey and trehalose are shown in Table 4.

[0059] Table 4 Effect of sugar solution composition on sensory quality of low-sweetness Polygonatum cyrtonema preserved fruit

[0060]

[0061]

[0062] It can be seen from Table 4 that when the ratio of honey to trehalose is 5:5, the low-sweetness Polygonatum sibiricum preserved fruit is brown-red, translucent, plump, without sand or soup, moderately sweet and sour, and soft and glutinous in taste. The texture results are hardness 10.85N, viscosity 4.0N, adhesion 0.049mj, cohesion 0.35Ratio, elasticity 0.76mm, and chewiness 3.20mj.

[0063] Experimental Example 1.2

[0064] High-pressure sugar cooking can make the sugar in the sugar solution penetrate into the polygonatum well, and can also increase the transparency of the polygonatum preserved fruit. However, when the sugar cooking time is too short, the polygonatum preserved fruit has a strong polygonatum flavor; when the sugar cooking time is too long, the polygonatum preserved fruit is too soft and rotten, which will destroy the polygonatum tissue structure and affect the appearance, flavor and taste of the polygonatum preserved fruit.

[0065] pass Figure 4 From the sensory evaluation results, it can be concluded that when the high-pressure sugar cooking time is 40 minutes, the sensory score of the finished product is the highest, so the high-pressure sugar cooking time range of this experimental example is 35 to 45 minutes. The texture test results are shown in Table 5.

[0066] Table 5 Effect of high pressure cooking time on the texture of low sweetness Polygonatum cyrtonema preserved fruit

[0067]

[0068] It can be seen from Table 5 that when the high-pressure sugar cooking time is 30 minutes, the hardness and chewiness of the prepared Polygonatum sibiricum preserved fruit are relatively large; when the high-pressure sugar cooking time is 50 minutes, the hardness and chewiness of the prepared Polygonatum sibiricum preserved fruit are relatively small; when the high-pressure sugar cooking time is 40 minutes, the prepared low-sweetness Polygonatum sibiricum preserved fruit is brown-red, translucent, plump, moderately soft and hard, and sweet and sour. The texture results are hardness 15.65N, viscosity 5.6N, adhesion 0.146mj, cohesion 0.34Ratio, elasticity 0.75mm, and chewiness 4.06mj.

[0069] Experimental Example 1.3

[0070] As the ultrasonic sugar soaking time increases, the amount of sugar absorbed by Polygonatum sibiricum preserved fruit also increases. Figure 4 It can be seen that the sensory scores show a trend of first increasing and then decreasing.

[0071] When the ultrasonic pickling time is 60 minutes, the pickling time is too short, the Huangjing preserved fruit cannot fully absorb the sugar in the sugar solution, the sweetness in the preserved fruit is low, and the finished product is brown-yellow; when the ultrasonic time is 80 minutes, the sensory score reaches a peak of 85.6 points, at which time the Huangjing preserved fruit has the best taste; when the ultrasonic time is 80 to 100 minutes, the sensory score gradually decreases, the preserved fruit absorbs too much sugar, resulting in a high sweetness of the finished product, which will stick to the teeth when eaten, and the texture is not full and the color is dark, which is slightly inferior to 80 minutes overall. Therefore, the ultrasonic pickling time range of this experiment is 70 to 90 minutes. The texture determination results are shown in Table 6.

[0072] Table 6 Effect of ultrasonic sugaring time on the texture of low-sweetness Polygonatum cyrtonema preserved fruit

[0073]

[0074] As shown in Table 6, when the ultrasonic sugaring time is 80 min, the product is brown-red, moderately hard and soft, chewy, and sweet and sour. The texture results are hardness 12.45N, viscosity 5.0N, adhesion 0.090mj, cohesion 0.40Ratio, elasticity 0.80N, and chewiness 3.87mj.

[0075] Experimental Example 1.4

[0076] Ultrasonic candied temperature affects the sensory quality of preserved polygonatum sibiricum. Figure 5From the sensory score results, it can be concluded that with the increase of ultrasonic candied temperature, the sensory score of Polygonatum sibiricum preserved fruit also gradually increased, but when the temperature reached above 60°C, the sensory score began to decrease. This is because when the ultrasonic candied temperature is too low, the sugar in the sugar solution cannot fully enter the Polygonatum sibiricum preserved fruit tissue, making the finished product less sweet and having a bad taste. When the ultrasonic candied temperature is too high, more sugar in the sugar solution penetrates into the Polygonatum sibiricum preserved fruit, causing the texture of Polygonatum sibiricum to be hard and taste bad. Therefore, the ultrasonic candied temperature range of this experiment was determined to be 50°C to 70°C. The texture determination results are shown in Table 7.

[0077] Table 7 Effect of ultrasonic temperature on the texture of low-sweetness Polygonatum cyrtonema preserved fruit

[0078]

[0079] As shown in Table 7, as the ultrasonic sugaring temperature increases, the hardness of the preserved fruit increases, making the preserved fruit harder to eat and having a poor taste. This is because when the ultrasonic temperature increases, the sugar penetration rate of the preserved fruit accelerates and the sugar content increases, resulting in a harder preserved fruit. Figure 5 It can be seen that when the ultrasonic temperature is 60℃, the sensory score is the highest. The product is brown-red, moderately sweet, has a sweet honey aroma, and is moderately soft and hard. The texture results are hardness 15.10N, viscosity 6.0N, adhesion 0.192mj, cohesion 0.34Ratio, elasticity 0.54mm, and chewiness 3.18mj.

[0080] Experimental Example 1.5

[0081] Sugar solution concentration will affect the sensory score of Polygonatum sibiricum preserved fruit. Figure 6 From the sensory score results, it can be concluded that with the increase of sugar solution concentration, the sensory score of preserved fruit first gradually increases and then gradually decreases. This is because when the sugar is first infiltrated, the concentration difference between the preserved fruit and the sugar solution is large and the mass concentration of the sugar solution has a greater impact on the tissue structure and taste of the preserved fruit. The lower the sugar solution concentration, the lower the sugar content of the preserved fruit, which will cause the preserved fruit tissue to be not full, and the water evaporates quickly, and it cannot show a sense of transparency; the higher the sugar solution concentration, the fuller the preserved fruit tissue, the better the transparency and taste, and the higher the sensory score. However, when the sugar solution concentration exceeds 40%, the sensory score gradually decreases. This is because when the sugar solution concentration is too high, the finished product has a strong honey flavor, the finished product tastes very sweet and greasy, and has poor palatability. Therefore, the sugar solution concentration range of this experiment is 35% to 45%. The texture determination results are shown in Table 8.

[0082] Table 8 Effect of sugar solution concentration on the texture of preserved Polygonatum sibiricum

[0083]

[0084] As shown in Table 8, as the concentration of sugar solution increases, the adhesion and chewiness of the preserved fruit also increase, making the preserved fruit harder to eat and having a poor taste. Figure 6 It can be seen that when the sugar solution concentration is 40%, the sensory score of Polygonatum sibiricum preserved fruit is the highest. The texture results obtained at this time are hardness 10.30N, stickiness 4.2N, adhesion 0.127mj, cohesion 0.36Ratio, elasticity 0.69mm, and chewiness 2.58mj. The product at this time is moderately soft and hard, moderately sweet and sour, and chewy.

[0085] The quality of low-sweetness Polygonatum cyrtonema preserved fruit was evaluated by sensory evaluation and the best formula was determined. A sugar solution composition, B high-pressure sugar cooking time, C ultrasonic sugaring temperature, and D ultrasonic sugaring time were used as influencing factors, and the sensory scoring and texture measurement results were used as indicators of the optimal sugar penetration process conditions. The orthogonal results are shown in Table 9.

[0086] Table 9 Orthogonal test results analysis table

[0087]

[0088]

[0089] It can be seen from the R value in Table 9 that the order of factors affecting the sensory quality of low-sweetness Polygonatum cyrtonema preserved fruit is: sugar solution composition > ultrasonic sugaring temperature > ultrasonic sugaring time > high-pressure sugaring time. The best processing technology combination is that the sugar solution composition (honey: trehalose) is 5:5, the high-pressure sugaring time is 40 minutes, the ultrasonic sugaring temperature is 70℃, and the ultrasonic sugaring time is 80 minutes.

[0090] On the basis of orthogonal test, in order to further verify the stability of the processing technology of low-sweetness Polygonatum preserved fruit, a repeatability test was carried out under the best combination, i.e., the sugar solution composition (honey: trehalose) was 5:5, the high-pressure sugar cooking time was 40 min, the ultrasonic sugaring temperature was 70 °C, and the ultrasonic sugaring time was 80 min

[20] . According to the experimental results, the sensory score of low-sweetness Polygonatum preserved fruit under this condition was 91.3 points, which proved that the processing technology of low-sweetness Polygonatum preserved fruit under this condition was relatively stable, as shown in Table 10.

[0091] Table 10 Process verification test of low sweetness Polygonatum sibiricum preserved fruit formula

[0092]

[0093]

[0094] The results of the determination of the sugar penetration rate and water content of low-sweetness Polygonatum sibiricum preserved fruit are shown in Table 11.

[0095] Table 11 Sugar penetration rate and moisture content of preserved Polygonatum sibiricum fruit

[0096]

[0097] The results of the determination of microbial indicators of low-sweetness Polygonatum sibiricum preserved fruit are shown in Table 12.

[0098] Table 12 Microbiological indexes of low sweetness preserved polygonatum

[0099]

[0100] This experiment used Polygonatum sibiricum as raw material, studied the processing technology of low-sweetness Polygonatum sibiricum preserved fruit and discussed its formula optimization.

[0101] Studies have shown that the order of influence on the sensory score of low-sweetness Polygonatum sibiricum preserved fruit is: sugar solution composition > ultrasonic candied temperature > ultrasonic candied time > high-pressure sugar cooking time.

[0102] The optimal processing technology for low-sweetness preserved Polygonatum sibiricum is as follows: sugar solution composition (honey: trehalose) is 5:5, high-pressure sugar cooking time is 40 minutes, ultrasonic sugaring temperature is 70℃, and ultrasonic sugaring time is 80 minutes.

[0103] During the processing, 0.9% citric acid, honey and trehalose are combined to improve the taste and color of the preserved fruit.

[0104] After verification by stability test, the sensory score of low-sweetness Polygonatum preserved fruit under the optimal process conditions was 91.3 points. The obtained low-sweetness Polygonatum preserved fruit was brown-red, translucent, full in texture, without sand or liquid, moderately sweet and sour, with sweet honey aroma and soft and glutinous taste.

[0105] 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, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing low-sweetness preserved polygonatum fruit, characterized in that: The following steps are involved: (1) Preparation of citric acid: Weigh 4.5 g of citric acid using a balance and add the mixture to a 500 ml volumetric flask to prepare a 0.9% citric acid solution; (2) Slice freezing: Use a reciprocating slicer to slice the peeled and cleaned Polygonatum into 5-7 mm slices, and then freeze them in a refrigerator; (3) Pre-cooking: Place the frozen polygonatum slices in 0.9% citric acid and pre-cook on an induction cooker for 20 minutes. The mass ratio of polygonatum slices to citric acid is 1:

5. This step plays a role in protecting the color. (4) Preparation of sugar solution: trehalose and honey are mixed in a ratio of 0:1 to 6:4, pure water is added in a certain ratio, and then heated and mixed evenly to prepare a sugar solution with a sugar content of 30% to 50%; (5) Sugar boiling: Put the color-protected polygonatum and the prepared sugar solution into a pressure cooker in a ratio of 1:4 and boil for 30 to 50 minutes; (6) Ultrasonic sugaring: put the cooked Polygonatum sibiricum into an ultrasonic cleaner and sugar-suck for 60 to 100 minutes at a temperature of 40 to 80°C; (7) Baking: Place the candied Polygonatum on a sieve to drain the excess sugar on the surface, and then place it in an electric heated air drying oven and dry it at 65°C; (8) Packaging: Cool the dried Polygonatum sibiricum preserved fruit, put it into a packaging bag, seal it, and finally store it in a cool and dry place.

2. The method for preparing low-sweetness preserved polygonatum fruit as claimed in claim 1, characterized in that: In step 4, the mass ratio of honey to white sugar is 1:1, and the sugar content of the sugar solution is 40%.

3. The method for preparing low-sweetness preserved polygonatum fruit as claimed in claim 1, characterized in that: In step 5, the sugar boiling time is 40 minutes.

4. The method for preparing low-sweetness preserved polygonatum fruit as claimed in claim 1, characterized in that: In step 6, the temperature of ultrasonic sugaring is 70° C., and the ultrasonic sugaring time is 80 minutes.

Images