Preparation method of low-sugar preserved cistanche

Abstract

The invention provides a preparation method of low-sugar preserved cistanche deserticola. The preparation method comprises the following steps: selecting cistanche deserticola, slicing, preparing citric acid, protecting color, preparing a sugar solution, performing high-pressure sugar infusion, performing ultrasonic sugar infusion, drying and packaging. The taste of the low-sugar preserved fruit is improved by utilizing the low sweetness of the trehalose, the low calorie of the honey and the pharmacological property of the cistanche and by utilizing the methods of microwave blanching, high-pressure sugar boiling and ultrasonic sugaring, and meanwhile, the sugar permeation efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of Cistanche deserticola preserved fruit, and particularly relates to a preparation method of low-sugar Cistanche deserticola preserved fruit. Background Art

[0002] Cistanche deserticola is a food with the same origin as medicine, which has multiple nutritional and functional properties; Cistanche deserticola is a precious medicinal material, which is rich in multiple biologically active substances, including polysaccharides, amino acids, fatty acids, etc.; In addition, Cistanche deserticola also contains other types of flavonoid compounds, which have certain anti-aging, anti-dementia and cell protection from free radical damage. In addition to its nutritional value, Cistanche deserticola also has certain medicinal value. It is often used to treat diseases such as kidney yang deficiency, blood deficiency, impotence and infertility, and weak muscles and bones; Cistanche deserticola tastes bitter and slightly sweet. After being made into preserved fruits, it tastes soft and glutinous, and the flavor is sweet and slightly bitter, which brings people a better eating experience.

[0003] At present, Cistanche deserticola is widely used in the food field. In 2020, the state announced a pilot project to produce and operate 9 substances including Cistanche deserticola as food and medicine. The number of health foods and functional foods using desert Cistanche deserticola as raw materials is increasing. In the announcement released in November 2023, Cistanche deserticola was once again honored and was officially included in the catalog of "Announcement on 9 New Substances Including Codonopsis Pilosula That Are Traditionally Both Food and Chinese Medicinal Materials". This move not only highlights the important position of Cistanche deserticola in the fields of traditional Chinese medicine and food, but also further confirms its dual identity as a traditional food ingredient and Chinese medicinal material.

[0004] As a food, Cistanche deserticola is highly safe and has a good taste. It can be used directly as a variety of meals, especially fresh. It has great advantages in food development and utilization. At present, the products that have been developed and circulated in the market include Cistanche wine, Cistanche health liquid, kidney-nourishing liquid, Cistanche oral liquid, Cistanche tea, Cistanche capsules, Cistanche tablets, Cistanche granules and Cistanche decoction pills and other medicines and health products.

[0005] However, in terms of food processing, products such as Cistanche drinks and preserved fruits have been less developed and utilized. The development of deep-processed products of Cistanche is particularly important. Cistanche preserved fruits not only retain the nutritional components and medicinal value of Cistanche, but also have a unique taste and excellent flavor. Compared with traditional preserved fruits, the sugar content of low-sugar preserved fruits is about 40%-55%, which is about 20% lower than traditional preserved fruits. How to improve the taste and flavor of low-sugar preserved fruits, optimize the production process, and improve product quality are the problems that need to be solved in the current processing of Cistanche preserved fruits. Summary of the invention

[0006] In view of the above problems, the present invention provides a method for preparing low-sugar Cistanche preserved fruit, which utilizes the low sweetness of trehalose, the low calories of honey and the pharmacology of Cistanche, and utilizes microwave blanching, high-pressure sugar boiling and ultrasonic sugaring methods to improve the taste of low-sugar preserved fruit and improve the sugar penetration efficiency, which is mainly achieved in the following ways:

[0007] A method for preparing low-sugar Cistanche deserticola preserved fruit comprises the following steps:

[0008] (1) Selection of Cistanche deserticola: Select Cistanche deserticola that is black in color, without spots, rot, mold, or odor;

[0009] (2) Slicing: Wash the semi-dried Cistanche deserticola with running water and cut it into 5-7 mm slices using a manual slicer;

[0010] (3) Preparation of citric acid: Weigh a certain amount of citric acid using a balance and add the amount to a 250 ml volumetric flask to prepare a citric acid solution with a concentration of 0.5% to 2%;

[0011] (4) Color protection: the sliced ​​Cistanche deserticola is placed in a 0.5% to 2% citric acid solution at a mass ratio of Cistanche deserticola to citric acid solution of 1:5, and subjected to a microwave color protection treatment for 2 to 10 minutes;

[0012] (5) Preparation of sugar solution: Mix honey and trehalose in a ratio of 3:7-6:4, add purified water to prepare a sugar solution with a concentration of 30%-70%;

[0013] (6) High-pressure sugar infiltration: Place the soaked Cistanche deserticola slices into the prepared sugar solution with a material-to-liquid ratio of 1:4, place in an electric safety pressure cooker and perform high-pressure sugar infiltration for 20-60 minutes, take out, cool to room temperature, weigh, and add pure water to the weight before high-pressure sugar infiltration;

[0014] (7) Ultrasonic sugar infiltration: Place the cooled Cistanche deserticola slices into an ultrasonic cleaner and ultrasonically infiltrate sugar at a temperature of 50-90° C. for 40-120 min. Take out, cool to room temperature, and weigh;

[0015] (8) Drying: Take out the Cistanche deserticola slices after ultrasonic sugar infiltration, drain off the excess sugar solution, spread them on a grate, and then put them into an electric hot air drying oven and dry them at a temperature of 65°C;

[0016] (9) Packaging: Cool the dried Cistanche deserticola preserves, vacuum seal, steam and sterilize, and store at room temperature after cooling.

[0017] Furthermore, the concentration of the citric acid solution in step 4 is 1%, and the time of the microwave oven color protection treatment is 4-8 minutes.

[0018] Furthermore, in step 5, the mass ratio of honey to trehalose is 4.5:5.5, and the sugar content of the sugar solution is 50%.

[0019] Furthermore, in step 6, the time of high pressure sugar infiltration is 50 minutes.

[0020] Furthermore, in step 7, the temperature of ultrasonic sugar infiltration is 70° C., and the ultrasonic sugaring time is 80 min.

[0021] Beneficial technical effects of the present invention:

[0022] 1. The present invention adopts microwave sugar infiltration and ultrasonic sugar infiltration in the processing of preserved fruits to improve the taste of low-sugar preserved fruits and improve the sugar infiltration efficiency at the same time. By utilizing the low sweetness of trehalose, the low calories of honey and the pharmacology of Cistanche deserticola, the methods of microwave blanching, high-pressure sugar boiling and ultrasonic sugar pickling are used, and the production process is optimized and the product quality is improved through single factor experiments and orthogonal experiments.

[0023] 2. The present invention utilizes the medicinal value of Cistanche deserticola, and after combining it with honey and trehalose to make preserved fruit, the bitter taste of Cistanche deserticola is removed, making it soft and sticky in taste, and the flavor is sweet with a slight bitter taste. Not only the nutritional components and medicinal value of Cistanche deserticola are retained, but also the unique taste and excellent flavor are deeply loved by consumers.

[0024] 3. The present invention utilizes trehalose's unique physical and chemical characteristics and processing characteristics superior to other sugars, and utilizes the low sweetness of trehalose to make the preserved fruit lightly sweet and non-greasy to eat; utilizes the all-round protective effect of trehalose to enable the preserved polygonatum to maintain its freshness during processing and storage such as heating, drying, freezing, etc., and maintain its original fresh flavor unchanged; and trehalose has strong storage resistance, which can improve the quality of the preserved polygonatum and the added value of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a process flow chart of the present invention;

[0026] Figure 2 The effect of microwave blanching time on the sensory quality of fresh Cistanche deserticola preserved fruit in the present invention;

[0027] Figure 3 The effect of microwave blanching time on sugar penetration rate in the present invention;

[0028] Figure 4 The effect of the sugar solution ratio in the present invention on the sensory quality of fresh Cistanche deserticola preserved fruit;

[0029] Figure 5 It is the influence of the sugar solution ratio on the sugar penetration rate in the present invention;

[0030] Figure 6The effect of high pressure sugar cooking time on the sensory quality of fresh Cistanche deserticola preserved fruit in the present invention;

[0031] Figure 7 The effect of high pressure sugar cooking time on sugar penetration rate in the present invention;

[0032] Figure 8 The effect of ultrasonic candied time on the sensory quality of fresh Cistanche deserticola preserved fruit in the present invention;

[0033] Fig. 9 The effect of ultrasonic sugaring time on sugar penetration rate in the present invention;

[0034] Fig.10 The effect of ultrasonic candied temperature on the sensory quality of fresh Cistanche deserticola preserved fruit in the present invention;

[0035] Fig.11 The effect of ultrasonic sugaring temperature on sugar penetration rate in the present invention;

[0036] Fig.12 The effect of the rehydration temperature and the rehydration time on the water absorption rate of the semi-dried Cistanche deserticola in the present invention;

[0037] Fig.13 The effect of the acid leaching concentration on the penetration rate of the sugar solution of the Cistanche deserticola preserved fruit in the present invention;

[0038] Fig.14 The effect of the acid leaching concentration on the sensory score of the low-sugar Cistanche deserticola preserved fruit quality in the present invention;

[0039] Fig.15 The effect of high pressure sugar infiltration time on the sugar infiltration rate of Cistanche deserticola preserved fruit in the present invention;

[0040] Fig.16 The effect of high pressure sugar infiltration time on the sensory score of the quality of Cistanche deserticola preserved fruit in the present invention;

[0041] Fig.17 The effect of the sugar solution concentration on the sensory score of the quality of the Cistanche deserticola preserved fruit in the present invention;

[0042] Fig.18 The effect of the sugar solution concentration on the sensory score of the low-sugar Cistanche deserticola preserved fruit quality in the present invention;

[0043] Fig.19 The effect of the ultrasonic sugar penetration time on the penetration rate of the sugar solution of the Cistanche deserticola preserved fruit in the present invention;

[0044] Fig. 20 The invention relates to the influence of the ultrasonic sugar penetration time on the sensory score of the quality of the Cistanche deserticola preserved fruit. Specific embodiments

[0045] 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.

[0046] Example

[0047] A method for preparing low-sugar Cistanche deserticola preserved fruit comprises the following steps:

[0048] (1) Selection of Cistanche deserticola: Select Cistanche deserticola that is black in color, without spots, rot, mold, or odor;

[0049] (2) Slicing: Wash the semi-dried Cistanche deserticola with running water and cut it into 5-7 mm slices using a manual slicer;

[0050] (3) Preparation of citric acid: Weigh 2.5 g of citric acid using a balance and add the citric acid to a 250 ml volumetric flask to prepare a 1% citric acid solution;

[0051] (4) Color protection: the sliced ​​Cistanche deserticola is placed in a 1% citric acid solution at a mass ratio of Cistanche deserticola to citric acid solution of 1:5, and subjected to a microwave color protection treatment for 4-8 minutes;

[0052] (5) Preparation of sugar solution: Mix honey and trehalose in a ratio of 4.5:5.5, add purified water to prepare a sugar solution with a concentration of 50%;

[0053] (6) High-pressure sugar infiltration: Place the soaked Cistanche deserticola slices into the prepared sugar solution with a material-to-liquid ratio of 1:4, place in an electric safety pressure cooker and perform high-pressure sugar infiltration for 50 min, take out, cool to room temperature, weigh, and add pure water to the weight before high-pressure sugar infiltration;

[0054] (7) Ultrasonic sugar infiltration: Place the cooled Cistanche deserticola slices in an ultrasonic cleaner and perform ultrasonic sugar infiltration at 70°C for 80 min. Take out, cool to room temperature, and weigh.

[0055] (8) Drying: Take out the Cistanche deserticola slices after ultrasonic sugar infiltration, drain off the excess sugar solution, spread them on a grate, and then put them into an electric hot air drying oven and dry them at a temperature of 65°C;

[0056] (9) Packaging: Cool the dried Cistanche deserticola preserves, vacuum seal, steam and sterilize, and store at room temperature after cooling.

[0057] Experimental Example 1

[0058] In this experimental example, the raw material of Cistanche deserticola preserved fruit was fixed as 50g of Cistanche deserticola slices, the mass fraction of citric acid solution was 1.0%, the oven temperature was 65℃, and the microwave blanching time (2min, 4min, 6min, 8min, 10min), sugar solution ratio (the mass ratio of honey to trehalose was 3:7, 4:6, 4.5:5.5, 5:5, 6:4 respectively), high-pressure sugar cooking time (20min, 30min, 40min, 50min, 60min), ultrasonic sugaring time (40min, 60min, 80min, 100min, 120min) and ultrasonic sugaring temperature (50℃, 60℃, 70℃, 80℃, 90℃) were controlled in sequence. The sensory score was used as the evaluation index, and one factor was optimized each time to examine the influence of each factor on the quality and moisture content of low-sugar Cistanche deserticola preserved fruit.

[0059] On the basis of single factor experiment, microwave blanching time, sugar solution ratio, high pressure sugar cooking time and ultrasonic candied time were taken as investigation factors, and sensory score was taken as evaluation index to optimize the formula process of low-sugar Cistanche deserticola preserved fruit. A 4-factor 3-level orthogonal experimental design was carried out. The orthogonal experimental factor level table is shown in Table 1.

[0060] Table 1 Orthogonal test factor level table

[0061]

[0062] The sensory evaluation index of low-sugar Cistanche preserved fruit includes three parts: appearance, flavor, and taste, with a full score of 100. The evaluation team is composed of 10 students majoring in food science and engineering. After training, the sensory evaluation of low-sugar Cistanche preserved fruit was conducted, and the average score of the 10 judges was calculated. The sensory evaluation standards of low-sugar Cistanche preserved fruit are shown in Table 2.

[0063] Table 2 Sensory evaluation table of low-sugar fresh Cistanche deserticola preserved fruit

[0064]

[0065]

[0066] Moisture content determination

[0067] The moisture content was determined using an oven. The steps were as follows: the oven temperature was set to 105°C, the sample was placed in a petri dish, and dried to constant weight.

[0068]

[0069] Sugar osmotic rate determination

[0070]

[0071] Experimental Example 1.1

[0072] Effect of microwave blanching time on the quality of fresh Cistanche deserticola preserved fruit:

[0073] pass Figure 2 , Figure 3 The results show that when the microwave blanching time is 2 minutes, the processing time of Cistanche is short, the bitterness is slightly stronger, the palatability is slightly worse, the tissue structure is less damaged, and the sugar penetration is not good; when the microwave blanching time is 10 minutes, the time is longer, the Cistanche is in a softer and more glutinous state, the tissue structure is more seriously damaged, the shape is incomplete, and the sugar penetration is average; when the microwave blanching time ranges from 4 to 8 minutes, the preserved fruit has a moderate hardness and softness, the shape is complete, and the sugar penetration rate is good.

[0074] Experimental Example 1.2

[0075] Effect of sugar-liquid ratio on the quality of fresh Cistanche deserticola preserved fruit:

[0076] pass Figure 4 , Figure 5 As a result, it can be concluded that when the ratio of honey: trehalose is 4:6-4.5:5.5, the sensory score of the obtained product is the best. However, when honey: trehalose is 3.5:6.5, the phenomenon of "returning to sand" is very likely to occur, so the obtained preserved fruit is very hard and has no color, the sweet aroma of honey is not obvious, affecting the taste, and the sugar penetration is poor; when sea honey: trehalose is 5:5, the surface of the obtained product is relatively soft and sticky, and sticks together, affecting the senses, and the sugar penetration is average. When honey: trehalose is 4:6-4.5:5.5, the surface of the preserved fruit is neither hard nor sticky, the sweetness is moderate, and the sugar penetration rate is high.

[0077] Experimental Example 1.3

[0078] Effect of high pressure sugar cooking time on the quality of fresh Cistanche deserticola preserved fruit:

[0079] pass Figure 6 , Figure 7 The results show that when the high-pressure sugar cooking time is 20 minutes, the time is too short, the sugar penetration is not thorough, the sweetness of the fresh Cistanche preserved fruit is low, the bitterness is heavy, and the surface color of the finished product is uneven; when the high-pressure sugar cooking time is 60 minutes, the time is too long, the shape of the fresh Cistanche preserved fruit is incomplete, the taste is soft and rotten, the taste is not good, and the sugar penetration is poor; when the high-pressure sugar cooking time ranges from 30 to 50 minutes, the preserved fruit has uniform color, complete shape, moderate taste, and good sugar penetration effect.

[0080] Experimental Example 1.4

[0081] Effect of ultrasonic candied time on sensory quality of fresh Cistanche deserticola preserved fruit:

[0082] according to Figure 8 , Fig. 9The results show that when the ultrasonic pickling time is 40 minutes, the Cistanche deserticola preserved fruit fails to fully absorb the sugar in the sugar solution, the texture is not full enough, the sweetness of the preserved fruit is low, and the taste is not good; when the ultrasonic time is increased to 120 minutes, the pickling time is too long, making it soft and rotten, and it will stick to the teeth when eaten; when the ultrasonic time range is adjusted to 60-100 minutes, the preserved fruit has moderate sweetness, uniform color and texture, and moderate hardness.

[0083] Experimental Example 1.5

[0084] Effect of ultrasonic candied temperature on the quality of fresh Cistanche deserticola preserved fruit:

[0085] pass Fig.10 , Fig.11 The results show that when the ultrasonic candied temperature is 50℃, the sugar in the sugar solution cannot fully enter the Cistanche deserticola preserved fruit tissue, making the finished product less sweet, with a more obvious bitter taste and a duller color; when the ultrasonic candied temperature is 90℃, the temperature is too high, the tissue structure is destroyed, so that there is not much sugar solution stored in the pulp, and the sugar penetration result is average. When the ultrasonic candied temperature ranges from 60 to 80℃, the preserved fruit has moderate sweetness, uniform color, moderate hardness, and good sugar penetration.

[0086] The quality of fresh Cistanche deserticola preserved fruit with low sweetness was evaluated by sensory evaluation and the best formula was determined. A microwave blanching time, B sugar solution ratio, C high pressure sugar cooking time, and D ultrasonic sugaring time were used as influencing factors, and sensory scores were used as indicators of the best sugar penetration process conditions. The orthogonal results are shown in Table 3.

[0087] Table 3 Orthogonal test results analysis table

[0088]

[0089] From the range R value in Table 3, it can be seen that the order of factors affecting the sensory quality of low-sugar fresh Cistanche deserticola preserved fruit is: microwave blanching time > ultrasonic sugaring time > sugar solution ratio > high-pressure sugar cooking time. The best processing technology combination is microwave blanching time 4 minutes, sugar solution ratio (honey: trehalose) 4.5:5.5, high-pressure sugar cooking time 50 minutes, ultrasonic sugaring time 80 minutes.

[0090] On the basis of orthogonal test, in order to further verify the stability of the processing technology of low-sugar Cistanche deserticola preserved fruit, according to the best combination A1B2C3D2, that is, microwave blanching time of 4 minutes, sugar solution ratio (honey: trehalose) of 4.5:5.5, high pressure sugar cooking time of 50 minutes, ultrasonic sugaring time of 80 minutes, three repeated experiments were carried out under this experimental condition to verify the optimal experimental results.

[0091] Table 4 Parallel experiment verification results analysis table

[0092]

[0093] The moisture content was determined by the oven method, and the preserved fruits produced under different conditions in this experiment were measured multiple times. The moisture content was always within 16% to 20%, which was in line with the national standard for low-sugar preserved fruits and moisture content specified in GB / T14884-2016.

[0094] This experimental example uses Cistanche deserticola as the main raw material, and then uses honey and trehalose for sugar infiltration process, determines its formula and then studies its production process. Firstly, five factors affecting the sugar infiltration process of Cistanche deserticola were selected, namely microwave blanching time, sugar solution composition, high-pressure sugar cooking time, ultrasonic sugaring time, and ultrasonic sugaring temperature. Through single-factor experiments, four main influencing factors and the optimal range of each factor were obtained, and then a four-factor three-level experiment was carried out. Finally, the optimal combination was obtained, and the optimal combination was verified by the test, and the optimal process and formula of low-sugar fresh Cistanche deserticola preserved fruit were obtained.

[0095] The optimal processing technology of low-sugar Cistanche deserticola preserved fruit is: microwave blanching time 4 minutes, sugar solution composition (honey: trehalose) is 4.5:5.5, high-pressure sugar cooking time 50 minutes, ultrasonic sugaring time 80 minutes. During the processing, 1.0% citric acid, honey and trehalose are combined to improve the taste and color of the preserved fruit. The obtained low-sugar fresh Cistanche deserticola preserved fruit is reddish brown, translucent, full in texture, without sand or soup, moderately sweet and sour, with sweet honey fragrance, and soft and glutinous taste.

[0096] Experimental Example 2

[0097] Rehydration condition design

[0098] The concentration of citric acid was fixed at 1.0%, the immersion temperature of Cistanche deserticola slices was controlled (20°C, 30°C, 35°C), the weight of Cistanche deserticola slices at different times (2h, 4h, 6h, 12h, 19h) was recorded, and the water absorption rate was used as the evaluation index to investigate the effects of different temperatures and times on the water absorption of Cistanche deserticola, and to determine the optimal water absorption conditions for Cistanche deserticola.

[0099]

[0100] In this experimental example, the raw material of Cistanche preserved fruit was fixed as 50.0g of Cistanche slices, and the composition of the sugar solution was the experimental result of another person in this laboratory, honey: trehalose = 4.5: 5.5 as the subsequent experimental parameters, and the citric acid immersion concentration (0%, 0.5%, 1.0%, 1.5%, 2.0%), high-pressure sugar infiltration time (20min, 30min, 40min, 50min, 60min), sugar solution concentration (30%, 40%, 50%, 60%, 70%), and ultrasonic sugar infiltration time (40min, 60min, 80min, 100min, 120min) were set in sequence to carry out the sugar infiltration experiment. The experiment used sugar solution penetration rate and sensory score as evaluation indicators, optimized one factor each time, examined the influence of each factor on the quality of Cistanche preserved fruit, and determined the value range of the four main factors affecting the high-pressure sugar infiltration process of Cistanche preserved fruit.

[0101] On the basis of the single factor experiment, a four-factor three-level orthogonal experiment was carried out with citric acid immersion concentration, sugar solution concentration, high-pressure sugar infiltration time and ultrasonic sugar infiltration time as the research objects. The sensory score of the product was used as the standard, and the range analysis method and TPA test results were used to determine the optimal formula of Cistanche deserticola preserved fruit. The orthogonal experiment factor level design is shown in Table 5.

[0102] Table 54 Factor 3 level orthogonal test design table

[0103]

[0104] According to the method in GB14884-2016 "National Food Safety Standard Preserved Fruit", a sensory scoring table for Cistanche deserticola preserved fruit was developed. The sensory evaluation panel consisted of 8 food major students (4 males and 4 females, aged 18-22 years old) who had been trained and had certain sensory evaluation experience. The total score of Cistanche deserticola preserved fruit was 100 points, of which appearance accounted for 30%, taste 30%, and flavor 40%. The scoring details are shown in Table 6.

[0105] Table 6 Sensory evaluation table of low-sugar Cistanche deserticola preserved fruit

[0106]

[0107] Determination of Moisture Content in Cistanche Deserticola Preserved Fruit

[0108] Finished product moisture: Moisture content determination: refer to GB5009.3-2016 "National Food Safety Standard Determination of Moisture in Food" direct drying method, the calculation formula is as follows:

[0109]

[0110] Experimental Example 2.1

[0111] Water absorption conditions selection:

[0112] Fresh Cistanche is brittle and easy to break. Due to its high water and sugar content, it is easily oxidized when exposed to air for a long time, causing browning, softening, and decay. Completely dried Cistanche is difficult to fully rehydrate and absorbs water slowly, which cannot meet the experimental conditions. Therefore, this experiment uses semi-dried Cistanche as raw material to appropriately reduce the moisture in Cistanche, thereby reducing its browning, softening, decay, etc. and extending the shelf life of Cistanche.

[0113] Taking the dry basis moisture content of Cistanche deserticola as the key evaluation index, we studied the effects of soaking temperature and soaking time on it. Take semi-dried Cistanche deserticola slices of similar mass and size, with no surface damage, 50g of each group of Cistanche deserticola slices, set the soaking temperature to 25℃, 30℃, and 35℃, put them into 250mL of 1% citric acid solution, and completely immerse the semi-dried Cistanche deserticola slices in water to start the rehydration experiment; take samples every 2h, and use the samples that have not absorbed water as the control sample, measure the moisture content of the samples, and analyze their rehydration characteristics.

[0114] according to Fig.12 It can be seen that as the temperature increases, the water absorption efficiency and water absorption rate continue to increase and gradually approach each other. As the water absorption time increases, the water absorption rate gradually increases and then tends to stabilize. The rehydration temperature will affect the rehydration rate of the rehydration substance, and the higher the water temperature, the faster the rehydration speed, and the greater the water absorption of the rehydration substance. As time goes by, the water absorption rate of semi-dried Cistanche increases greatly, and then it slows down, which means that the water absorption rate of Cistanche has a certain upper limit. Therefore, combined with the experimental data, the rehydration time and temperature of semi-dried Cistanche are determined to be 16h for rehydration time and 20℃ for rehydration temperature.

[0115] Experimental Example 2.2

[0116] Effects of acid immersion concentration on sensory quality of Cistanche deserticola preserved fruit:

[0117] The composition of the sugar solution was honey: white sugar = 4.5:5.5, the acid immersion time was set to 16h, the acid immersion temperature was set to 20℃, and the sugar solution concentration was adjusted to 50%. In the high-pressure infiltration stage, the infiltration time was set to 40min, the ultrasonic infiltration time was set to 80min, and the drying process was set to 150min. The effects of different citric acid concentrations on the infiltration rate and sensory score of Cistanche deserticola preserved fruit were studied. The results are shown in Fig.13 , Fig.14 .

[0118] Citric acid can not only inhibit the growth of microorganisms by lowering the pH value of food, thereby extending the shelf life of food, but also interfere with the taste buds' perception of other flavors and mask the bad taste in the mouth. In addition, citric acid has the function of changing and protecting color, and can effectively mask bitterness while increasing its sourness, providing a unique flavor for food.

[0119] Therefore, Fig.13 It can be seen that as the concentration of citric acid gradually increases, the penetration rate of sugar solution also increases; Fig.14 It can be seen that as the concentration of citric acid gradually increases, the sensory score shows a trend of first rising and then falling. When the concentration is too low, citric acid cannot well cover up the unpleasant bitterness of Cistanche itself, and the sensory score is low; when the concentration of citric acid is 1.5%, the unpleasant bitterness of Cistanche itself is covered by citric acid, and at the same time, citric acid can also increase the acidity of the product, making it moderately sweet, so the sensory score is the highest; but too high a concentration will make the preserved fruit sour, thus affecting its sensory score to be low; therefore, this test example determines a citric acid concentration of 1.0% to 2.0% as a parameter for further orthogonal experiments.

[0120] Experimental Example 2.3

[0121] Effect of high pressure sugar infiltration time on sensory quality of Cistanche deserticola preserved fruit:

[0122] The effects of different high-pressure infiltration times on the infiltration rate of sugar solution and sensory scores of Cistanche deserticola preserved fruit were studied under the conditions of a sugar solution composition of honey: white sugar = 4.5:5.5, an acid immersion time of 16 h, an acid immersion temperature of 20 ° C, an acid immersion concentration of 1.5%, a sugar solution concentration of 50%, an ultrasonic infiltration time of 80 minutes, and a drying process of 150 minutes. The results are shown in Table 1. Fig.15 , Fig.16 .

[0123] After high pressure, the preserved fruit tissue is damaged and becomes loose, so it is easy to infiltrate sugar and the taste becomes better. However, if the high pressure time is too long, the air inside the preserved fruit cannot completely escape when it expands due to heat, resulting in internal pressure and eventually causing the fruit to break. Fig.15 , Fig.16 It can be seen that with the continuous increase of high-pressure sugar infiltration time, the sugar solution penetration rate and sensory score both increase first and then decrease. When the high-pressure sugar infiltration time is short, the tissue of Cistanche deserticola preserved fruit cannot be destroyed, the sugar infiltration speed is slow, the color is dull, the sweetness is light, and the sensory score is low; when the high-pressure sugar infiltration time is 40 / min, the tissue of Cistanche deserticola is damaged to a certain extent, becoming sparse but not completely destroyed, and the preserved fruit presents a bright brown-red color, uniform color, full texture, no sand or soup flow, moderate sweetness, a light honey aroma, good chewiness, and a high sensory score; when the high-pressure sugar infiltration time is too long, the tissue of Cistanche deserticola is completely destroyed and cannot retain the infiltrated sugar, resulting in poor chewiness of the preserved fruit, sticky teeth, serious nutritional loss, and a low sensory score; therefore, this test case determines the sugar pressure time of 30min to 50min as a parameter for further orthogonal experiments.

[0124] Experimental Example 2.4

[0125] Effect of sugar solution concentration on sensory quality of Cistanche deserticola preserved fruit:

[0126] The effects of different sugar solution concentrations on the sugar solution penetration rate and sensory scores of Cistanche deserticola preserved fruit were studied under the conditions of honey: white sugar = 4.5:5.5, acid immersion time of 16h, acid immersion temperature of 20℃, acid immersion concentration of 1.5%, high pressure sugar infiltration time of 40min, ultrasonic sugar infiltration time of 80min, and drying time of 150min. The results are shown in Table 1. Fig.17 , Fig.18 .

[0127] according to Fig.17 It can be seen that with the continuous increase of sugar solution concentration, the sugar solution penetration rate of Cistanche preserved fruit continues to increase, and the sugar content of Cistanche preserved fruit gradually increases. The main reason is that the higher the sugar concentration in the solution, the greater the concentration difference formed between the cells, which produces a greater driving force for the migration of sugar molecules. When the sugar solution concentration is 55%, the sugar solution penetration rate gradually tends to be stable, because when the concentration of the sugar solution is too high, the viscosity of the sugar solution is high, the diffusion rate slows down, which is not conducive to the penetration of the sugar solution.

[0128] according to Fig.18 It can be seen that with the continuous increase of sugar solution concentration, the sensory score first increases and then decreases. When the concentration is too low, the concentration difference between the sugar solution and the cells is relatively small, so the thrust on the migration of sugar molecules is small, and the sugar solution penetrates less into the preserved fruit or cannot penetrate completely, so the preserved fruit is light or has no sweetness, and the sensory score is low; when the concentration of the sugar solution is 50%, the concentration between the cells of Cistanche preserved fruit is just enough to promote the migration of sugar molecules without destroying the cells, and the preserved fruit is bright brown-red, with uniform color, full texture, no sand or soup, moderate sourness and sweetness, a light honey aroma and good chewiness, etc., and the sensory score is the highest; when the concentration of the sugar solution is too high, the sugar content of Cistanche preserved fruit is high, the taste is sweet, the preserved fruit is soft and chewy, and the sensory score is low. Therefore, this test example determines the sugar solution concentration of 40% to 60% as a parameter for further orthogonal experiments.

[0129] Experimental Example 2.5

[0130] Effect of ultrasonic sugar infiltration time on sensory quality of Cistanche deserticola preserved fruit:

[0131] Under the conditions of honey: white sugar = 4.5:5.5, acid immersion time of 16h, acid immersion temperature of 20℃, acid immersion concentration of 1.5%, sugar concentration precisely controlled at 50%, ultrasonic infiltration stage, 80 minutes of infiltration time, and drying process lasting 150 minutes, the effects of different ultrasonic infiltration times on the infiltration rate of sugar solution and sensory scores of Cistanche deserticola preserved fruit were studied. The results are shown in Table 1. Fig.19 , Fig. 20 .

[0132] Studies have shown that ultrasonic treatment can form micro-channels in the fruit pulp, thereby accelerating dehydration and helping the diffusion of the osmotic agent. The higher the concentration, the faster the diffusion. The jet intensity and shock wave generated by ultrasonic waves during operation are sufficient to penetrate the cell membrane of plant cells in an instant, but do not cause damage. Therefore, the production of preserved fruits through ultrasonic-assisted sugar infiltration can not only maintain the original structure and appearance of fruit and vegetable tissues, but also improve the sugar infiltration efficiency of preserved fruits.

[0133] Depend on Fig.19 , Fig. 20 It can be seen that with the continuous increase of the ultrasonic sugar penetration time, the sugar solution penetration rate and sensory score both increase first and then decrease. When the ultrasonic sugar penetration time is too low, the sugar penetration speed of the preserved fruit is slow, the sugar penetration is insufficient, the color is dull, and the sweetness is light; when the ultrasonic sugar penetration time is 80 / min, the ultrasound can penetrate the cells of Cistanche but not completely destroy them, and small channels are formed inside the pulp, and the sugar solution penetration efficiency is improved. Therefore, the preserved fruit is bright brown-red, with uniform color, full texture, no sand or soup, moderate sweetness, light honey fragrance, good chewiness, and the highest sensory score; when the ultrasonic sugar penetration time is too long, the texture of Cistanche preserved fruit continues to decline, the preserved fruit becomes softer and softer, the chewiness becomes worse and sticky, the sweetness becomes heavier, and the nutritional loss is serious, and the sensory score is reduced; therefore, this test example determines the sugar pressure time of 60min to 100min as a parameter for further orthogonal experiments.

[0134] Orthogonal optimization experiment was used to determine the optimal sugar infiltration process of low-sugar Cistanche deserticola. A acid immersion concentration, B high-pressure sugar infiltration time, C sugar solution concentration and D ultrasonic sugar infiltration time were used as influencing factors. Sensory scores and TPA test results were used as indicators to determine the optimal sugar infiltration process conditions. The orthogonal results are shown in Table 7.

[0135] Table 7L9(3 4 )Orthogonal test results analysis table

[0136]

[0137]

[0138] According to the range R value in Table 7, it can be seen that the order of the main factors affecting the sugar penetration effect is: high-pressure sugar penetration time takes the first place, followed by sugar solution concentration, followed by acid leaching concentration, and finally ultrasonic sugar penetration time. Based on this analysis, the best processing technology combination was determined: 40 minutes of high-pressure sugar penetration under the condition of acid leaching concentration of 1.5%, ensuring that the sugar solution concentration is 50%, and 80 minutes of ultrasonic sugar penetration to further promote sugar penetration. Such a combination can optimize the sugar penetration effect of Cistanche deserticola preserved fruit to the greatest extent and improve the quality of the product.

[0139] After verification, it was determined that the best combination of Cistanche deserticola preserved fruit was A2B2C2D2. In order to ensure the reliability and stability of this combination, three parallel verification tests were carried out. From the sensory evaluation results and TPA (texture detection) test results, it can be seen that the average values ​​of each data are hardness 58.200N, adhesion 0.232mJ, elasticity 1.353mm, chewiness 41.613mj, and sensory score 89.3.

[0140] After three parallel validation tests, the sensory scores of the three parallel validation tests were higher than the 9 orthogonal test results recorded in Table 7. It can be seen that A2B2C2D2 is the optimal sugar infiltration process for Cistanche deserticola preserved fruit. The Cistanche deserticola preserved fruit produced under this process is bright brown-red, glossy, transparent to light, without crystallization and sand, moderately sweet and sour, with honey fragrance, no adverse drug bitterness, light Chinese medicine flavor, moderate hardness, support but not sticky.

[0141] The present invention selects the rehydration conditions (rehydration temperature and time) of semi-dried Cistanche deserticola for preliminary research, and combines the actual temperature and time to conclude that the rehydration conditions of semi-dried Cistanche deserticola are 20°C rehydration for 16h. The factors for selecting the sugar infiltration process of Cistanche deserticola include acid leaching concentration, sugar solution concentration, high-pressure sugar infiltration time and ultrasonic sugar infiltration time. The optimal range of each of the four main influencing factors can be determined by single factor experiment. An orthogonal experimental design with four factors and three levels is designed to determine the optimal combination scheme, thereby improving the efficiency and output quality of the sugar infiltration process of Cistanche deserticola. The results show that the optimal sugar conditions for Cistanche deserticola preserved fruit are acid leaching concentration of 1.5%, high-pressure sugar infiltration time of 40min, sugar solution concentration of 50%, ultrasonic sugar infiltration temperature of 70°C, and ultrasonic sugar infiltration time of 80min.

[0142] 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-sugar Cistanche deserticola preserved fruit, characterized in that: The following steps are involved: (1) Selection of Cistanche deserticola: Select Cistanche deserticola that is black in color, without spots, rot, mold, or odor; (2) Slicing: Wash the semi-dried Cistanche deserticola with running water and cut it into 5-7 mm slices using a manual slicer; (3) Preparation of citric acid: Weigh a certain amount of citric acid using a balance and add the amount to a 250 ml volumetric flask to prepare a citric acid solution with a concentration of 0.5% to 2%; (4) Color protection: the sliced ​​Cistanche deserticola is placed in a 0.5% to 2% citric acid solution at a mass ratio of Cistanche deserticola to citric acid solution of 1:5, and subjected to a microwave color protection treatment for 2 to 10 minutes; (5) Preparation of sugar solution: Mix honey and trehalose in a ratio of 3:7-6:4, add purified water to prepare a sugar solution with a concentration of 30%-70%; (6) High-pressure sugar infiltration: Place the soaked Cistanche deserticola slices into the prepared sugar solution with a solid-liquid ratio of 1:4, place in an electric safety pressure cooker and perform high-pressure sugar infiltration for 20-60 minutes, take out, cool to room temperature, weigh, and add pure water to the weight before high-pressure sugar infiltration; (7) Ultrasonic sugar infiltration: Place the cooled Cistanche deserticola slices into an ultrasonic cleaner and ultrasonically infiltrate sugar at a temperature of 50-90° C. for 40-120 min. Take out, cool to room temperature, and weigh; (8) Drying: Take out the Cistanche deserticola slices after ultrasonic sugar infiltration, drain off the excess sugar solution, spread them on a grate, and then put them into an electric hot air drying oven and dry them at a temperature of 65°C; (9) Packaging: Cool the dried Cistanche deserticola preserves, vacuum seal, steam and sterilize, and store at room temperature after cooling.

2. The method for preparing the low-sugar Cistanche deserticola preserved fruit as claimed in claim 1, characterized in that: The concentration of the citric acid solution in step 4 is 1%, and the time of the microwave oven color protection treatment is 4-8 minutes.

3. The method for preparing the low-sugar Cistanche deserticola preserved fruit as claimed in claim 1, characterized in that: In step 5, the mass ratio of honey to trehalose is 4.5:5.5, and the sugar content of the sugar solution is 50%.

4. The method for preparing the low-sugar Cistanche deserticola preserved fruit as claimed in claim 1, characterized in that: In step 6, the high pressure sugar infiltration time is 50 minutes.

5. The method for preparing the low-sugar Cistanche deserticola preserved fruit as claimed in claim 1, characterized in that: In step 7, the temperature of ultrasonic sugar infiltration is 70° C., and the ultrasonic sugaring time is 80 minutes.

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