Preparation method of Longtan pearl plum low-sugar jam

Abstract

The invention belongs to the technical field of jam processing, and provides a preparation method of Longtan pearl plum low-sugar jam, which comprises the following steps: ripening / sorting fruits; cleaning and denucleating; blanching; performing color protection and pulping; concentrating and blending; carrying out hot filling and sealing; performing sterilization; cooling to obtain a finished product. During concentration and blending, a coagulant aid is added firstly, then citric acid is added, a pectin solution is added finally, the coagulant aid is composed of CaCl2 and chromium-enriched yeast, and the pectin solution is formed by compounding low-methoxyl pectin, starch sodium octenylsuccinate, microcrystalline cellulose and sodium alginate. According to the invention, through improvement of a preparation process technology, including pretreatment blanching, addition of a browning inhibitor to inhibit browning, selection of a proper composite thickening agent, and bridging formed by polyvalent metal ions and carboxyl groups in pectin molecular chains, a relatively good gelling effect is achieved, and through combined action of multiple aspects, the problem of bleeding of the low-sugar pearl plum jam is solved; meanwhile, the low-sugar pearl plum jam product with excellent appearance, taste and nutrition is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of jam processing, and in particular to a method for preparing Longtan pearl plum low-sugar jam. Background Art

[0002] Jam is a popular food. It can be eaten directly or used as a raw material for cold drinks, baked goods, western food, etc. It has long been a "regular guest" on people's tables. The market demand for healthy jam products is large. Especially in developed regions such as Europe and America, jam is one of the most popular and beloved foods by consumers. The eating habit of bread with jam has become a part of people's dietary culture in Europe and America, and it is also the most common and popular lifestyle. In addition, the fast pace of modern cities makes many office workers unable to spend too much time and energy to prepare and enjoy homemade breakfast, so this simple and quick food combination has become their first choice, and it also meets their nutritional needs.

[0003] However, in order to obtain good gel properties and preservation, traditional jam products usually contain 55% to 75% sugar, which makes them too sweet. In addition, high-sugar foods are not good for human health, which leads to a decline in the consumption of traditional jams. As people's awareness of nutrition and health increases, they are fully aware of the series of diseases that may be caused by excessive sugar intake, and the demand for low-sugar products is increasing day by day. The advantage of low-sugar jam is that its sugar content is less than 45%, with a prominent and rich original fruit flavor and a refreshing taste. This low-sugar and low-calorie food caters to the needs of consumers and has become a nutritious, all-ages accompaniment and convenience food, meeting the development trend of low calorie and low sweetness in the food industry, and has huge market potential.

[0004] In the development of low-sugar jam, in order to further reduce the amount of sucrose and the calories of the product, people generally add sweeteners such as xylitol to partially replace or completely replace the use of sucrose. Due to the low sugar content, low-sugar jam is difficult to form a stable gel like high-sugar jam. The texture of the jam is poor and it is easy to precipitate water. One of the reasons for the water precipitation of low-sugar jam is that the local gel formation speed is too fast, the bridging attraction is too large, it is not easy to form a uniform gel network in the whole jam, the water holding capacity of the jam decreases, and water is precipitated. The activity of polyphenol oxidase and peroxidase in fruits will be inhibited during the jam production process. The color of the finished product is relatively normal when it is just produced. After a period of time, the enzyme activity will recover and it will come into contact with phenolic substances, resulting in enzymatic browning, which seriously affects the appearance of the product; due to long-term high-temperature cooking or improper sterilization processing technology, the problem of nutrient loss occurs.

[0005] The Chinese invention patent application with publication number CN117256824A discloses a passion fruit sugar-reduced jam and a preparation method thereof, which obtains a "xylitol-sucralose" sweetener combination that is closest to the flavor of sucrose from both instrumental and sensory dimensions, which not only solves the problem of high sugar content and high calories in traditional jams, but also makes the flavor of sugar-reduced jams more acceptable to consumers. At the same time, the use of a compound of low-methoxyl pectin and kappa-carrageenan as a thickener solves the problem of large addition amounts of low-methoxyl pectin alone and easy water precipitation in the later stages of product storage. The jam made from the compound thickener combination has a texture and rheological properties similar to those of traditional commercial jams.

[0006] The Chinese invention patent application with publication number CN107319450A discloses a processing technology for low-sugar cherry tomato jam, which uses konjac gum, locust bean gum and sodium carboxymethyl carboxylate as thickeners for cherry tomato jam. Konjac gum and sodium carboxymethyl carboxylate can improve the poor viscosity and easy water precipitation of locust bean gum, increase the viscosity of the compound thickener, and improve the taste of the jam.

[0007] However, since the ingredients of Longtan Pearl Plum are quite different from those of passion fruit and cherry tomatoes, although the above-mentioned composite thickener can solve the dehydration problem of passion fruit jam and cherry tomato jam respectively, it still has the problems of dehydration and poor taste when used to prepare Longtan Pearl Plum jam. The document "Processing Technology of European Plum Jam Series Products" (Tian Jinqiang et al., "Agricultural Product Processing·Journal" No. 5, May 2011) discloses a jam made of European Plum as the main raw material. By adding appropriate amounts of low-ester pectin and xanthan gum, the jam can have a more satisfactory taste, and the jam dehydration problem that is easy to occur when low-ester pectin is used alone is also prevented. However, the amount of white sugar added in the formula of the jam is still 50% of the pulp, which cannot be regarded as a low-sugar product.

[0008] Therefore, it is a difficult problem to completely replace sucrose with sweeteners such as xylitol to prepare low-sugar Longtan pearl plum jam with a sugar content of less than 45%, solve its water precipitation problem and obtain better texture and rheological properties. Summary of the invention

[0009] The purpose of the present invention is to provide a method for preparing Longtan Pearl Plum low-sugar jam in view of the above-mentioned problems. The present invention solves the problem of water separation of low-sugar Longtan Pearl Plum jam and obtains a low-sugar jam product with excellent appearance, taste and nutrition.

[0010] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0011] A method for preparing Longtan pearl plum low-sugar jam comprises the following steps:

[0012] (1) Fruit ripening / sorting: Select the Longtan Pearl Plums with a maturity level of 10 and a deep red skin; or the fruits with a maturity level of 8, ripen them with ethylene until the skin is deep red, and remove the diseased, insect-infested, rotten, or injured fruits;

[0013] (2) Cleaning and pitting: Clean the fruit thoroughly, paying attention to cleaning the concave part of the fruit stem, cut it in half manually with a stainless steel knife, remove the pit, or use a pitting machine to remove the pit to obtain the pulp;

[0014] (3) Blanching: Pour the pulp into boiling water to destroy enzyme activity and soften the pulp tissue;

[0015] (4) Color protection pulping: add color protection agent and pulp until the pulp is fine and pulp-free, then grind into fine pulp by colloid mill;

[0016] (5) Concentration and preparation: The slurry is concentrated by low-temperature vacuum using a rotary evaporator at a temperature of 40 to 50°C and a vacuum degree of 80 to 100 Pa until the soluble solid content of the slurry reaches 18% to 22%, and the air pressure in the concentration tank is adjusted to normal pressure; the pre-dissolved sweetener and coagulant are added; low-temperature vacuum concentration is continued at a temperature of 50 to 65°C and a vacuum degree of 80 to 110 Pa until the soluble solid content of the slurry reaches 23% to 26%, and the air pressure in the concentration tank is adjusted to normal pressure; dripping Add the pre-dissolved acidulant citric acid solution to adjust the pH value of the jam to 3.4-3.6; continue low-temperature vacuum concentration, the concentration conditions are: 65-80°C, vacuum degree 80-130Pa, concentrate until the soluble solid content of the slurry reaches 27%-30%, add the pre-dissolved thickener, continue to concentrate until the soluble solid content is 31%-35%, turn off the vacuum pump, break the vacuum, heat the jam to 90-100°C, keep it for 1-2 minutes, and immediately can it; seal it; sterilize it to obtain the finished product;

[0017] The sweetener is composed of xylitol and maltitol in a mass ratio of 1:1, and the amount of the sweetener is 15% to 25% of the mass of the pearl plum pulp; the coagulant is composed of CaCl2 and chromium-rich yeast, and the amount of both is 0.1% to 0.3% of the mass of the pearl plum pulp; the thickener is a compound of low-methoxy pectin, sodium octenyl succinate starch, microcrystalline cellulose and sodium alginate, and the amounts are 0.1% to 0.3%, 0.1% to 0.2%, 0.1% to 0.2%, and 0.1% to 0.3% of the mass of the pearl plum pulp, respectively; the sweetener, coagulant, citric acid and thickener are all dissolved in an appropriate amount of water.

[0018] In the present invention, preferably, the color preservative is composed of sodium D-isoascorbate, tea polyphenols and ascorbic acid, and the dosage is 0.1% to 0.2%, 0.1% to 0.2% and 0.2% to 0.3% of the mass of pearl plum pulp respectively.

[0019] In the present invention, preferably, the blanching time is 2 to 3 minutes.

[0020] In the present invention, preferably, the temperature of the sauce body is not lower than 85° C. during canning, and the can is sealed immediately after canning.

[0021] In the present invention, preferably, during the sterilization, the glass bottle packaging is sterilized in 95-100° C. boiling water for 10-30 min; the can packaging can be sterilized by high pressure sterilization at 121° C. for 10-30 min, and then cooled in stages to 40° C.

[0022] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0023] 1. The present invention solves the problem of water separation of low-sugar pearl plum jam by improving the preparation process technology, including blanching in pretreatment, adding browning inhibitor to inhibit browning, selecting a suitable composite thickener, and using multivalent metal ions to form a bridge with the carboxyl group in the pectin molecular chain to achieve a better gelling effect. The present invention solves the problem of water separation of low-sugar pearl plum jam by working together, and at the same time, the amount of low-methoxy pectin added is small, so that the low-sugar pearl plum jam product obtained has excellent appearance, taste and nutrition.

[0024] 2. When preparing the pearl plum jam product of the present invention, no sucrose is added, and the sugar content is much lower than that of ordinary jam products, so it is a healthier food. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figures 1 to 8 The figures are comparison diagrams of the jams prepared in Example 1, Example 2 and Comparative Examples 1 to 6 after storage for 30 days. DETAILED DESCRIPTION

[0026] 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, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Example 1

[0028] A method for preparing Longtan pearl plum low-sugar jam comprises the following steps:

[0029] (1) Fruit sorting: Select the Longtan Pearl Plums that are at the tenth level of maturity and have a deep red skin at the ripe stage; remove diseased, insect-infested, rotten, and injured fruits;

[0030] (2) Cleaning and pitting: Clean the fruit and remove the pit using a pitting machine to obtain the pulp;

[0031] (3) Blanching: Pour 1 kg of pulp into boiling water and blanch for 3 min to destroy enzyme activity, inhibit enzymatic browning and pectin degradation, and soften the tissue to facilitate pulping;

[0032] (4) Color protection and pulping: add color protection agent and pulp until the pulp is fine and pulp-free, and then grind into fine pulp by colloid mill, wherein the color protection agent is composed of 1g sodium D-isoascorbate, 2g tea polyphenols, and 2g ascorbic acid, and the amount used is 0.1%, 0.2%, and 0.2% of the mass of pearl plum pulp respectively;

[0033] (5) Concentration and preparation: The slurry is concentrated by low-temperature vacuum using a rotary evaporator, and the concentration conditions are: 45-50°C, vacuum degree 100Pa, and concentrated until the soluble solid content of the slurry reaches 18%, and the air pressure in the concentration tank is adjusted to normal pressure; the pre-dissolved sweetener and coagulant are added; the low-temperature vacuum concentration is continued, and the concentration conditions are: 58-65°C, vacuum degree 110Pa, and concentrated until the soluble solid content of the slurry reaches 23%, and the air pressure in the concentration tank is adjusted to normal pressure; a pre-dissolved citric acid solution with a concentration of 10%wt is added dropwise to adjust the pH value of the sauce to 3.6; and the low-temperature vacuum concentration is continued. Vacuum concentration, the concentration conditions are: 73-80℃, vacuum degree 130Pa, concentrate until the soluble solid content of the slurry reaches 27%, add the pre-dissolved thickener, continue to concentrate until the soluble solid content is 31%, turn off the vacuum pump, break the vacuum, heat the jam to 95-100℃, keep it for 1-2min and can it immediately; the temperature of the jam should not be lower than 85℃ when canning, and seal it immediately after canning; sterilization, glass bottle packaging is sterilized in 95-100℃ boiling water for 30min; cans are sterilized at 121℃ high pressure for 30min, and then cooled to 40℃ in stages to obtain the finished product.

[0034] The sweetener is composed of xylitol and maltitol in a mass ratio of 1:1, and the amount of the sweetener is 150g, which is 15% of the mass of the pearl plum pulp, and is dissolved in 100g of distilled water; the coagulant is composed of 3g CaCl2 and 1g chromium-rich yeast, and the amounts of the two are 0.3% and 0.1% of the mass of the pearl plum pulp respectively, and are dissolved in 10g of distilled water; the thickener is a compound of 3g low-methoxy pectin, 1g sodium octenyl succinate starch, 1g microcrystalline cellulose and 2g sodium alginate, and the amounts are 0.3%, 0.1%, 0.1% and 0.2% of the mass of the pearl plum pulp respectively, and is dissolved in 80g of distilled water at a temperature of 80°C in advance for use.

[0035] Example 2

[0036] A method for preparing Longtan pearl plum low-sugar jam comprises the following steps:

[0037] (1) Fruit ripening / sorting: Select fruits of grade 8 maturity and ripen them with ethylene until the skin turns deep red. Remove diseased, insect-infested, rotten, and injured fruits.

[0038] (2) Cleaning and pitting: Clean the fruit and remove the pit using a pitting machine to obtain the pulp;

[0039] (3) Blanching: Pour 2 kg of pulp into boiling water and blanch for 2 min to destroy enzyme activity, inhibit enzymatic browning and pectin degradation, and soften the pulp tissue to facilitate pulping;

[0040] (4) Color protection and pulping: add color protection agent and pulp until the pulp is fine and pulp-free, and then grind into fine pulp by colloid mill. The color protection agent is composed of 4g sodium D-isoascorbate, 2g tea polyphenols, and 6g ascorbic acid, and the amount used is 0.2%, 0.1%, and 0.3% of the mass of pearl plum pulp respectively;

[0041] (5) Concentration and preparation: The slurry is concentrated by low-temperature vacuum using a rotary evaporator, and the concentration conditions are: 40-45°C, vacuum degree 80Pa, and concentrated until the soluble solid content of the slurry reaches 22%, and the air pressure in the concentration tank is adjusted to normal pressure; the pre-dissolved sweetener and coagulant are added; the low-temperature vacuum concentration is continued, and the concentration conditions are: 50-55°C, vacuum degree 80Pa, and concentrated until the soluble solid content of the slurry reaches 26%, and the air pressure in the concentration tank is adjusted to normal pressure; the pre-dissolved citric acid solution with a concentration of 10%wt of the acidulant is added dropwise to adjust the pH value of the sauce to 3.4; and the low-temperature vacuum concentration is continued. Warm vacuum concentration, the concentration conditions are: 65-72℃, vacuum degree 80Pa, concentrate until the soluble solid content of the slurry reaches 30%, add the pre-dissolved thickener, continue to concentrate until the soluble solid content is 35%, turn off the vacuum pump, break the vacuum, heat the jam to 90-95℃, keep it for 1-2min, and can it immediately; the jam temperature should not be lower than 85℃ when canning, and seal it immediately after canning; sterilization, glass bottle packaging is sterilized in 95-100℃ boiling water for 10min; canning is sterilized at 121℃ high pressure for 10min, and then cooled to 40℃ in stages to obtain the finished product.

[0042] The sweetener is composed of xylitol and maltitol in a mass ratio of 1:1, and the amount of the sweetener is 500g, which is 25% of the mass of the pearl plum pulp, and is dissolved in 300g of distilled water; the coagulant is composed of 2g CaCl2 and 6g chromium-rich yeast, and the amounts of the two are 0.1% and 0.3% of the mass of the pearl plum pulp respectively, and are dissolved in 20g of distilled water; the thickener is a compound of 2g low-methoxy pectin, 4g sodium octenyl succinate starch, 4g microcrystalline cellulose and 6g sodium alginate, and the amounts are 0.1%, 0.2%, 0.2% and 0.3% of the mass of the pearl plum pulp respectively, and is dissolved in 120g of distilled water at a temperature of 80°C in advance for use.

[0043] Comparative Example 1

[0044] The difference between Comparative Example 1 and Example 1 is that the color preservative is different, and the color preservative used is only sodium D-isoascorbate, and the amount used is 0.5% of the mass of pearl plum pulp. The other steps are the same as those in Example 1.

[0045] Comparative Example 2

[0046] The difference between Comparative Example 2 and Example 1 is that the chromium-rich yeast in the coagulant is replaced by an equal amount of CaCl2. The other steps are the same as those in Example 1.

[0047] Comparative Example 3

[0048] The difference between Comparative Example 3 and Example 1 is that the sodium alginate in the thickener is replaced by an equal amount of low-methoxyl pectin. The other steps are the same as those in Example 1.

[0049] Comparative Example 4

[0050] The difference between Comparative Example 4 and Example 1 is that the thickeners are low-methoxyl pectin and kappa-carrageenan, and the added amounts thereof are 1.225% and 0.4% of the mass of the pearl plum pulp, respectively. The other steps are the same as those in Example 1.

[0051] Comparative Example 5

[0052] The difference between Comparative Example 5 and Example 1 is that the thickener is a compound of low methoxy pectin and xanthan gum, and the dosage is 0.6% and 0.2% of the mass of the pearl plum pulp respectively; the coagulant is calcium lactate, and the dosage is 0.2% of the mass of the pearl plum pulp. The other steps are the same as those in Example 1.

[0053] Comparative Example 6

[0054] The difference between Comparative Example 6 and Example 1 is that the thickener is a compound of low methoxy pectin, sodium octenyl succinate starch, and xanthan gum, and the dosage is 0.4%, 0.4%, and 0.3% of the mass of the pearl plum pulp, respectively; the coagulant is calcium chloride, and the dosage is 0.2% of the mass of the pearl plum pulp. The other steps are the same as those in Example 1.

[0055] Performance Test:

[0056] (1) The ingredients of the jam products prepared in Examples 1 and 2 were tested by the following method:

[0057] ①Soluble solids: Use the refractometry method, repeat the measurement 3 times and take the average value.

[0058] ② Titratable acid: Use acid-base titration method, repeat the measurement 3 times and take the average value.

[0059] ③Total flavonoids: Use spectrophotometer method, repeat the measurement 3 times and take the average value.

[0060] ④Total sugar: Use phenol-sulfuric acid method, repeat the measurement 3 times and take the average value.

[0061] The test results are shown in Table 1.

[0062] Table 1 Comparison of jam ingredients

[0063] jam Soluble solids / % Titratable acid / % Total flavonoids / ‰ Total sugar / % Example 1 31.50±0.50 0.23±0.03 6.47±0.15 15.40±0.36 Example 2 34.43±0.40 0.19±0.01 5.90±0.20 18.77±0.25

[0064] (2) The texture test of the jam products prepared in Examples 1 and 2 and Comparative Examples 1 to 6 was performed using the following method:

[0065] The American Broofield CT3 texture analyzer was used to measure the hardness, chewiness, elasticity, cohesion and adhesiveness of the jam samples. The test results are shown in Table 2.

[0066] Table 2 Jam texture comparison

[0067] jam Hardness / g Chewability / mJ Elasticity / mm Cohesion Adhesion / g Example 1 212.33±19.66 13.80±0.26 21.53±0.54 0.65±0.04 165.33±2.08 Example 2 233.67±11.24 14.73±0.68 21.22±0.77 0.61±0.03 166.67±6.51 Comparative Example 1 267.33±8.50 15.63±0.47 20.72±0.40 0.59±0.04 176.33±6.66 Comparative Example 2 338.33±7.02 17.13±0.85 19.15±0.65 0.52±0.03 201.67±3.79 Comparative Example 3 389.33±18.50 17.57±0.61 18.91±0.21 0.49±0.04 218.33±19.60 Comparative Example 4 442.67±18.88 20.20±0.75 16.22±0.50 0.41±0.02 294.33±9.24 Comparative Example 5 415.00±14.00 18.30±0.50 17.19±0.50 0.46±0.02 278.00±11.00 Comparative Example 6 402.33±10.97 17.80±0.30 17.71±0.73 0.48±0.03 249.00±5.57

[0068] (3) The jams prepared in Examples 1 and 2 and Comparative Examples 1 to 6 were subjected to sensory evaluation. The evaluation criteria are shown in Table 3. The color, flavor, taste and texture of the jams were observed after they were stored at 40° C. for 30 days. The appearance pictures of the products prepared in Examples 1 and 2 and Comparative Examples 1 to 6 after 30 days are shown in Table 3. Figures 1 to 8 , the sensory evaluation and water analysis results are shown in Table 4.

[0069] Table 3 Jam sensory scoring standards

[0070]

[0071] Table 4 Evaluation and scoring of sensory quality of jam

[0072]

[0073]

[0074] From the above results, it can be seen that whether the low-sugar jam of the present invention precipitates water is affected by multiple factors. In comparative example 1, the color retaining agent is a single sodium D-isoascorbate, which not only affects its color retaining effect, making the product dark in color, but also has a slight effect on the gelling effect, and slight water precipitation occurs after 30 days. The coagulant in comparative example 2 is only CaCl2, and the bridge formed is not ideal; the composite thickeners used in comparative examples 3 to 6 are different, which also causes water precipitation, poor texture and taste. The present invention inhibits browning by adding a composite browning inhibitor, selects a suitable composite thickener, and forms a bridge with the carboxyl group in the pectin molecular chain to achieve a better gelling effect, and adopts a suitable addition order. The synergistic effect of multiple aspects solves the water precipitation problem of low-sugar pearl plum jam, and at the same time obtains a low-sugar pearl plum jam product with excellent appearance, taste, texture and nutrition.

[0075] The above description is a detailed description of the preferred feasible embodiments of the present invention, but the embodiments are not intended to limit the scope of the patent application of the present invention. All equivalent changes or modified changes completed under the technical spirit suggested by the present invention should fall within the patent scope covered by the present invention.

Claims

1. A method for preparing Longtan Pearl Plum Low-Sugar Jam, characterized in that: The following steps are involved: (1) Fruit ripening / sorting: Select Longtan Pearl Plum fruits with a maturity level of 10 and a deep red skin at the ripening stage; or Longtan Pearl Plum fruits with a maturity level of 8, ripen with ethylene until the skin is deep red, and remove diseased, insect-infested, rotten, or injured fruits; (2) Cleaning and removing the core: Cleaning and removing the core to obtain the pulp; (3) Blanching: Pour the pulp into boiling water to destroy enzyme activity; (4) Color protection pulping: add color protection agent and pulp until the pulp is fine and pulp-free, then grind into fine pulp by colloid mill; (5) Concentration and preparation: The slurry is concentrated by low-temperature vacuum using a rotary evaporator at a temperature of 40 to 50° C. and a vacuum degree of 80 to 100 Pa until the soluble solid content of the slurry reaches 18% to 22%. The pressure in the concentration tank is adjusted to normal pressure. The pre-dissolved sweetener and coagulant are added. Continue low-temperature vacuum concentration, the concentration conditions are: 50-65°C, vacuum degree 80-110Pa, concentrate until the soluble solid content of the slurry reaches 23%-26%, and adjust the air pressure in the concentration tank to normal pressure; drop the pre-dissolved and prepared acidulant citric acid solution to adjust the pH value of the jam to 3.4-3.6; continue low-temperature vacuum concentration, the concentration conditions are: 65-80°C, vacuum degree 80-130Pa, concentrate until the soluble solid content of the slurry reaches 27%-30%, add the pre-dissolved thickener, continue to concentrate until the soluble solid content is 31%-35%, turn off the vacuum pump, break the vacuum, heat the jam to 90-100°C, keep it for 1-2 minutes, and immediately can it; seal it; sterilize it to obtain the finished product; The sweetener is composed of xylitol and maltitol in a mass ratio of 1:1, and the amount of the sweetener is 15% to 25% of the mass of the pearl plum pulp; the coagulant is composed of CaCl2 and chromium-rich yeast, and the amount of both is 0.1% to 0.3% of the mass of the pearl plum pulp; the thickener is a compound of low-methoxy pectin, sodium octenyl succinate starch, microcrystalline cellulose and sodium alginate, and the amounts are 0.1% to 0.3%, 0.1% to 0.2%, 0.1% to 0.2%, and 0.1% to 0.3% of the mass of the pearl plum pulp, respectively; the sweetener, coagulant, citric acid and thickener are all dissolved in an appropriate amount of water.

2. The preparation method according to claim 1, characterized in that: The color preservative is composed of sodium D-isoascorbate, tea polyphenols and ascorbic acid, and the dosages thereof are 0.1%-0.2%, 0.1%-0.2% and 0.1%-0.3% of the mass of pearl plum pulp respectively.

3. The preparation method according to claim 1, characterized in that: The blanching time is 2 to 3 minutes.

4. The preparation method according to claim 1, characterized in that: The temperature of the sauce is not lower than 85° C. during canning, and the sauce is sealed immediately after canning.

5. The preparation method according to claim 1, characterized in that: During the sterilization, the glass bottle packaging is sterilized in 95-100° C. boiling water for 10-30 minutes; the can packaging can be sterilized by high pressure sterilization at 121° C. for 10-30 minutes, and then cooled in stages to 40° C.

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