A freeze-thaw stable frozen durian filling and a method of making the same

Abstract

The application discloses a freeze-thaw stable frozen durian filling and a preparation method thereof, and belongs to the technical field of food processing. The filling comprises durian pulp, flavor microcapsule powder, polyglycerol fatty acid ester, sodium caseinate, high-acyl gellan gum, calcium salt and trehalose. The antioxidant is dispersed in the wall material of the flavor microcapsule, and the wall material has a self-supply antioxidant function; calcium ions provided by the calcium salt crosslink durian endogenous pectin and high-acyl gellan gum, forming a double-network gel with internal and external cooperation; and trehalose forms a glassy matrix in the double-network gap. The preparation method comprises calcium crosslinking treatment, emulsification and homogenization, gel construction and microcapsule dispersion, and quick freezing treatment. Through multi-mechanism cooperation, the application realizes high flavor retention and high structure stability of the frozen durian filling in frozen storage and freeze-thaw cycles.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, and more particularly to a freeze-thaw stable frozen durian filling and its preparation method. Background Technology

[0002] Frozen fillings are commonly used intermediate ingredients in the food processing industry. With their advantages of convenient storage, easy consumption, and maximum preservation of flavor, they are widely used in the production of pastries, desserts, and frozen foods. Durian, due to its unique flavor and rich nutrition, has become one of the most popular ingredients for frozen fillings. Frozen durian fillings retain the sweet taste of durian while solving the problems of short shelf life, inconvenient transportation, and uneven seasonal supply associated with fresh durian. This satisfies consumers' year-round demand for durian-flavored foods, leading to continuous market growth.

[0003] Currently, most frozen durian fillings are prepared using fresh durian pulp as the main ingredient, along with small amounts of emulsifiers, stabilizers, and other additives, through processes such as pulping, mixing, and quick-freezing. To improve the stability of the filling, some technologies add single colloids such as carrageenan or xanthan gum for thickening, while also adding single antioxidants to delay browning of the pulp. The quick-freezing process mostly employs conventional plate freezing or tunnel freezing methods.

[0004] However, existing frozen durian fillings still have many shortcomings: First, they have poor freeze-thaw stability, and are prone to problems such as water separation, collapse, and soft texture after repeated freeze-thaw cycles. This is mainly because the pectin in the fruit pulp is easily degraded at low temperatures, and the existing single colloids cannot form a stable network structure. Second, they have poor flavor retention. The volatile aroma substances of durian are easily volatilized and oxidized, and adding antioxidants alone is not enough to effectively inhibit oxidation, resulting in a fading flavor after storage. Third, the quick-freezing process is unreasonable, with a slow cooling rate. The filling stays in the maximum ice crystal formation zone of 0℃-5℃ for too long, forming large ice crystals that damage the fruit pulp tissue and further aggravate freeze-thaw deterioration, failing to meet the high quality requirements of food processing for fillings. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, this invention provides a freeze-thaw stable frozen durian filling and its preparation method.

[0006] The objective of this invention can be achieved through the following technical solutions: In a first aspect, the present invention provides a freeze-thaw stable frozen durian filling, comprising the following components: Durian pulp; Flavored microcapsule powder, wherein the microcapsules are made of β-cyclodextrin and soy protein isolate as composite wall material, encapsulating durian extract, and the microcapsule wall material contains antioxidants tea polyphenols and vitamin E dispersed in it; Polyglycerol fatty acid esters; Sodium caseinate; High acyl gellan gum; Calcium salts; Trehalose; The calcium ions provided by the calcium salt simultaneously crosslink with the low-methoxyl pectin in durian pulp and the high-acyl gellan gum.

[0007] Furthermore, the frozen durian filling comprises the following components in weight percentage: Flavor microcapsule powder 0.5-2.0%; polyglycerol fatty acid ester 0.15-0.25%; sodium caseinate 0.4-0.6%; high acyl gellan gum 0.15-0.35%; calcium salt 0.08-0.18%; trehalose 2.0-5.0%; the balance is durian pulp.

[0008] Among them, the calcium ions provided by calcium salts crosslink with the naturally occurring low-methoxyl pectin in durian pulp, constructing a calcium bridge framework inside and on the surface of the pulp fiber network, thereby strengthening the mechanical strength of the pulp fibers from the inside and effectively resisting tissue damage and juice loss caused by freeze-thaw cycles; in addition, high-acyl gellan gum is sensitive to calcium ions, which induce gellan gum molecules to form double helix aggregation and crosslinking, forming a soft and highly elastic gel coating layer around the pulp particles, effectively binding free water and inhibiting ice crystal aggregation and water migration; its elastic characteristics can absorb the stress of ice crystal growth through deformation when ice crystals form, preventing sharp ice crystals from piercing the pulp cells and microcapsule wall material.

[0009] In the preparation of flavor microcapsules, the addition of tea polyphenols and vitamin E gives the microcapsules a dual antioxidant protection function: (1) the antioxidants in the wall material directly remove free radicals that attempt to penetrate the wall material and intercept them in the shell layer, preventing free radicals from contacting sulfur-containing flavor substances in the core material; (2) during the long-term frozen storage of the filling, the microcapsule wall material is slowly hydrated, and the antioxidants loaded in the wall material are gradually released into the filling system, continuously removing free radicals generated by the oxidation of sulfur-containing compounds and breaking the oxidation chain reaction.

[0010] The present invention also provides a method for preparing the above-mentioned frozen durian filling, comprising the following steps: S1. Blend durian pulp into a puree, add calcium salt and stir well. Let it stand for 5-15 minutes, then add polyglycerol fatty acid ester and sodium caseinate and mix. Shear and homogenize to form a puree. S2. Add the flavor microcapsule powder, high acyl gellan gum and trehalose to the fruit puree obtained in S1 and stir well. S3. Quick-freeze the filling obtained in S2, so that the time for the center temperature of the filling to pass through the maximum ice crystal formation zone of 0℃-5℃ does not exceed 5 minutes, and the final center temperature is ≤-18℃.

[0011] Furthermore, the quick-freezing process employs a combination of liquid nitrogen spraying and plate quick-freezing: first, liquid nitrogen spraying rapidly freezes the surface of the filling at -55°C to -65°C, forming an ice shell protective layer; then, it is transferred to a plate quick-freezing machine at -30°C to -40°C to continue freezing until the core temperature is ≤-18°C. This combined process ensures that the total time for the core temperature of the filling to drop from 20°C to -18°C does not exceed 25 minutes, and the time to pass through the maximum ice crystal formation zone of 0°C-5°C does not exceed 3 minutes.

[0012] The beneficial effects of this invention are as follows: (1) In this invention, calcium ions provided by calcium salts crosslink with low-methoxyl pectin and high-acyl gellan gum in durian pulp to form a double crosslinked gel network. This double network system strengthens the mechanical strength of fibers from the inside and binds free water and absorbs ice crystal growth stress from the outside, effectively resisting tissue damage and water migration caused by freeze-thaw cycles. At the same time, soy protein isolate in the microcapsule wall material is released and migrates to the oil-water interface during thawing, forming a dense composite interfacial protein film with sodium caseinate in the emulsion system through hydrophobic interactions and hydrogen bonds, further preventing oil droplet aggregation and oil-water separation.

[0013] (2) The present invention uses β-cyclodextrin and soy protein isolate as composite wall material for flavor microcapsules to encapsulate durian extract, thereby improving the encapsulation rate of flavor substances and reducing the loss of volatile aroma. At the same time, tea polyphenols and vitamin E are dispersed in the microcapsule wall material to form a dual antioxidant protection system. The antioxidants in the wall material directly scavenge free radicals in the shell layer, preventing them from penetrating the wall material and contacting sulfur-containing flavor substances in the core material. During long-term frozen storage, the wall material slowly hydrates and releases antioxidant components into the filling system, continuously interrupting the oxidation chain reaction of sulfur-containing compounds.

[0014] (3) The quick-freezing process of the present invention ensures that the core temperature of the filling passes through the maximum ice crystal formation zone (0℃ to -5℃) in no more than 5 minutes; the combination of liquid nitrogen spraying and plate quick-freezing can quickly make the filling pass through the maximum ice crystal formation zone of 0℃-5℃, shorten the cooling time, inhibit the formation of coarse ice crystals, reduce damage to the fruit pulp tissue, and work synergistically with the formula system to further improve the freeze-thaw stability and flavor retention of the filling. Detailed Implementation

[0015] To further illustrate the technical means and effects of the present invention in achieving the intended purpose, the following detailed description of the specific implementation methods, structures, features and effects of the present invention, in conjunction with preferred embodiments, is provided below.

[0016] Example 1 A freeze-thaw stable frozen durian filling, comprising the following components by weight percentage: Flavor microcapsule powder 1.0%; polyglycerol fatty acid ester 0.2%; sodium caseinate 0.5%; high acyl gellan gum 0.25%; calcium lactate 0.12%; trehalose 3.0%; balance is durian pulp.

[0017] Preparation steps: (1) Preparation of flavor microcapsule powder: 6.7 parts by weight of β-cyclodextrin and 3.3 parts by weight of soy protein isolate were added to 90 parts by weight of deionized water and stirred at 55°C to dissolve; 0.3 parts by weight of tea polyphenols were added and stirred evenly; 0.2 parts by weight of vitamin E were pre-dissolved in 1 part by weight of edible ethanol and slowly added dropwise to the above solution, and stirred at high speed to disperse it evenly to form a wall material solution containing antioxidants; 1.5 parts by weight of durian extract were added to the wall material solution and homogenized at 10,000 rpm for 3 minutes to form an oil-in-water emulsion; the emulsion was spray-dried at an inlet air temperature of 180°C and an outlet air temperature of 85°C, and the powder was collected to obtain flavor microcapsule powder.

[0018] (2) Calcium cross-linking treatment: Take fresh durian pulp, remove the seeds and mash it, add calcium lactate, stir evenly and let it stand for 10 minutes to allow calcium ions to fully cross-link with the low methoxy pectin in the pulp.

[0019] (3) Emulsification and homogenization: Add polyglycerol fatty acid ester and sodium caseinate to the base material obtained in step (2), and homogenize at 10,000 rpm for 3 minutes to form fruit puree.

[0020] (4) Gel construction and microcapsule dispersion: Add the flavor microcapsule powder obtained in step (1), high acyl gellan gum, and trehalose to the fruit puree obtained in step (3) and stir evenly.

[0021] (5) Quick-freezing treatment: The filling obtained in step (4) is divided into portions, and the surface of the filling is first sprayed with liquid nitrogen at -60°C to quickly freeze it. Then it is transferred to a -35°C plate freezer to continue freezing until the core temperature is -18°C. The total time for the core temperature to drop from 20°C to -18°C is 22 minutes, and the time to pass through the maximum ice crystal formation zone (0°C to -5°C) is 2.8 minutes.

[0022] Example 2 A freeze-thaw stable frozen durian filling, comprising the following components by weight percentage: Flavor microcapsule powder 1.0%; polyglycerol fatty acid ester 0.2%; sodium caseinate 0.5%; high acyl gellan gum 0.25%; calcium chloride 0.1%; trehalose 3.0%; balance is durian pulp.

[0023] Preparation steps: (1) Preparation of flavor microcapsule powder: 6.7 parts by weight of β-cyclodextrin and 3.3 parts by weight of soy protein isolate were added to 90 parts by weight of deionized water and stirred at 55°C to dissolve; 0.3 parts by weight of tea polyphenols were added and stirred evenly; 0.2 parts by weight of vitamin E were pre-dissolved in 1 part by weight of edible ethanol and slowly added dropwise to the above solution, and stirred at high speed to disperse it evenly to form a wall material solution containing antioxidants; 1.5 parts by weight of durian extract were added to the wall material solution and homogenized at 10,000 rpm for 3 minutes to form an oil-in-water emulsion; the emulsion was spray-dried at an inlet air temperature of 180°C and an outlet air temperature of 85°C, and the powder was collected to obtain flavor microcapsule powder.

[0024] (2) Calcium cross-linking treatment: Take fresh durian pulp, remove the seeds and mash it, add calcium chloride, stir evenly and let it stand for 10 minutes to allow calcium ions to fully cross-link with the low methoxyl pectin in the pulp.

[0025] (3) Emulsification and homogenization: Add polyglycerol fatty acid ester and sodium caseinate to the base material obtained in step (2), and homogenize at 10,000 rpm for 3 minutes to form fruit puree.

[0026] (4) Gel construction and microcapsule dispersion: Add the flavor microcapsule powder obtained in step (1), high acyl gellan gum, and trehalose to the fruit puree obtained in step (3) and stir evenly.

[0027] (5) Quick-freezing treatment: The filling obtained in step (4) is divided into portions, and the surface of the filling is first sprayed with liquid nitrogen at -60°C to quickly freeze it. Then it is transferred to a -35°C plate freezer to continue freezing until the core temperature is -18°C. The total time for the core temperature to drop from 20°C to -18°C is 22 minutes, and the time to pass through the maximum ice crystal formation zone (0°C to -5°C) is 2.8 minutes.

[0028] Example 3 A freeze-thaw stable frozen durian filling, comprising the following components by weight percentage: Flavor microcapsule powder 1.0%; polyglycerol fatty acid ester 0.2%; sodium caseinate 0.5%; high acyl gellan gum 0.35%; calcium lactate 0.18%; trehalose 3.0%; balance is durian pulp.

[0029] Preparation steps: (1) Preparation of flavor microcapsule powder: 6.7 parts by weight of β-cyclodextrin and 3.3 parts by weight of soy protein isolate were added to 90 parts by weight of deionized water and stirred at 55°C to dissolve; 0.3 parts by weight of tea polyphenols were added and stirred evenly; 0.2 parts by weight of vitamin E were pre-dissolved in 1 part by weight of edible ethanol and slowly added dropwise to the above solution, and stirred at high speed to disperse it evenly to form a wall material solution containing antioxidants; 1.5 parts by weight of durian extract were added to the wall material solution and homogenized at 10,000 rpm for 3 minutes to form an oil-in-water emulsion; the emulsion was spray-dried at an inlet air temperature of 180°C and an outlet air temperature of 85°C, and the powder was collected to obtain flavor microcapsule powder.

[0030] (2) Calcium cross-linking treatment: Take fresh durian pulp, remove the seeds and mash it, add calcium lactate, stir evenly and let it stand for 10 minutes to allow calcium ions to fully cross-link with the low methoxy pectin in the pulp.

[0031] (3) Emulsification and homogenization: Add polyglycerol fatty acid ester and sodium caseinate to the base material obtained in step (2), and homogenize at 10,000 rpm for 3 minutes to form fruit puree.

[0032] (4) Gel construction and microcapsule dispersion: Add the flavor microcapsule powder obtained in step (1), high acyl gellan gum, and trehalose to the fruit puree obtained in step (3) and stir evenly.

[0033] (5) Quick-freezing treatment: The filling obtained in step (4) is divided into portions, and the surface of the filling is first sprayed with liquid nitrogen at -60°C to quickly freeze it. Then it is transferred to a -35°C plate freezer to continue freezing until the core temperature is -18°C. The total time for the core temperature to drop from 20°C to -18°C is 22 minutes, and the time to pass through the maximum ice crystal formation zone (0°C to -5°C) is 2.8 minutes.

[0034] Example 4 A freeze-thaw stable frozen durian filling, comprising the following components by weight percentage: Flavor microcapsule powder 0.5%; polyglycerol fatty acid ester 0.15%; sodium caseinate 0.4%; high acyl gellan gum 0.15%; calcium lactate 0.08%; trehalose 2.0%; balance is durian pulp.

[0035] Preparation steps: (1) Preparation of flavor microcapsule powder: 6.7 parts by weight of β-cyclodextrin and 3.3 parts by weight of soy protein isolate were added to 90 parts by weight of deionized water and stirred at 55°C to dissolve; 0.3 parts by weight of tea polyphenols were added and stirred evenly; 0.2 parts by weight of vitamin E were pre-dissolved in 1 part by weight of edible ethanol and slowly added dropwise to the above solution, and stirred at high speed to disperse it evenly to form a wall material solution containing antioxidants; 1.5 parts by weight of durian extract were added to the wall material solution and homogenized at 10,000 rpm for 3 minutes to form an oil-in-water emulsion; the emulsion was spray-dried at an inlet air temperature of 180°C and an outlet air temperature of 85°C, and the powder was collected to obtain flavor microcapsule powder.

[0036] (2) Calcium cross-linking treatment: Take fresh durian pulp, remove the seeds and mash it into a pulp, add calcium lactate, stir evenly and let it stand for 5 minutes.

[0037] (3) Emulsification and homogenization: Add polyglycerol fatty acid ester and sodium caseinate to the base material obtained in step (2), and homogenize at 10,000 rpm for 3 minutes to form fruit puree.

[0038] (4) Gel construction and microcapsule dispersion: Add the flavor microcapsule powder obtained in step (1), high acyl gellan gum, and trehalose to the fruit puree obtained in step (3) and stir evenly.

[0039] (5) Quick-freezing treatment: The filling obtained in step (4) is divided into portions, and the surface of the filling is first sprayed with liquid nitrogen at -55°C to quickly freeze it. Then it is transferred to a -30°C plate freezer to continue freezing until the core temperature is -18°C. The total time for the core temperature to drop from 20°C to -18°C is 25 minutes, and the time to pass through the maximum ice crystal formation zone (0°C to -5°C) is 3 minutes.

[0040] Example 5 A freeze-thaw stable frozen durian filling, comprising the following components by weight percentage: Flavor microcapsule powder 2.0%; polyglycerol fatty acid ester 0.25%; sodium caseinate 0.6%; high acyl gellan gum 0.35%; calcium lactate 0.18%; trehalose 5.0%; balance is durian pulp.

[0041] Preparation steps: (1) Preparation of flavor microcapsule powder: 6.7 parts by weight of β-cyclodextrin and 3.3 parts by weight of soy protein isolate were added to 90 parts by weight of deionized water and stirred at 55°C to dissolve; 0.3 parts by weight of tea polyphenols were added and stirred evenly; 0.2 parts by weight of vitamin E were pre-dissolved in 1 part by weight of edible ethanol and slowly added dropwise to the above solution, and stirred at high speed to disperse it evenly to form a wall material solution containing antioxidants; 1.5 parts by weight of durian extract were added to the wall material solution and homogenized at 10,000 rpm for 3 minutes to form an oil-in-water emulsion; the emulsion was spray-dried at an inlet air temperature of 180°C and an outlet air temperature of 85°C, and the powder was collected to obtain flavor microcapsule powder.

[0042] (2) Calcium cross-linking treatment: Take fresh durian pulp, remove the seeds and mash it into a pulp, add calcium lactate, stir evenly and let it stand for 15 minutes.

[0043] (3) Emulsification and homogenization: Add polyglycerol fatty acid ester and sodium caseinate to the base material obtained in step (2), and homogenize at 10,000 rpm for 3 minutes to form fruit puree.

[0044] (4) Gel construction and microcapsule dispersion: The flavor microcapsule powder obtained in step (1), high acyl gellan gum, and trehalose are added to the fruit puree obtained in step (3) and stirred evenly so that the high acyl gellan gum forms a gel network under the action of free calcium ions in the system.

[0045] (5) Quick-freezing treatment: The filling obtained in step (4) is divided into portions, and the surface of the filling is first sprayed with liquid nitrogen at -65°C to quickly freeze it. Then it is transferred to a -40°C plate freezer to continue freezing until the core temperature is -18°C. The total time for the core temperature to drop from 20°C to -18°C is 20 minutes, and the time to pass through the maximum ice crystal formation zone (0°C to -5°C) is 2.5 minutes.

[0046] Comparative Example 1 Based on Example 1, instead of preparing flavor microcapsule powder, an equal amount of durian flavor extract was directly added to the fruit puree in step (4) and stirred and dispersed, with the rest being the same as in Example 1.

[0047] Comparative Example 2 Based on Example 1, when preparing the wall material solution, tea polyphenols and vitamin E were not added, but otherwise the same as in Example 1.

[0048] Comparative Example 3 Based on Example 1, without the addition of calcium lactate, the rest is the same as in Example 1.

[0049] Comparative Example 4 Based on Example 1, the high-acyl gellan gum was replaced with an equal amount of xanthan gum, and the rest was the same as in Example 1.

[0050] Comparative Example 5 Based on Example 1, trehalose was not added, and an equal amount of durian pulp was used to make up the difference, otherwise the same as in Example 1.

[0051] Comparative Example 6 Based on Example 1, step (5) adopts conventional air-cooled quick-freezing (-35℃ cold air freezing) instead of liquid nitrogen spraying and plate quick-freezing combination process; the air-cooled quick-freezing center temperature drops from 20℃ to -18℃ in a total of 90 minutes, and the time to pass through the maximum ice crystal formation zone is 28 minutes; the rest is the same as in Example 1.

[0052] Comparative Example 7 Based on Example 1, sodium caseinate was not added, and the rest was the same as in Example 1.

[0053] Performance testing: Freeze-thaw stability: The sample was frozen at -18℃ for 24 hours and then thawed at 25℃ for 4 hours, which was considered as one freeze-thaw cycle. After 5 cycles, 10g of sample was weighed and centrifuged at 4000rpm for 20 minutes. The supernatant was discarded, and the centrifugal water retention rate was calculated as: weight of filling after removing supernatant / 10 × 100%. Juice loss: Weigh the frozen sample M1, thaw it naturally at 25℃ until the core temperature reaches 10℃, collect and weigh the precipitated juice M2, juice loss rate = M2 / M1×100%; Flavor retention: Samples frozen for 6 months (-18℃) were used to extract volatile components using headspace solid-phase microextraction (HS-SPME); the relative content of the key aroma component diethyl disulfide was quantitatively analyzed; flavor retention rate = peak area of ​​diethyl disulfide after refrigeration / peak area of ​​diethyl disulfide in fresh filling × 100%; Taste evaluation: A panel of 15 trained sensory evaluators scored the food using a 10-point scale (10 points = very much liked, 1 point = very disliked). Evaluation dimensions included appearance, aroma (intensity, purity), and texture (fibrous texture, no burnt or mushy texture).

[0054]

[0055] Example 1, as the optimal example, demonstrated excellent performance across all four indicators, proving the effectiveness of the four-pronged mechanism of calcium ion dual network, self-supplied antioxidant properties of the microcapsule wall material, trehalose molecular protection, and interfacial synergy. Example 2, using calcium chloride as an equimolar substitute for calcium lactate, showed no significant difference from Example 1. Example 3, by increasing the amounts of calcium salt and gellan gum, achieved a water retention rate of 94.0% and a juice loss rate of 3.2%. Example 4, using the lower limits of each component, showed a slight decrease in all indicators but was still significantly better than the comparative example. Example 5, using the upper limits of each component, achieved a flavor retention rate of 83.0%, making it the optimal flavor example. Comparative Example 1, by removing microencapsulation, saw its flavor retention plummet from 82.1% to 31.5%, and its taste score drop to 4.0. Comparative Example 2, with its microcapsule wall material lacking antioxidants, experienced a flavor retention rate of 58.3% and a taste score of 6.8. Comparative Example 3, lacking calcium salts, saw its water retention rate drop to 78.3%, its juice loss rate increase to 12.5%, and its taste score drop to 4.5. Comparative Example 4, by replacing high-acyl gellan gum with xanthan gum, saw its water retention rate drop to 88.5% and its juice loss rate increase to 5.2%. Comparative Example 5, lacking trehalose, saw its water retention rate drop to 89.0% and its juice loss rate to 5.5%, showing a less severe degradation than Comparative Examples 3 and 6, but still significant. Comparative Example 6, using conventional air-cooling quick-freezing, had a water retention rate of only 80.0%, a juice loss rate of 12.5%, a flavor retention rate of 52.0%, and a taste score of 3.0, with both structure and flavor declining across the board. Comparative Example 7, lacking sodium caseinate, saw its water retention rate drop to 83.5% and its juice loss rate increase to 7.0%.

[0056] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A freeze-thaw stable frozen durian filling, characterized in that, It contains the following components: Durian pulp; Flavored microcapsule powder, wherein the microcapsules are made of β-cyclodextrin and soy protein isolate as composite wall material, encapsulating durian extract, and the microcapsule wall material contains antioxidants tea polyphenols and vitamin E dispersed in it; Polyglycerol fatty acid esters; Sodium caseinate; High acyl gellan gum; Calcium salts; Trehalose; The calcium ions provided by the calcium salt simultaneously crosslink with the low-methoxyl pectin in durian pulp and the high-acyl gellan gum.

2. The freeze-thaw stabilized durian filling according to claim 1, characterized in that, The durian filling comprises the following components by weight percentage: Flavored microcapsule powder 0.5-2.0%; Polyglycerol fatty acid esters 0.15-0.25%; Sodium caseinate 0.4-0.6%; High-acyl gellan gum: 0.15-0.35%; Calcium salt content: 0.08-0.18%; Trehalose 2.0-5.0%; The remainder is durian pulp.

3. The freeze-thaw stabilized frozen durian filling according to claim 1, characterized in that, The mass ratio of β-cyclodextrin to soy protein isolate in the flavor microcapsule powder is 1.8-2.2:1; the microcapsule particle size is 15-25 μm.

4. The freeze-thaw stabilized frozen durian filling according to claim 1, characterized in that, The content of tea polyphenols in the microcapsule wall material is 0.02-0.04% of the total weight of the filling, and the content of vitamin E is 0.01-0.03% of the total weight of the filling.

5. The freeze-thaw stabilized durian filling according to claim 1, characterized in that, The calcium salt is calcium lactate or calcium chloride.

6. The freeze-thaw stabilized frozen durian filling according to claim 1, characterized in that, The flavored microcapsule powder is prepared by a method comprising the following steps: adding β-cyclodextrin and soy protein isolate to water, stirring and dissolving at 50-60°C, then adding tea polyphenols and vitamin E, stirring evenly to form a wall material solution containing antioxidants; adding durian extract to the wall material solution containing antioxidants, mixing and then spray drying to obtain the final product.

7. The method according to claim 6, characterized in that, The spray drying conditions are an inlet air temperature of 175-185℃ and an outlet air temperature of 80-90℃.

8. A method for preparing freeze-thaw stable frozen durian filling according to any one of claims 1 to 7, characterized in that, Includes the following steps: S1. Blend durian pulp into a puree, add calcium salt and stir well. Let it stand for 5-15 minutes, then add polyglycerol fatty acid ester and sodium caseinate and mix. Shear and homogenize to form a puree. S2. Add the flavor microcapsule powder, high acyl gellan gum and trehalose to the fruit puree obtained in S1 and stir well. S3. Quick-freeze the filling obtained in S2, so that the time for the center temperature of the filling to pass through the maximum ice crystal formation zone of 0℃-5℃ does not exceed 5 minutes, and the final center temperature is ≤-18℃.

9. The method according to claim 8, characterized in that, The quick-freezing process described in step S3 uses a combination of liquid nitrogen spraying and plate quick-freezing: first, liquid nitrogen spraying is used to quickly freeze the surface of the filling at -55℃ to -65℃, and then it is transferred to a plate quick-freezing machine at -30℃ to -40℃ to continue freezing until the core temperature is ≤-18℃.

10. The method according to claim 8, characterized in that, In step S3, the total time required for the filling's center temperature to drop from 20°C to -18°C does not exceed 25 minutes.

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